Energy Conservation in Existing Office Building: Case study Petrojet Company Head Office Buildings in Cairo, Egypt

Transcription

1 Energy Conservation in Existing Office Building: Case study Petrojet Company Head Office Buildings in Cairo, Egypt Speakers: Nayera Refaat Abd-Allah 1, Ahmed Hamza H. Ali 1, Ali K. Abel-Rahman 1 and S. Ookawara 1,2 1 Energy Resources Engineering Department, Egypt- Japan University of Science and Technology E-JUST, New Borg Elarab, Alexandria 21934, Egypt 2 Department of Chemical Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan Abstract: The energy performance in two administrative office buildings in Egypt is evaluated. One building is a traditional classic building while in the other building the designer consider energy efficiency and solar energy generated power contribution to the power required. The office buildings in this study has been designed with the compliance of the building regulation during their contraction time. The evaluation is done by ENERGY STAR. The main conclusions were that ENERGY STAR can be used to evaluate energy performance of office buildings in Egypt. Egyptian office buildings can compete the USA office buildings in applying energy efficiency strategies. In addition, energy efficient lighting and HVAC systems used in the new building save 19% and 64% of the energy used respectively and will save about 46% from the source energy used. In addition the GHG emissions / m 2 in the new building is half that of the existing one. Keywords: energy efficient building, ENERGY STAR, GHG reduction, energy performance Introduction Sustainability of the built environment needs to go in parallel with sustaining the natural environment. Therefore, building energy conservation measures received a fair amount of attention lately around the world as they offer a potential impact for significant energy consumption savings and environmental impact reduction. Industrial Modernization Program [1] reported that GHG emissions in Egypt are expected to grow up by 2030 contributing to ~0.9% of world emissions. It was added that the 5 main sectors of emissions are power production, building, cement industries, road transport and agriculture will grow up to 77% of total emissions by 2030 while the building sector accounts for 12 % of the total emissions among the 5 main sectors. Hartungi et al. [2] cited that building more energy efficient structures may reduce carbon emissions by 60% or more, and will conserve conventional energy. Wang et al. [3] stated that a significant proportion of the energy used by building sector - about 40% of the global energy use - might be wasted due to various faults in building design, construction and particularly in operation stages. Liu et al. [4] stated that primary energy consumption in Egypt by residential and commercial buildings is expected to reach more than 35% by Hanna [5] cited that more than 60% of the total electricity consumption in Egypt is attributed to residential, commercial, and institutional buildings. He added that a significant increase in electricity demand is expected over the next few years with a growth rate of 8%. Artificial lighting is estimated to account for 36% of the electricity 1410

2 used in the nonresidential sector and 35% of the electricity used for HVAC system. Sheta et al. [6] stated that climate affects the amount of energy that is used for heating, cooling and lighting. They added that experience from traditional architecture, which was fairly well adapted to the climate, is often lost or difficult to adapt to modern techniques and society. Lamborn et al. [7] stated that the operation stage can amount to the greatest proportional impact a building can have on the environment. Various governments and business organizations have recently tried to encourage the implementation of energy efficient strategies in the commercial building industry by funding the development of performance assessment tools. Lamborn et al. [7] stated that rating tools represent one of the latest initiatives to assess a building s performance during the design stages and informing designers of the impact of their decisions. This initiative provides benefits of reducing operations and maintenance costs from the reduction of energy consumption. It also facilitates reduce CO 2 emission from the building sector. There are various examples of rating tools. The Environmental and Energy Design (LEED) green building rating system and the ENERGY STAR are well known in USA. The requirements for the certification of LEED buildings are more complex than those for ENERGY STAR, and the certification process measures six distinct components of sustainability, one of which is energy performance. Energy Star certification is based only upon energy efficiency in building operation; this is clearly more important in property markets in which the price of energy is higher [8]. Currently, the primary standard for comparison is the ENERGY STAR Portfolio Manager (ESPM) [9]. ESPM looks at the whole building in use and evaluates a property based on its utility bills (after weather normalization). For the past two decades, the Egyptian government has worked feverishly to improve building energy efficiency and address GHG emissions. In that sense, developing energy efficiency building codes was a critical first step [10]. Egyptian Commercial Energy Code (ECEC) was released in However, there is little indication that there is a change in the overall design practices in Egypt towards improved energy efficiency. [12]. Throughout the survey, it was found that energy efficiency in buildings is a prime objective for energy policy on all levels due to the striking figure of environmental impact and energy consumption. Traditional design processes seem inappropriate for practices today due to the number of participants involved and the many issues to be considered. In addition, the absence of performance assessment tools in Egypt makes several questions remain unanswered on how energy efficient strategies can become a regular part of the design process. Howerver, ENEGY STAR is a well-established rating tool. Therefore, the aim of this study is to evaluate the energy performance in two administrative office buildings in Cairo, Egypt using ENERGY STAR thus providing recommendations to enhance energy efficiency in existing office buildings for stakeholders. Methodology and procedures The energy performance in two administrative office buildings (Petrojet company head buildings) in Cairo, Egypt is evaluated. On one hand, the first is the existing head office which is a traditional classic building. On the other hand is the new head office that the designer consider energy efficiency and the solar energy generated power contribution to the 2411

3 power required to this building. The office buildings in this case study were designed with the compliance of the building regulation during their contraction time. The evaluation is done by ESPM using the energy use intensities (EUI), i.e. kwh/m 2. Performance assessment results are obtained by comparing the performance indicators (e.g. EUI or CO2 emission) against established benchmarks. [3]. ESPM requires a set of data based on a minimum of 50% occupancy, 12 consecutive months of metered utility bills, and basic building and space use characteristics, such as building size and location, operating hours, and number of occupants, to compute performance metrics. It normalizes for factors including climate, vacancy, and space use. ESPM does provide the means to prospectively analyze a building via a tool called ENERGY STAR Target Finder (ESTF). ESTF provides an estimate of what ESPM rating a building might obtain upon completion of 12 months of operation, if managed to achieve the estimated EUI [9]. Case study Various data is collected for analysis from: (the projects concept design documents and reports and available bills - inspecting the buildings and its systems closely - energy efficiency and building codes in Egypt - trusted sites/organizations about ENERGY STAR program). The grounds for the selection and analyzing this two buildings is based on the fact that there are quite a few good practices that could be adopt to improve the building energy performance and energy conservation. The power of the systems and equipment used in the two office buildings was available. The energy used by the most energy consuming systems (HVAC, Lighting, and computers) was determined from the collected power data and illustrated in Table 1. Table 1 illustrates the collected data and the determined energy values (KWh/month) for the two buildings existing office building New office building Location Cairo New Cairo Operating hours From 7.5 a.m. to 3.5 p.m. (8 hours x 22 days) per month started operating 1962, Some modifications Under construction were made to the building 10 years ago. total gross floor area m m 2 Open plan offices to allow more workspaces and more occupants. Plan design They are part of the energy conservation strategy as only one centralized area is being heated, or cooled, and lighted. total conditioned area m m 2 set point 25 o C 22 o C as indoor summer condition Number of Occupants Number of computers Lighting HVAC Split Units Natural gas (m 3 /month) Equipment Photovoltaic cells supplies

4 Figure 1 shows the old head office building Figure 2 shows the northern east corner of the new head office building design Regarding the design strategy adopted in the new building has demonstrated the level of complexity involved in the design of an office building. The design is based on the aspiration for high quality architectural design, visual transparency from inside to outside, and a profile in keeping with the surrounding landscape providing a good view for the occupants that help enhance their performance. Regarding the lighting system, the daylight depth in the existing building decrease with increasing the width of the exterior walls as shown in Figure 1. In addition, 4x18 W fluorescent lighting fixtures are installed. On the other hand, in the new building, daylight is provided by allowing large openings in the North and East facades. However, Vertical and horizontal louvers are distributed on the building facades as shown in Figure 2 to prevent direct sunlight from entering the building. To complement the daylighting, the building energy conservation features are also increased by using a variety of energy efficient artificial lighting installations. It differs according to its location and the luminance level required. Compact fluorescent and led lamps are used. The compact fluorescent tube produce approximately the same light output as the larger diameter lamps of the same length and color temperature, but consume about 8% less energy [2]. Also reflectors have been carefully selected to make the artificial lighting to become more efficient. In some areas, the reduced overhead lighting is applied as appropriate, as it is anticipated that the task lighting will be used at some workspaces. Lighting control system is used (timers, dimmers and occupant sensors). Regarding HVAC system, in the existing building self-contained air cooled System is installed and closed spaces are served with separate split units. On the other hand, in the new building, roof gardens distributed on facades helps in filtering the air and decreasing its temperature through evaporative cooling. In addition, absorption chillers directly fired using natural gas is installed. Variable speed pumps are used to feed the chillers. Separated fan coils serve closed spaces. Two-way valves are used before each fan coil to control water flow. During winter, the chillers are totally turned off. Heat exchangers are used between supplied and exhausted air. The whole HVAC is connected to a monitoring and controlling system. Regarding the energy sources, grid electricity is the only source of energy used in the old building. On the other hand, in the new building natural gas is used. Approximately two third of the electricity used is supplied from the grid. The rest of the electricity needed is supposed to be provided from photovoltaic (PVs) modules. It was proposed by the project designer to install photovoltaic system on the building roof. RET Screen 4 software was used to calculate the possible energy that can be provided by PVs considering the available roof area. RET Screen 4 is an Excel-based clean energy project 4413

5 analysis software tool that helps decision makers quickly and inexpensively determine the technical and financial viability of potential renewable energy, energy efficiency and cogeneration projects. The software provides a variety of PVs. Sungen poly-si-sgm-230p with capacity 230 W/unit, efficiency 14.1 % and surface area of 1.63 m 2 /unit was selected. The system contained an inverter with capacity 500 KW and efficiency 95%. The roof area available for installing PVs can be used to install 3000 PV units producing 1215 MWh/year leaving 1936bMWh/year to be supplied from the grid. Results and discussion The energy use meter readings of the existing building are illustrated in Figure 3. This illustration represent the actual energy performance in the building. There are two meters applied. One is for the energy used by the HVAC system and split units. The other is for the energy used by lighting, computers and any other equipment using electricity. Total energy used during the period from January 2012 to April 2014 by HVAC and split units (3 GWh) is approximatly double the total energy used (1.6 GW) during the same period by lighting and equipment. Therefore increasing efficiency of the HVAC system shows a great oppourtunity to save energy. The energy use distribution in the existing building is shown in Figure 4. It was found that the split units uses 68% of the total energy used by the existing building. Lighting and Equipment HVAC and Split units Total Energy use ENERGY USE (KWH/MONTH) ene-12 feb-12 mar-12 abr-12 may-12 jun-12 jul-12 ago-12 sep-12 oct-12 nov-12 dic-12 ene-13 feb-13 mar-13 abr-13 may-13 jun-13 jul-13 ago-13 sep-13 oct-13 nov-13 dic-13 ene-14 feb-14 mar-14 abr-14 Figure 3 shows meter readings for energy use in the old head office building ENERGY USE (KWH/MONTH) Lighting HVAC Split Units equipment Figure 4 shows the monthly determined energy use distribution for the existing building Considering lighting system, the monthly lighting and equipment energy use /m 2 (the determined and the obtained meter readings) for the two buildings is illustrated in figure 5. It was found that the energy use in the existing building for July 2012 is zero while the use for August 2012 is the most high value reaching 218 MWh/month which is nearly double the second most high value which is nearly equal to 112 MWh/month. This can be explained that the reading for both month July and August 2012 was taken at the end of August For about 11 months the meter reading is double the value of the determined energy use which 5414

6 ISBN: means that there is excess in the energy used. The annual energy used artificial lighting in the existing building is 16.2 KWh/m2, while in the new building is 13.1 KWh/m2. This means that the lighting system used in the new building is more energy efficient and saves 19% of the energy used in lighting. Considering HVAC system, the monthly HVAC system and the split units energy use /m2 (the determined and the obtained meter readings) for the two buildings is illustrated in figure 6. For the existing building, it was found that the determined values are so close to meter readings which means that this system is working almost properly. Increasing HVAC system efficiency may need high cost measurements to be done. The annual energy used by HVAC system and split units in the existing building is KWh/m2, while in the new building is 42.4 KWh/m2. This means that the absorption chillers used in the new building are more energy efficient and saves 64% of the energy used in conditioning. Figure 5 shows monthly lighting and equipment energy use per m2 in the old head office building Figure 6 shows HVAC and split units energy use per m2 in the old head office building ESPM and ESTF evaluation results came as illustrated in Table 2 and Table 3. On one hand, the existing building estimated score as a design if the building was using the determined energy is 95. On the other hand, the score according to the actual energy use for 2013 is 75. The source and site EUI of the building is approximately double the targeted value. This means that by applying some energy efficient measures in this building, its score can increase and compete the USA office buildings in applying energy efficiency strategies. However, the new building estimated score as a design if the building was using the determined energy is 95 when targeting 100. The source and site EUI of the building is approximately exceed the targeted value by one third. This means that this building will be able to compete USA office buildings if it is constructed as it was designed using the same energy determined. 6415

7 Table 2 presents ENERGY STAR results for the old head office building Property Baseline Current Median Metric Estimate at Target* (Nov 2012) (Oct 2013) Design Property* ENERGY STAR score (1-100) Source EUI (GJ/m²) Site EUI (GJ/m²) Total GHG Emissions (Metric Tons CO2e) , , , Table 3 presents ENERGY STAR results for the New head office building Metric Property Estimate at Design Target* Median Property* Design ENERGY STAR score (1-100) Source EUI (GJ/m²) Site EUI (GJ/m²) Total GHG Emissions (Metric Tons CO2e) 2, , , The source EUI in 2013 for the existing building is 2.31 GJ/m², while for the estimated design of the new building is 1.25 GJ/m². This means that the new building will save about 46% from the source EUI than the existing building. The estimated annual GHG emissions as evaluated by ENERGY STAR from the existing building is 0.11 tco 2 e /m 2 while for the new building is tco 2 e/m 2. This reduction includes the net GHG reduction of 622 tco 2 /year provided when applying the PVs system proposal. Conclusion In this study, the energy performance of two administrative office buildings is evaluated using ENERGY STAR. After analyzing the collected data and applying the assessment tool, the main conclusions are: 1. Installing meter and sub-meter in building might provide potential benefit to energy conservation through monitoring. While this potential could be turned into real benefit only when awareness of the potential energy saving is turned into actions. 2. Split units use 68% of the total energy used while the total energy used during the period from January 2012 to April 2014 by HVAC and split units is approximatly twice the that used by lighting and equipment. Therefore replacing the split units with energy efficient HVAC system and the increasing efficiency of the existing HVAC system shows a great oppourtunity to save energy. 3. The lighting and HVAC systems used in the new building are more energy efficient than that used in the existing one as lighting saves 19% and the HVAC saves 64% of the energy used. 4. ENERGY STAR rating tools (ESPM and ESTF) can be used to evaluate energy performance of office buildings in Egypt as the weather data for the Egyptian weather stations are defined on these tools. However, it is only allowed for American and Canadian facilities to apply for the certification from ENERGY STAR program until now. 5. Applying some energy efficient measures in the old head office building can increase its score and compete the USA office buildings in applying energy efficiency strategies. 7416

8 Regarding the new head office building, if will be able to compete USA office buildings if it is constructed as it was designed using the same energy determined. 6. The results of ESPM and ESTF showed that the new building would save about 46% from the source EUI than the existing building. This proves that the systems installed in the new building are more energy efficient and also consumes less energy despite the fact that the new building is five times the gross floor area of the old one and include more occupants, more equipment and larger HVAC system. In addition the GHG emissions tco 2 e/ m 2 in the new building is half that of the existing one making the environmental impact of one meter in the new building is half that of the existing one. Acknowledgment The first author would like to thank Egyptian Ministry of Higher Education (MoHE) for providing him the financial support (Master scholarship) for this research as well as the Egypt Japan University of Science and Technology (E-JUST) for offering the facility and tools needed to conduct this work. References [1] Industrial Modernisation Programme Egypt GHG emissions, reduction strategy. [2] Hartungi, R. and Jiang, L Achieving Energy Efficiency in Office Building. Sustainability in Energy and Buildings. 7, [3] Wang, S., Yan, C. and Xiao, F Quantitative energy performance assessment methods for existing buildings. Energy and Buildings. 55, [4] Liu, F., Meyer, A.S. and Hogan, J.F WO R L D WO R K I N G PA P E R Mainstreaming Building Energy Efficiency Codes in Developing Countries. [5] Hanna, G Energy efficiency building codes for Egypt. Journal of Energy and Power Engineering. 5, [6] Sheta, W. and Sharples, S A Building Simulation Sustainability Analysis to Assess Dwellings in a New Cairo Development. Fourth National Conference of IBPSA-USA, New York City, New York, [7] Lamborn, C., Altomonte, S., Luther, M.B. and Fuller, R Ecologically Sustainable Development and Architecture : the impact of rating tools. International PLEA Conference (23rd : 2006 : Geneva, Switzerland). Passive an, 1 6. [8] Kok, N., McGraw, M. and Quigley, J The diffusion of energy efficiency in building. The American Economic Review. 101, [9] McCabe, M. and Wang, N Commercial Building Energy Asset Rating Program: Market Research. [10] Consultant, S.E Energy Efficiency in the Buildings Sector : Egyptian Experience Energy outlook Concerning Primary Energy. [11] Fahmy, M., Mahdy, M.M. and Nikolopoulou, M Prediction of future energy consumption reduction using GRC envelope optimization for residential buildings in Egypt. Energy and Buildings. 70, [12] Huang, J., Deringer, J., Krarti, M. and Jamil Masud The Development of Residential and Commercial Building Energy Standards for Egypt. Proc. Energy Conservation in Buildings Workshop, Kuwait 8417