Evaluation of Energy Performance on Lighting by Using Dialux and Bep-Tr

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1 Evaluation of Energy Performance on Lighting by Using Dialux and Bep-Tr Res. Assist. Arzu CILASUN, Department of Architecture, Yaşar University, İzmir, Turkey Murat ANBARCI, Istanbul University, Department of Civil Abstract As the industrialisation has gained speed, energy consumption and given harm to environment has become one of the biggest global problems. Designing buildings and constructing them with conventional methods cause damages to environment and increase energy consumption. To avoid consequences, governments have issued legislative efforts for construction sector to decrease the negative impacts of the conventional buildings and prepared regulations and standards to lower energy consumption. Each country prepared these regulations by using their own unique values and enforced building sector to adapt and follow them. The Ministry of Public Works and Settlement of Turkey prepared its own regulation named BEP-TR (Building Energy Performance regulation of Turkey) with the help of scientists and academicians. In this regulation, to classify buildings energy efficiency, all factors that affect energy consumption were taken into consideration (heating, cooling, hot-water supply and lighting). This regulation is used to evaluate energy performance for residence, office, education buildings, health facilities, hotels, malls and trade centers. Since lighting is one of the major energy consumption segments, BEP-TR also involves lighting related subjects and calculations. Calculations can be done manually or by the help of BEP-TR s extension. BEP-TR s web based program can calculate energy consumptions just like many other programs which can be found on the market. Among these various programs, DIALux is one of the most commonly used programs in Turkey. DIALux can calculate and evaluate both artificial and daylight solutions. Energy consumption for lighting is being a burden to economy, especially for the office buildings. For example in Europe, energy consumption in office buildings due to lighting is approximately %50 of the total lighting consumption. Therefore in this paper, a sample office room will be evaluated to see the possible energy savings. Main aim of this paper is to introduce BEP-TR s and DIALux s lighting energy evaluations over a sample office room. Using the same room, lighting energy consumptions will be evaluated and results will be compared as well as the procedure itself. With this comparision, BEP-TR s and DIALux s featured properties will be analyzed and introduced to the lighting designers. Keywords: BEP-TR, Energy Performance, Lighting, Control Systems, LED

2 1. Introduction There has been a growing sense that global warming and climate change are almost impossible problems to overcome and their consequences will affect the next generations in long term [1]. Actually considering some key issues and increasing awareness on those issues may diminish the problems of the climate change. Climate change is caused by gases which are generally called greenhouse gases, (such as carbon dioxide, methane, nitrous oxide and etc.) but among all of them carbon dioxide is the most significant contributor [1]. Buildings happen to be a very big contributor to carbon dioxide emissions with a share of 40%. Due to that reason, in order to decrease the release of CO2 some precautions should be taken in building scale. To lower the harm given to environment by buildings and to improve the energy performance of both new and existing buildings some general precautions must have been taken. With the Kyoto Protocol, which was signed by majority of the countries all over the world, governments prepared regulations and long term commitments have been prepared to enforce precautions. The development of these legal regulations has improved energy efficiency in buildings, environmental protection and sustainability. These improvements include the widespread development of energy efficiency strategies and action plans, innovative financial instruments, active policies promoting energy efficiency in buildings, extensive adoption of standby power policies and policies to phase out inefficient lighting [2]. 2. Energy Performance Regulationof Turkey (BEP-TR) Turkey is one of the countries which prepared a regulation to reduce energy consumption which is called BEP-TR (Building Energy Performance regulation Program of Turkey). This regulation deals with important energy consuming aspects (like heating, lighting, ventilation etc.) and can be adapted to both new and existing buildings. Although the scopes of regulations vary, Building Energy Performance Regulation of Turkey mainly assesses energy use, control systems and also implementation of Energy Performance Certificates. Building Energy Performance Regulation involves a calculation method which is called BEP-CM (Building Energy Performance Calculation Method) to calculate the amount of annual energy consumption and CO2 emissions per square meter. Internet-based software called BEP-TR uses this calculation method to lay out the appropriate Energy Performance Certificate, which was developed by Turkish Ministry of Environment and Urban Planning in Building Energy Regulation s properties can be seen on Table 1. Table I. Properties of Building Energy Regulation In Turkey [3] Building Energy Performance Regulation Introduction Turkey The Energy Performance of Buildings (Certificates and Inspections) Regulations 2008 (the Energy Performance Regulations ) implement article 5627 of the Energy Law directive in Turkey. Requirements in Turkey over 1,000 m 2 as of 1 January General information about the building (i.e. Technical and administrative information Energy performance operational rating, Total CO2 emissions The Certificate Features Accompanying recommendation report with recommendations for improving energy performance Total energy used for heating, cooling, air conditioning, ventilation of the building. Certificate valid for ten years Rating The system rates buildings from A to G, similar to the system used to rate domestic white goods; 3. Energy Consumption Due To Lighting Lighting happens to be the one of the biggest energy consumption source since the invention of electricity. At the end of the 19th century initiated a new era for architecture, where electric lighting became a crucial component for spatial quality [4]. As Mies van der Rohe stated, the history of architecture is the history of man s struggle for light [5]. With the introduction of artificial light, daylight was moved to a lower level of priority in the design process and this resulted with increase in energy consumption due to lighting [6]. Nowadays since world is facing environmental problems due to excessive energy consumption new methods for reducing are searching through. Lighting is one of those important issues to be looked at.

3 Though electricity consumption for lighting differs according to the building types, office buildings, on the average, use the largest share of their total electricity consumption in lighting [7]. Approximately 50% of lighting energy (531 TWh) in IEA member countries is used for service sector [8]. Since lighting energy consumption of offices are in significant amounts, lighting designers have to very attentive while deciding on a lighting solution and should try to reduce energy consumption either with daylight or control systems (or both of them). Since lighting plays a major role, in order to reduce energy consumption of lighting, architects/engineers/lighting designers have to take some pre-cautions by evaluations especially on design phase. There are many strategies to lower energy consumption due to lighting. Improvement of lamps, ballast, luminaire, maintenance factor, utilization factor, reduction of switch on time, use of task/ambient lighting, occupancy sensors are some of the strategies related with artificial lighting. All these strategies and their relative saving potentials can be seen on Table 2 [9]. Table 2: Overview of energy saving strategies and relative energy saving potential [9] Overview of energy saving strategies and relative energy saving potential. Energy saving strategy Relative saving potential References 1 1 Improvement in lamp technology 10% (T12 tot8) 40% a (T12 tot5) [19][13,19] 2 Improvement in ballast technology 4-8% [19] 3 Improvement in luminaire technology 40% b [13] 4 Use of task/ambient lighting 22-25% [14.25] 5 Improvement in maintenance factor 5% c 12] 6 Improvement in utilization factor Depends on application and context 7 Reduction of maintained illuminance levels 20% (500 to 400 Ix) [34] 8 Reduction of total switch-on time 6% d [3] 9 Use of manual dimming 7-25% [33,45,46] 10 Use of switch-off occupancy sensors 20-35% [33,48,49] 11 Use of daylight dimming 25-60% e [54,74] a However, this number also includes improvements due to HF ballast and improvement in luminaire. b However, this number also includes dimming (occupancy and daylight) and improved (HF) ballasts. c About 5% of light output would be lost each year without a proper maintenance programme. d By reducing average existing total switch-on time to only 2600 h/year. e This number is highly dependent on the climate, the shading strategy and the base line for comparison (if compared to a case where lights are on 100% of the time, the savings appear to be much higher than a more realistic case with e.g. manual on/off switch at the door). 4. DIALux and BEP-TR s Energy Evaluation for Lighting In recent years, use of the computers has spread to all areas and designing is definitely one of those areas. As Liddament mentioned computationalism is one of the most pervasive and influential paradigms currently operating in the area of design research [10]. Computationalism also affected lighting design so that now there are numerous energy evaluation prediction software for lighting. These software programs are powerful tools that can solve variety of problems. They can evaluate energy consumptions easier, faster and more accurately, handle repetitive layouts, keep track of fixture counts, and determine potential savings [11]. Among the oodles programs, DIALux is one of the most commonly used lighting calculation software programs in Turkey. Besides it s a user friendly program with a simple interface, it is prepared and served free of charge by DIAL GmbH. Both artificial and daylight solutions can be calculated and simulated on DIALux. With the simulation window, user can follow the consequences of each preference instantly. In addition to calculation of lighting solutions, DIALux can also evaluate energy consumptions within a module in the program. Evaluations are done according to either EN or DIN standards. In order to evaluate a room, user has to first generate the room, just like in calculation. While generating a room, all the information entered (geometry of the room, obstructions, location, alignment, windows, lighting solution, materials etc.) are transferred to evaluation process automatically by DIALux. In addition to that information, user has to fill in/ answer serious number of parameters about both room and utilization. Considering all the information gathered, DIALux divides the room into daylit and non-daylit assessment zones automatically [12]. BEP-TR works similar with DIALux, though it s not free and can only be used by trained energy certificate specialist. BEP-TR defines a calculation and evaluation method for energy requirements in various types (residence, offices, public buildings, hotels, restaurants, sport centers, halls, factories etc.) both for existing and new buildings. BEP-TR involves a calculation method to calculate the lighting energy consumption based on European Union Standard EN15193 in Turkey conditions. LENI (Lighting Energy Numeric Indicator) is a numerical indicator for total annual lighting energy in building and has been developed to determine the energy performance class. In this calculation method, the effect of daylight to energy consumption determined by taking into several criteria, such as the area which is benefited from daylight, external obstacles, facade and dependence on window ratios and characteristics. Beside all these, control systems contribution to energy saving is also taken into consideration [3]. 5. Sample Office Room The typology and function of the building effects the energy consumption but among all types, commercial and primarily office buildings constitutes the highest energy consumption among all other types. The total annual energy use in office buildings varies in the range of kwh/m 2 yr, depending on the geographic location, use and type of office equipment, operational schedules, type of envelope, use of HVAC systems, type of lighting etc [8]. In reducing the energy consumptions of buildings, lighting plays a major role among all these factors. In commercial buildings, lighting constitutes generally 20-45% of electricity demand but it varies a lot from one building to another and the consumption of electric lighting can sometimes be as much as 40% of the gross energy consumption in some buildings [9]. 1 This table is directly taken from Dubois, M.C.; Blomsterberg, A. -Energy saving potential and strategies for electric lighting in future North European, low energy office buildings: A literature review. Energy Buildings, Vol. 43, pp (2011). The stated references can be found from the original article.

4 Therefore within the context of this study, a sample office room (length: 11.8, width: 6.7, height: 3m) for six people will be evaluated for energy consumption due to lighting manner (Figure 1a-1b).Since the main aim is to reduce energy consumption, control systems contribution to energy savings will be also a part of this study. While doing evaluations,in order to make evaluations more specific for the analyzed room, programs ask users to fill in the blanks or choosing the most appropriate one from the givens. However, any remaining blanks filled in by the software as default parameters can considerably mislead the results [1]. Therefore it s very important to fill each of the blanks with the most appropriate answers. For the case study, selected parameters and specification of the room can be seen on Table 3. Table 3: Common values for Sample Room Common Values For Sample Room City Đstanbul Geographical Position (longitude/latitude) 29/41 Alignment South Dimensions of the room 6,70 x x 3.00 m Room Height of working plane 0,80 m The distance between walls and working plane 0,50 m Room reflectances 70/50/20 Dimensions of the window 9 m x 1,25 m Degree of transmission 0,8 Operating Factors Maintenance Control Room index 2,5 Function/description of the room Office (for 6 people) Operating Hours (day) 2150 Operating Hours (night) 190 Maintenance factor 0,84 Light loss factor 0,80 m Luminaire maintenance type D-IP 2X Room Maintenance interval 2 years Luminaire maintenance interval 2 years With control system Without control system Constant illuminance factor 0,9 1.0 Maintained illuminance 500 lux 500 lux Occupancy dependency factor 0,80 1,00 Absence Factor 0,3 0,3 Control type On/ Off on/ Automatic Switching As we mentioned earlier in Table 2, there are various ways to reduce energy consumption of lighting. One of them happens to be the improvement of luminaire technology. Because the most significant environmental impact (80 90%) of lighting is generated during the operation of the lighting system, the cost of an electric lighting installation typically represents only15% of total costs, while electricity use during operation represents around 70% of total costs [7]. Since operation cost is a primary cost, it s vital to reduce it by choosing lamp type considering energy consumption as well as visual comfort. In this study, to different luminaires are used to see the change of energy consumption during operation (Table 4). Number of luminaires used in the sample room differs due to their luminaire efficacy. These numbers are determined by calculation of lighting levels on the workplane. In order to obtain 500 lux on workplane, 9 luminaires of fluorescent and 12 luminaires of LED lamp were used (Figure 1a and 1b). Table 4: Two different lighting solutions for the case study Number of Solution Properties Light Source Type Manufacturer/ Code Lum. Efficacy Luminaire Solution A 2 35 W T16 fluorescent Zumtobel Luminous intensity 9 76W 5788 lm Luminaire intensity diagram Solution B 2x48 W LED Zumtobel W 5020 lm

5 Figure 1a: Solution A- Fluorescent Figure 1b: Solution B- LED 6. RESULTS By using the parameters for the given sample room, evaluations are done both in DIALux and BEP-TR using EN15193 standard. The results of these evaluations in terms of energy consumption and LENI can be seen on Table 5. Table 5: DIALUX and BEP-TR Results DIALUX BEP-TR Comparison Of The Fluorescent LED Fluorescent LED Results Energy Consumption 1337,23 610, ,14 846, ,22 622, ,13 863,43 Area (m 2 ) 78,81 78,81 LENI 16,97 7,75 27,37 10,74 17,08 7,90 27,93 10,96 7. CONCLUSIONS In this study, main aim was to introduce the lighting evaluation properties of DIALux and BEP-TR over a sample office room. In order to show the contribution of control systems and different lamp technology to energy savings, different cases were analyzed and compared. Since both of the programs use EN15193 standard for evaluations, results are found to be parallel with each other. The difference between the results of these two programs is smaller than 2%. Therefore we can conclude that, both of the programs stick to the EN15193 standard s equations and values in evaluation process. Luminaires with fluorescent and LED lighting were chosen to see the variation of energy consumption. By looking at the evaluation results we can conclude that fluorescent lamps are more economic than LED. But for sure, these numbers (on Table 5) are the results of the comparison of only these two luminaires and cannot be generalized. Also as it was explained before, number of luminaires used in the solutions is different because the main aim was not to keep these solutions identical but to obtain 500 lux on the workplane as average illuminance level. So this fact probably has affected the results. For reducing energy costs and consumption, usage of control systems on commercial and public spaces show an increase. In this study, to emphasize their contribution to energy savings, manual on/off and manual on/automatic switching off situations was compared. As it is shown on Table 5, only by using automatic switching, energy consumption almost reduced by %50. Usage of computer programs in evaluation easies the work of designer/architect/engineer. Especially while doing energy evaluations, since they use the regulations and standards as the main source, the results are more reliable in addition to convenience compared to manual evaluations. DIALux and BEP-TR s evaluation processes actually resemble with each other, yet they vary in many ways. For instance DIALux is a free software and can be used by anyone with computer skills, while BEP-TR can be only used by specialists who are trained by The Ministry of Public Works and Settlement of Turkey. In context they vary as well, for example DIALux is capable of only doing lighting evaluations while BEP-TR involves other energy related evaluations like heating, cooling and ventilation. Consequently, as long as the parameters and specifications of the room are known, evaluation processes are easy, fast and reliable. As a result, using DIALux or BEP-TR for lighting energy evaluations would ease the job of lighting designer/architect/engineer. List of References [1] Jankovic, L. - Designing Zero Carbon Buildings Using Dynamic Simulation Methods, Routledge, New York, 2012 [2] OECD (2012) - Review of the Implementation of the OECD Environmental Strategy for the First Decade of the 21st Century, Making Green Growth Deliver, March 29-30, 2012 from the World Wide Web:

6 [3] BEP (2008) - Building Energy Performance Regulation No Publication Date: [4] Kutlu, G. - An Evaluation Methodology for Assesing Artificial Lighting Quality in Architecture: The Case of APIKAM. ĐYTE, Đzmir, [5] Trauthwein, C.- Back to Basics: Daylighting. Architectural Lighting Magazine. Vol.20, pp [6] Velds, M.- Assesment of Lighting Quality in Office Rooms with Daylighting Systems, TechnischeUniversiteit Delft, Steenwijk, [7] EC, (2007) - Energy Performance on Buildings Directive 2002/91 EC.s.l. : European Comission. [8] Chiogna, M.; Mahdavi, A.; Albatici, R.; Frattari, A. -Energy Efficiency of Alternative Lighting Control Systems. Lighting Res. Technol. Vol 44, pg , [9] Dubois, M.C.; Blomsterberg, A. -Energy saving potential and strategies for electric lighting in future North European, low energy office buildings: A literature review. Energy Buildings, Vol. 43, pp (2011). [10] Liddament, T. -The Computationalist Paradigm in Design Research. Design Studies (1996), pg [11] Cilasun, A. - Analysis of Energy Evaluation on Lighting Programs, Proceedings of the IAHS XVIII World Congress, April 16-19, Istanbul, Turkey (2012). [12] DIALux. (2011). DIAL. DIALux website: [13] Stern, N. -The Economics of Climate Change, HM Treasury, s.l.(2006).