DESIGN APPROACH BASED ON ENERGY OPTIMIZATION OF ATMA JAYA YOGYAKARTA UNIVERSITY LIBRARY TO ACHIEVE SUSTAINABLE BUILT ENVIRONMENTAL REQUIREMENTS

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1 DESIGN APPROACH BASED ON ENERGY OPTIMIZATION OF ATMA JAYA YOGYAKARTA UNIVERSITY LIBRARY TO ACHIEVE SUSTAINABLE BUILT ENVIRONMENTAL REQUIREMENTS J. Ade Prasetya Seputra 1) and Amos Setiadi 2) 1) Mahasiswa Magister Teknik Arsitektur Univ. Atma Jaya Yogyakarta 2) Magister Teknik Arsitektur Univ.Atma Jaya Yogyakarta ABSTRACT Numerous numbers of energy conservation strategies were implemented with neither sufficient consideration of building performance nor occupancy needs and this has led to many failures in building performance. In order to find out the level of environmental conduciveness in a library, this research is done as an evaluation process to assess the building performance mandates of Atma Jaya University s library in Yogyakarta. Building performance mandates examined were ventilation performance, lighting performance (both natural and artificial), and thermal comfort represented in the form of cooling loads as the main energy usage inside the building. The result could be used as a comparison tool to identify the range of deviation occurred between the predesign and the current operational process. Furthermore, it could be utilized to form the appropriate energy management system of building. Building performance analysis is conducted in order to find the ventilation and lighting problems emerged in the existing building, by help of ESI CFD, Autodesk Ecotect software and local weather data of Yogyakarta. Hence, the main objective is focused on the optimization of the passive system to reduce or maintain the current level of energy consumption (cooling loads) inside the building. Although the models were created according to the physical field observation and its different usage, the user pattern is not further investigated. The aim is to show how to find and solve the problems using computer simulation as the representation of the actual building. The thermal comfort is represented by level of cooling loads of chosen rooms inside the building. Lower loads leads to be lower utilization of auxiliary energy for air-conditioning and hence to lower pollutants on the energy production side. Keywords: energy optimization, sustainable built environment. INTRODUCTION Current world population and environment problems have made radical changes in building planning and construction process. The concept of total building performance application could reduce energy consumption, pollution, and waste produced by the new or existing building. This would gradually increase living quality by assuring sufficient thermal and visual comfort inside buildings, which are measured through the occupant's level of satisfaction, health, and productivity. METHODOLOGY The applied methodology of this research was an objective approach. It s impossible to do detailed subjective measurement because the examined building had not yet operated when this research was conducted. The Atma Jaya Yogyakarta University s library has been chosen as the case study. The information was obtained by various techniques ranging from interviews, walk-through and visual inspection. Field's measurement was recorded using luxmeter, HOBO U12 data logger, non-contact infrared thermometer and anemometer. Subjective measurement was merely carried out by conducting a survey on the building staffs to assess two performance criteria i.e. thermal comfort and visual comfort. Data obtained from the surveys were analyzed and used to simulate the actual conditions by help of computer programs. ESI CFD and Autodesk Ecotect software was chosen to do the simulation tasks. Computational Fluid Dynamics (CFD) built by ESI is a form of numeric calculation software in order to predict and assume fluid flows aided by computer. It will be utilized to examine the airflow inside the building. Autodesk Ecotect is a building analysis program that allows designers to apply all the tools, which integrate lighting, energy, acoustics and environmental analyses for an energy efficient J Ade Prasetya S & Amos Setiadi Design Approach Based on Energy Optimization of Atma Jaya Yogyakarta University Library to Achieve Sustainable Built Environmental Requirements 11

2 and sustainable future. Most of the building performance analysis, i.e. visual and thermal comfort, will be measured by this software. Non Residential Design Guideline Energy Efficiency Building The UAJY s library is a new building which has been designed according to energy conscious mandates in relation to the passive and active building designs, constructions and building operations pertaining to the architecture, mechanical and electrical systems, office equipments, landscaping and implementation of energy management systems. Nevertheless, there were no further studies conducted to assess the performance of the currently erected building. This research will measure the chosen mandates of thermal, visual comfort and the energy efficiency means according to the criterion below. Thermal Comfort Visual 20 0 C (room with books) and 26 0 C (without books) Comfort DBT RH % Illumination Lv Lux Building Facades OTTV RTTV EEI (Energy Efficiency Index) <45 <45 <189 W/m 2 W/m 2 Kwh/ m 2 /year Table 1. Parameters of thermal, visual comfort and the energy efficiency Source: Jimmy Priatman. Energy Conscious Design, Konsepsi dan Strategi Perancangan. Objective Measurement Objective measurements were carried out based on a walk-through and visual inspection inside the building. All the corresponding rooms are zoned according to the usage and each particular requirement. The data recorded were about thermal and visual comfort properties in each room as well as its natural and auxiliary lighting and the air conditioning system. same level of sensitivity to the comfort of the environment. Data Analysis Due to the halted operation of the building during this research was being composed, there were assumptions created to compensate with the limited data inputs.: a).building s energy analysis based on computer simulation without actual electricity bill input. b).no subjective data input gathered from the occupants because the building has not operated yet. c).prediction of number and heat produced from electric equipment is done due to some building s equipment have not been installed. d).materials used for the simulation process assumed equivalent with the actual building as well as lighting properties and air conditioning system. Simulation is conducted in order to compare the actual condition of chosen building s performance with the newly improved design performance. The problems occurred in the simulation process will be identified and further examined to determine the application of appropriate solution in each case. Geographically, Yogyakarta is located on South Latitude and East Longitude (Source: Google Earth Pro 4.2). Based on this location, Yogyakarta is classified in the warm humid climate region with high humidity and rainfall throughout the year, has constantly high temperatures throughout the year, diurnal temperature variations around 8 C, minimal seasonal variation in temperature, and solar radiation intensity varies widely with cloud conditions. Subjective Measurement Subjective measurements were carried out based on a personal interview from the building s staffs. The sample size for the survey is 20 staffs, and they were assumed to have the 2

3 Model C has been chosen by reason that cross-ventilation concept will happen much often when the air got minimum distance to escape as soon as it enters the room. Furthermore, in the actual world, the availability of high book shelves will greatly affect the airflow and hinder it to cross over the other side of openings. Picture 1. Climate Data of Yogyakarta Source: Meteonorm CFD Simulation Results Existed 1 st Floor of Building ANALYSIS Identification process was begun with the assessment of natural airflow inside the building. The airflow distribution and its behaviour were examined to find out the best configuration of openings and other architectural elements, which may improve the air change rate and its relationship with user s comfort and indoor air quality. It s found that the worst case of natural ventilation potential occurred when the wind blows parallel with the building s long axis (from west and east side). The experiment below is done by applying wing walls on the north and south side of building to create both negative and positive pressure at once on each side thus improving the airflow inside the building. The main focus is taken on the first, second and third floor where the greatest potential of natural ventilation takes place. Flow Vectors Experiment Model A Experiment Model B Experiment Model C Mainstreams Table 2. Comparison of The Experimental Models Existing model shows strong airflow speed ( m/s) at north side and weak airflow at south side. Proposed 1 st Floor of Building Proposed model shows more even distribution with air speed m/s on almost every corner of examined workplane. Cross ventilation is created at each north and south side of building. Table 3. Airflow distribution of the existed and proposed building. Conclusion of Natural Ventilation Analysis Wing-walls application on both sides of outer walls has altered airflow distribution inside building. Basement and ground floor in proposed design which are not equipped with wing-walls have the same pattern as the existing one. Wing-walls placement on the windward side proven to be effective to draw air enters and leaves the interior. On the other side, wing-walls which are on the leeward side are no longer effective, and they tend to have the same behavior as the ordinary openings due to J Ade Prasetya S & Amos Setiadi Design Approach Based on Energy Optimization of Atma Jaya Yogyakarta University Library to Achieve Sustainable Built Environmental Requirements 31

4 their incapability of creating positive and negative pressure. Eco- Daylight Analysis using Autodesk tect and Desktop Radiance 2.1 Reflectance level of surface materials inside the rooms also has a great impact on the distribution of daylight. Floors, walls, and ceilings all have reflectance value of 60%, 80%, and 90% respectively. The simulation process started by defining desired output, that is the illumination level on a work plane 80 cm above the floor level. Sky model used in the calculation is the CIE Overcast Sky Model to represent the worst case scenario when sky light is scattered evenly in the hemisphere. According to the field observation of existing building, the level of daylight illuminance is severely insufficient especially in the middle of the building. It was discovered that the furniture arrangement inside the building has become the major cause. Daylight enters the building through the windows is blocked by book shelves that are perpendicularly placed from the incoming daylight from the perimeter windows. c) Re-arranging the furniture layout, especially the tall book shelves which blocked the daylight penetration. d) Utilizing light pipe and hidden skylight to increase the illumination level in the basement. e) Detaching the outdoor corridor on the ground level from the main building in order to allow daylight penetrates further to the building. Picture 3. The Proposed Building Model Existed 1 st Floor of Building Picture 2. The Existed Building Model An experiment has been done by considering the factors above. Simulation once more is utilized as tools to predict the changes attempted to improve the daylight distribution qualitively and quantitatively. The improvement applied are: a) Separating the usage of windows into view and light source windows by adding clerestories as the daylight source above the existed windows, supplemented by high reflective light shelves to allow daylight penetrates deeper into the building. View windows are equipped with rayband glass 40% to reduce glare. b) Increasing the reflectance value of furniture to 50% by re-painting the book shelves with brighter colour. Average illuminance is 150 lux. Most of them are far below the recommended level of illumination. The furniture arrangement does not accommodate the daylight distribution inside the building. Proposed 1 st Floor of Building Average illuminance is 234 lux. The distribution is improved and the area below 100 lux is reduced. Furniture arrangement has been altered to accommodate daylight distribution. The gradation of illumination level near windows is smooth which means reduced glare. Table 4. Comparison of Illumination level and distribution of daylight in existed and proposed building. 4

5 Field Measurement to Validate The Simulation Results In order to test the accuracy of the daylight simulation results, a field observation to record the daylight levels inside the building has been conducted. The measurement was done in the overcast sky of midday at pm to match the simulation process. All the electric lights were turned off, then a luxmeter was used to measure and record the daylight illumination level on 80 cm above the floor. Finally, the result shows the similar tendency with the simulation process. Conclusion of The Daylight Simulation Generally, the pattern of daylight distribution has been greatly improved. Average illuminance has increased up to 200%, especially in the basement. The previous strategies of daylight utilization are successful in improving and distributing light intensity needed by rooms inside the building. The usage of two type windows (view and light source) effectively enhanced the distribution pattern on the work plane. The placement of high clerestory windows equipped with light shelf allows the daylight to penetrate further into the middle of rooms. Furniture re-arrangement helps daylight to light the room evenly. Increased reflectance values on the book shelves add more positive effects in light distribution. Utilization of light pipe and hidden skylight has increased average illumination level in the basement up to 600%. Artificial Lighting Simulation using Autodesk Ecotect and Desktop Radiance 2.1 SAVY Downlight Philips Compact Fluorescent 1440 FBS 18W Roset ESS 18W Compact Fluorescent 1000 Spot model QBS Compact Fluorescent 1000 Table 5. Lamps used based on lumens In the design process, the artificial lights have been considered nicely by distributing the lights evenly in every area, yet in fact the prediction is missed because of the insufficient space needed to place the book shelves. It has made the shelves arranged closer one to another than the previous prediction. Consequently, the lights' placement is then ignored to meet the spatial needs. Furthermore, books have bad reflectance value as well as the old shelves used. The above situation makes the lights quality and distribution inside building decreasing. Experimental method in artificial lighting is done by re-arranging the furniture according to the existed light's placement and increasing its reflectance value to 50%. The method is simple yet enough to improve the lighting distribution for ambient needs. Existed 1 st Floor of Building Picture 3. Artificial Lighting Illuminance Contours Artificial lighting simulation is done in order to measure how effective the placements of light points are in fulfilling minimum requirement 100 lux of ambient illumination level. Since there were no IES data found, the simulation assumed the photometrics are omni-directional and only lumens are used as input. Based on the blue print, the building model and the lights are created in Autodesk Ecotect as below: Existing Lamp Type Simulation Lamp Lumens Type Lampu Baret BCS 22 Clean Metal Halide 3600 RM 2x36W MO Fluorescent 2200 SAVY GMS 1x36W ACR Fluorescent 1100 Image and false color of atria s stairs in collection room Image and false color of book shelves in reference room Picture 4. Artificial Lighting Image Impressions Average illuminance level is 108 lux. Clipped area appears in the middle of room. The layout and low reflectance values of furniture do not accommodate light distribution thus degrading its quality. Even if both daylight and auxiliary lighting utilized all the day, it s still doubtful that they could provide the required light intensity inside this area, especially for reading J Ade Prasetya S & Amos Setiadi Design Approach Based on Energy Optimization of Atma Jaya Yogyakarta University Library to Achieve Sustainable Built Environmental Requirements 51

6 activity. Proposed 1 st Floor of Building application of brighter paints are able to increase the average illuminance level up to 30% as well as maintaining the effective distribution of artificial lighting inside the building. Eco- Thermal Simulation using Autodesk tect Picture 5. Artificial Lighting Illuminance Contours Image and false color of atria s stairs in collection room Image and false color of book shelves in reference room Picture 6. Artificial Lighting Image Impressions Average illuminance level is 152 lux. The distribution has improved in the collection rooms. The layout has been adjusted as necessary and the reflectance of furniture has been increased as well to accommodate light distribution inside the room. Created ambient lighting has met the minimum requirement of light intensity in the library (> 100 lux). Table 6. Illumination level and distribution of artificial lighting in existed and proposed building. Field Measurement to Validate The Simulation Results In order to test the accuracy of the artificial lighting simulation results, a field observation to record the illumination levels of auxiliary lighting inside the building has been conducted. The measurement was done in the evening at pm to avoid any daylight interference during the day. All the electric lights were turned on, then a luxmeter was used to measure and record the light illumination level on 80 cm above the floor. Finally, the result shows the similar tendency with the simulation process. Conclusion of Artificial Lighting Simulation The simulation shows positive changes on energy efficiency means since the lights installed effectively lit every area inside the building. Little adjustment in furniture layout and the Thermal data gained from the field observation will be calculated in Autodesk Ecotect to assess the building performance from the thermal comfort aspect. Energy analysis then will be done as representation for the previous thermal simulation expressed by the form of Air-Conditioning cooling loads. Focus will be given on the worst case scenario by finding the maximum cooling loads for each room in a year. Rooms will be examined are the main room with an atria which covers the basement, ground floor, first floor, and second floor. It consists of thesis room (basement), transition room (ground floor), collection room (first floor), and reference room (second room). Additional experiment of computer room in basement is also done as comparison to the atria room. Comparison method will be done by comparing required cooling loads from the simulation result with the manual calculation done by the building s consultant. Cooling Loads Manual Calculation Since the manual calculation has been done in the design process by a trusted building consultant, then it will be the benchmark of the simulation process. The calculation was done based on the atria with open partition of room scenario shows the required cooling loads of Btu/h. It needs to be converted to watts in order to compare directly with the simulation result. The calculation then becomes kw. By the same method, the computer room in the basement shows Btu/h or 8.79 kw. Cooling Loads Simulation using Autodesk Ecotect Here the simulation will calculate cooling loads prediction in the developed design according to the previous experiments made by means of ventilation and lighting quality improvements. This process can be merely said to be a test about the impact of design 6

7 changes that have been made so far on the building s energy consumption aspect. Some variables need to be included in the simulation process are described in the table below. System Efficiency Operating time / day Main Room with Atria (<20 0 C) Full AC 80% 13 hrs Computer Room in Basement (<26 0 C) Full AC 80% 13 hrs Table 7. HVAC System Input Data Max Cooling: W at 12:00 on 11th April Table 10. Comparison of Max Cooling Loads on The Existing and Proposed Design of Main Room with Atria Computer Room (Basement) Existed Room Occupants Numbers Clothes Activity Main Room with Atria (<20 0 C) 325 Light sedentary Computer Room in Basement (<26 0 C) 41 Light sedentary Table 8. Occupant s Input Data Max Cooling: 6056 W at 12:00 on 11th October Proposed Room Equipment Heat Air Infiltration Latent Sensible ACH Sensitivity Main Room with Atria (<20 0 C) Computer Room in Basement (<26 0 C) Table 9. Heat and Ventilation Input Data Main Room with Atria Existed Ground Floor s Transition Room Max Cooling: 5599 W at 12:00 on 11th October Table 11. Comparison of Max Cooling Loads on The Existing and Proposed Design of Computer Room Cooling loads profile in the main atria room shows the required energy to maintain room temperature below 20 0 C. Lowest loads shown by thesis room, which has the smallest room volume, otherwise the greatest loads is shown by collection room in the first floor due to its biggest volume among others. Total cooling loads required in the existing main atria room is 245 kw and the proposed one is 242 kw. Meanwhile, cooling loads required in the existing computer room is only 6 kw and the proposed is 5.5 kw. Conclusion of Cooling Loads Calculation Max Cooling: W at 12:00 on 11th April Proposed Ground Floor s Transition Room Autodesk Ecotect simulation has a lower prediction of maximum cooling loads than the manual calculation. It is likely that the assumptions used in the manual calculation for unpredictable loads up to 30% have caused little differences between them. However, it needs further investigation to find out the exact cause of this deviation. For now, the error of Autodesk Ecotect for cooling loads calculation based on the manual prediction is 2.4%. The developed design which has been made so far could not reduce the energy consumption significant- J Ade Prasetya S & Amos Setiadi Design Approach Based on Energy Optimization of Atma Jaya Yogyakarta University Library to Achieve Sustainable Built Environmental Requirements 71

8 ly, it can only save about 10-15% of total cooling loads in the chosen room. CONCLUSION The result indicates that the investigated building performance in the form of actual ventilation and lighting quality have many unexpected deficiencies. The worst natural ventilation performance occurred when the wind blows from west and east side of building. The improvement is done by applying wing walls on the north and south side of building in order to create both negative and positive pressure at once on each side thus improving the airflow distribution inside the building. Daylight and artificial light distribution inside the building are not satisfactory either, there are many areas which have the illumination level below the standards of 100 lux. The utilization of view type and light source type windows, light shelf, light pipe, skylight, furniture rearrangement, and reflectance value modification contribute significantly in improving the visual quality and daylight as well as artificial light distribution up to 200% inside the building. The cooling loads calculation on proposed design could not reduce the energy usage significantly (only 10-15%) due to the restrictions that forbid to do major changes on the building. Nevertheless, the previous building performance problems in ventilating and lighting quality have been solved and greatly improved. Peter Burberry, 1978, Building for Energy Conservation, Architectural Press Ltd, London. Walter F. Wagner, Jr., AIA, Energy Efficient Buildings, Architectural Record Magazine, New York. Prasasto Satwiko, 2005, Arsitektur Sadar Energi, Andi Offset, Yogyakarta. Prasasto Satwiko, 2009, Fisika Bangunan, Andi Offset, Yogyakarta. REFERENCES Norbert Lechner, 2001, Heating, Cooling, Lighting: Metode Desain untuk Arsitektur Edisi Kedua,, John Wiley & Sons Inc, PT RajaGrafindo Persada, Jakarta. Unified Facilities Criteria (UFC) N, 16 January Cooling Buildings by Natural Ventilation, Department of Defense, USA Peter F. Smith, 2001, Architecture in a Climate of Change: A guide to sustainable design, Architectural Press, Oxford. Terry S.Boutet, 1987, Controlling Air Movement, McGraw-Hill Book Company. Mark Karlen and James R. Benya, 2004, Lighting Design Basics, John Wiley & Sons, Inc., Hoboken, New Jersey Ali Malkawi and Godfried Augenbroe, 2004, Advanced Building Simulation, Spon Press New York and London. 8