Universitat Politécinica de Valencia Escuela Técnica Superior de Ingeniería de Edificación Camino de Vera Valencia Master of Science in Engineering Tecnology: Construction Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. Promotor: Dr. Carolina Aparicio Fernández Tesis submitted to obtain te degree of Master of Science in Engineering Tecnology Construction Olivier Deboo Edouard Bertrand Academic year: 3-4
Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
ACKNOWLEDGEMENTS We would like to tank Kao Sint-Lieven, Universitat Politecnica de Valencia (Spain) and te European Union to give us te opportunity to go on Erasmus. We would like to express te deepest appreciation to Javier Calvo Diaz, wo welcomed and elped us a lot wen we arrived at UPV and during our stay. In addition, a tanks to Professor Guido Kips wo elped us wit te preparation and te paperwork in Belgium. We would also like to express our gratitude to our promoter lecturer Carolina Sabina Fernández for te useful comments, remarks and engagement troug te learning process of tis master tesis. A special tanks to José Luis Vivancos Bon and Rafael Royo Pastor for teir time and elp wit te writing of tis paper. Tis was a great experience for us to learn new tings, different approaces and to meet new people wo were very elpful. We will never forget tis. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
ABSTRACT Te title of te tesis is Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. Te objective of te tesis is to create a digital model of an existing university building wit TRNSYS, an advanced simulation program, and modify it to lower te cooling and eating demand to meet te passive ouse standard. TRNSYS generates te temperatures as well as te eating and cooling demand tat are expected in te building during one year. Terefore measurements wit a weater station combined wit te data from te official weater station at UPV elped obtaining annual weater data as input for TRNSYS. Te Cp generator was used to calculate te wind pressure coefficients, wic affect te air infiltration into te building. Also te termal bridges in te termal envelope were calculated using THERM as input for TRNSYS. Te model is validated to ceck its correctness and precision by comparing it wit te actual temperatures in te building. Terefore te temperatures on places in te building were measured wile obtaining te outside weater data. Finally modifications are imported into te model and teir effect on te cooling and eating demand is analysed. Te fact tat te building is located in a warm climate makes te application of te passive ouse standard complicated. Also tis fact as important influences on wic modifications to apply and ow to analyse tem. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
TABLE OF CONTENTS ACKNOWLEDGEMENTS 3 ABSTRACT 4 LIST OF FIGURES 7 LIST OF GRAPHS 9 LIST OF TABLES. INTRODUCTION 3. CONCEPTS 4.. BUILDING SIMULATION WITH TRNSYS 4... TRNSYS SIMULATION STUDIO WITH TRNBUILD 5... TRNBUILD 9..3. TRNFLOW.. WIND PRESSURE SIMULATION WITH C P GENERATOR 4... WIND PRESSURE COEFFICIENTS C P 4... TNO C P -GENERATOR 5.3. THERMAL BRIDGE CALCULATION WITH THERM 7. 6 3. CASE STUDY 7 3.. LOCATION 7 3.. ELEMENTS OF THE THERMAL ENVELOPE 9 3... THE WALLS 9 3... THE FLOOR 3 3..3. THE ROOF 3 3..4. THE FALSE CEILING 3 3..5. THE WINDOWS 3 3..6. THE SKYLIGHTS 3 3.3. BUILDING CHARACTERISTICS 33 3.3.. HEATING, COOLING AND VENTILATION 33 3.3.. INFILTRATION 34 3.3.3. INTERNAL HEAT GAINS 34 4. METHODOLOGY 35 4.. THE MEASUREMENTS 35 4... WATCHDOG SERIES WEATHER STATION 35 4... TESTO 435 37 4..3. BLOWERDOOR TEST 38 4.. CALCULATION OF THE CP-VALUES WITH CP GENERATOR 4 4... RESULTS OF PART A 4 4... RESULTS OF ZONE B 43 4..3. RESULTS OF ZONE C 45 4.3. THERMAL BRIDGE CALCULATION WITH THERM 7. 47 4.3.. CALCULATION METHODOLOGY 47 4.3.. THE OUTER WALL WITH STEEL PROFILE 5 4.3.3. THE ROOF-WALL CONNECTION 5 4.3.4. THE FLOOR-WALL CONNECTION 53 4.4. TRNSYS-FILE 55 4.4.. MODEL IN SKETCH-UP 55 4.4.. INSERTING THE MODEL IN TRNSYS 56 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
4.4.3. ADJUSTMENTS IN TRNBUILD 57 4.4.4. ADJUSTMENTS IN TRNFLOW 65 4.4.5. MODIFICATIONS TO THE MODEL TO ACHIEVE A PASSIVE HOUSE 7 5. RESULTS 74 5.. RESULTS OF THE MEASUREMENTS 74 5... ANALYSIS OF THE OUTSIDE WEATHER DATA 74 5... ANALYSIS OF THE INSIDE MEASUREMENTS 8 5..3. COMPARING INSIDE AND OUTSIDE MEASUREMENTS 86 5..4. CONCLUSION 9 5.. VALIDATING THE TRNSYS MODEL 9 5... COMPARING TEMPERATURE MEASUREMENTS WITH OUTPUTS TRNSYS 9 5... ANALYZING THE ENERGY DEMAND 97 5.3. MODIFICATION OF THE BUILDING 99 5.3.. MODIFICATION OF THE THERMAL INSULATION 99 5.3.. CHANGING THE WINDOWS 4 5.3.3. ADJUSTMENT OF THE OUTER BLINDS 5 5.3.4. CHANGING THE INTERNAL HEAT GAINS 7 5.3.5. INFLUENCE OF INFILTRATION 8 5.3.6. THE EFFECT OF NATURAL VENTILATION 5.4. COMBINING THE MODIFICATIONS 5 6. CONCLUSION 7 BIBLIOGRAFIE 9 APPENDIX A: INPUT AND RESULTS OF THE C P GENERATOR APPENDIX B: GROUND PLAN OF THE THERMAL ZONE 35 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
LIST OF FIGURES FIGURE - SYMBOL OF BUILDING PROJECT... 5 FIGURE - SYMBOL OF 3D BUILDING PROJECT... 5 FIGURE 3 - SYMBOL OF TYPE 56 WITH AIRFLOW ( TRNFLOW )... 5 FIGURE 4 - SYSTEM IN THE SIMULATION STUDIO... 6 FIGURE 5 - LINKS... 7 FIGURE 6 - SYMBOL FOR EQUATIONS... 7 FIGURE 7 - WINDOW FOR EQUATIONS... 8 FIGURE 8 - SYMBOL OF ONLINE PLOTTER... 8 FIGURE 9 - THE PROJECT INITIALIZATION WINDOW... 9 FIGURE - THE ZONE WINDOW... FIGURE WORKINGSCHEME OF TRNFLOW... FIGURE DEFINITION OF AIRNODE AND LINK PRESSURE... 3 FIGURE 3 - LOCATION OF BUILDING B AT UPV... 7 FIGURE 4 - LOCATION UPV IN VALENCIA... 7 FIGURE 5 - LOCATION OF THE THERMAL ZONE AND THE SECRETARY... 8 FIGURE 6 - SECTION OF THE VERTICAL WALLS... 9 FIGURE 7 - VENETIAN BLINDS IN FRONT OF WINDOWS... 3 FIGURE 8 - EXTRA HEATING DEVICE... 33 FIGURE 9 - CONICAL CEILING DIFFUSER... 33 FIGURE - WATCHDOG SERIES... 35 FIGURE - WATCHDOG SERIES ON ROOF... 35 FIGURE - DATA OF WATCHDOG SERIES... 36 FIGURE 3 - IMPLEMENT OF WEATHER DATA... 36 FIGURE 4 - HUMIDITY PROBE... 37 FIGURE 5 - TESTO 435-... 37 FIGURE 6 - DATA OF TESTO 435-... 37 FIGURE 7 - THE SERIE CALIBRATED FAN... 38 FIGURE 8 - DM- DIGITAL MANOMETER... 38 FIGURE 9 - VISUALIZATION OF THE C P MODEL... 4 FIGURE 3 - LOCATION OF THE PRESSURE POINTS IN PART A... 4 FIGURE 3 LOCATION OF C P -POINTS IN PART B... 43 FIGURE 3 - LOCATION OF C P -POINTS IN PART C... 45 FIGURE 33 - MATERIAL DEFINITIONS IN THERM... 47 FIGURE 34 - DEFINING BOUNDARY CONDITIONS IN THERM... 48 FIGURE 35 - BOUNDARY CONDITION TYPE IN THERM... 48 FIGURE 36 - CALCULATED U-VALUES IN THERM... 48 FIGURE 37 SECTION OF THE THERMAL BRIDE IN THE OUTER WALL... 5 FIGURE 38 INFRARED TEMPERATURES IN OUTER WALL BY THERM... 5 FIGURE 39 SECTION ROOF-WALL CONNECTION THERMAL BRIDGE... 5 FIGURE 4 INFRARED TEMPERATURES IN ROOF-WALL CONNECTION BY THERM... 5 FIGURE 4 - SECTION FLOOR-WALL CONNECTION THERMAL BRIDGE... 54 FIGURE 4 INFRARED TEMPERATURES IN FLOOR-WALL CONNECTION BY THERM... 54 FIGURE 43 - TOOLBAR FOR TRNSYS3D IN SKETCH-UP... 55 FIGURE 44 - RESULT IN GOOGLE SKETCH-UP WITH THE SECRETARIAT IN BLUE... 55 FIGURE 45 - CONVEX AND CONCAVE SURFACE... 55 FIGURE 46 - SYSTEM OF TYPES AND LINKS FOR A MULTIZONE BUILDING... 56 FIGURE 47 GEOMETRY MODES... 57 FIGURE 48 - LAYER TYPE MANAGER... 57 FIGURE 49 - WALL TYPE MANAGER... 58 FIGURE 5 - INSERTING A THERMAL BRIDGE MANUALLY... 59 FIGURE 5 - HEATING TYPE MANAGER... 6 FIGURE 5 - VENTILATION TYPE MANAGER... 6 FIGURE 53 - COOLING TYPE MANAGER... 6 FIGURE 54 - WINDOW TYPE MANAGER... 63 FIGURE 55 SKETCH FOR CALCULATING SHADING... 64 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
FIGURE 56 ACTIVATING SHADING IN TRNBUILD... 64 FIGURE 57 - MAIN WINDOW OF TRNFLOW... 65 FIGURE 58 - LARGE OPENING TYPE MANAGER... 66 FIGURE 59 - CRACK TYPE MANAGER... 67 FIGURE 6 - THERMAL AIRNODE MANAGER... 69 FIGURE 6 - EXTERNAL NODE MANAGER... 7 FIGURE 6 INPUT FORMULA... 73 FIGURE 63 - SKETCH OF THE ANGLE OF BLINDS... 5 FIGURE 64 - GROUND PLAN WITH DEFINITIONS... FIGURE 65 - DEFINITION OF CP POSITIONS... Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
LIST OF GRAPHS GRAPH - C P VALUES ON FAÇADE IN PART A... 4 GRAPH - C P VALUES ON FAÇADE 4 IN PART A... 4 GRAPH 3 - C P VALUES ON FAÇADE IN PART B... 43 GRAPH 4 - C P VALUES ON FAÇADE IN PART B... 44 GRAPH 5 - - C P VALUES ON FAÇADE IN PART C... 45 GRAPH 6 - C P VALUES ON FAÇADE IN PART C... 46 GRAPH 7 - C P VALUES ON FAÇADE 3 IN PART C... 46 GRAPH 8 - MEASURED OUTSIDE TEMPERATURE... 74 GRAPH 9 - MEASURED OUTSIDE RELATIVE HUMIDITY... 75 GRAPH - MEASURED SOLAR IRRADIANCE OUTSIDE... 76 GRAPH - ZOOM OF MEASURED SOLAR IRRADIANCE OUTSIDE... 76 GRAPH - MEASURED OUTSIDE WIND DATA... 77 GRAPH 3 - COMPARISON OUTSIDE TEMPERATURE-SOLAR IRRADIATION... 78 GRAPH 4 - ZOOM OUTSIDE TEMPERATURE-SOLAR IRRADIATION... 78 GRAPH 5 - COMPARISON OUTSIDE TEMPERATURE-RELATIVE HUMIDITY... 79 GRAPH 6 - ZOOM OUTSIDE TEMPERATURE-REALTIVE HUMIDITY... 79 GRAPH 7 TEMPERATURES MEASURED BETWEEN -3/3... 8 GRAPH 8 TEMPERATURES MEASURED BETWEEN 7-/3... 8 GRAPH 9 TEMPERATURES MEASURED BETWEEN 4-5/3... 8 GRAPH TEMPERATURES MEASURED BETWEEN 7-3/3... 8 GRAPH - MEASURED INSIDE RELATIVE HUMIDITY -3/3... 8 GRAPH - MEASURED INSIDE HUMIDITY 7-/3... 83 GRAPH 3 - MEASURED INSIDE HUMIDITY 4-5/3... 83 GRAPH 4 - MEASURED INSIDE HUMIDITY 7-3/3... 83 GRAPH 5 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY -3/3... 84 GRAPH 6 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY 7-/3... 84 GRAPH 7 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY 4-5/3... 85 GRAPH 8 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY 7-3/3... 85 GRAPH 9 COMPARISON TEMPERTURES-SOLAR IRRADIANCE -3/3... 86 GRAPH 3 COMPARISON TEMPERATURES-SOLAR IRRADIANCE 7-3/3... 87 GRAPH 3 COMPARISON TEMPERATURES-SOLAR IRRADIANCE 4-5/3... 87 GRAPH 3 COMPARISON TEMPERATURES-SOLAR IRRADIANCE 7-/3... 87 GRAPH 33 COMPARISON INSIDE-OUTSIDE HUMIDITY RATES -3/3... 88 GRAPH 34 - COMPARISON INSIDE-OUTSIDE HUMIDITY RATES 7-/3... 88 GRAPH 35 - COMPARISON INSIDE-OUTSIDE HUMIDITY RATES 4-5/3... 89 GRAPH 36 - COMPARISON INSIDE-OUTSIDE HUMIDITY RATES 7-3/3... 89 GRAPH 37 COMPARISON INSIDE TEMPERATURES -3/3... 9 GRAPH 38 - COMPARISON INSIDE TEMPERATURES 7-/3... 9 GRAPH 39 - COMPARISON INSIDE TEMPERATURES 4-5/3... 9 GRAPH 4 COMPARISON INSIDE TEMPERATURES 3/3-4/4... 93 GRAPH 4 COMPARISON INSIDE TEMPERATURES 7-3/3... 93 GRAPH 4 COMPARISON OUTSIDE TRNSYS TEMPERATURE -3/3... 94 GRAPH 43 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 7-/3... 94 GRAPH 44 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 4-5/3... 95 GRAPH 45 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 7-3/3... 95 GRAPH 46 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 3/3-4/4... 96 GRAPH 47 - PRESENT MONTHLY HEATING AND COOLING DEMAND... 98 GRAPH 48 - PRESENT ANNUAL ENERGY DEMANDS... 98 GRAPH 49 - ENERGY DEMANDS FOR MODIFICATION OF THE WALL INSULATION... GRAPH 5 VARIATION OF ENERGY DEMANDS FOR MODIFICATION OF THE WALL INSULATION... GRAPH 5 - ENERGY DEMANDS FOR MODIFICATION OF THE ROOF INSULATION... GRAPH 5 VARIATION OF ENERGY DEMANDS FOR MODIFICATION OF THE ROOF INSULATION... GRAPH 53 - ENERGY DEMANDS FOR MODIFICATION OF THE FLOOR INSULATION... 3 GRAPH 54 VARIATION OF ENERGY DEMANDS FOR MODIFICATION OF THE FLOOR INSULATION... 3 GRAPH 55 - ENERGY DEMANDS FOR CHANGES OF THE WINDOWS... 4 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
GRAPH 56 VARIATION OF ENERGY DEMANDS FOR CHANGES OF THE WINDOWS... 5 GRAPH 57 - ENERGY DEMANDS FOR ADJUSTMENTING THE BLINDS... 6 GRAPH 58 VARIATION OF THE ENERGY DEMANDS FOR ADJUSTING THE BLINDS... 7 GRAPH 59 - ENERGY DEMANDS OF CHANGING INTERNAL HEAT GAINS... 7 GRAPH 6 VARIATION OF ENERGY DEMANDS OF CHANGING INTERNAL HEAT GAINS... 8 GRAPH 6 - ENERGY DEMANDS OF MODIFICATION OF THE INFLILTRATION... 9 GRAPH 6 VARIATION OF ENERGY DEMANDS OF MODIFICATION OF THE INFLILTRATION... GRAPH 63 - ENERGY DEMANDS WITH AIR CHANGE RATE + VENTILATION... GRAPH 64 VARIATION OF ENERGY DEMANDS WITH AIR CHANGE RATE + VENTILATION... GRAPH 65 - ENERGY DEMANDS WITH AIR CHANGE RATE 4 + VENTILATION... GRAPH 66 VARIATION OF ENERGY DEMANDS WITH AIR CHANGE RATE 4 + VENTILATION... GRAPH 67 - ENERGY DEMANDS WITH AIR CHANGE RATE.6 + VENTILATION... 3 GRAPH 68 VARIATION OF ENERGY DEMANDS WITH AIR CHANGE RATE.6 + VENTILATION... 3 GRAPH 69 - ENERGY DEMANDS IN INITIAL MODEL + VENTILATION... 4 GRAPH 7 VARIATION OF ENERGY DEMANDS IN INITIAL MODEL + VENTILATION... 4 GRAPH 7 - ENERGY DEMANDS OF THE MODIFICATION COMBINATIONS... 6 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
LIST OF TABLES TABLE - REGIME DATA... TABLE - TOTAL THERMAL RESISTANCE OF THE OUTSIDE WALL... 3 TABLE 3 - TOTAL THERMAL RESISTANCE OF THE INSIDE WALL... 3 TABLE 4 - TOTAL THERMAL RESISTANCE OF THE FLOOR... 3 TABLE 5 - TOTAL THERMAL RESISTANCE OF THE ROOF... 3 TABLE 6 - TOTAL THERMAL RESISTANCE OF THE FALSE CEILING... 3 TABLE 7 - U-VALUES ROOF-WALL CONNECTION BY THERM... 5 TABLE 8 - U-VALUES FLOOR-WALL CONNECTION BY THERM... 53 TABLE 9 - THERMAL RESISTANCE AT THE SURFACE IN CONTACT WITH EXTERNAL AIR... 58 TABLE - AREAS OF THE WINDOWS FOR EACH OFFICE... 63 TABLE LIST WITH LARGE OPENINGS... 66 TABLE - EXAMPLES OF MASS FLOW COEFFICIENT CS AND AIRFLOW EXPONENT N... 67 TABLE 3 - LIST WITH ALL THE DIFFERENT CRACK-TYPES... 68 TABLE 4 - LIST WITH CP-VALUES... 7 TABLE 5 ANALYZED ANGLES AND SHADES... 7 TABLE 6 AREA FOR OPENINGS DEPENDING ONS AIR CHANGE RATE... 7 TABLE 7 PERCENTAGES FOR VENTILATION/INFILTRATION... 73 TABLE 8 PRESENT ENERGY DEMANDS MONTHLY AND ANNUAL... 97 TABLE 9 - ENERGY DEMANDS FOR MODIFICATION OF THE WALL INSULATION... 99 TABLE - ENERGY DEMANDS FOR MODIFICATION OF THE ROOF INSULATION... TABLE - ENERGY DEMANDS FOR MODIFICATION OF THE FLOOR INSULATION... TABLE TYPES AND SPECIFICATIONS OF THE WINDOWS... 4 TABLE 3 - ENERGY DEMANDS FOR CHANGES OF THE WINDOWS... 4 TABLE 4 - ENERGY DEMANDS FOR ADJUSTMENTING THE BLINDS... 6 TABLE 5 - ENERGY DEMANDS OF CHANGING INTERNAL HEAT GAINS... 7 TABLE 6 ENERGY DEMANDS OF MODIFICATION OF THE INFLILTRATION... 9 TABLE 7 - ENERGY DEMANDS WITH AIR CHANGE RATE + VENTILATION... TABLE 8 - ENERGY DEMANDS WITH AIR CHANGE RATE 4 + VENTILATION... TABLE 9 - ENERGY DEMANDS WITH AIR CHANGE RATE.6 + VENTILATION... 3 TABLE 3 - ENERGY DEMANDS IN INTITIAL MODEL + VENTILATION... 4 TABLE 3 ENERGY DEMANDS OF MODIFICATION COMBINATIONS... 6 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
. INTRODUCTION Before we arrived at UPV we ad to coose a title of a tesis out of a list. We bot preferred te tesis: Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. We are bot interested in building pysics and we bot don t dislike working wit a new computer program. Tis was one of te many reasons we coose for Valencia to go on Erasmus. As in te title of tis tesis is sown, one part is modelling a building using an advanced simulation program and comparing te outputs of te program wit data obtained by measurements in te building. At te end we made improvements on te building model. Te program simulates te conditions inside te building wit all te canges we implemented in te program and in accordance wit te weater data we obtained. Te results will be analysed and conclusions about te model and improvements will be taken. We ad to take into account tat te building is situated in a warm climate. So te corrections ave different influences depending on te season. Tis was a difficult issue for us, because we really ad to cange our way of tinking. In Belgium we primarily focus on te eating demand of a building and not so muc on te cooling demand. In a climate like ere in Valencia it s te oter way around. Wit te prospects of adapting, renovating or even rebuilding te faculty of building management, tis tesis can ave some importance. In time of economic crisis and increasing environmental awareness, a ig quality design in terms of energy demands and consumption is indispensable. Tat s wy improvements suc as insulation, renewable energy, better equipment for cooling/eating, ventilation etc. are important to acieve tis quality design. A passive ouse is te example of suc a design. A passive ouse is a building wit comfortable indoor conditions trougout te year, acieved wit minimum energy input. Te design and construction are very important in tis matter. Before we started wit te computer program and doing te measurements we did some researc about tis subject. We read some articles tat our promoter in Spain, Lecturer Carolina Sabina Fernández and our Professor Hilde Brees in Belgium suggested. We also read te manuals of TRNSYS (TRNSYS, TRNFlow and Multi-zone Building). Te building tat we are evaluating is a university building. Tis means tat tis is a non-residential building. Te following criteria ave to be obtained to receive a passive ouse certificate (www.passiveouse-international.org): Specific space eating demand: 5 kw/(m²a) Specific useful cooling demand: 5 kw/(m²a) Total specific primary energy demand: kw/(m²a) Airtigtness:.6/ Tese criteria will be used to implement modifications to te model and in tis way reacing te Passive House standard. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
. CONCEPTS.. BUILDING SIMULATION WITH TRNSYS TRNSYS is te abbreviation of Transient System Simulation Tool. It is a complete and extensible simulation environment for te transient simulation of systems, including multi-zone buildings. It is used by engineers and researcers around te world to validate new energy concepts, from simple domestic ot water systems to te design and simulation of buildings and teir equipment, including control strategies, occupant beaviour, alternative energy systems (wind, solar, potovoltaic, ydrogen systems), etc. (Klein S.A. et al,, p8) TRNSYS contains two parts. Te first is an engine tat reads and processes te input file, iteratively solves te system, determines convergence, and plots system variables. Te kernel also provides utilities tat (among oter tings) determine termopysical properties, invert matrices, perform linear regressions, and interpolate external data files. Te second part of TRNSYS is an extensive library of components, eac of wic models te performance of one part of te system. Te standard library includes approximately 5 models ranging from pumps to multizone buildings, wind turbines to electrolyzers, weater data processors to economics routines, and basic HVAC equipment to cutting edge emerging tecnologies. Te user as te possibility to modify existing components or write teir own, extending te capabilities of te environment. TRNSYS is very successful due to its open, modular structure. Te source code of te kernel as well as te component models, is delivered to te end users. Tis simplifies extending existing models to make tem fit te user s specific needs. Te DLL-based arcitecture allows users and tird-party developers to easily add custom component models, using all common programming languages (C, C++, PASCAL, FORTRAN, etc.). In addition, TRNSYS can be easily connected to many oter applications, for pre- or post-processing or troug interactive calls during te simulation (e.g. Microsoft Excel, Matlab, COMIS, etc.). TRNSYS applications include: Solar systems (solar termal and PV) Low energy buildings and HVAC systems wit advanced design features (natural ventilation, slab eating/cooling, double façade, etc.) Renewable energy systems Cogeneration, fuel cells Anyting tat requires dynamic simulation Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
... TRNSYS SIMULATION STUDIO WITH TRNBUILD Simulation Studio is a complete simulation package containing several tools, from simulation engine programs and grapical connection programs to plotting and spreadseet software. It is an integrated tool wic can be used from te design of a project to its simulation. (Klein S.A. et al,, p.) Te simulation studio contains 3 main steps to become a valid result: Inputs Calculation: Type 56 Multizone Building Interaction wit TRNBUILD and TRNFLOW Outputs... INPUTS Te main inputs are: Te TRNBUILD file. Te Weater Data Reading and Processing (Type 5). Te TRNBUILD file You ave te coice to import a 3D construction made in Google Sketc-up by using te TRNSYS3d-plugin or you can design te building in TRNSBUILD yourself. Wen tere are no defaults, you can import tis to TRNSYS. FIGURE - SYMBOL OF 3D BUILDING PROJECT FIGURE - SYMBOL OF BUILDING PROJECT Eventually te type56 will be canged to type 56: Multi-Zone Building wit Airflow (TRNFLow). Tis way it will be able to do te calculations and simulations in combination wit TRNFlow. FIGURE 3 - SYMBOL OF TYPE 56 WITH AIRFLOW ( TRNFLOW ) Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
Tis component models te termal beaviour of a building divided into different termal zones. In order to use tis component, a separate pre-processing program must first be executed. (Klein S.A. et al,,p.8) Te TRNBUILD program reads in and processes a file containing te building description and generates two files tat will be used by te TYPE 56 component during a TRNSYS simulation. Te file containing te building description processed by TRNBUILD can be generated by te user wit any text editor or wit te interactive program TRNBUILD. Te required notation is described fully in te TRNBUILD documentation in te following section. Te Weater Data Reading and Processing - Type 5 Tis component serves te purpose of reading data at regular time intervals from an external weater data file, interpolating te data (including solar radiation for tilted surfaces) at time steps of less tan one our, and making it available to oter TRNSYS components. (Klein S.A. et al,, p.98) Te model also calculates several useful terms including te mains water temperature, te effective sky temperature, and te eating and cooling season forcing functions.... CALCULATION It is in te Simulation Studio tat te calculation takes place. It is possible to pick any type out of te TRNSYS Library or take any option needed out of te toolbar. All te different inputs and outputs can be connected by te link tool. Now te program can do te calculations and simulations. Te obtained results can be compared and judged wit result obtained in real life experiments. FIGURE 4 - SYSTEM IN THE SIMULATION STUDIO Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
Creating Links Links allows to excange information between two component models. In tis way te outputs from te first model can be used as inputs in te second model. Wen te mouse is in te area of te first model, 8 ports appaer around te icon. Wen you coose one and click, you will see te same at te second model. A line will be drawn between te two components to indicate information flow between tem. Tis line will initially be empty (blue). Wen te variable is specified in te link, it will turn black. Equations FIGURE 5 - LINKS A very useful feature in TRNSYS is te ability to define equations witin te input file. Tese are not integrated in a component. Tese equations can be: functions of outputs of oter components, numerical values, previously defined equations... Tey can ten be used as: inputs to oter components, parameters, initial values of inputs Te use of equations is most easily accomplised by using a special equations component. Tis equations component can be placed in an assembly or saved like any oter component. FIGURE 6 - SYMBOL FOR EQUATIONS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
Te equation component will not be represented in te generated input file by a UNIT, TYPE statement. Rater, te information contained in tis component will be placed in an EQUATIONS statement witin te TRNSYS input file. Te user can specify te location of te equations in te Control Cards window. Different blocks of equations can be placed anywere witin te input file and are arranged just like different components....3. OUTPUTS In TRNSYS Simulation Studio te user can coose out of several output metods, suc as: Economics Online plotter Histogram plotter Printegrator Printer Scope Simulation summary TRNSYS Plugin for SketcUp Printer Online Plotter (no units) type 65c FIGURE 7 - WINDOW FOR EQUATIONS Te online grapics component is used to display selected system variables wile te simulation is progressing. Tis component is used a lot because it provides valuable variable information and allows users to immediately see if te system is not performing as desired. (Klein S.A. et al,, p.6) Te selected variables will be displayed in a separate plot window on te screen. In tis instance of te Type65 online plotter, data sent to te online plotter is automatically printed, once per time step to external file wic as been defined by te user. FIGURE 8 - SYMBOL OF ONLINE PLOTTER Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
... TRNBUILD In TRNBUILD tere are 3 main windows: Project Te zone window Definition of te airflow network for detailed calculation wit TRNFlow It is possible to model te termal beaviour of a building wic is divided into different termal zones. Te TRNBUILD program reads in and processes a file containing te building description and generates two files tat will be used by te TYPE 56 component during a TRNSYS simulation. Te parameters of TYPE 56 are not defined directly in te TRNSYS input file because a multizone building is very complex. Instead, a file building file (*.BUI) is assigned containing te required information. TRNBUILD as been developed to provide an easy-to-use tool for creating te BUI file. Starting wit some basic project data, te user describes eac termal zone. Finally, te desired outputs are selected. All data entered are saved in te so-called building file (*.BUI). (Klein S.A. et al,, p.9)... PROJECT FIGURE 9 - THE PROJECT INITIALIZATION WINDOW In tis window te user as te possibility to enter general information about te project, te orientation of te required walls, basic material properties, view a list of required inputs to type 56 and selects te desired outputs of type 56. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
Inputs Te user can link components from TRNSYS Simulation Studio wit TRNBuild. Outputs Te user may adjust te time base of te transfer function if necessary. Te default value of is adequate for most cases and.5 for ligt walls. Te user can edit, add or delete outputs of TYPE 56, so-called NTYPES. Te results give te simulated results back to te Simulation Studio.... THE ZONE WINDOW Tis window contains all te information of a termal zone of te building. All te different zones are listed in te TRNBuild Navigator. In TRNSYS 7 it s possible to ave more tan one airnode in a termal zone. Tey can be moved from one zone to anoter (multi-airnode zone). Te 4 main parts to describe te data for an airnode are: a) Te required REGIME DATA b) Te WALLS of te airnode c) Te WINDOWS of te airnode d) Optional equipment data and operating specifications including INFILTRATION, VENTILATION, COOLING, HEATING, GAINS and COMFORT. FIGURE - THE ZONE WINDOW Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
a) Te required REGIME DATA Data Description unit volume Volume of air witin airnode m³ Capacitance Total termal capacitance of airnode plus tat of any mass not kj/k considered as wall Init. Initial temperature of te airnode air C Temperature Init. Rel. Initial relative umidity of te airnode air % umidity Humidity model A simple (capacitance) detailed (buffer storage) model - b) Te WALLS of te airnode TABLE - REGIME DATA In tis part e user can add, delete or edit te walls of an airnode. It gives an overview off all te different walls. Teir properties (wall type, area, category, geosurf, surface number and wall gain) can be defined. Wit te Wall Type Manager and Layer Type Manager it is possible to create respectively new walls and new materials. Te program will calculate te U-value of te wall. It needs te tickness of every layer and its properties (conductivity, capacity and density). c) Te WINDOWS of te airnode Tis is very similar to te previous option. Te user as te possibility to add more parameters suc as te saded area, te g-value d) Optional equipment data and operating specifications Tere are 6 optional equipment data or operating specifications tat can be defined: Infiltration: an airflow into te zone from outside te zone Ventilation: an airflow e.g. from eating and/or cooling equipment into te airnode. Te user can add, delete or edit a previous defined type. Heating: te user can add, delete or edit a previous defined type. For eac eating system te set temperature (= maximum eating temperature) as to be added. Cooling: te user can add, delete or edit a previous defined type. For eac cooling system te set temperature (= minimum eating temperature) as to be added. Gains: tese are internal gains (persons, electrical devices, etc.) Comfort: te user can define te cloting factor, metabolic rate, external work, and te relative air velocity Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
...3. DEFINITION OF THE AIRFLOW NETWORK FOR DETAILED CALCULATION WITH TRNFLOW Wen we canged te type 56 - Multi-Zone Building to type 56 - Multi-Zone Building wit Airflow (TRNFLow), we obtained te possibility to add an airflow network in TRNBuild...3. TRNFLOW TRNFLOW is te integration of te multizone airflow model COMIS (Conjunction of Multizone Infiltration Specialists) into te termal building module of TRNSYS (Type 56). Wit TRNFLOW te airflows between airnodes (coupling), from outside into te building (infiltration) and from te ventilation system (ventilation) can be calculated. (Klein S.A. et al,, p.4) Figure workingsceme of trnflow sows us tat te airflow- and termal model are linked wit eac oter. In tis picture te information flow between te models is represented by one air temperature node and one airflow. Te model starts wit te input node temperature ϑ in,. Te corresponding airflow is calculated and used in te termal model. Here te output room temperature ϑ out, is calculated. Wit an iterative solver algoritm, te input temperatures set is found wic matces te output temperatures set. FIGURE WORKINGSCHEME OF TRNFLOW An airflow model is based on te network model of te building. Te network is a collection of connected air nodes. Tey are connected wit air links. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
..3.. AIRFLOW NODES Tere are 4 possible classes of nodes to build an airflow network: Constant pressure nodes: fixed pressure of te building Termal airnodes: corresponds to te airnodes in te termal model. Tey ave a omogenous temperature and can be represented by a node wit single values for temperature, umidity and pressure. Auxiliary nodes: used to define a ductwork of a ventilation system. External nodes: represents te wind pressure at te outside of a building. Te pressure coefficients (Cp) can be added to te external nodes for several wind directions...3.. AIR LINK Tere are 4 different air link types: Crack: component (small opening/ group of small openings) tat uses te power law form to express te leakage caracteristic of cracks. Duct: in a straigt duct te flow is defined by te friction loss and te dynamic losses due to fittings. Fan: used to define its flow caracteristic at a certain fan speed. Large vertical opening: a large opening wit a vertical velocity profile. Te flow in tis model is strictly orizontal. FIGURE DEFINITION OF AIRNODE AND LINK PRESSURE Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
.. WIND PRESSURE SIMULATION WITH CP GENERATOR... WIND PRESSURE COEFFICIENTS C P Te pressure on a building façade is given by: Ptotal = Patm + Pw Were: Ptotal = pressure on te façade (Pa) Patm = atmosperic pressure (Pa) Pw = pressure due to te wind effect (Pa) Te wind-effect is caused by te wind pressure Pw and can be estimated by te equation: Pw =.5 ρ Cp V² (Pa) Were: ρ = air density (kg/m³) Cp = wind pressure coefficient ( - ) V = local wind velocity at a specified reference eigt (m/s) From te previous equation it appears tat te wind pressure coefficient Cp can be understood as a dimensionless description of te dynamic wind pressure at a specific point of te building envelop. It depends on four parameters: te spatial location on te building envelope, te building sape, te surroundings and te wind direction. It can also be influenced by large openings in facades. As wind is a major actuator for natural ventilation, Cp-values are used as input in natural ventilation simulation programs wic is in our case TRNSYS. As it is practically impossible to take into account te full complexity of pressure coefficient variation some analytical programs ave been developed over te years. Some metods to evaluate Cp-values are briefly discussed below: Tabulated values (e.g. AIVC tables) are very easy to use but ave a limited range of applications. Tey give an average value for eac building facade, under different assumptions (low-rise building, exposition to wind etc.). On te opposite site, te wind tunnel tecnique can give Cp-values under any circumstances. But tis requires a lot of efforts and tecnology. Terefore, it can only be used in te design process of big projects. Simulations tools include Computational Fluid Dynamic (CFD) calculations, wic is also time- consuming and expensive. Specific Cp-generators (TNO model) ave been developed as a trade-off between accuracy and complexity. We used te Cp-generator in our project. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
... TNO C P-GENERATOR A computer program as been developed in te Neterlands to predict te Cp-values on facades and roofs of block-saped buildings. Tis program is based on fits of experiments in a wind tunnel: on typical block-saped buildings, in different terrain rougness, wit and witout obstacles on systematically varying distances. Te calculation process takes tree steps. Step : te pressure at te centre of te building facades is calculated as function of te wind direction, te terrain rougness, and te building dimension, but in an exposed environment (no local obstacles). Tose two assumptions will be dropped in te next steps. Step : a first correction is calculated for oter points of te facades, as function of ratios of te building dimensions, wind attack angle and terrain rougness. Step 3: a second correction is calculated for local obstacles, according to teir size, distance, orientation and azimut. Te main advantage of tis tool is tat only a small amount of data is required.... THE INPUTS Te input for te Cp Generator is simple. On te website you find a.txt -file as an example and tey recommend you to work in (a copy of) tis file by adjusting te file to your own specific situation. Te different inputs are: Title Wind.Zo Nort arrow Obstacles Cp positions To get more details about te input, see Appendix A. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
... THE OUTPUTS After preparing te input.txt -file we let te web application do te calculation in four easy steps were we declare te name and te format of te output file. Te web application calculates a Cp-value per wind direction for eac defined point. We put tese values in a polar grap to see if te calculations meet te reality. Te Cp simulation program is based on fits of earlier measured data of on-site tests and systematic performed wind tunnel tests. It still is a simulation program, wic means tat te results ave to be used wit great care and at our own risk. Te accuracy of te predicted wind pressures for a simple environment is good. Tis is sown by several validations. However, complex building and obstacle sapes ave to be dealt wit more care, as well as small passages. Tat is te reason wy we narrowed most of te problem down to basic sapes. Also we neglected te sapes tat we didn t reckon to be important in our case..3. THERMAL BRIDGE CALCULATION WITH THERM 7. THERM is a state-of-te-art, Microsoft Windows -based computer program developed at Lawrence Berkeley National Laboratory (LBNL) for use by building component manufacturers, engineers, educators, students, arcitects, and oters interested in eat transfer. Using THERM, you can model two-dimensional eat-transfer effects in building components suc as windows, walls, foundations, roofs, and doors; appliances; and oter products were termal bridges are of concern. THERM's eat-transfer analysis allows you to evaluate a product s energy efficiency and local temperature patterns, wic may relate directly to problems wit condensation, moisture damage, and structural integrity. THERM s two-dimensional conduction eat-transfer analysis is based on te finite-element metod, wic can model te complicated geometries of building products. THERM as tree basic components: Grapic User Interface: It allows you to draw a cross section of te product or component for wic you are performing termal calculations. Heat Transfer Analysis: It includes: an automatic mes generator to create te elements for te finite-element analysis, a finite-element solver, an optional error estimator and adaptive mes generator, and an optional view-factor radiation model. Results: Te results from THERM s finite-element analysis of a building component can be viewed in various ways: U-factors, isoterms, colour-flooded isoterms, eat-flux vector plots, colour-flooded lines of constant flux and temperatures (local and average, maximum and minimum). Te features of THERM ave been used to calculate te termal bridges in te building and particularly for te linear termal transmittance in te dimensional construction knots. Wit tis value te eat flow troug te connection of two construction elements is calculated per meter of te termal bridge and per Kelvin. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
3. CASE STUDY Te case study involves gatering information and gatering indoor and outdoor air parameters suc as temperature and umidity in te secretariat of te scool of building engineering at Universitat Politecnica de Valencia. Te gatered information can be compared wit te output of TRNSYS. To make te calculations wit TRNSYS, we considered not only te secretariat but a wole termal zone. Te wole termal zone was introduced into TRNSYS to make te calculations more veracious, because te secretariat is not an isolated building but a part of te faculty building. Te offices and corridors tat surround te secretariat ave a big influence on te secretariat s inside conditions. 3.. LOCATION Te secretariat is oused at te Universitat Politecnica de Valencia, Campus de Vera. It is located in building B: ETS d Enginyeria d Edificacio, tis is te red part on te picture below (Figure 3). Te campus is on te nortern boundary between te city of Valencia and te countryside (Figure 4). It is surrounded by open areas on te nort and by buildings up to m ig in te oter directions. Te distance to te sea is approximately km. FIGURE 3 - LOCATION OF BUILDING B AT UPV FIGURE 4 - LOCATION UPV IN VALENCIA Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
Te position of te termal zone in te faculty of building engineering and te secretariat witin it can be seen on te picture below in blue and red respectively (Figure 5). Tis case study only analyses te secretariat area considering a useful area of 4m. It s a large open room in wic te administrative staff is working. Te small adjacent offices tat are also used by te administrative staff are not considered as secretariat area in te model. In te secretariat we measured te temperature and te umidity of te room and te false ceiling. On te roof of te secretariat we placed te weater station. FIGURE 5 - LOCATION OF THE THERMAL ZONE AND THE SECRETARY Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
3.. ELEMENTS OF THE THERMAL ENVELOPE Te building as been constructed in a single storey and te floor as an elevation of approximately.5m compared to te ground level. Also underneat te floor tere is a low ventilated basement wit an average eigt of.8m and a false ceiling between te roof and te working area wit a eigt of.m. Different from te working area, tese two volumes are not confined by separating elements and are spread over te wole surface of te termal zone. Te working area is 3.5m ig. Te building is more tan 4 years old and was built on a provisional base, terefore a lot of simple prefabricated construction materials were used in te floor, te roof and te walls. Te values of total termal resistance and overall eat transfer coefficient of te different elements of te building envelope were calculated below. 3... THE WALLS Te walls are made out of prefabricated panels. Te dimensions of te panels are:.5m lengt by.5m eigt. Te tickness depends on weter it s an inside wall (7cm) or an outside wall (cm). Te panels are made out of a main layer of wood fibre between layers of cement mortar. Te panels don t ave any structural function watsoever tey just are used as partitioning walls. A steel frame fulfils te structural balance of te building. Steel U-profiles are used for te frame. As mentioned earlier te building was constructed on a provisional base, so te cost of te building and te way of constructing it ad to be as low and as easy as possible. Terefore all te U-profiles ave te same section and only differ in lengt. Te steel profiles are welded togeter per two so tey get a rectangular sape and are ollow inside. Te composition of te walls and te calculation of te eat transfer coefficients of te two walls are represented below (Figure 6)(Table and Table 3). Te steel column is located at te inside of te building. Te wall as been recalculated to count in te influence of te steel profiles, tis can be seen in section 4.3.. FIGURE 6 - SECTION OF THE VERTICAL WALLS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
Outside Inside Layer Tickness [m] Conductivity [W/mK] Termal Resistance [m K/W] Exterior.4 Cement mortar..3.8 Wood fibre.8.6.5 Cement mortar..3.8 Interior.3 Total Tickness (m). R t (m K/W):.69 TABLE - TOTAL THERMAL RESISTANCE OF THE OUTSIDE WALL Layer Tickness [m] Conductivity [W/mK] Termal Resistance [m K/W] Interior.3 Cement mortar..3.8 Wood fibre.5.6.3 Cement mortar..3.4 Interior.3 Total Tickness (m).7 R t (m K/W):.63 TABLE 3 - TOTAL THERMAL RESISTANCE OF THE INSIDE WALL Te overall eat transfer coefficient of te considered enclosures including te termal resistance of te surfaces is.46 W/m K for te outside and.59 W/m K for te inside wall. Here we didn t consider te influence of te steel profiles in te calculation of te U-values of te wall neverteless tese ave a big influence on te termal caracteristics of te wall. Tis will be implemented furter in tis paper wen termal bridges are added. 3... THE FLOOR Te floor as an elevation of approximately.5m compared to te ground level. Underneat te floor slab tere is a ventilated low basement of.8m ig. Because it s a ventilated basement we assumed outside conditions at te bottom of te floor slab. Te calculation of te total termal resistance of te slab is represented below (Table 4). Layer Tickness m Conductivity W/mK Termal Resistance m K/W Interior.7 Tiles (Terrazo).3.3.3 Mortar (Mortero).3.8.38 Sand (Arena).3..5 Reinforced concrete (Hormigón).3.43. Exterior.4 Total Tickness (m).39 R t (m K/W):.5 TABLE 4 - TOTAL THERMAL RESISTANCE OF THE FLOOR Te overall eat transfer coefficient for te floor including te termal resistance of te surfaces is. W/m K. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
3..3. THE ROOF Te total concrete slab of te roof as a total tickness of.3m, wic is very tick for a roof tat as to be supported by a steel frame. Te packed sand ensures te slope of 3cm/m to drain te roof. We took an intermediate value for te tickness of te packed sand layer. Te stones on top of te impermeable layer ave multiple purposes, as tere are te protection of te underlying layers against te influences of te wind and te sun. Te calculation of te total termal resistance of te slab is represented below (Table 5). Layer Tickness Conductivity Termal Resistance [m] [W/mK] [m K/W] Exterior.4 Gravel (Grava).5..5 Bitumen (Bétun)..7.59 Packed sand (Arena).5..75 Reinforced concrete (Hormigón armado).5.55.7 Prefabricated concrete slab (Losa).5.5.3 Interior. Total Tickness (m).5 R t (m K/W):.7 TABLE 5 - TOTAL THERMAL RESISTANCE OF THE ROOF Te overall eat transfer coefficient for te roof including te termal resistance of te surfaces is.4 W/m K. 3..4. THE FALSE CEILING Tiles of syntetic fibre are used to compose te false ceiling. Te dimensions of te tiles are 5x5x3 cm. Te layout of te false ceiling is a web of U-profiles every one and a alf metre wit in-between te syntetic tiles. Te calculation of te total termal resistance of te slab is represented below (Table 6). Te false ceiling is te barrier between te working zone, were we wis to ave a comfortable temperature, and te zone wit te pipes. Tis needs to ave a good isolating capacity because we only want to eat up te working zone. If tis is not te case tan te zone tat as to be eated up becomes muc bigger. Layer Tickness [m] Conductivity [W/mK] Termal Resistance [m K/W] Interior. Fibre (Falso tecno fibro).3.3 Interior. Total Tickness (m).39 R t (m K/W):. TABLE 6 - TOTAL THERMAL RESISTANCE OF THE FALSE CEILING Te overall eat transfer coefficient for te floor including te termal resistance of te surfaces is.83 W/m K. Tis is a reasonable value. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
3..5. THE WINDOWS Te windows are made out of a stainless steel frame. Te glass used in te windows is clear single glass of 6mm tick wit a eat transfer coefficient (U-value) of 5.68 W/m K and a window solar factor (g-value) of.9. Also wort mentioning are te blinds in front of every window (Figure 7). Every window disregarding te orientation is equipped wit permanent adjustable outdoor blinds. Te type of sading is Venetian blinds. Tey allow controlling te ligt flow tat enters te secretariat, protect te windows from external influences and prevent eating of te glass. Te blades are made out of PVC and te dimension of eac blade is 7x5x.5 cm. Te distance between te blades is 5 cm and eac column counts 5 blades. Te inclination of eac column of blades can be manually adjusted on te outside. Te blinds already are very old, a lot of tem can t be adjusted anymore because tey are rusted. FIGURE 7 - VENETIAN BLINDS IN FRONT OF WINDOWS 3..6. THE SKYLIGHTS Te skyligts are composed out of polyester resin reinforced wit plates of glass fibre. Tey are double plated, i.e. two overlapping plates stacked togeter, forming an isolation room tat gives a ig termal insulation. We don t know te U-value of te skyligts tat are used but if we look for some reference values we find U-values of.68 W/m K (ttp://www.walbers.be). We neglected te skyligts in te TRNSYS-file because it was not possible for us to make te connection wit te working area because te false ceiling area is in-between. If we wanted to put te skyligts into te TRNSYS-file we ad to add a zone between every skyligt and te working area, wic would lead to anoter 3 extra termal zones and multiple connections to make. In teory tis is perfectly possible but we tink tat te small extra zones would make te model less precise. Tis as definitely an effect on our result, because we didn t consider teir sare in te solar eat gains or Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
in te risk of overeating. But on te oter and te effect of te skyligts as to be put in perspective. Firstly tere is te eat transfer coefficient of te skyligts tat is less tan alf of te value for te windows, wic means tat tey insulate better. Also te skyligts are not clear and ave a ligt colour so te solar factor will be small. Tis is positive in summer wen te risk of overeating is iger. Neverteless we cannot forget tis neglect in te interpretation of te results especially if te U-value of te roof is being improved. 3.3. BUILDING CHARACTERISTICS 3.3.. HEATING, COOLING AND VENTILATION Te scool of building engineering is eated, cooled and ventilated wit te same installations and same pipe networks. Tereby it s really difficult to estimate tese units for te secretariat alone. Also we ave no information about te present installations placed on te faculty s roof. Fres air is conditioned and ten blown into te different spaces. Te reference value for te ventilation is.4 volumes per our during business ours. Te conditioned fres air is blown into te secretariat by 8 conical diffusers in te false ceiling (Figure 9). Te set points for te eating and cooling installation are C and 6 C respectively. Tese temperatures sould ensure comfortable working conditions during business ours. Business ours in te secretariat and practically te wole department are from 8 a.m. to 8 p.m. from Monday until Friday. Tis scedule is considered te same for all active conditioning devices tat are used in te building. By nigt all te devices are switced off. Te secretariat as extra eating and cooling devices installed on te ceiling and also some electrical eaters are used (Figure 8). Tese devices ensure tat te comfort temperature demands in te secretariat are answered. But it also makes us believe tat te conditioning installation leaves muc to be desired. FIGURE 8 - EXTRA HEATING DEVICE FIGURE 9 - CONICAL CEILING DIFFUSER Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 33
3.3.. INFILTRATION Te airtigtness of te termal envelope leaves muc to be desired. A lot of infiltration is expected troug te windows and troug every joint and connection. Te most important ones are te joints between te steel frame and te prefabricated panels, between two panels, between te wall and te connections wit floor and roof and between te panels and te windows. To know te airtigtness of te termal envelope we performed a BlowerDoor test in one of te offices (see 4..3). Unfortunately it was not possible to obtain good results for te airtigtness so tis is still an unknown factor. 3.3.3. INTERNAL HEAT GAINS Te internal eat gains are composed out of te different loads in te secretariat. Tere are only eat gains wen te faculty is open. Te same time scedule as for te eating, cooling and ventilation devices is assumed, wic is from Monday to Friday from 8 a.m. until 8 p.m. Tere are tree factors tat define te quantity of te eat gains, namely te number of persons, te number of computers or oter electronic devices and te number of artificial ligts in te room. Tese units could be empirically determined and we found te following quantities: Number of persons: 6 Number of computers or oter electronic devices: Number of artificial ligts: 7 luminaires wit eac 3 fluorescent lamps 6 fluorescent lamps Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 34
4. METHODOLOGY 4.. THE MEASUREMENTS 4... WATCHDOG SERIES WEATHER STATION Te watcdog series (Figure - Watcdog series) is a full weater station from Spectrum Tecnologies. It is completely weater proof and features a -bit resolution for iger accuracy. FIGURE - WATCHDOG SERIES Te weater station sould be located in an open and unobstructed area to ensure accurate measurement. Tat s wy it was installed on te roof above te secretariat (Figure - Watcdog series on roof). Tis way an accurate measuring for te temperature, solar irradiance, umidity, rainfall, wind speeds and direction and dew point is obtained on te exact location of te secretariat. FIGURE - WATCHDOG SERIES ON ROOF Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 35
SpecWare 9 Professional Specware 9 Professional software is used to transfer data to te computer. We can connect te Watcdog series wit a USB connection. Tis software is used to transfer te data and gives you te possibility to obtain a grapical display or in tables (Figure - Data of watcdog series). In our researc we only need tables in Microsoft Excel or saved as a.txt file. FIGURE - DATA OF WATCHDOG SERIES TRNSYS gives te opportunity to implement tese files in TRNSYS. Figure 3 sows te window tat appears were te preferred weater data can be cosen. FIGURE 3 - IMPLEMENT OF WEATHER DATA Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 36
4... TESTO 435 Te Testo 435- (Figure 5 - Testo 435-) is a measuring instrument for ambient air conditions, for assessment of Indoor Air Quality and adjusting and testing VAC systems. We used te umidity probe (Figure 4 - Humidity probe). Tis is used to measure te air moisture and te air temperature. Clear analysis and arciving ensure practical PC documentation. Tere is te possibility to connect additional temperature and umidity probes (up to 3 probes)(ttp://www.testo-international.com). Te probe as following specifications: Meas. range - to +7 C / Meas. Range to + %RH FIGURE 4 - HUMIDITY PROBE FIGURE 5 - TESTO 435- Comfort Software X35 We need tis software to transfer te obtained data to a computer. It is also possible to analyse separate measurement values and measurement series. Tis involves in letting te date been sowed in a grapic display but we only used it to transform it to tables in Microsoft Excel. Te transfer of a Testo instrument to te PC appens via USB. Wen te instrument is connected, it plots a proper table wit all te measurements as sown in following figure. (Instruction Manual Comfort Sorftware x35 Professional) FIGURE 6 - DATA OF TESTO 435- Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 37
4..3. BLOWERDOOR TEST 4..3.. DEFINITION Windows, doors or ventilation systems are provided to ventilate buildings. Unfortunately air excange also occurs troug openings caused by poorly designed termal bridges in te joints and connections. Uncontrolled air excange troug te termal envelope causes iger eating and cooling demand and can cause feelings of discomfort. Te BlowerDoor test is a way to examine uncontrolled air excange, locate leakages in te termal envelope and determine te rate of air excange. By measuring te differential pressure te airtigtness of a building is determined. Bot under and overpressure of 5 Pa are used. By performing a BlowerDoor test many disadvantages can be eliminated or prevented, suc as: draugts, poor sound insulation and living comfort, ig energy consumption, condensation build-up, moisture damage and mould formation. 4..3.. EQUIPMENT FOR THE BLOWERDOOR TEST DM- Series Cannel Digital Pressure Gauge (Figure 8) Retrotec s DM-, dual cannel, digital manometer puts te operator in command of virtually every parameter of interest to te BlowerDoor tester. Te DM- represents a uge advance in building and envelope diagnostic instrumentation. It calculates: o Te pressure on two cannels o Te airflow o Te equivalent leakage area o Te air-canges per our Te -Serie calibrated fan (Figure 7) Software Retrotec FanTestic version 5..6 FIGURE 8 - DM- DIGITAL MANOMETER FIGURE 7 - THE SERIE CALIBRATED FAN Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 38
4..3.3. CONCLUSION OF THE TEST Te BlowerDoor test was performed in a smaller office in te close surrounding of te secretariat and as te same structural composition as te secretariat. Te test setup was done and te fan was powered to put te office in an under pressure. Te pressure wasn t decreased at all in te building, so it became clear tat tere was a big problem. Te built up pressure by te fan was built up so low tat it couldn t be just some small air leak. We tried to make te volume muc smaller by closing inside doors, but te pressure didn t cange a lot. We ad to conclude tat te bad airtigtness of te office is caused by te air coming troug te false ceiling. As we mentioned before te space between te false ceiling and te roof slab of te wole termal zone is connected wit eac oter. So in fact, all te separate offices are connected wit eac oter, because te false ceiling is not really a separating construction. Tis is exactly wy we cose tis office to perform te test, and not te secretariat, because it was semidetaced from te oter offices and was assumed to be a closed entity. Unfortunately it became clear during te test tat tis was definitely not te case. We ad to conclude tat it is impossible to perform a BlowerDoor test in tis building, so tat we are not able to obtain a value for te airtigtness of te building. Te result of te failure of tis test is tat tere is anoter unknown parameter about te building. Te airtigtness of te building as a very big influence on te energy demand of te building. Because tis parameter is unknown, we can t compare it wit te results of te wind pressure coefficients to validate te model. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 39
4.. CALCULATION OF THE CP-VALUES WITH CP GENERATOR Te ground plan of te department of te scool of building management as a difficult sape to define te obstacles. Terefore we simplified te plan in rectangular saped blocks and only considered te parts wic are in directly surrounding of te termal zone wic te secretariat is part of. Tese parts ave te biggest influence on te magnitude of te Cp-values. Also wen tere are too many separate obstacles close to eac oter, te result of te Cp prediction only is reduced. We divided te energy zone into tree parts and made a separate Cp-value calculation for eac part. A visualization of te simplified model of te building can be seen below (Figure 9). FIGURE 9 - VISUALIZATION OF THE C P MODEL To visualize te results we made a polar grap per part and per façade. Tus we can easily see if te Cp-values meet te real situation. Also a visualization of te location of te points were te Cp-values were calculated per façade is added (Figures 3,3 and 3). Te points are numbered according to te façade its local coordinate system. Some similarities can be perceived on eac grap. For example te magnitude and te sign of eac Cp-value depend on te orientation of te façade and te presence of an obstacle in te direct surrounding of te façade. Te nort arrow as an angle of counter clockwise. Tis angle as not been taken into account in te Cp generator s output. Te inputs and outputs of te Cp Generator are added in Appendix A. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
4... RESULTS OF PART A FIGURE 3 - LOCATION OF THE PRESSURE POINTS IN PART A On Grap te result of te Cp-values for façade can be seen. It is oriented to te East. Te Cp points reac teir maximum value between and 5 degrees. In addition only between 8 and 8 tere are positive values, wic mean an overpressure on te wall. Everywere else tere are negative values or an under pressure. An extreme negative value is reaced by curves and on and by 4 and 5 between and 3. In te middle of te façade te igest value is reaced. Grap sows te results of te Cp-values for façade 4. Te façade as similar conditions but 8 turned. Te curves reac teir maximum value between 6 and 33. Tese values are wider spread possibly because of te absence of an obstacle in tis direction. Also te maximum values are smaller. 33 Part A - Facade,8,6,4 3 3, -, -,4 -,6 6 7 -,8 9 4 5 8 Facade Cp Facade Cp Facade Cp3 Facade Cp4 Facade Cp5 GRAPH - C P VALUES ON FAÇADE IN PART A Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
33 Part A - Facade 4,6,4, 3 3 -, -,4 -,6 6 7 -,8 9 4 5 8 Facade 4 Cp Facade 4 Cp Facade 4 Cp 3 GRAPH - C P VALUES ON FAÇADE 4 IN PART A Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
4... RESULTS OF ZONE B FIGURE 3 LOCATION OF C P-POINTS IN PART B 33 Part B - Facade,8,6,4, 3 3 -, -,4 -,6 6 7 -,8 9 4 5 8 Facade Cp Facade Cp Facade Cp3 GRAPH 3 - C P VALUES ON FAÇADE IN PART B Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 43
33 Part B - Facade,8,6,4, 3 3 -, -,4 -,6 6 7 -,8 9 4 5 Facade Cp 8 Facade Cp GRAPH 4 - C P VALUES ON FAÇADE IN PART B Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 44
4..3. RESULTS OF ZONE C FIGURE 3 - LOCATION OF C P-POINTS IN PART C Part C - Facade,8 33,6 3,4 3, 6 -, -,4 7 -,6 9 4 5 Facade Cp 8 Facade Cp Facade Cp3 GRAPH 5 - - C P VALUES ON FAÇADE IN PART C Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 45
7 3 33 Part C - Facade,4, -, -,4 -,6 -,8 - -, -,4 -,6 3 6 9 4 5 Facade Cp 8 Facade Cp GRAPH 6 - C P VALUES ON FAÇADE IN PART C 33 Part C - Facade 3,8,6 3,4 3, 6 -, -,4 7 -,6 9 4 5 Facade 3 Cp Facade 3 Cp8 Facade 3 Cp3 Facade 3 Cp3 GRAPH 7 - C P VALUES ON FAÇADE 3 IN PART C Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 46
4.3. THERMAL BRIDGE CALCULATION WITH THERM 7. We used te features of THERM to calculate te linear termal transmittance values, Ψ, of te termal bridges, wic are ten introduced into TRNSYS. Te tree kinds of outer slabs ave te same composition everywere in te building. We calculated tree termal bridges namely te connections of te vertical outer wall wit bot te floor and te roof slabs and te vertical wall wit te steel profiles. 4.3.. CALCULATION METHODOLOGY THERM was used to calculate te dimensional U-values of te termal bridges but also te U-values of te separate slabs were calculated. Te different steps for introducing and a termal bridge into THERM and calculating te dimensional U-value are: Drawing of te termal bridge wit a CAD based software program. Introduction of te CAD-file in THERM as an Underlay. Ten te contours can be overdrawn wit te polygon drawing tools of THERM. Putting te Gravity arrow in te rigt direction. Troug tis te program knows te direction and te sense of te eat flow. Definition of te different U-values tat ave to be calculated. For every termal bridge we calculated tree U-values, namely one for every slab separately and for te D U-value. Definition of te materials in Material definitions. Here te name, colour and conductivity (λ) value of eac material are introduced (Figure 33) and allocated to te rigt polygon. FIGURE 33 - MATERIAL DEFINITIONS IN THERM Definition of te Boundary Conditions of te outer borders of te termal bridge drawing (Figure 34). Te boundary conditions ensure tat defined borders surround te termal bridge. Tree different boundary conditions were used, namely: o Inside conditions ave a temperature of C and are allocated to all te inside borders of te termal bride. o Outside Conditions ave a temperature of C and are allocated to all te outside borders. o Adiabatic conditions are used to connect te outside and inside conditions and to close te cain of boundary conditions. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 47
FIGURE 34 - DEFINING BOUNDARY CONDITIONS IN THERM Connection of te boundary conditions to te different U-values tat need to be calculated wit Boundary Condition Type (Figure 35). Tis step makes te program clear over wic distance te termal bridge as to calculated by allocating a boundary condition to a specific U-value calculation. FIGURE 35 - BOUNDARY CONDITION TYPE IN THERM Calculation of te U-values. Depending on te orientation of te desire U-value te lengt over wic te U-value is calculated can be canged to Total Lengt, Projected X or Projected Y (Figure 36). FIGURE 36 - CALCULATED U-VALUES IN THERM Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 48
Wit te calculated dimensional U-values, te linear termal transmittance construction knots can be calculated for te connections between te outer wall en bot te floor and te roof. Te general formula for te linear termal transmittance, Ψ [W/mK], of a linear termal bridge separating te two environments being considered in defined as (Werkgroep PaTB, 9, p.) : Wit: ( ) ΦD: Te total eat flux tat is lost from te indoor environment, calculated on basis of a two-dimensional, validated numerical calculation [W]. Tis is te eat flux tat we want to calculate wit THERM. ΦD: Te total eat flux tat is lost from te indoor environment, calculated according to te reference. Te reference calculation of te eat transport is caracterized by te U-values Ui and surfaces Ai of te partitions of te losing surface, wic occur in te construction node. Te following applies: ( ). L: Te lengt over wic te construction node occurs. (θi θe): Te temperature difference between te indoor and outdoor environment. Tis formula can be simplified to become a value for te linear termal transmittance per meter: Wit : Is te total U-value of te dimensional construction node tat is calculated by THERM. : Te total lengt of te dimensional construction node over wic te total U-value is calculated. : Te product of te U-value and lengt of eac partitions of te losing surface, wic occur in te construction node. We also cecked te risk of condensation and terefore mold growt on te inner surface of te termal bridges. Te risk of mold formation compares te temperature drop across te building fabric, wit te total temperature drop between te inside and outside air. It is a critical calculation, as te consequences of condensation and mould growt are likely to be more serious for building occupiers tan any local eat loss. If low internal surface temperatures in te area of a termal bridge are below te dew point of te air, condensation is almost certain to form. Tis in turn is likely to result in structural integrity problems wit absorbent materials suc as insulation products or plasterboard and of even greater concern, te occurrence of mould growt. Tis risk is expressed by te temperature factor and as to be greater tan a minimum value, Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 49
wic depends on te purpose of te considered building. For office buildings te temperature factor as to be greater tan.5 (ttp://www.scoeck.co.uk/en_gb/press/te-surface-temperature-factor-frsi--434 ). Te formula for te temperature factor is: Wit: : Te minimum inside temperature of te evaluated surface. Te minimum temperature in tis case is te temperature in winter, tis way te worst situation is considered. Te outside temperature ( C) : Te inside temperature ( C) 4.3.. THE OUTER WALL WITH STEEL PROFILE Te section of te outside wall and te steel profiles can be seen on Figure 37. Te connection between te prefabricated wall panels and te steel profiles is clearly a termal bridge. Steel as a really bad termal conductivity value of 5 W/mK and te wood fibre layer, wic in tis building is te termal insulator, is interrupted. Te steel profiles are ollow so inside tere is stationary air, wic is a good insulator but te steel offsets tis effect. Te result of te calculation is presented wit infrared temperatures, wic can be seen on Figure 38. Te temperatures in te prefabricated panels evolve gradually, but te closer to te steel profiles te more te colours are deflected. Te inside surface temperatures of te steel profile is muc iger tan te one of te panels. Also conversely te outside surface steel temperature is muc iger tan te panel s temperature. Tis makes clear tat te termal steel profile inertia is muc smaller and terefore a poorly designed termal bridge. Tis termal bridge was calculated over a total lengt of,5m because tat s te centre-to-centre distance of te profiles. Terefore te result of THERM could be introduced into TRNSYS as te U-value of te outer wall per meter. Te overall eat transfer coefficient of tis wall is.946 W/m K. FIGURE 37 SECTION OF THE THERMAL BRIDE IN THE OUTER WALL Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
FIGURE 38 INFRARED TEMPERATURES IN OUTER WALL BY THERM Te lowest inside surface temperature is on te steel profile and amounts 6,5 C. Te temperature factor is: We can conclude tat tere is no big risk of mold growt on te vertical walls neverteless tis is a poorly designed termal bridge. 4.3.3. THE ROOF-WALL CONNECTION Te section of te connection between te roof slab and te wall can be seen on Figure 39. Te result of te calculation is presented wit infrared temperatures, wic can be seen on Figure 4. Te temperatures in te prefabricated panels as well as in te roof slab evolve gradually, but te closer to te corner te more te colours are deflected. Te inside corner temperature is muc iger tan on te oter inside surfaces. Te calculated U-values and te lengts to make te linear termal transmittance calculation are represented in Table 7 and Figure 4 respectively. Te Ψ-value amounts: Tis makes clear tat tis termal bridge is not tat poorly designed, knowing tat to be a good design te Ψ-value sould be around W/mK. For te connection te Ψ-value is still acceptable, but tere may not be forgotten tat te U-values for te two construction entities are quite ig. Te lowest inside surface temperature can be found in te corner and amounts 7.3 C. Te temperature factor is: We can conclude tat tere is no big risk of mold growt on te vertical walls neverteless tis is a poorly designed termal bridge. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
U-value [W/m K] Outer wall.46 Roof slab.4 Termal bridge (D).493 TABLE 7 - U-VALUES ROOF-WALL CONNECTION BY THERM m m FIGURE 39 SECTION ROOF-WALL CONNECTION THERMAL BRIDGE FIGURE 4 INFRARED TEMPERATURES IN ROOF-WALL CONNECTION BY THERM Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
4.3.4. THE FLOOR-WALL CONNECTION Te section of te connection between te floor slab and te wall can be seen on Figure 4. Te result of te calculation is presented wit infrared temperatures, wic can be seen on Figure 4. Te temperatures in te prefabricated panels as well as in te floor slab evolve gradually, but te closer to te corner te more te colours are deflected. Te inside corner temperature is muc iger tan on te oter inside surfaces. Te calculated U-values and te lengts to make te linear termal transmittance calculation are represented in Table 8 and Figure 4 respectively. Te Ψ-value amounts: Tis makes clear tat tis termal bridge is really poorly designed, knowing tat to be a good design te Ψ-value sould to be around.5 W/mK. Tis is mainly because te floor as a ig U-value wit no insulating layers of any kind. Tis leads to a ig dimensional U-value and terefor a poorly designed termal bridge. Te lowest inside surface temperature is on te steel profile and amounts 6 C. Te temperature factor is: We can conclude tat tere is no big risk of mold growt on te vertical walls neverteless tis is a poorly designed termal bridge. U-value [W/m K] Outer wall.46 Floor slab. Termal bridge (D).959 TABLE 8 - U-VALUES FLOOR-WALL CONNECTION BY THERM Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 53
m m FIGURE 4 - SECTION FLOOR-WALL CONNECTION THERMAL BRIDGE FIGURE 4 INFRARED TEMPERATURES IN FLOOR-WALL CONNECTION BY THERM Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 54
4.4. TRNSYS-FILE 4.4.. MODEL IN SKETCH-UP Google Sketc-Up is a computer program tat is used to draw buildings in 3D and tere is a connection wit TRNSYS to create a multi-zone building. Tere is a TRNSYS3d plugin were te file can be saved as an.idf file (Identification file), wic can be implemented in TRNSYS. Anoter way is by inserting te volumes by putting all te different surfaces off eac room directly into TRNSYS. Sketc-Up makes tis easier and gives a visual control. Te.idf -file is te file were te dimensions are saved. So first te building was drawn. Normally eac room as 3 different storeys: basement, te room and te ceiling. For eac volume, a new termal area ad to be made. We ad to define te surfaces wic are in contact wit a different termal zone. So if tere is a wall, ten te surfaces ave to be defined in bot directions. FIGURE 43 - TOOLBAR FOR TRNSYS3D IN SKETCH-UP Some problems occurred wen we tried to load te file into TRNSYS 7. Tat s wy only on storey was drawn. Later te basement and ceiling was inserted manually in TRNSBuild. FIGURE 44 - RESULT IN GOOGLE SKETCH-UP WITH THE SECRETARIAT IN BLUE In te secretariat termal zone tere are in fact no internal walls, but wen te.idf -file as to be introduced in TRNSYS, we ave to divide te secretariat into different termal zones. A Trnsys3d termal zone must be convex. Tis means tat te connecting line between every point in te zone to anoter point in te zone can t cross any surface of te zone (Figure 45). FIGURE 45 - CONVEX AND CONCAVE SURFACE Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 55
4.4.. INSERTING THE MODEL IN TRNSYS Wen tis.idf file is created, a new 3D Building Project (Multizone) type 56 can be created. Tis component models te termal beaviour of a building aving multiple termal zones. Te building description is read by tis component from a set of external files aving te extensions *.bui, *.bld, and *.trn. Te files can be generated based on user supplied information by running te pre-processor program called TRNBuild. (KLEIN S.A. et al, ) Wen te specific weaterdata and.idf file is selected, TRNSYS will make a standard system off types wic are combined wit several links. Tis system can be canged by using te types and creating equations. FIGURE 46 - SYSTEM OF TYPES AND LINKS FOR A MULTIZONE BUILDING Tte Multizone building (Loads and Structures )ad to be replaced into a multizone building wit AirFlow ( TRNFlow). Tis will give te possibility to know te eat flow in te different room/layers and windows. Te type for te weater data as to be canged as well. It I canged into type 99. Tis component serves te main purpose of reading weater data at regular time intervals from a data file, converting it to a desired system of units and processing te solar radiation data to obtain tilted surface radiation and angle of incidence for an arbitrary number of surfaces. (Klein S.A. et al,, p.) Te weater data tat we obtained will be supplemented wit te weater data of anoter weater station. Tey are joined togeter in a txt-file and as to be saved as an.99 file. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 56
4.4.3. ADJUSTMENTS IN TRNBUILD By rigt-clicking on te symbol of te TRNBuild file and coosing Edit Building, te building can be adjusted. Now te walls (tickness and materials), rooms, windows can be defined. Te ceiling and basement are defined in TRNBuild. But first te Geometry Modes of every volume ad to be canged to manual (witout 3D data) (Figure 47). 4.4.3.3. WALLS FIGURE 47 GEOMETRY MODES First te different kinds of materials ad to be defined in te Layer Type Manager (Figure 48). For eac material we need: Conductivity [kj/mk] Capacity [kj/kgk] Density [kg/m³] FIGURE 48 - LAYER TYPE MANAGER Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 57
After declaring every necessary layer, te different kind of walls could be defined. Tere are 5 different kinds off wall types: Adj_ceiling: te floor between te basement and te room Adj_ceiling : te ceiling between te room and te ext_roof Adj_wall: te wall between adjacent rooms Ground_floor: te floor between te basement and te soil Ext_roof: te ceiling between te top layer and te outside Tese walls ave to be introduced in te Wall Type Manager. Every different material/layer was added to te specific wall type in order from front/inside to back. Tis as its influence on te values of te Convective Heat Transfer Coefficient of te Wall. Position of wall and eat flow Vertical walls or >6 and orizontal eat flow Horizontal wall or <6 and flow going up Horizontal wall and flow going down Rse Rsi Rse Rsi [m²k/w] [m²k/w] [kj/m²k] [kj/m²k].4.3 9. 7.7.4. 9. 36..4.7 9..8 TABLE 9 - THERMAL RESISTANCE AT THE SURFACE IN CONTACT WITH EXTERNAL AIR To know exact composition for eac type off wall, see 3... FIGURE 49 - WALL TYPE MANAGER Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 58
4.4.3.4. THERMAL BRIDGES In EXT_WALL and EXT_ROOF te presence off several termal bridges needed to be added: Termal bridge of te columns (of steel) in te wall Termal bridge of te wall wit te roof Termal bridge of te wall wit te floor Tere are two ways to introduce tese canges in TRNBuild: Introduce te termal bridges by and in every Airnode Manager Calculate (wit anoter program: THERM 7., see ) te U-value and make a new layer. Tis layer will be introduced as te material in a new wall in Wall Type Manager. It is easier to introduce te termal bridges of te columns in te wall as a new layer/wall and te ones for te wall/floor and wall/roof manually in te airnodes. a) Introducing in airnode manager Every termal bridge needed to be introduced and TRNBuild will keep it in its library. FIGURE 5 - INSERTING A THERMAL BRIDGE MANUALLY Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 59
Wall/roof: o Ψ =.6 W/mK =.6 mk/kj o Rsi = 7.7 kj/m²k o Rse = 9 kj/m²k Wall/floor: o Ψ =.84 W/mK =.33 mk/kj o Rsi = 7.7 kj/m²k o Rse = 9 kj/m²k After adding te needed termal bridges, select te one necessary in eac airnode and define te total distance tis termal bridges as influence on. b) Introducing as a layer As calculated in paragrap 4.3. te U-value of te wall wit te termal bridge is:.946 W/m²K. So instead of using EXT_WALL, a new layer EXT_WALL_COLD is made in te Layer Type Manager wit following properties: Conductivity: Conductivity:.5 kj/mk Capacity:.56 kj/kgk Density: 76 kg/m³ U = / (Rsi + Rwall + Rse) wit Rsi =.3 m²k/w and Rse =.4 m²k/w Rwall =.344 m²k/w Rwall = d/ λ wit d =. m λ =.9 W/mK λ =.5 kj/mk To calculate te capacity and te density te weigted average is taken by using te tickness and properties of te used materials. Capacity = ( * + 8*.7 ) / =.56 kj/kgk Density = ( 8*5 + *8 ) / = 76 kg/m³ Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
4.4.3.5. HEATING In te Heating Type Manager te maximum temperature and te minimum umidity in a room can be defined. We set te maximum temperature to C and an unlimited umidity just to get started. FIGURE 5 - HEATING TYPE MANAGER 4.4.3.6. VENTILATION In te Ventilation Type Manager all te parameters (air cange rate, temperature of airflow and umidity of airflow), wic ave influence on te ventilation system are defined. Te air cange rate was set to.8 canges per our. FIGURE 5 - VENTILATION TYPE MANAGER Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
4.4.3.7. COOLING In te Cooling Type Manager te opportunity is given to cange te set temperature for a room, te control of te cooling power and if you want deumidication. We only set te temperature to 6 C. 4.4.3.8. WINDOWS FIGURE 53 - COOLING TYPE MANAGER Tere is te possibility to add different kinds of windows in Te Window Type Manager. Te actual windows in te building ave following properties: g-value (Solar factor ):.9 %/ U-value (Termal Transmittance): 5.68 W / m²k Single glass (6 mm) Stainless steel framework We took a window type tat was already in te WinID-library wit te following properties (Figure 54): g-value (Solar factor):.837 %/ U-value (Termal Transmittance): 5.73 W / m²k Single glass (6 mm) Stainless steel framework Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
FIGURE 54 - WINDOW TYPE MANAGER Table sows te areas of te windows in every office. Te location of every office can be found in Appendix B. OFFICE AREA [m²] OFFICE AREA [m²] Off 3 Off38 8.86 Off 9 Off 9. Off3 6 Off.945 Off4 9. Off3 3 Off5 8 Off4 5.6 Off6 9.6 Off5 6.4 Off7 8.9 Off6 8.68 Off8 8.86 Off7 9 Off3.6 Off8 9. Off33 6 Off9 Off34 4.6 Secr 5 Off35 8 Secr3 5 Off36 9.6 Co 8.5 Off37 8.9 Co3 3 TABLE - AREAS OF THE WINDOWS FOR EACH OFFICE Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 63
Te sading devices are on te outside of te windows. Tey used venetian blinds, as described in paragrap 3..5. Tey are very old and for most off tem it s impossible to cange teir angle. Tat is wy te angle was generalised for all te blinds and an average angle of 3 wit te orizontal was supposed. To insert tis in TRNSYS a new equation ad to be made in te Simulation Studio. Wen te zenit angle is, tere is a minimal sading on te window: Min_sad = 5*.5*sin(3 ) =.5 m.5m of m is saded, so tis makes 56.5% Te zenit angle alfa as to be known to know ow muc te wole window is saded. AB² = 5² + 5² - *5*5*cos(6 ) AB = 5cm 5² = 5² + 5² - *5*5*cos(3+alfa) alfa = 3 FIGURE 55 SKETCH FOR CALCULATING SHADING Tese numbers were inserted in te equation wit te value for no sading and for zero transmission. Sading = min( max( min_sad + z_angle/alfa*(-min_sad),), ) Te min and max is to avoid tat te number for sading is not more ten and less ten. After tis we ave to add te sading to every window in TRNBuild (Figure 56). Tis equation doesn t take te diffusion radiatioon in account and te sading doesn t depend on te azimut angle. FIGURE 56 ACTIVATING SHADING IN TRNBUILD Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 64
4.4.4. ADJUSTMENTS IN TRNFLOW Wen TRNFLOW is turned on in te main window, te defined TRNFLOW data is displayed and more links can be added to te airflow network. In te simulation te defined infiltrations, ventilations and links will be canged by te calculated airflows. FIGURE 57 - MAIN WINDOW OF TRNFLOW Te left part of te window of Figure 57 gives te opportunity to add or erase data of te airflow network. For adding a part of te network, te following as to be defined: Link type we will only use large opening and crack From node and to node we will only use external node and termal airnode 4.4.4.. LINK TYPE We use te large opening wen we connect te external airnode wit te inside troug a window and oter situations. Wen tis option in te window is selected, a new type of large opening can be created and te Large Opening Type Manager appears (Figure 58). Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 65
FIGURE 58 - LARGE OPENING TYPE MANAGER In Table different types of large openings are listed wit teir description, maximum widt and maximum eigt of te opening. Name Description Max. widt [m] Max. eigt [m] WI_CO_4_5 Opening corridor.5. 4-5 WI_CO_ Opening corridor 3 3 - WI_CO_4 Opening corridor.5 3-4 WI_CO3_ Opening corridor 3 3-3 WI_DOOR Opening door. WI_EXT Opening in.. external wall WI_SESCR_3 Opening between 7.46 3.5 secr -3 WI_SECR4_3 Opening between 3.5 3.5 secr 3-4 WI_SECR_ Opening between secr - 4.6 3.5 TABLE LIST WITH LARGE OPENINGS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 66
For te normal walls inside te building, te crack-type was used. Wen a crack is defined te air mass flow coefficient Cs and te airflow exponent n needs to be known. Te air mass flow coefficient is typical for different types of walls, based on its materials. Te exact value of tis coefficient is obtained by doing experiments. Tis wasn t possible, tat s wy te value of a plastered brick wall out of Table was used. TABLE - EXAMPLES OF MASS FLOW COEFFICIENT CS AND AIRFLOW EXPONENT N Te standard value of.65 for te airflow exponent is not canged because most cracks ave a mixed flow regime wit a flow exponent of.6 to.7. In Table 3, all different types of cracks are listed, eac wit tere name, lengt, eigt, Cs and n. We use. * ^(-5) as value for te air mass flow coefficient Cs. FIGURE 59 - CRACK TYPE MANAGER Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 67
NAME LENGTH HEIGHT Cs [kg*^(-4)/s at n [m] [m] Pa] CR_6M 6 3.5 4..65 CR_3_6 3.5 3.5.35.65 CR_3_6.95 3.5.65.65 CR_CO4_5 4.59 3.754.65 CR_5_4 4.59 3.5 3.3.65 CR_3_4.8 3.5.96.65 CR_CO5_3 3. 3.9.65 CR_CO_.5 3.9.65 CR_CO_SECR3 7.56 3 4.536.65 CR_3M 3 3.5..65 CR_3_SECR 4.7 3.5 3.97.65 CR SECR.93 3.5.35.65 CR 4.7 3.5.99.65 CR_RECR_ 3. 3.5.7.65 CR_CO3_LOBBY 4.46 3.676.65 TABLE 3 - LIST WITH ALL THE DIFFERENT CRACK-TYPES Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 68
4.4.4.. FROM-NODE TO TO-NODE Wen te airflow network is made, all te termal zones could be connected wit eac oter. If termal zones, wic are adjacent wit outside, are made ten tey are connected wit te external node. Never forget tat only connected network can be defined. Te direction of te from-node to te to-node is defined as te positive flow direction. First te Termal Airnode as to be defined. Te reference eigt measured from ground plane to te top edge of te floor, te airnode eigt (inside) and te airnode dept (inside) as to be inserted. Last-mentioned is te distance from te external wall to te opposite internal wall (Figure 6). FIGURE 6 - THERMAL AIRNODE MANAGER Te reference eigt measured from plane to te top edge of te floor, te eigt of link relatively to From-node and te eigt of link relatively to To-node are.75m in every case. We ave to use te Cp values obtained in paragrap 4., wen we ave to connect a termal zone wit an external zone. Tey are added in te External Node Manager, were all te different necessary external nodes are made. Te reference eigt of te Cp values is m75 as well. No valid result was obtained wen te ceiling and te basement were connected wit te rooms. It is not possible to connect tem wit large openings because te link eigt ave to be te same (KLEIN S.A. et al, ). Te results wit te cracks or wit ducts gave bad results as well. Tis is because te ceiling and basement are big zones for te wole model. In reallity ter are sometimes separating walls and ducts in te ceiling and basement. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 69
FIGURE 6 - EXTERNAL NODE MANAGER In Table 4 all te external nodes and teir Cp values (per 9 ) for eac office its external wall are sown. To see te location of te offices, see Appendix B. OFFICE NAME 9 8 7 EN_8.458 -.4 -.83 -.395 EN_9.66..77.358 3 EN_.66.98 -.36 -.9 4 EN_ -.764 -.97 -.9 -. 5 EN_ -.797 -.94 -.67 -.6 6 EN_4 -.43 -.95.49. 7 EN_5 -.94 -.344.46 -.47 8 EN_6 -.8 -.4.56 -.88 9 EN_7 -.683 -.46 -.68 -. EN_.63 -.38 -.8.443 EN_.63 -.38 -.8.443 3 EN_ -.56 -. -.388.533 4 EN_ -.56 -. -.388.533 5 EN_ -.56 -. -.388.533 6 EN_ -.56 -. -.388.533 7 EN_ -.39 -.3 -.54.54 8 EN_3 -.39 -.3 -.54.54 3 EN_7 -.647 -.79 -.49 -.6 33 EN_7 -.647 -.79 -.49 -.6 34 EN_8 -.438 -. -.55 -.63 35 EN_9 -.359 -.4 -.65 -.6 36 EN_ -.93.36 -.9 -.69 37 EN_ -.93.36 -.9 -.69 38 EN_ -.5.8 -.9 -.66 SECR_ EN_4 -.48.74 -.94 -.83 SECR_3 EN_3 -.47.78 -.47 -.78 CO EN_5 -.9 -.465.48 -.4 CO3 EN_6 -.93 -.36.35 -.74 TABLE 4 - LIST WITH CP-VALUES Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
4.4.5. MODIFICATIONS TO THE MODEL TO ACHIEVE A PASSIVE HOUSE We will make some canges to te model to acieve te goal of developing a passive ouse. Te modifications tat are made: Insulation in te walls, roof and floor Different angle for sading devices Different types of windows and framework Infiltration Ventilation Internal gains 4.4.5.. WALLS, ROOF AND FLOOR Depending on te results of te initial model, some canges are made to te compositions of te walls, roof and floor. Te insulation is added to te structure in steps from 3cm, 6cm and 9cm. Afterwards conclusions are drawn wic improvements are te best to accomplis te conditions for a passive ouse. Te used insulation is PUR (RECTICEL EUROWALL): Conductivity =.88 kj/mk Capacity =.4 kj/kgk Density = 3 kg/m³ Te position of te insulation in te roof is between te stones and te waterproofing. Te position of te insulation in te floor is between te concrete and te dry concrete. 4.4.5.. WINDOWS AND SHADING Te windows are canged to see wic influence tey ave on te eating and cooling demand for te secretariat. A different type of glass and framework is used. Te influence of te angle of te blinds on te energy demand is analyzed as well. Te analyzed angles, teir percent of minimal sading and angle for maximal sading are presented in Table 5. Tese numbers are te values used in te equation in te simulation studio tat is connected wit te TRNBuild file for te sading on te windows. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
Angle from te blinds [ ] Minimal sading area [%] Angle maximum sading [ ].5 45 3 56.5 3 45 79.55.5 6 97.43 5 4.4.5.3. INFILTRATION TABLE 5 ANALYZED ANGLES AND SHADES Te influence of te infiltration can be obtained in different ways in TRNSYS. One way is by introducing a fixed air cange rate and activate tis in every room of te building. Te strategy we used is by using TRNFlow. Te area were te air flows troug (leakage) can be calculated wit following formula: Wit: Q te airflow troug te opening Cd te discarge coefficient of te opening ρ te density of air Δp air pressure difference between outside and inside Te only unknown parameter is Q [m³/s] and is calculated by multiplying te volume of te secretariat by te considered air cange rate. Te results for tis calculation are presented in Table 6 area for openings depending ons air cange rate. Square openings are assumed, so te maximum eigt and widt of te opening is te square root of te area. Air cange rate [ - ] Area [m²] Max. eigt/widt in TRNFLOW [m].45.6439 4.66.47.6.5.577 original.. TABLE 6 AREA FOR OPENINGS DEPENDING ONS AIR CHANGE RATE Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
4.4.5.4. VENTILATION A new system of ventilation is introduced tat uses passive ventilation to cool and refres our building. Te ventilation is activated wen certain conditions are obtained. Wen te ventilation is working, te cooling is inactive. Conditions for ventilation: Tis system works only during te summer and can be active on every moment of te day. Te system is only activate wen te outside temperature is less tan 5 C. Te temperature outside as to be lower tan te temperature inside. Tis way te building is cooled down mostly by te nigt. Tis system is introduced in TRNFlow. Te large openings are becoming bigger wen te ventilation is on. Tat is wy te large openings ave to be controlled by an inputformula. Wen te ventilation is not working, te normal infiltration is active. Wen it is active, a bigger opening is obtained. To accomplis tis, an opening (wen it is completely open) of m² for every type of infiltration is considered. Te input-formula is based on te percentage of te leak area (depending on te infiltration) to te total of m². FIGURE 6 INPUT FORMULA Te rigt part is for te present infiltration and wen VENT_ON ( output from equation) is (ventilation active) te wole large opening is open. Following table contains te percentage of te m² depending on te infiltration rate: Infiltration rate [ - ] Percentage for infiltration [%] Percentage for total opening [%].73 79.7 4 8.9 9.7.6.45 98.755.4 (original).5 99.5 4.4.5.5. INTERNAL GAINS TABLE 7 PERCENTAGES FOR VENTILATION/INFILTRATION Te ligts were originally set on 55W/m². Te difference will be compared for 9 and W/m². Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 73
5. RESULTS 5.. RESULTS OF THE MEASUREMENTS Te analyzed measurements are te weaterdata obtained by te Watcdog weaterstation and te secretariat s inside air temperatures obtained by te Testo eat sensors. Tere ave also been made some combinations of parameters to watc teir mutual influence. Te measurements were taken during a period were te temperatures are quite moderate, so no extreme conditions were determined. Tereby we cannot take any determinations for te wole year or every season. But analysing tese measurements is important to understand te beaviour of te different parameters over time and teir influence on te air conditions in buildings. 5... ANALYSIS OF THE OUTSIDE WEATHER DATA Te weaterstation was located on te roof of te secretariat and collected te temperature, te umidity, te solar irradiation, te wind speed, wind gusts and wind direction and te rainfall and te dew point. Te outside weaterdata were collected every minutes starting from t of marc on 3: until 4 t of april on :. Tese parameters are used as input for te TRNSYS model. Tey are an important basis to compare te inside temperatures wit. 5... TEMPERATURE Te outside temperatures for te measuring period are presented on Grap 8. Te mainly difference between minima and maxima are around 5 C. Te maxima differ from less tan 5 C to more tan 5 C. Te minima ave a smaller dispersion from around 7 C to 5 C. 3 5 5 5 Outside Temperature ( C) GRAPH 8 - MEASURED OUTSIDE TEMPERATURE Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 74
5... HUMIDITY Te relative umidity of te outside air is presented on Grap 9. A wide spread over time can be determined. 9 8 7 6 5 4 3 Relative Humidity (%) GRAPH 9 - MEASURED OUTSIDE RELATIVE HUMIDITY 5...3. SOLAR IRRADIANCE Te solar irradiance is defined as te solar radiation energy per unit area. Te unit is W/m. Te outside temperatures as well as te surface temperatures are igly influenced by te solar irradiance. Terefore it as a big influence on te eating and cooling demand. Te solar irradiance received by te weater station during te wole measuring period is presented on Grap and Grap. Te different days can be clearly seen and are divided by pieces wit irradiance, wic represent te nigts. Te time data on te x-axis ave been left out to keep te grap clear. Te average daily maximum value for a sunny day is around 8 W/m of solar irradiance. Tere are also very cloudy days, represented on peaks and, wit almost no sun reacing te eart s surface. Still tese days ave a solar irradiance peak of more tan W/m. Te peak value is reaced on te 6 t of Marc. Also can be concluded tat te weater station doesn t ave any sade from surrounding buildings. Tis would lead to a daily relapse of te solar irradiance at te same time. Tis is not te case in tis grap. To view te solar irradiance on different parts of te day, a magnification of 3 days was made on Grap. On tis grap te influence of clouds can be seen very clearly. Clouds can cause a differentiation of te solar irradiance from a few units to more tan 6 W/m. Te 7 t of Marc seems to be very sunny day until around 3 p.m. Sunrise can be determined at around 5 a.m. and te sun directly reaces te device at Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 75
7:3 a.m., wen te grap raises sarply. Around 4:3 p.m. te sun sets to become nigt one our later at around 5:3 p.m. 8 6 4 Solar irradiance (W/m) GRAPH - MEASURED SOLAR IRRADIANCE OUTSIDE 8 6 4 4 8 6 4 8 6 4 8 6 6/3/4 7/3/4 8/3/4 GRAPH - ZOOM OF MEASURED SOLAR IRRADIANCE OUTSIDE 5...4. WIND Te wind measurements ave been converted to relative values to make a proper analysing of te data. Te data ave been simplified into direction interval wit a range of 5 degree (so to 5, 6 to 3 ) to make it clearer. Also data wit only a wind direction and km/ for wind speed and gusts ave been deleted, because wen tere is no wind, te wind doesn t ave a direction. Te result of tis calculation can be seen on Grap. Te wind direction correlation means ow many times te wind came from a certain direction in comparison wit te oter directions. Te average wind speeds and gusts are te average speeds per interval. Te wind gusts are clearly a lot bigger tan te normal wind speeds, te iger te wind gust te bigger te difference between speed and gust speed. Te wind speed as nearly te same sape as te wind gusts. Te grap determines te directions wit te igest wind Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 76
speeds, wic are souteast and between sout and soutwest. Te most directions tat are most frequent are norteast and to a lesser extent soutwest. So te most frequent direction is te one wit low wind speeds from te norteast. Te wind is influenced a lot by te different obstacles. And because we ave a ig building in te close vicinity of te secretariat tese values are really specific for tis location. 345 5 5 33 3 35 45 3 5 6 85 5 75 7 9 55 5 4 5 35 5 95 8 65 Wind direction distribution (%) Wind gusts (km/) Wind speed (km/) GRAPH - MEASURED OUTSIDE WIND DATA 5...5. COMPARISON OF TEMPERATURE AND SOLAR IRRADIANCE Te influence of te solar irradiation on te outside temperatures can be determined on Grap 3 and more in detail on Grap 4. Tese two parameters are directly related to eac oter. Wen tere is a lot of solar irradiation reacing te eart s surface we can determine iger temperatures and vice versa. So wen tere is sun, it s warm. Wen tere are a lot of clouds, and tereby little solar irradiance te outside temperatures are lower. On te oter and tere are some days wit iger value of solar irradiance tan oters but don t ave a iger temperature. Tis contradicts wit our previous determination. Tis can be caused by te time wen te maximum solar irradiance appears and ow long te ig solar irradiance is maintained. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 77
3 5 8 5 6 4 5 Outside temperature ( C) Solar irradiance (W/m) GRAPH 3 - COMPARISON OUTSIDE TEMPERATURE-SOLAR IRRADIATION 3 5 8 5 6 4 5 4 8 6 4 8 6 4 8 6 4 8 6 /3/4 /3/4 /3/4 3/3/4 GRAPH 4 - ZOOM OUTSIDE TEMPERATURE-SOLAR IRRADIATION 5...6. COMPARISON OF TEMPERATURE AND HUMIDITY Te combination of outside temperature and relative umidity are presented on Grap 5 and more in detail for four consecutive days on Grap 6. A reversed relation can be determined between te two parameters. Wen temperatures peak during day umidity rates reac teir minima and vice versa. We can see a clear difference between days wen it was probably raining or treatening to rain wit lower temperatures, and brigt days wit iger temperatures and low umidity rates. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 78
3 5 5 5 Outside temperature ( C) Relative umidity (%) 9 8 7 6 5 4 3 GRAPH 5 - COMPARISON OUTSIDE TEMPERATURE-RELATIVE HUMIDITY 5 5 5 4 8 6 4 8 6 4 8 6 4 8 6 9 8 7 6 5 4 3 6/3/4 7/3/4 8/3/4 9/3/4 GRAPH 6 - ZOOM OUTSIDE TEMPERATURE-REALTIVE HUMIDITY Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 79
5... ANALYSIS OF THE INSIDE MEASUREMENTS Te inside temperatures and umidity rates were measured over a period of one mot. Tese measurements are important to evaluate te level of air comfort in te secretariat. Unfortunately we ad some setbacks wit obtaining te measurements from te eat sensors. Te sensors ad to collect temperatures 4 ours a day and terefore te batteries of te only lasted for maximum tree days. Togeter wit te opening ours of te secretariat tat ad to be respected and te malfunctioning of te sensors sometimes, te final result is rater poor. Tere are a lot of dateless gaps in te graps. Neverteless we tried to analyse and compare te measurements as good as possible by only plotting te periods were every parameter is known. We obtained measurements of te termal sensors for 4 separate periods: /3/ (:4) 3/3/4 (:) 7/3/4 (4:) /3/4 (:) 4/3/4 (3:) 5/3/4 (8:) 7/3/4 (5:) 3/3/4 (:4) 5... TEMPERATURE Te curves of te room temperature and te temperature in te false ceiling are presented in four graps representing te consecutive periods of data collection (Grap 7,8,9 and ). Tere can be seen a clear difference between te periods wen te eating devices are switced on and off during daytime, wic are during weekends (9 t and 3 t of Marc) and olidays (7 t,8 t and 9 t of Marc). Te reaced temperatures are muc lower wen devices are switced of. Also te slopes of te temperature curves are muc smaller. Te temperature curves are similar to eac oter. Te ceiling temperatures are mostly lower tan te inside temperatures. Tis is probably because te room as a more direct effect of te eating devices. Also te eat is faster lost troug te roof slab, wic as a big surface, causing lower minima in te ceiling. Te ceiling temperature curve reaces its minimum always one or two ours before te temperature in te secretariat. Tis wasn t expected, because te curves ave a very similar progression wen te eating devices are switced. Tis difference in minimum temperatures can also be ascribed to te iger influence of te outside temperature and te solar irradiance on te ceiling temperature. Te inside temperature curve peaks always at around 6 during working days. Tis makes us suspect tat te time during wic te eating devices are switced on muc sorter tan assumed. Te secretary is eated during working oures wic are from 8 a.m. until 8 p.m. But if we look to te temperature curves, we can see tat tis is probably not te case. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
5 5 6 4 8 /3/4 /3/4 3/3/4 Inside temperature ( C) 6 Inside ceiling temperature ( C) GRAPH 7 TEMPERATURES MEASURED BETWEEN -3/3 5 5 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 /3/4 /3/4 3 GRAPH 8 TEMPERATURES MEASURED BETWEEN 7-/3 5 5 3 6 4 8 6 8 4/3/4 5/3/4 GRAPH 9 TEMPERATURES MEASURED BETWEEN 4-5/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
5 5 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 3/3/4 3/3 /4 5... HUMIDITY RATES GRAPH TEMPERATURES MEASURED BETWEEN 7-3/3 Te curves of te relative umidity in te room and te false ceiling are presented in four graps representing te consecutive periods of data collection (Grap, Grap, Grap 3 and Grap 4). Te umidity rate in te working area is always lower tan te umidity rate in te false ceiling. Tis can be related wit te absence of ventilation in te false ceiling. Te air is not refresed tat fast, so te umid air is less fast drained. Te amounts of relative umidity differ a lot from day till day. 7 6 5 4 3 6 4 8 /3/4 /3/4 3/3/4 Inside relative umidity (%) Inside ceiling relative umidity (%) 6 GRAPH - MEASURED INSIDE RELATIVE HUMIDITY -3/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
7 6 5 4 3 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 /3/4 /3/4 GRAPH - MEASURED INSIDE HUMIDITY 7-/3 5 4 3 3 6 4 8 6 8 4/3/4 5/3/4 GRAPH 3 - MEASURED INSIDE HUMIDITY 4-5/3 9 8 7 6 5 4 3 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 3/3/4 3/3 /4 GRAPH 4 - MEASURED INSIDE HUMIDITY 7-3/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 83
5...3. COMPARISON OF TEMPERATURE AND HUMIDITY RATE IN THE SECRETARIAT Comparing te temperatures and te umidity rates in te secretariat (Grap 5, Grap 6, Grap 7 and Grap 8) we can see some similarities wit Grap 5. During te day wen temperatures are iger, te umidity is lower and vice versa. Tere can also be seen a clear difference between working days and weekends or olidays, because during tese last ones te air conditioning devices are switced of. It can be clearly seen tat umidity rates are muc iger wen ventilation is switced of. 5 6 5 4 5 3 6 4 8 /3/4 /3/4 3/3/4 Inside temperature ( C) Inside relative umidity (%) 6 GRAPH 5 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY -3/3 5 7 6 5 4 3 5 6 4 8 6 4 8 7/3/4 8/3/4 9/3/4 /3/4 /3/4 6 4 8 6 GRAPH 6 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY 7-/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 84
3 5 5 4 3 5 3 6 4 8 6 8 4/3/4 5/3/4 GRAPH 7 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY 4-5/3 5 8 7 6 5 4 3 5 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 3/3/4 3/3 /4 GRAPH 8 - COMPARISON INSIDE TEMPERATURE-RELATIVE HUMIDITY 7-3/3 5...4. TEMPERATURES AND HUMIDITY RATES OF FALSE CEILING Te comparison of temperatures and umidity rates in te false ceiling are similar to te paragrap te previous paragraps and terefore not added to te paper. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 85
5..3. COMPARING INSIDE AND OUTSIDE MEASUREMENTS 5..3.. TEMPERATURES AND SOLAR IRRADIANCE Te measured in- and outside temperatures are compared and presented in Grap 9,grap 3, grap 3 and Fout! Verwijzingsbron niet gevonden.tere can be made a difference between working days and weekends or olidays. During weekends or olidays te inside temperatures depend muc more on te outside weater conditions. On warm, sunny days comfortable inside temperatures are reaced and te difference between outside and inside maxima is small. On colder, cloudy days te inside temperatures are more levelled. If we compare a oliday (9 t ) and a working day ( t ) wit similar outside temperatures next to te obvious difference in inside temperatures te difference in te slope of te curves in te beginning and te end of te day indicates te beginning and ending of te period during wic te eating is switced on. During working ours, te inside temperatures are more independent from te outside weater conditions. Te temperatures are kept iger tan C. Tere is never any risk of overeating during te measuring period. Taking into account te period of collecting te measurements tis is quite normal, but tis is certainly not te case te wole year round. 5 8 7 6 5 5 4 3 5 6 4 8 /3/4 /3/4 3/3/4 6 Inside temperature ( C) Outside temperature ( C) Inside ceiling temperature ( C) Solar irradiance (W/m) GRAPH 9 COMPARISON TEMPERTURES-SOLAR IRRADIANCE -3/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 86
5 9 8 7 6 5 5 4 3 5 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 /3/4 /3/4 GRAPH 3 COMPARISON TEMPERATURES-SOLAR IRRADIANCE 7-/3 3 9 5 8 7 6 5 5 4 3 5 3 6 4 8 6 8 4/3/4 5/3/4 GRAPH 3 COMPARISON TEMPERATURES-SOLAR IRRADIANCE 4-5/3 5 9 8 7 6 5 5 4 3 5 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 3/3/4 3/ 3/4 GRAPH 3 COMPARISON TEMPERATURES-SOLAR IRRADIANCE 7-3/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 87
5..3.. HUMIDITY RATES Te in- and outside umidity rates are compared and presented on Grap 33, Grap 34, Grap 35 and Grap 36. Te inside umidity rates is te secretariat and te false ceiling follow approximately te same pat. During a big part of te data-collecting period te outside umidity rates are rater ig. On Grap 33 and Grap 34 tere can be seen two contradictory periods. On te first grap te outside umidity stays ig during several days, tis can also be seen on Grap 36. On te second grap te outside umidity meats te inside umidity rates during daytime. Tis as someting to do wit te time during wic it was raining. Tere can be concluded tat during weekends or olidays te inside umidity rates follow te outside umidity rates wit ceiling umidity can mount up iger tan te secretariat s umidity rate. During working days on te oter and te inside umidity rates are kept witin bounds by te air conditioning. 9 8 7 6 5 4 3 6 4 8 6 /3/4 /3/4 3/3/4 Inside relative umidity (%) Inside ceiling relative umidity (%) Outside relative umidity (%) GRAPH 33 COMPARISON INSIDE-OUTSIDE HUMIDITY RATES -3/3 9 8 7 6 5 4 3 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 /3/4 /3/4 GRAPH 34 - COMPARISON INSIDE-OUTSIDE HUMIDITY RATES 7-/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 88
6 5 4 3 3 6 4 8 6 8 4/3/4 5/3/4 GRAPH 35 - COMPARISON INSIDE-OUTSIDE HUMIDITY RATES 4-5/3 9 8 7 6 5 4 3 6 4 8 6 4 8 6 4 8 6 7/3/4 8/3/4 9/3/4 3/3/4 3/ 3/4 GRAPH 36 - COMPARISON INSIDE-OUTSIDE HUMIDITY RATES 7-3/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 89
5..4. CONCLUSION By tis making tis comparison it as become clear tat te outside weater conditions ave influence on te inside air conditions. But it s not tat simple, because a lot of different parameters ave to be considered to make a conclusion. A general conclusion cannot be made, but it can be separated into working days and weekends or olidays. During working days te inside temperatures and umidity rates are less independent from te outside parameters. Tis is due to te air conditioning devices inside. During olidays and weekends te opposite is determined. Te weater data are taken in a mont wit very moderate conditions. It would ave been better to measure extreme weater conditions during winter and summer. Tey ave te biggest influence on te energy demand of te building. Hot temperatures to determine te amount over overeating and tereby te effect on te cooling demand and on te oter and cold temperatures to determine te effect on te eating demand. Unfortunately our time scope was too small to do so. Neverteless some insigts were created to understand te mutual influences of te different parameters. Lastly, tere no information known about te low basement between te ground and te floor slab. It may ave been a good idea to put a eat sensor tere as well. 5.. VALIDATING THE TRNSYS MODEL Te TRNSYS model as to be cecked on its correctness and precision of te outputs before making modifications or improvements. Te model s accurateness can be revised by comparing te measured inside temperatures wit te output temperatures from TRNSYS. Also te energy demand of te model is analysed. 5... COMPARING TEMPERATURE MEASUREMENTS WITH OUTPUTS TRNSYS Te inside temperature measurements are very important parameters for te validation of te TRNSYS model. Tey are te connection between reality and te virtual air conditions created in te model. To compare tem, te output of TRNSYS as to be fitted to te measured data. We obtained te secretariat s temperature measurements for 5 separate periods: /3/ (:4) 3/3/4 (:) 7/3/4 (4:) /3/4 (:) 4/3/4 (3:) 5/3/4 (8:) 7/3/4 (5:) 3/3/4 (:4) 3/3/4 (3:3) 4/4/4 (:4) (no ceiling temperature) First of all te minimum and maximum temperature in te room (during a workday) ad to be cecked. Te initial set temperature of te eating and cooling ad to be te same as te one in reality. Te set temperature in reality was around C for te eating. Tis corresponds wit te initial estimated value in TRNSYS. It s more difficult to ceck te set temperature of te cooling. Te maximum temperatures inside te secretariat Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
were never reaced like in summer. But te initial temperature of 5 C tat we supposed in TRNSYS was never exceeded, so tis value could be retained. A problem occurred wile designing te connection between te suspended ceiling and te room. Wen te airflow connections were made, te temperatures were not following te measured ones. Tat s wy eating and cooling in te ceiling was introduced to obtain a similar curve for tese temperatures. In reality te temperature curves of te ceiling and room are close to eac oter. So by conditioning te ceiling te influence of te ceiling can be minimalized, but not equalized. Te big difference is tat te temperature raise caused by te eat gains doesn t ave influence on te temperatures in ceiling. As result we ave a temperature curve of te ceiling te follows te temperature in te secretariat but witout te irregular sape. 5... COMPARISON OF THE INSIDE TEMPERATURES On te following graps te measured inside temperature curve is compared wit te temperature curve tat is given by TRNSYS (Grap 37, Grap 38, Grap 39, Grap 4 and Grap 4). Te difference in volatility between te two curves immediately stands out. Tis is because te TRNSYS model is a computer simulation, wic is not te same as real time data collection. Te curve of te TRNSYS model follows te inside temperatures rougly. Differences can be determined in te time and values of te peaks and trougts. Te difference in te values are acceptable never exceeding C and te amplitude of te curves is largely te same. Between te ours 85 and 875 tere is a big difference, tis is because tese were olidays and are not taken into account by TRNSYS. Te time difference between peaks and trougts is a more difficult issue to understand. We see tat te eating periods of te TRNSYS curve starts earlier and continues longer. Tis confirms te insecurity about te time during wic te eating devices are switced on in reality. For TRNSYS te temperatures during a working day ave to be between C and 6 C. Tis is a big difference wit te real temperature data. Te slope of te temperature curves are different as well. Tis can be due to te absence of some issues in te TRNSYS model. First of all we ave te two extra air eating and cooling devices and te electrical eaters in te secretariat tat aven t been taken into account in te model. Also we ave to keep in mind tat in reality te furniture olds an amount of eat. So te room reaces te requested temperature faster, due to tis extra eat load. TRNSYS assumes and empty secretariat wit te only eating gains are te internal and internal eating gains wic we put in. Moreover, in reality tere can be more or less persons present or more or less computers and ligts switced on. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
5 3 9 7 5 665 67 675 68 685 69 695 7 75 7 Measured inside temperature ( C) Measured inside ceiling temperature ( C) TRNSYS Average inside temperature ( C) GRAPH 37 COMPARISON INSIDE TEMPERATURES -3/3 6 4 8 6 8 8 83 84 85 86 87 88 89 9 GRAPH 38 - COMPARISON INSIDE TEMPERATURES 7-/3 6 4 8 6 98 987 99 997 7 GRAPH 39 - COMPARISON INSIDE TEMPERATURES 4-5/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
6 4 8 6 4 5 6 7 8 9 3 4 5 GRAPH 4 COMPARISON INSIDE TEMPERATURES 7-3/3 6 4 8 6 5 6 7 8 9 3 4 5 GRAPH 4 COMPARISON INSIDE TEMPERATURES 3/3-4/4 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 93
5... COMPARING INSIDE AND OUTSIDE TEMPERATURE If te TRNSYS output temperature is compared wit te outside temperature (Grap 4, Grap 43, Grap 44, Grap 45 and Grap 46) we can determine some similarities and some differences wit te measured inside temperatures. During working days, wen te conditioning devices are switced on, tere can be no real influence on te inside temperature determined. Tis is in line wit te measurements. On te oter and during weekends te outside weater conditions don t ave an influence on te inside temperature. Tis different from reality were inside temperatures are evolving wit te outside ones. Tis makes us believe tat tere are some differences in te performance of te structural elements and te pysical aspects of te building and te TRNSYS model. As tere are for example te eat, air and solar transfer troug te termal envelope of te building. A lot of tese parameters were made on assumptions because of te lack te real data. 5,, 5,, 5, 665, 67, 675, 68, 685, 69, 695, 7, 75, 7, TRNSYS Average inside temperature ( C) Measured outside temperature ( C) GRAPH 4 COMPARISON OUTSIDE TRNSYS TEMPERATURE -3/3 5,, 5,, 5, 8, 8, 83, 84, 85, 86, 87, 88, 89, 9, GRAPH 43 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 7-/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 94
3, 5,, 5,, 98, 987, 99, 997,, 7,, GRAPH 44 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 4-5/3 5,, 5,, 5, 5, 6, 7, 8, 9,,,, 3, 4, 5, GRAPH 45 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 7-3/3 Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 95
3, 5,, 5,, 5, 6, 7, 8, 9,,,, 3, 4, 5, GRAPH 46 - COMPARISON OUTSIDE TRNSYS TEMPERATURE 3/3-4/4 5...3. CONCLUSION We conclude tat te output of TRNSYS is acceptable considering te big amount of assumption tat ad to be made. Tis model could of course be finetuned to ave an even better correspondence wit te real situation. Unfortunatly tis exceeds our knowledge about TRNSYS and about te building. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 96
5... ANALYZING THE ENERGY DEMAND To obtain te total annual cooling and etaing demand of te secretariat te simulation is runned for one year. Te results of te calculation are presented in Table 8 and in Grap 47 and Grap 48, wic present te montly and annual total eating demands respectively. Te first conclusion is tat te energy demand for cooling is muc bigger tan te energy demand for eating. Also during one year tere are 6 monts wen cooling is needed and 7 monts were eating is needed. Te total energy demand for te secretariat is 43. kw/m for one year. Tis value is very small and muc smaller tan expected. It was expected tat te cooling demand would be bigger tan te eating demand, because of te Mediterrenean climate wit mild winters and ot summers but was not expected to be tat low. If we compare wit te main total annual energy demand for Valencia tat amounts around 45 kw/m² according to Boletin Oficial de Estado for Valencia. (ttp://www.boe.es/boe/dias/3/9//pdfs/boe-a- 3-95.pdf, p.9). But tis building is very old and as poor termal envelope conditions, so te energy demand was expected to be even iger tan tis value. On te oter and it as to be meantioned tat tis is te energy demand for te secretariat alone. Because te secretariat is surrounded by areas tat are conditioned as well and tere is only contact wit outside over a small piece of wall, tis energy demand as to be put in perspective. Obtaining te energy demand for te wole termal zone, would be a good way to watc if tis value is acceptable. Unfortunately we were not capable to calculate tis value due to errors we couldn t resolve. Classifying tis result as good or bad is really ard because we can t compare it wit any previous studies. Tere ad to be made a lot of assumptions tat could cause a big difference in te secretariat s energy demand tat we were unable to define properly. Tis result as to be considered and put more into perspective in te follow-up of tis paper wen modifying te building caracteristics. QHEAT_TOT[kW/(m²a)] QCOOL_TOT [kw/(m²a)] January,54, February,963, Marc,53, April,, May,,355 June, 4,845 July,,478 August, 9,64 September, 4,67 October,7,538 November,5, December,76, Total year 4,33 9,9 Global energy demand: 34. [kw/(m²a)] TABLE 8 PRESENT ENERGY DEMANDS MONTHLY AND ANNUAL Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 97
8 6 QHEAT_TOT[kW/(m²a)] QCOOL_TOT [kw/(m²a)] 4,, 3, 4, 5, 6, 7, 8, 9,,,, GRAPH 47 - PRESENT MONTHLY HEATING AND COOLING DEMAND 4, 35, 3, 5,, 5, QHEAT_TOT [kw/m² annual] QCOOL_TOT [kw/m² annual] QTOT [kw/m² annual], 5,, QHEAT_TOT [kw/m² annual] QCOOL_TOT [kw/m² annual] QTOT [kw/m² annual] GRAPH 48 - PRESENT ANNUAL ENERGY DEMANDS To meet te passive ouse standard te requirements for energy demand ave to be fullfilled by te building. Te standard requires eating and cooling demands to be 5 kw/(m²a) or less. Te secretariat s eating demand meets te objective, but te cooling demand doesn t meet te target value. Te eating demand doesn t ave to be reduced to meet te passive ouse standard, but some modifications are still made to evaluate teir effect on bot te cooling and eating demand. Also te modifications can effect te oter rooms wic can in teir turn ave an effect on te secretariat. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 98
It was impossible to know if te primary energy demands is kw/(m²a) or less. Tere was not enoug information about te macines used in tis zone to calculate tis value. Tere is no ot water in te building and tere is no specific data about te eating, cooling and extra electrical devices. So witout knowing te energy needed to obtain te 5 kw/(m²a) for cooling and eating, it is impossible to compare tem. 5.3. MODIFICATION OF THE BUILDING Modifications are done to te secretariat s building components to decrease te energy demand. Te modifications are all implemented and analysed separately to see teir individual influence on te energy demand. 5.3.. MODIFICATION OF THE THERMAL INSULATION 5.3... WALL INSULATION Te effect of improving te U-value of te outer wall on te energy demand of te secretary by adding different ticknesses of insulation is analysed and represented in Table 9 and in Grap 49 and Grap 5. Te secretariat as only a small part of outside wall, te main part is of te vertical walls are next to interior spaces. Te outer wall as a surface of 3.9m² out of te total surface for te termal zone of 776.3 m² tat is analysed. Te present U-value of te wall is.95 W/(m²K). QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] Original 4,33 9,9 34, 3 mm, 33,66 34,76 6 mm,8 34,7 35,5 9 mm,7 35,7 35,87 TABLE 9 - ENERGY DEMANDS FOR MODIFICATION OF THE WALL INSULATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 99
4, 35, 3, 5,, 5, QHEAT_TOT QCOOL_TOT QTOT, 5,, original 3 mm 6 mm 9 mm GRAPH 49 - ENERGY DEMANDS FOR MODIFICATION OF THE WALL INSULATION 4 - -4-6 original 3 mm 6 mm 9 mm QHEAT_TOT QCOOL_TOT QTOT -8 - GRAPH 5 VARIATION OF ENERGY DEMANDS FOR MODIFICATION OF THE WALL INSULATION Adding termal insulation to te outer wall as a positive influence on te eating demand and a negative effect on te cooling demand. Te termal insulation decreases te eat transfer troug te wall. So conditions inside are less influenced by te outside weater conditions in winter and summer. To tat extent a decrease of bot eating and cooling demand is expected. Te insulation as a negative effect on te cooling demand because te internal eat gains ensure an increase of te temperature but te temperature is less transmitted to te outside. Also during summer nigts for example wen te temperature outside as decreased, te inside temperature doesn t decrease automatically because of te iger termal resistance of te wall. A positive effect could ave been expected wen te outer wall was oriented to te sout, so it as more influence on te cance of overeating of te secretariat. Tis is not te case for te secretariat. Tis leads to a faster overeating of te building and a iger cooling demand. Te result is also a iger total energy demand because te cooling demand is dominant to te eating demand. Tis is normal in warm climates were te reason of insulation in te winter as a reverse effect in te summer. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
5.3... ROOF INSULATION Te effect of improving te U-value of te roof slab on te energy demand of te secretary by adding different ticknesses of insulation is analysed and represented in Table and in Grap 5 and Grap 5. In comparison wit te outside wall te roof of te secretariat as a muc larger contact area wit outside. Te roof s contact area is 4.39m² of te total 5.68m² of te termal zone. Te present U-value of te roof is.4 W/(m²K). Te insulation is placed between te waterproofing and te gravel. QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] Present case 4,33 9,9 34, 3 mm 3,9 9,3 3, 6 mm,94 8,69 3,64 9 mm,84 8,5 3,34 TABLE - ENERGY DEMANDS FOR MODIFICATION OF THE ROOF INSULATION 4, 35, 3, 5,, 5, QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)], 5,, original 3 mm 6 mm 9 mm GRAPH 5 - ENERGY DEMANDS FOR MODIFICATION OF THE ROOF INSULATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
original 3 mm 6 mm 9 mm -5 - -5 - -5 QHEAT_TOT [%] QCOOL_TOT [%] QTOT [%] -3-35 -4 GRAPH 5 VARIATION OF ENERGY DEMANDS FOR MODIFICATION OF THE ROOF INSULATION Adding termal insulation to te roof slab as a positive influence on bot te eating and cooling demand. Te termal insulation decreases te eat transfer troug te roof slab. Tis positive effect on te eating demand is te same as for te wall insulation. Less eat is lost in winter. Te positive effect on te cooling demand is smaller because tere are two opposite effects. Te building can t lose teir eat tat easy but on te oter and it s also more difficult for te eat to enter te building wen te sun is sining on te roof and te surface temperature becomes really ig. Te positive effect on te eating demand is muc lower tan te effect of te wall insulation. Tis is due to bigger exposure of te roof to te sun in comparison wit te wall. Tat s wy te effect on te eating demand is smaller. We can conclude tat tis is a good improvement for te energy demand of te secretariat. 5.3..3. FLOOR INSULATION Te effect of improving te U-value of te floor slab on te energy demand of te secretary by adding different ticknesses of insulation is analysed and represented in Table and in Grap 53 and Grap 54. Te floor as a present U-value of. W/(m²K). Te area is 4.39m², wic is te same as te area of te roof. QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] original 4,36 9,899 34,4 3 mm 3,66 36,33 39,937 6 mm 3,45 37,466 4,96 9 mm 3,35 37,947 4,99 TABLE - ENERGY DEMANDS FOR MODIFICATION OF THE FLOOR INSULATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
45, 4, 35, 3, 5,, 5, QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] Present case 4,33 9,9 34, 3 mm 3,6 36,33 39,94 6 mm 3,45 37,47 4,9 9 mm 3,35 37,95 4,3 QHEAT_TOT QCOOL_TOT QTOT, 5,, original 3 mm 6 mm 9 mm GRAPH 53 - ENERGY DEMANDS FOR MODIFICATION OF THE FLOOR INSULATION 3 original 3 mm 6 mm 9 mm - QHEAT_TOT QCOOL_TOT QTOT - -3 GRAPH 54 VARIATION OF ENERGY DEMANDS FOR MODIFICATION OF THE FLOOR INSULATION Adding termal insulation to te outer wall as a positive influence on te eating demand and a negative effect on te cooling demand. During winter te colder soil temperature will cool down te air in te basement. Tis will affect te temperature in te room due to te eat stream from te rooms to te basement. Tis means tat te eating as to do an effort to keep te temperature on level. Wen we insert insulation, tis will be reduced. In summer te opposite will occur. Normally te cooler air in te basement, due to te colder soil, will lead to a natural cooling effect of te secretariat. Wen we put insulation in between, tis will not appen and an increase off te cooling demand is inevitable. Te termal insulation decreases te eat transfer troug te floor. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
5.3.. CHANGING THE WINDOWS Te present windows are in clear single glass of 6mm wit framework in painted stainless steel. Te windows are canged to analyse teir effect on te energy demand. Te new windows are coosen out of te library in TRNSYS. In Table te different types off windows and teir specifications tat we used to evaluate teir influence are listed. We cose to only consider double glass windows wit a frame eiter in steel or aluminium. types Glass ID Window Solar factor g [%/] Uglass [W/m²K] Window frame Uframe [W/m²K] Initial Clear 4mm 393.84 5.73 Steel 5.7 4/6/4 Clear 4/6/4 399.76 3.44 Al 3 6/8/6 Clear 6/8/6 39.7 3. Al 3 4/6/4 Clear 4/6/4 399.76 3.44 Steel 5.7 4/8/4 Double emis. 4/8/4 39.76.48 Al 3 TABLE TYPES AND SPECIFICATIONS OF THE WINDOWS QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 393+steel 4,3 9,9 34,3 399al,34 36,9 38,43 39al,8 36,84 39, 399+steel, 37,8 39,8 39al,69 39,99 4,68 TABLE 3 - ENERGY DEMANDS FOR CHANGES OF THE WINDOWS 45, 4, 35, 3, 5,, 5, QHEAT_TOT QCOOL_TOT QTOT, 5,, 393+steel 399al 39al 399+steel 39al GRAPH 55 - ENERGY DEMANDS FOR CHANGES OF THE WINDOWS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
4 - -4 393+steel 399al 39al 399+steel 39al QHEAT_TOT [%] QCOOL_TOT [%] QTOT [%] -6-8 GRAPH 56 VARIATION OF ENERGY DEMANDS FOR CHANGES OF THE WINDOWS Te results of tese modifications are presented in Table 3 and in Grap 55 and Grap 56. To analyse tese results two influences ave to be considered. First of all tere is te improvement of te insulating capacity of te windows caused by te air (or sometimes gas) between te two glass plates and by te bigger termal resistance of te framework. Also te airtigtness of te windows is improved. Secondly te solar energy transmittance (g-factor) of te glass is decreased. Tese two factors cause less influence of te outside weater conditions on te inside ones. Wit single glass te eat flows very easily to te colder volume. Te eating demand decreases wen te single glass is canged by double glass. Te cooling demand on te oter and increases quite a lot depending on te type of window. Tis as te same explanation as te previous modifications were te insulating capacity of te components is improved. Te better te insulating part te more te eat transfer is decreased. Tis as positive effect on te eating demand and a negative effect on te cooling demand. Te magnitude of te effect depends on te quantity of te two previous explained values. Tere must not be forgotten tat te blinds are still in front of te windows. Te effect of te sading will be analysed below. 5.3.3. ADJUSTMENT OF THE OUTER BLINDS Te effect of te sading factor on te secretariat s energy demand is evaluated by canging te angle alfa (Figure 63) of te blinds. Te iger te angle of te blinds te bigger is te sading on te windows. Te effect of te blind adjustments on te energy demand of te secretariat is sown in Table 4 and in Grap 57 and Grap 58. FIGURE 63 - SKETCH OF THE ANGLE OF BLINDS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
In te equation in te simulation studio we only took te direct radiation into account. Te diffuse radiation is important to ave natural ligt into te building but it doesn t ave a lot of influence on te cooling and eating demand. As expected te lowest cooling demand is wen te angle is te biggest. Tis is te angle wit te biggest saded area on te window. Te effect on te eating demand is almost noting. It increases just a little bit because in winter, wen te azitmut of te sun is lower, te secretariat will gain more eat from te sun for tan wit 6, so te eat demand at 6 will be a little bit bigger. As can be deducted from Grap 58 tis is a important modicifaction to reduce te cooling demand of te building because te eating demand is almost not affected. alfa QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 4,3 35,8 39,39 3 4,33 9,9 34, 45 4,33 9,8 33,4 6 4,33 8,95 33,8 TABLE 4 - ENERGY DEMANDS FOR ADJUSTMENTING THE BLINDS 45, 4, 35, 3, 5,, 5, QHEAT_TOT QCOOL_TOT QTOT, 5,, 3 45 6 GRAPH 57 - ENERGY DEMANDS FOR ADJUSTMENTING THE BLINDS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
,, -, -4, -6, -8, -, -, -4, -6, -8, -, 3 45 6 QHEAT_TOT QCOOL_TOT QTOT GRAPH 58 VARIATION OF THE ENERGY DEMANDS FOR ADJUSTING THE BLINDS 5.3.4. CHANGING THE INTERNAL HEAT GAINS Only a decrease of te eat gains by te ligts was considered because it wouldn t be realistic to reduce te number of persons or te number of electronic devices in te secretariat. Te energy gains from te ligts were canged gradually canged from 55 W/m to 9 W/m and W/m. Canging te internal eat gains means less eat production by te internal components, wic will ave it s effect on te energy demands. Te results are represented in Table 5 and in Grap 59 and Grap 6. QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 55 W/m² 4,36 9,899 34,4 9 W/m² 5,7 5,443,67 W/m²,37,53 3,9 TABLE 5 - ENERGY DEMANDS OF CHANGING INTERNAL HEAT GAINS 4, 35, 3, 5,, 5, QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)], 5,, 55 W/m² 9 W/m² W/m² GRAPH 59 - ENERGY DEMANDS OF CHANGING INTERNAL HEAT GAINS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
5 55 W/m² 9 W/m² W/m² 4 3 QHEAT_TOT [%] QCOOL_TOT [%] QTOT [%] - - GRAPH 6 VARIATION OF ENERGY DEMANDS OF CHANGING INTERNAL HEAT GAINS As expected, te influence of a reduction of te ligting energy as a big influence on bot energy demands. Wen using ligts wit W/m, wic is 5.5 times less tan initially, te eating demand is almost quadrupled. Te cooling demand on te oter and is only reduced by almost %. Te global result for tis modification is still good, because of te stake of te cooling demand in te total energy demand. In any case tis is an important improvement because not only te energy demand of te building is reduced. Heat producting by te ligts is a very inefficient way of producing eat. It is not te purpose of ligts. Tis emprovement will terefore probably ave a big influence in te total primary energy of te building. Tis item is not considered in tis paper, but tis doesn t make it less important. 5.3.5. INFLUENCE OF INFILTRATION Te effect of canging te air infiltration into te building by fixed air cange rates is represented in Table 6 and in Grap 6 and Grap 6. Te initial model was designed wit openings of on cm. Tis was randomly cosen to get started. Also tere was no bases to deduct a value for te airtigtness of te building because of te impossibility of te BlowerDoor test. Wile making improvements on te model it turned out tat te size of te openings was a bad coice, according to airtigtness of te actual building. A passive ouse building as an air cange rate of maximum.6 times te volume per our. In older buildings wit single glass windows, tis value is located somewere between 8 and volumes per our. If te output of te initial model is compared wit te models were a fixed air cange rate is introduced, te influence of te assumption becomes clear. As Grap 6 and Grap 6 are observed, tere can be seen tat our initial model as a smaller energy demand tan any oter case. Tis means tat te infiltration of te initial model is smaller tan.6 volumes per our, wic is te requirement to meet te passive ouse standard. Tis is off course not te case in practice. Altoug te actual airtigtness value is unknown, it s impossible tat tis building as tis level of Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
airtigtness. Tere are a lot of airleaks present in te building wereof te windows and te outside walls wit te steel profiles and prefabricated panels are te most important ones. Unfortunately we ave to conclude tat te model contains some assumptions tat turn out to be wrong. Tis was expected considering te low energy demands tat were obtained in paragrap 5... Making a building airtigt as possitive influence on bot eating and cooling demand. Te effect is bigger on te eating demand. Wat is striking is te small differences between te various airtigtnesses. Muc bigger values and differences between te values for cooling and eating demand were expected. So ere tere also as to be concluded tat tis part of te model contains some malfunctions tat are not representable. Lastly we want to remark tat TRNSYS doesn t consider any practical way of reacing tese levels of airtigtness. Te size of te infiltration opening is introduced and te rest of te building is considered as airtigt. Tis is off course not ow it is in reality. QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 5,956 3,55 37,46 4 4,856 3,56 35,46,6 4,353 9,947 34,3 original 4,36 9,899 34,4 TABLE 6 ENERGY DEMANDS OF MODIFICATION OF THE INFLILTRATION 4 35 3 5 5 QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 5 4,6 original GRAPH 6 - ENERGY DEMANDS OF MODIFICATION OF THE INFLILTRATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
, 4,6 original -5, -, -5, QHEAT_TOT [%] QCOOL_TOT [%] QTOT [%] -, -5, -3, GRAPH 6 VARIATION OF ENERGY DEMANDS OF MODIFICATION OF THE INFLILTRATION 5.3.6. THE EFFECT OF NATURAL VENTILATION Te analysis of te effect of natural ventilation in te building is based on te previous models wit te various infiltration rates. Tis is because ventilation and infiltration are connected wit eac oter in TRNSYS, so it s impossible to analyse te effect of ventilation separately. Te effect of natural ventilation into te building in represented below per air cange rate. Te opening were te air flows troug is set on m² wen te ventilation switces on. Making te infiltration opening bigger is a way to simulate te natural ventilation for example troug a ventilation opening or a window. Wen te ventilation is switced on, te cooling doesn t work. On te oter and wen te natural ventilation switces off, te normal infiltration rate is working. Wen te ventilation is on, te infiltration opening becomes m². Te criteria for wic tis system is activated are: Te system can only be activated in summer Te temperatures outside as to be lower tan 5 Te temperature inside as to be iger tan outside. We assume tat te criteria will mostly be fulfilled during nigtfall or by nigt. So tis type of ventilation can be seen as intensive nigt ventilation. Te way tis is introduced in TRNSYS, see 4.4.5.4. Te results per air cange rate sow a general trend. Adding ventilation makes te eating demand increase and te cooling demand decrease. Te cooling decreases because wen te ventilation is working, te cooling suts down. Tis means tat wen te criteria are fulfilled, te rooms are ventilated wit fres cooler air from outside. Tis is good to ave clean air in te room and to cool te building. For buildings wit a big termal capacity, tis modification will ave te biggest influence. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
Te eating demand increases because te temperature can be low in te morning (in summer) and te eating as to work. Tis is a factor tat is difficult to take into account. Sometimes te building can eat up quicker in te morning or slower, depending on te weater outside (clouded or sunny). If we introduce a minimum temperature in te secretariat to control te ventilation, tis will eat up te builing muc faster. Tis will make te cooling demand bigger again. a) air canges - QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 5,956 3,55 37,46 +ventilation 8,65,894 8,959 TABLE 7 - ENERGY DEMANDS WITH AIR CHANGE RATE + VENTILATION 4 35 3 5 5 QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 5 +ventilation GRAPH 63 - ENERGY DEMANDS WITH AIR CHANGE RATE + VENTILATION 4 3 - +ventilatie QHEAT_TOT [%] QCOOL_TOT [%] QTOT [%] - -3-4 GRAPH 64 VARIATION OF ENERGY DEMANDS WITH AIR CHANGE RATE + VENTILATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
b) 4 air canges - QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 4 4,856 3,56 35,46 4+ventilation 6,566 9,9 6,477 TABLE 8 - ENERGY DEMANDS WITH AIR CHANGE RATE 4 + VENTILATION 4 35 3 5 5 QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 5 4 4+ventilation GRAPH 65 - ENERGY DEMANDS WITH AIR CHANGE RATE 4 + VENTILATION 4 3-4 4+ventilatie QHEAT_TOT [%] QCOOL_TOT [%] QTOT [%] - -3-4 GRAPH 66 VARIATION OF ENERGY DEMANDS WITH AIR CHANGE RATE 4 + VENTILATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
c).6 air canges - QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)],6 4,353 9,947 34,3,6+ventilation 5,7 9,5 4,963 TABLE 9 - ENERGY DEMANDS WITH AIR CHANGE RATE.6 + VENTILATION 4 35 3 5 5 QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 5,6,6+ventilation GRAPH 67 - ENERGY DEMANDS WITH AIR CHANGE RATE.6 + VENTILATION 4 3 -,6,6+ventilatie QHEAT_TOT [%] QCOOL_TOT [%] QTOT [%] - -3-4 GRAPH 68 VARIATION OF ENERGY DEMANDS WITH AIR CHANGE RATE.6 + VENTILATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 3
d) Initial model QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] Initial 4,33 9,9 34, Initial+ventilation 5,63 9,78 4,8 TABLE 3 - ENERGY DEMANDS IN INTITIAL MODEL + VENTILATION 4, 35, 3, 5,, 5, QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)], 5,, original original+ventilation GRAPH 69 - ENERGY DEMANDS IN INITIAL MODEL + VENTILATION 4, 3,,, QHEAT_TOT [kw/(m²a)], -, original original+ventilation QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] -, -3, -4, GRAPH 7 VARIATION OF ENERGY DEMANDS IN INITIAL MODEL + VENTILATION Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 4
5.4. COMBINING THE MODIFICATIONS In tis last paragrap te various modifications to te initial model are combined to a ultimate model tat meets te criteria of te passive ouse standard. Te combinations were made based on te conclusions of te separate modifications to te initial model. Te coice was made to take te model wit te air cange rate of volumes per our as te initial model to apply te modifications on. Te actual value for te infiltration into te building is unknown and it s muc more probable tat te air cange rate of te building is somewere around -. Te air cange rate of less tan.6 -, as we ad to conclude wit te actual model, is not representative. Te combination of improvements to te building model wit te related energy demands are represented in Table 3 and Grap 7. Te first improvement tat was applied was decreasing te airtigtness of te model to te required.6 - for te passive ouse standard. Ten te ventilation is introduced in te model to reduce te cooling demand. In te initial model te eating demand is already under te limit of 5 kw/(m²a) so no specific improvements are needed. But tere is noting implemented by TRNSYS to reac any level of airtigtness in practice. TRNSYS just assumes tat, next to te infiltration openings, te connections are perfect, witout any airflow between bot sides of te termal envelope. To take into account tis issue a different type of window and framework togeter wit termal insulation in te roof and te outer wall was inserted. Tese are components tat are known for teir insulating and airtigtening properties assuming tat tey are installed in te rigt way. Tis is by making good connections between te framework of te windows and te termal insulation, as well as te breaks between te insulating plates. Tese modifications are just a few tat are necessary to obtain an airtigt building in reallity. By inserting tese modifications into te model te eating demand decreased and an increase of te cooling demand can be determined. Tis could be expected considering te previous analysis. Te termal insulation in te floor was not added because of te cooling effect tat can occur wit te ground. Te cooling demand is still above 5 kw/(m²a), so te angle of te sading devices are increased to 6. Tis ensures a more sade on te windows, so less eat enters by direct or indirect irradiation. In tis way, less cooling demand is needed. Wen te internal eat gains of te ligts are reduced to 9 W/m a big drop of more tan 5 kw/(m²a) occurs. Constraining te internal eat gains leads to an immense decrease of te cooling demand. By applying tis improvement te cooling demand drops a lot below te annual cooling demand goal of 5 kw/m². Te result of tis combination is a building model wit a very low cooling, eating and total annual energy demand. Besides aving a building tat is igly energy efficient, te Passive House standard also gives a guideline for involving te optimum standard of termal comfort. Te overeating frequency as to be smaller tan % of te ours over 5 C during one year. In te final model 9.58% of te ours are above 5 C annually. So good termal comfort inside te building model is garanteed. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 5
QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] infiltration (/) 5,956 3,55 37,46 infiltration (,6/) 4,353 9,947 34,3 +ventilation 5,7 9,5 4,963 +window (39al),998 3,778 6,776 +6cm PUR roof,77,74 4,449 +6cm PUR wall,3 8,95 8,99 +sading ( 6 ),3 7,9 7,95 +internal gains ( 9W/m²),4,66 3,7 TABLE 3 ENERGY DEMANDS OF MODIFICATION COMBINATIONS 4 35 3 5 5 QHEAT_TOT [kw/(m²a)] QCOOL_TOT [kw/(m²a)] QTOT [kw/(m²a)] 5 GRAPH 7 - ENERGY DEMANDS OF THE MODIFICATION COMBINATIONS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 6
6. CONCLUSION Te importance of a passive ouse is reacing a ig level of comfort inside togeter wit very low energy consumption. Te climate as a big influence wen designing a passive ouse. Here in Valencia te eating demand is low due to mild winters and te cooling demand as a bigger importance because of te ot summers. Active cooling and eating sould be low and passive eating and cooling tecniques sould be used as muc as possible. Te goal was modifying a scool building tat fulfils te conditions of te Passive House standard. Tis was developed in tree steps: obtaining measurements of te temperature inside and outside, making a model of te building in TRNSYS and make adjustments to ave a passive ouse. Te initial model of te secretariat ad a low energy demand. Tis was an unexpected result knowing te age and te construction metod of te building. Making wrong assumptions probably caused tis. Te ceiling for example was modelled witout implementation of te skyligts. It was difficult to modify it more because of te limited knowledge of TRNSYS, te lack of detailed information about te building and te installations. Keeping in mind te incorrect model, five improvements to te model were evaluated to see teir impact on te energy demand: Te termal insulation - Te influence of termal insulation was evaluated in te wall, te roof and te floor. Bot te wall and te floor insulation result in a iger cooling demand and a lower eating demand. Increasing te tickness of te roof insulation lowers te eating as well as te cooling demand. Te profitability of a few centimetres is ig but tis effect decreases as te tickness of te insulation increases. At a certain point tis effect stabilizes as can be determined from Grap 5 and Grap 5. Insulation in te floor is not recommended because te soil as passive cooling capacities in summer, wic is important in designing passive ouses. Te ventilation - Te improvement of te ventilation as a big influence on te cooling demand as can be seen on Graps 64, 66, 68 and 7. Wen te ventilation is activated, te building is cooled wit colder air from outside wic makes tis a passive cooling strategy. Tis is an important strategy against overeating and to provide te building wit fres air. Te internal eat gains - Te electric devices, te ligts and te people produce a big amount of eat. Especially in offices tese eat production can be quite ig. Canging te type of ligts decreased te internal eat gains in te secretariat. Canging only te type of ligts to low eat-emitting ligts, te cooling demand decreases a lot. Tis effect is illustrated in Grap 6. Te Windows and te outer blinds - Wen te windows are canged from single glass to double glass, te eating demand will decrease due to te insulating property of double glazed windows. Tis as a reverse influence on te cooling demand. Te sading devices ave a big impact on te cooling demand. Tis depends on te angle of te Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 7
blades. In tis model tey were fixed blinds and ad te biggest demand for and te lowest for 6. Tis can be seen on Grap 56 and 58. A better improvement tat we didn t use in our model was a sading device tat can cange te angle of te blades. Tis way it can obtain te natural eat in summer and avoid it during te summer. Tis model is based on assumptions and is not always modelled like it is built in reality but te improvements give an idea of te effect tat tey ave on te cooling and eating demands. Tis is of great importance to model a passive ouse, especially in times were environmental awareness is increasing. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 8
BIBLIOGRAFIE [] Boletin Oficial del Estado. (n.d.). Retrieved Marc 4, from Boletin Oficial del Estado: ttp://www.boe.es/boe/dias/3/9//pdfs/boe-a-3-95.pdf [] Cp GENERATOR. (n.d.). Retrieved April 4, from TNO Webapplications: ttp://www.cpgen.bouw.tno.nl [3] HEIJMANS N., W. P. (n.d.). Impact of uncertainties on wind pressures on te prediction of termal comfort performances. Brussels: BBRI. [4] HUIZENGA C. et al. (999). Teacing students about two-dimensional eat transfer effects in building components, equipment and appliances using THERM.. ASHRAE. [5] Instruction Manual Comfort Sorftware x35 Professional. (n.d.). Retrieved Marc 4, from TESTO: ttp://www.testo-international.com/ [6] KLEIN S.A. et al. (). TRNSYS 7 Add-Ons A. TRNFLOW. In TRNSYS 7 Documentation (p. 58). Wisconsin: University of Wisconsin-Madison. [7] KLEIN S.A. et al. (). Volume : Getting Started. In TRNSYS 7 Documentation (p. 8). Wisconsin: University of Wisconsin-Madison. [8] KLEIN S.A. et al. (). Volume : Using Te Simulation Studio. In TRNSYS 7 Documentation (p. 9). Wisconsin: University of Wisconsin-Madison. [9] KLEIN S.A. et al. (). Volume 3: Standard Component Library Overview. In TRNSYS 7 Documentation (p. ). Wisconsin: University of Wisconsin-Madison. [] KLEIN S.A. et al. (). Volume 5: Multizone Building ( type56-trnbuild ). In TRNSYS 7 Documentation (p. 3). Wisconsin: University of Wisconsin-Madison. [] KNOLL B., P. J. (n.d.). Pressure coefficient simulation program. Delft: DNO. [] MITCHELL R. et al. (3). THERM 6.3/WINDOW 6.3 NFR Simulation Manual. Berkeley: LBNL. [3] Passive ouse certification criteria. (n.d.). Retrieved Marc 4, from Passive House International: ttp://www.passiveouse-international.org [4] RECTICEL EUROWALL. (n.d.). Retrieved May 4, from Recticel: ttp://www.recticelinsulation.be/product/eurowall/tecnisce-fice [5] RETROTEC Calibrated Fans. (n.d.). Retrieved May 4, from Retrotec: ttp://www.retrotec.com [6] SKYLIGHT. (sd). Opgeroepen op April 4, van Walbers: ttp://www.walbers.be [7] TESTO 435-. (n.d.). Retrieved Marc 4, from Testo Instuments: ttp://www.testo-international.com/ [8] Watcdog series Weater Station. (n.d.). Retrieved Marc 4, from Spectrum Tecnologies: www.spectmeters.com Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools. 9
[9] Werkgroep PaTB. (9). Toelictingsdocument volgens "Ontwerp tot wijziging van BIJLAGE IV/V van et EPB-Besluit". Brussels: Werkgroep PaTB. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
APPENDIX A: INPUT AND RESULTS OF THE CP GENERATOR Te input for te Cp Generator is simple. On te website you find a.txt -file as an example and tey recommend you to work in (a copy of) tis file by adjusting te file to your own specific situation. Te different inputs are: Title General data of te project. Te program doesn t need tis to work. Wind.Zo In tis section we define te terrain rougness for different flow directions of te wind. For all four wind directions (N, E, S, W) we cose Zo = 3, m wic means a terrain rougness of a normal suburb, industrial estate or village. Nort arrow Tis is te direction in degrees to wic te nort arrow points in our plan wit reference to te cosen coordinate system. Obstacles Here we define te different objects of te problem. In te text block 'Name: building' we fill in te data of te object of wic we want to ave te Cp -values calculated. We specify coordinates X and Y for a base point of te building in te ground plan. Also we specify te azimut in degrees for te first facade anti-clockwise from tis base point (Figure 64). Te Lengt (L), Widt (W) and Heigt (H) of te building may be followed by a key (=) for a pitced roof, te roof angle in degrees and te size of te roof basis. We specify te same variables for te obstacles wic are te objects surrounding te calculated one. In te text block Name: meteo we fill in te coordinates of our weater station. FIGURE 64 - GROUND PLAN WITH DEFINITIONS Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.
Cp positions In tis part we specify te coordinates of te Cp points at eac façade looking towards it wit X, Z =, down left, and te roof looking from above wit te base point situated down left is X, Y =, (Figure 65). Te facades are numbered anti-clockwise from to 4. FIGURE 65 - DEFINITION OF CP POSITIONS Calculating te Cp-values Te ground plan of te department of te scool of building management as a difficult sape to define te obstacles terefore we simplified te project. Wen tere are to many separate obstacles close to eac oter, te result of te Cp prediction only is reduced. Te energy zone of wic te secretariat is part of was divided into tree blocks. For eac block tere ad to be made a separate Cp-value calculation. Passive ouse standard in a warm climate. Analysis of closures wit tests in a university building. Passive ouse modelling wit advanced computer tools.