Simple hourly method internal heat capacity of the building

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1 Evaluation of the Heating & Cooling Energy Deand of a Case Residential Building by Coparing The National Calculation Methodology of Turkey and EnergyPlus through Theral Capacity Calculations Merve Ataca 1, Ece Kalaycioglu 2, Prof.Dr.Zerrin Yilaz 3 1Instıtute of Science and Technology, Istanbul Technical University, Turkey 2Ekoi Ecological Architectural Consultancy Copany, Turkey 3Instıtute of Science and Technology, Istanbul Technical University, Turkey ABSTRACT In all around the world, because of the rapid population growth and exhausting energy sources over tie, energy efficiency and energy conservation gradually coe into proinence. Hence, in 22, a directive (EPBD) which obligates reducing energy usage and energy perforance in buildings was published by European Union. In this scope, Turkey has developed a National Building Energy Perforance Calculation Methodology, BepTr, which is based on siple hourly ethod in ISO EN 1379 Ubrella Docuent to deterine the energy perforance of buildings. The ai of the paper is to display the energy deand differences resultant fro only the envelope s theral capacity between siplified ethod which is projected in ISO EN 1379 Ubrella Docuent and EnergyPlus which is based on full dynaic siulation ethod. INTRODUCTION In all around the world, because of the rapid population growth and exhausting energy sources over tie, energy efficiency and energy conservation gradually coe into proinence. Hence, a directive which obligates reducing energy usage in buildings iproving building energy perforance (22) was published by European countries as a frae work of EPBD. As an eerging country, in Turkey the energy deand is also rapidly rising. The Energy Density is an indicator that is used by all around the world, and it represents priary energy aount which is consued per gross national product. In Turkey, energy consuption per person is around one fifth of OECD average (29) and the Energy Density rate is ore than twice of European Union Countries (TUIK, 29). In the view of such inforation, in our country that cannot use energy efficiently in production and consuption, and its energy deand rapidly rising for reduction of the energy density, in addition to Building Energy Perforance Regulation and Theral Insulation Regulation in Buildings, as a requireent of the EU accession period Energy Efficiency Act (27), Enhancing The Efficiency of Usage of Energy Sources and Energy regulation are also cae into force. In Turkey, % 4 of the produced energy is consued in buildings. As fro now on, Turkey has the potential of energy saving to iniize the energy consuption without conceding life cofort by providing efficient usage of the energy. According to the Ministry of Energy (21), the ratio of energy saving potential is %3 in building sector, %2 in industry sector, and %15 in transportation sector. Within the scope of this paper, there are two different calculation ethodologies for deterination of the energy class of buildings by priary energy consuption, has been tested for residential building typologies, such as a single faily house as a case study. Calculation of heating and cooling energy deand in ISO EN 1379 ubrella docuent is based on siple hourly ethod. The coparison ethodologies are siple hourly ethod and EnergyPlus which is a well known dynaic calculation ethodology basing on siultaneous ulti-zone calculation. OLOGY According to EPBD, Building Energy Perforance is an aount of the energy which is used in buildings to supply typical requireents of a building such as heating, cooling, ventilation and lighting depending on building typology. All paraeters which affect Building Energy Perforance are needed to be handled as an integrated syste. The energy balance which is the basic principle of the calculation procedure at the building zone level includes:

2 o transission heat transfer between the conditioned space and the external environent, governed by the difference between the teperature of the conditioned zone and the external teperature; o ventilation heat transfer (by natural ventilation or by a echanical ventilation syste), governed by the difference between the teperature of the conditioned zone and the supply air teperature; o transission and ventilation heat transfer between adjacent zones, governed by the difference between the teperature of the conditioned zone and the internal teperature in the adjacent space; o internal heat gains (including negative gains fro heat sinks), for instance fro persons, appliances, lighting and heat dissipated in, or absorbed by, heating, cooling, hot water or ventilation systes; o solar heat gains (which can be direct, e.g. through windows, or indirect, e.g. via absorption in opaque building eleents); o storage of heat in, or release of stored heat fro, the ass of the building; o energy need for heating: if the zone is heated, a heating syste supplies heat in order to raise the internal teperature to the required iniu level (the set-point for heating); o energy need for cooling: if the zone is cooled, a cooling syste extracts heat in order to lower the internal teperature to the required axiu level (the set-point for cooling). Different Calculation Methods In basic, there are two types of calculation ethods: o quasi-steady-state ethods, calculating the heat balance over a sufficiently long tie (typically one onth or a whole season), which enables one to take dynaic effects into account by an epirically deterined gain and/or loss utilization factor; o dynaic ethods, calculating the heat balance with short ties steps (typically one hour) taking into account the heat stored in, and released fro, the ass of the building. Energy perforance of buildings Calculation of energy use for space heating and cooling EN ISO 1379:28 International Standard covers three different types of ethod: o o o a fully prescribed onthly quasi-steadystate calculation ethod (plus, as a special option, a seasonal ethod); a fully prescribed siple hourly dynaic calculation ethod; calculation procedures for detailed (e.g. hourly) dynaic siulation ethods. The alternative siple ethod for hourly calculations has been added to facilitate the calculation using hourly user schedules (such as teperature set-points, ventilation odes, operation schedule of ovable solar shading and/or hourly control options based on outdoor or indoor cliatic conditions). The procedures for the use of ore detailed siulation ethods ensure copatibility and consistency between the applications of different types of ethod. At national level, it ay be decided which of these three types of ethod are andatory or are allowed to be used, depending on the application (purpose of the calculation) and building type. This choice typically depends on the use of the building (residential, office, etc.), the coplexity of the building and/or systes, the application (energy perforance requireent, energy perforance certificate or recoended energy perforance easures, other). Dynaic ethods In the dynaic ethods, an instantaneous surplus of heat during the heating period has the effect that the internal teperature rises above the set-point, thus reoving the surplus heat by extra transission, ventilation and accuulation, if not echanically cooled. Also, a therostat set-back or switch-off ight not lead directly to a drop in the internal teperature, due to the inertia of the building (heat released fro the building ass). A siilar situation applies to cooling. A dynaic ethod odels theral transission, heat flow by ventilation, theral storage and internal and solar heat gains in the building zone. The heat capacity calculation is defined in ISO EN Theral Perforance of Building Coponents Dynaic Theral Characteristics Calculation Methods :27. Quasi-steady-state ethods In the quasi-steady-state ethods, the dynaic effects are taken into account by introducing correlation factors. For heating, a utilization factor for the internal and solar heat gains takes account of the fact that only part of the internal and solar heat gains is utilized to decrease the energy need for heating, the rest leading to an undesired increase of the internal teperature above the set-point. For cooling, there are two different ways to represent the sae ethod: 2

3 a) utilization factor for losses (irror iage of the approach for heating) b) utilization factor for gains (siilar as for heating) Siple hourly ethod coupling the theral ass Heat transfer by transission is split into the window part, H tr,w, taken as having zero theral ass, and the reainder, Htr,op, containing the theral ass which in turn is split into two parts: Htr,e and Htr,s. The theral ass is represented by a single theral capacity, C, located between Htr,s and Htr,e. A coupling conductance is defined between the internal air node and the central node. Siple hourly ethod internal heat capacity of the building For the siple hourly ethod, the internal heat capacity of the building zone, C, expressed in joules per Kelvin, is calculated by suing the heat capacities of all the building eleents in direct theral contact with the internal air of the zone under consideration, also by using Equation (4). C = x A j x κj (4) Table 1 - Maxiu to be considered for internal heat capacity. Maxiu Application Deterination of the gain or,1 loss utilization factor (period of variations: 1d) Alternatively, it ay be decided nationally, for specific applications and building types, to use default values as a function of the type of. In the absence of national values, the values fro Table 2 ay be used. Table 2 - Default values for dynaic paraeters. Figure 1 Five resistances, one capacitance (5R1C) odel H e 1/(1/H op 1/H s ) (1) H s h s A (2) H s h s A is the coupling conductance between nodes and s, expressed in watts per kelvin; is the heat transfer coefficient between nodes and s, with fixed value hs = 9,1, expressed in watts per square etres kelvin; is the effective ass area, expressed in square etres. A = C ² / ( x A j x κ j ) (3) C Aj κj is the internal heat capacity, deterined in accordance with , expressed in joules per kelvin; is the area of the eleent j, expressed in square etres; is the internal heat capacity per area of the building eleent j, expressed in joules per square etres kelvin. THE CASE BUILDING The case study presented and evaluated is a residential building, located in Istanbul city, TURKEY. Case building is a floor which is located in between two other conditioned floors in a ultistory apartent block. The floor area is 65,3 2 consisting living and cooking areas. Three occupants accoodate in the house. The transparency is only on the south façade of the building while other facades are totally opaque. The boundary conditions of the facades are deterined as adiabatic for north and east exterior (adjacent to other residential units) walls. The case building is located in the low density city and it is open to environental effects. Air tightness level is high depending on air change value (n5). By this way, obtained air change rate per hour is shown in the Table 3. The selected aterials which are given in Table 4 are sae for both siple hourly and dynaic ethod. The transparency ratio of the south surface is selected %2 to show the effect of the theral ass fro 3

4 the opaque parts (Figure 2). The heating set point is 19 C and the cooling is 26 C. Five different and aterial types are selected for the external walls as shown in Table 4. Basically all the layers are the sae except the core aterials as air gap, brick, aerated concrete, concrete and stone. Table 3. Air change rate per hour. Air Shielding change Tightness class value 1/h (n5) Air change per hour (n) Open 2 High,5 Table4. Material list STEEL CONSTRUCTION Only BepTr Only EnergyPlus Nae of the Material Ceent ortar Thickness Theral conductivity (d) (λ) W/(2K) ρ (kg/3) Density Eissivity C A Roughness Cp ε (ISO EN 1379) J/kgK EN1456,3 1,6 14,9 2,5 165 Mediu 1 EPS,4,4 3-2,5 11 Mediu 92 Fiberceent Panel Air Gap (Steel Stud) Gypsu Board,1,37 1-2,5 165 Mediu 125,15,16(R) - Sooth,25,25 8-2,5 165 Mediu 19 BRICK CONSTRUCTION Only BepTr Only EnergyPlus Nae of the Material Ceent ortar Thickness Theral conductivity (d) (λ) W/(2K) ρ (kg/3) Density Eissivity C A Roughness Cp ε (ISO EN 1379) J/kgK EN1456,3 1,6 14,9 2,5 165 Mediu 1 EPS,4,4 3-2,5 11 Mediu 92 Fiberceent Panel,1,37 1-2,5 165 Mediu 125 Brick,15, ,5 11 Mediu 1 Gypsu Board,25,25 8-2,5 165 Mediu 19 AERATED CONCRETE CONSTRUCTION Only BepTr Only EnergyPlus Nae of the Material Ceent ortar Thickness Theral conductivity (d) (λ) W/(2K) ρ (kg/3) Density Eissivity C A Roughness Cp ε (ISO EN 1379) J/kgK EN1456,3 1,6 14,9 2,5 165 Mediu 1 EPS,4,4 3-2,5 11 Mediu 92 4

5 Fibroceent Panel Aerated Concrete Gypsu Board,1,37 1-2,5 165 Mediu 125,15,14 4-2,5 11 High 1,25,25 8-2,5 165 Mediu 19 CONCRETE CONSTRUCTION Only BepTr Only EnergyPlus Nae of the Material Ceent ortar Thickness Theral conductivity (d) (λ) W/(2K) ρ (kg/3) Density Eissivity C A Roughness Cp ε (ISO EN 1379) J/kgK EN1456,3 1,6 14,9 2,5 165 Mediu 1 EPS,4,4 3-2,5 11 Mediu 92 Fibroceent Panel,1,37 1-2,5 165 Mediu 125 Concrete,15 2, Mediu 84 Gypsu Board,25,25 8-2,5 165 Mediu 19 MASONRY CONSTRUCTION Only BepTr Only EnergyPlus Nae of the Material Ceent ortar Thickness Theral conductivity (d) (λ) W/(2K) ρ (kg/3) Density Eissivity C A Roughness Cp ε (ISO EN 1379) J/kgK EN1456,3 1,6 14,9 2,5 165 Mediu 1 EPS,4,4 3-2,5 11 Mediu 92 Fibroceent Panel,1,37 1-2,5 165 Mediu 125 Concrete,15 2, Mediu 84 Stone Wall,15, Mediu 1 Gypsu Board,25,25 8-2,5 165 Mediu 19 5

6 kwh/a Table 5 - U values of the five different exterior walls. Construction naes U Values W/²K Steel Construction,687 Brick Construction,587 Aerated Concrete Construction,422 Concrete Construction,732 Masonry Construction,62 Figure 2 - Case Building Table 6 - Lighting, occupant and electric equipent schedules. Occupancy Schedule Lighting Schedule Equipent Schedule : - 6:59 : - 16:59 : - 6:59 1,3 W,65 W 7: - 24: 17: - 22:59 7: - 16:59,5 117,6 W 32,7 W RESULTS Results for Steel Wall : - 24: 17: - 24: 65,3 W 65,3 W Steel Wall Steel Wall Cooling Heating Cooling Heating Cooling Heating U Value:,687 changing insulation (4,82c EPS) changing U Value:, , ,4 797, ,75 844, ,4 532,28 262,97 522, ,95 532,28 252,97 Figure 3 - Annual heating and cooling deand analysis results for of the aterials on steel. 6

7 kwh/a kwh/a Results for Brick Wall Brick Wall Brick Wall Cooling Heating Cooling Heating Cooling Heating U Value:,587 changing insulation (3,75c EPS) changing U Value:,6 (13c Brick) 71,17 154,71 14, ,88 719,5 1531,83 519, ,1 522,42 188,12 522, ,87 Figure 4 - Annual heating and cooling deand analysis results for of the aterials on brick. Results for Aerated Concrete Wall Ytong Wall Ytong Wall Cooling Heating Cooling Heating Cooling Heating U Value:,422 changing insulation U Value:,6 (1,2c EPS) changing U Value:,6 (5,2c ytong) 67, ,95 735, , 775, ,81 54,7 1471,98 522, ,87 522, ,87 Figure 5 - Annual heating and cooling deand analysis results for of the aterials on aerated concrete. 7

8 kwh/a kwh/a Results for Concrete Wall Concrete Wall Concrete Wall Cooling Heating Cooling Heating Cooling Heating U Value:,732 changing insulation U Value:,6 (5,2c EPS) changing (77c Concrete) 738,8 1659,45 77, ,26 141, ,54 537,6 2158,46 522, ,87 522,4 1879,65 Figure 6 - Annual heating and cooling deand analysis results for of the aterials on concrete. Results for Stone Wall Stone Wall Stone Wall Cooling Heating Cooling Heating Cooling Heating changing insulation (4 c EPS) changing (15c StoneWall) 713, ,2 713, ,2 713, ,2 522,43 188,29 522,43 188,29 522,43 188,29 Figure 7 - Annual heating and cooling deand analysis results for of the aterials on stone. 8

9 C kwh/a Stone Wall Stone Wall Cooling Heating 713, ,2 522,43 188, steel 21 Jan brick 21 Jan Ytong 21 Jan Concrete 21 Jan Stone 21 Jan hours Figure 8 - Daily teperature differences in 21 January for each type. 9

10 C steel 21 july brick 21 july Ytong 21 july Concrete 21 july Stone 21 july hours Figure 9 - Daily teperature differences in 21 July for each type. According to the results of Siple Hourly Method and Dynaic Siulation the Building Energy Perforances of a siple residential unit are changing siilarly for each type. The results showed that Siple Hourly Method s Theral ass calculations ay be reliable in noncoplex building types. According to the results obtained fro both calculation ethodology showed that although the concrete is the aterial which has the highest theral storage capacity, it should be used in very CONCLUSION In conclusion, for the non-coplex building types the siplified calculation ethod of theral ass in the building energy perforance calculations gives results parallel to dynaic calculations. The studies should be extended for the coplex building definitions to evaluate and copare the both siple hourly and dynaic building energy perforance calculation ethodologies. However the liits of building description in the siplified ethodology ay interfere to copare the ass storage capacities of building aterials precisely. REFERENCES ISO EN 1379:28. Energy perforance of buildings Calculation of energy use for space heating and cooling. ISO EN 13786:27. Theral Perforance of Building Coponents Dynaic Theral Characteristics Calculation Methods :27. Bep-Tr, 21, Official Gazette, Building energy perforance calculation ethodology of Turkey. thick s. However the best building energy perforances are obtained by aerated concrete s. DIN V , 27-2, Energy efficiency of buildings Calculation of the net, final and priary energy deand for heating, cooling, ventilation, doestic hot water and lighting Part 1: Boundry conditions of use, cliatic data, Deutsches Institut für Norung, Gerany. Directive 22/91/EC, Directive of the European Parliaent and of the Council on the Energy Perforance of Buildings. Energy, U.D.o., EnergyPlus Manual Version , plus/. BS EN ISO 1456, 27, Building aterials and products -- Hygrotheral properties -- Tabulated design values and procedures for deterining declared and design theral values, British Standards, UK. TUIK, 29, Turkish Statistical Institute, Statistical Research of energy consuption per person, Turkey. 1