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Geothermal heat pump's energy effect and economical benefits

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Geothermal heat pump's energy effect and economical benefits

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Content GEOTHERMAL HEAT PUMP‟S ENERGY EFFECT AND ECONOMICAL BENEFITS by Yang Shen A Thesis Presented to the FACULTY OF THE USC SCHOOL OF ARCHITECTURE UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree MASTER OF BUILDING SCIENCE May 2011 Copyright 2011 Yang Shen ii ACKNOWLEDGEMENTS I am grateful to everyone who helped me to complete this thesis and 2 years beautiful graduate study in USC. Without their support, I am impossible to finish this thesis. First of all, I would express my deepest appreciation to Professor Edwin, Woll, the committee chair of my thesis, since his guidance, dedication and encouragement on the whole process of my thesis. Secondly, I give a big thank to other committee members, Mr. Peter Simmonds, Mr. Tianxin xing, who help me on every phase of my thesis. Finally, thanks to Miss Guoxia Wu, who provides an excellent case study for my thesis. Many thanks to Professor Marc Schiler, direct of Master of Building Science program, who gave me an opportunity to 2 years great experience in MBS program. Thanks to all MBS professors and teachers, you gave me great help in such important two years. Thanks to my parents and all family members, without the motivation and encouragement from you, I cannot finish this thesis. I love you! iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................ ii LIST OF TABLES .......................................................................................................... v LIST OF FIGURES ...................................................................................................... viii LIST OF CHARTS ........................................................................................................ xi ABSTRACT…………...…………..…………………………………..……..............xiii CHAPTER 1: INTRODUCTION ................................................................................... 1 1.1. Background Introduction ...................................................................................... 1 1.2. Geothermal Heat Pump Introduction .................................................................... 5 1.3. Building Background ............................................................................................ 7 1.4. Objective ............................................................................................................... 8 CHAPTER 2: LITERATURE REVIEW ...................................................................... 11 2.1. Development of Geothermal (Ground Source) Heat Pump ................................ 11 2.1.1. Development of Ground Source Heat Pumps in the United States ............. 12 2.1.2. Development of Ground Source Heat Pump in Europe ............................... 12 2.2. Types of Heat Pump ........................................................................................... 15 2.3. Terminology Explanation ................................................................................... 17 2.4. Ground Source Heat Pump Overview ................................................................ 18 2.5. Principle and Performance of GSHP .................................................................. 21 2.6. Types of GHP/GSHP .......................................................................................... 29 2.7. Current Research Situation ................................................................................. 33 CHAPTER 3: METHODOLOGY ................................................................................ 34 3.1. Methodology Overview ...................................................................................... 34 3.2. ASHRAE and CBECS Introduction ................................................................... 35 3.3. Simulation Tools and Energy Performance ........................................................ 36 3.4. DOE2 and eQUEST............................................................................................ 38 3.5. eQUEST Modeling Approach and Simulation Process ...................................... 40 CHAPTER 4: SIMULATION MODELING PROCESS .............................................. 42 4.1. Building Model Description ............................................................................... 42 4.2. Building Block Simulation………...………………………………………...…43 CHAPTER 5: DATA RESULT .................................................................................... 70 5.1. Baseline Model Result and Calibration .............................................................. 70 iv 5.2. Detailed Result for Baseline, Alternative I and Alternative II model ................ 74 CHAPTER 6: RESULT ANALYSIS .......................................................................... 103 6.1. Comparison between Baseline Model and Real Building ................................ 103 6.2. Comparison between Baseline Model and Alternative I Model ....................... 104 6.3. Comparison between Alternative I model, Alternative II model and CBECS Database ...................................................................................................................... 115 6.4. Life Cycle Cost Analysis .................................................................................. 124 CHAPTER 7: CONCLUSION .................................................................................... 129 7.1. Hypothesis Verification .................................................................................... 129 7.2 Future Work ....................................................................................................... 131 BIBLIOGRAPHY……………………………………………………………………133 APPENDIX ................................................................................................................. 136 v LIST OF TABLES Table 1-1: Comparison between superficial and deep layer …………………….…..........5 Table 2-1: Leading country using GSHP (J. Lund 2004) …………...…….…………….11 Table 2-2: General Heat Pump (Total) and Ground-Source Heat Pump Systems (GSHP) Installed 1993-1996 in Various European Countries (Burkhard Sanner 2000)...13 Table 2-3: Number of annual heat pump sales in Germany (J. Lund 20)……………......14 Table 2-4: The energy efficiency of different heating ways (Huang 2010)……………..27 Table 4-1: Climate data for Shanghai (1971-2000) (China Meteorological Administration)…..............................................................................................................44 Table 4-2: Design related climate data (shanghai xiandai architecture) …………….......44 Table 4-3: Conventional HVAC system design parameter (Xiandai Architecture)….….46 Table 4-4: GSHP system design parameter (Xiandai Architecture) ………………..…...46 Table 4-5: Chiller specification in eQUEST ……………………………..………...……48 Table 4-6: Chilled water loop properties ………………………...….…………………..48 Table 4-7: Chilled water loop properties ……………………………….…………….....49 Table 4-8: Heat rejection specification in eQUEST ………...…………….…………….49 Table 4-9: Pump properties for CHW loop and CW loop in eQUEST……………….....50 Table 4-10: Ground loop heat exchanger properties in eQUEST …………………..…...50 Table 4-11: Circulation loop properties in eQUEST …………………………..……......51 Table 4-12: Pump properties for GSHP system in eQUEST …………………..………..51 Table 4-13: Zone load feature (basement) ……………………………………..……......54 Table 4-14: Zone temperature control (basement) ……………………...…………….....54 vi Table 4-15: Zone design flow rate (basement) ……………………………...…..………54 Table 4-16: Zone load feature (1st floor) …………………………………..…...……….56 Table 4-17: Zone temperature control (1st floor) ……………………….………………57 Table 4-18: Zone design flow rate (1st floor) …………………………..…………….....58 Table 4-19: Zone load feature (2nd floor) ………………………………...…….………60 Table 4-20: Zone temperature control (2nd floor) …………………………..………......61 Table 4-21: Zone design flow rate (2nd floor) …………………………...……..……….62 Table 4-22: Zone load feature (3rd floor) ………………………………..…...…………64 Table 4-23: Zone temperature control (3rd floor) ……………………...………..………65 Table 4-24: Zone design flow rate (3rd floor) …………………………..………...…….66 Table 4-25: Zone load feature (4th floor) ………………………………….……………68 Table 4-26: Zone temperature control (4th floor) ……………………..………...………68 Table 4-27: Zone design flow rate (4th floor) …………………………………..……....69 Table 5-1: Pudong natatorium‟s utility bills from 2007 to 2009 …………………..…....70 Table 5-2: Baseline model simulated electrical consumption of Pudong natatorium…...72 Table 5-3: Baseline model electrical consumption ………………………………..….....75 Table 5-4: Baseline model gas consumption ……………………………………....……76 Table 5-5: Baseline model total energy consumption (000KWH) ………………...…....78 Table 5-6: Source-Site Ratios for all Portfolio Manager Fuels (Energy Star 2009)…..…80 Table 5-7: Baseline model energy consumption end-use category proportion…………..81 Table 5-8: Baseline model monthly energy demand by end-use categories (KW)…...…83 Table 5-9: Baseline model monthly energy demand end-use categories propotion…..…84 vii Table 5-10: Baseline model energy cost ($) ……………………………..………….......86 Table 5-11: Alternative I model electrical consumption ………………….….………....88 Table 5-12: alternative I model monthly energy consumption end-use category proportion……………………………………..…………….…………………………....90 Table 5-13: Alternative I model monthly energy demand by end-use categories (KW)...92 Table 5-14: Alternative I model monthly energy demand end-use categories proportion……...………………………………….……………………………..……….93 Table 5-15: Alternative I model energy cost ($) ……………………………..……….....94 Table 5-16: Alternative II model electrical consumption ……….……………..………..96 Table 5-17: Alternative II model monthly energy consumption end-use category proportion………………………………………………………………...…...………….98 Table 5-18: Alternative II model monthly energy demand by end-use categories (KW)………..…………………………………………………………………………..100 Table 5-19: Alternative II model monthly energy demand end-use categories proportion…….……..……...…………………..…………………………..……...…....101 Table 6-1: HVAC energy consumption of baseline and alternative I model…………...105 Table 6-2: Total energy consumption of baseline and alternative I model ………...…..109 Table 6-3: End-use category energy use proportion of baseline and alternative I model……...………………………………………………..……………..……….……111 Table 6-4: Annual energy cost for baseline and alternative I model ………...…….......112 Table 6-5: Monthly peak demand of baseline and alternative I model...……....….........114 Table 6-6: HVAC energy consumption of alternative I and alternative II model….......116 Table 6-7: Total energy consumption of alternative and alternative II model…………120 Table 6-8: Summarized CBECS table C21 ………………...………………….……….122 viii Table 6-9: End-use category energy use proportion of alternative I and alternative II model……………………………………………………………………………………123 Table 6-10: Monthly peak demand of alternative I and alternative II model……...…...123 Table 6-11: Life cycle cost analysis table …………………………….……..…………125 Table 6-12: Total cost at cost of two models in 14th and 15th year (replacement Happens at beginning of 15th year)…………………………………………………….127 Table A-1: Building shell design parameter....................................................................136 Table A-2: Window and glazing design parameter……………………….…….……...137 Table A-3: Building Internal Load…………………………………..………...……….138 Table A-4: Building schedule and operation…………………………….….………….142 ix LIST OF FIGURES Figure 1-1:U.S. energy consumption by sector (architecture2030 2010)……...……...…..2 Figure 1-2:U.S. CO2 emission by sector (architecture2030 2010) ……………..……..…2 Figure 1-3:U.S. electricity consumption by sector (architecture2030 2010)…………......3 Figure 1-4: The 2030 challenge (architecture2030 2010) …………..………………..…..3 Figure 1-5: Schematic GSHP heating cycle (Oklahoma State University) ……...…….…6 Figure 1-6: Schematic GSHP cooling cycle (Oklahoma State University) …………....…6 Figure 1-7: pudong natatorium, shanghai, China (temcor) ……………………..……..…8 Figure 2-1: Location of BHE systems in Switzerland (Burkhard Sanner 2000)……..….14 Figure 2-2: Air-source heat pump (trademasteruk 2011) ……...………………….….....16 Figure 2-3:Ground source heat pump (gfbowman 2011) ………………….……………17 Figure 2-4: Water source heat pump (gfbowman 2011) ………………..…..…………..17 Figure 2-5: Heating cycle of ground source heat pump (Kongkun Charoenvisal 2009)……………………………………………………………………………………..19 Figure 2-6: Cooling cycle of ground source heat pump (Kongkun Charoenvisal 2009)……………………………………………………………………………………..20 Figure 2-7: Schematic of vapor-compression refrigeration system …………..……....…22 Figure 2-8: Pressure-enthalpy diagram (ASHRAE 2005) ……..………………….……22 Figure 2-9: Pressure-enthalpy diagram (stage1-2) (ASHRAE 2005) ………………....23 Figure 2-10: Pressure-enthalpy diagram (stage2-3) (ASHRAE 2005) …...……………..24 Figure 2-11: Pressure-enthalpy diagram (stage3-4) (ASHRAE 2005) ………...………..25 Figure 2-12: Pressure-enthalpy diagram (stage4-1) (ASHRAE 2005) ………...…….….26 x Figure 2-13: Variance in ground temperature with depth (H. Dowlatabadi and J.Hanova 2007)…………………………………………………………………………..29 Figure 2-14: Annual ground temperature range for different depth (H. Dowlatabadi and J.Hanova 2007)……………...………………………………………………………30 Figure 2-15: Ground coupled heat pump (Huang 2010) …………..…………….……...32 Figure 2-16: Ground water heat pump (Huang 2010) ……..…………………………...32 Figure 2-17: Surface water heat pump (Huang 2010) ……………………..…………...33 Figure 3-1: eQUEST screenshot ………..………………………………..……………..40 Figure 4-1: Southwest view of Equest model of Pudong natatorium ……………….…..42 Figure 4-2: Northeast view of eQUESTt model of the Pudong natatorium…..………...43 Figure 4-3: Schematic conventional system (water side HVAC) ……..………….…….47 Figure 4-4: Schematic GSHP system (water side HVAC) ………..……………….…...47 Figure 4-5: Schematic HVAC zoning design for Pudong natatorium (basement plan)....53 Figure 4-6: Schematic HVAC zoning design for Pudong natatorium (1 st floor plan)…...55 Figure 4-7: Schematic HVAC zoning design for Pudong natatorium (2 nd floor plan)…..59 Figure 4-8: Schematic HVAC zoning design for Pudong natatorium (3 rd floor plan)…...63 Figure 4-9: Schematic HVAC zoning design for Pudong natatorium (4 th floor plan)…...67 xi LIST OF CHARTS Chart 1-1: Energy usage in commercial building (EPA 2008) ………….………..………4 Chart 2-1: General Heat Pump (Total) and Ground-Source Heat Pump Systems (GSHP) installed 1993-1996 in Various European Countries (Breembroek and Lazá ro 1999)……………………………………………………………………..………13 Chart 2-2: Number of annual heat pump sales in Germany (J. Lund 2004) …...….…….15 Chart 5-1: Real monthly electrical consumption of Pudong natatorium ………...…...…71 Chart 5-2: Comparison of yearly electrical consumption of Pudong natatorium ……….71 Chart 5-3: Electrical consumption in eQUEST baseline model of Pudong natatorium…73 Chart 5-4: Monthly electrical consumption comparison between year 2009 and Baseline model of Pudong natatorium…………………………………………..……….73 Chart 5-5: Yearly electrical consumption comparison of Pudong natatorium ……...…..74 Chart 5-6: Baseline model electrical consumption ………...……………………….…...77 Chart 5-7: Baseline model electrical consumption (000KWH) ………………..….……79 Chart 5-8: Baseline model monthly energy consumption end–use category proportion...82 Chart 5-9: Baseline model energy cost ($) ………………...……………………………87 Chart 5-10: Alternative I model electrical consumption …………………...….………...89 Chart 5-11: Alternative I model energy consumption end-use category proportion …....91 Chart 5-12: Alternative I model energy cost ($) ……………...…………….…………...95 Chart 5-13: Alternative II model electrical consumption …………...…………………..97 Chart 5-14: Alternative II model energy consumption end-use category proportion .......99 Chart 6-1: Monthly electrical comparison between real building and baseline model (KWH) ……………………..……………...……………………………………..…….104 xii Chart 6-2: Space heating consumption of baseline and alternative I model …………...106 Chart 6-3: Space cooling consumption of baseline and alternative I model ..…..……..107 Chart 6-4: Total HVAC energy consumption of baseline and alternative I model …....108 Chart 6-5: Total energy consumption of baseline and alternative I model …...……..…110 Chart 6-6: Annual energy cost for baseline and alternative I model ……………...…...113 Chart 6-7: Monthly peak demand of baseline and alternative I model ………………...115 Chart 6-8: Space heating consumption of alternative I and alternative II model …..….117 Chart 6-9: Space cooling consumption of alternative I and alternative II model ...…....118 Chart 6-10: Total HVAC energy consumption of alternative I and alternative II model………………………………………..…………………………………..…..…..119 Chart 6-11: Total energy consumption of alternative I and alternative II model ……...121 Chart 6-12: Monthly peak demand of alternative I and alternative II model …...….….124 Chart 6-13: Total cost at cost of two models in 14 th and 15 th year (replacement happens at beginning of 15 th year)……………………………………………………...127 Chart 7-1: Ground temperature variation at well bore of alternative I model……....….132 xiii ABSTRACT The Heating, Ventilation and Air Conditioning system (HVAC) is one of the most important aspects of building energy efficiency. In order to enhance energy efficiency, design strategies always pay primary attention to the HVAC system design. The Ground Source Heat Pump is a relatively new system which has high performance with respect to energy efficiency and reduces carbon emissions correspondingly. This research focuses on the energy consumption and economic benefits of a Ground Source Heat Pump installation. This system has been installed in the Pudong natatorium in Shanghai, a building which was formerly serviced by a conventional package VAV system with natural gas boiler. Measurements were be made of system performance and energy use for the former system and will be repeated for the newly installed Ground Source Heat Pump system. Computer simulation tools will also be applied for the two systems and the results compared with measured data. Computer simulations will be based on the simulation tool---Equest 3-63(DOE2). We anticipate the result will prove the Geothermal Heat Pump has a high performance on energy efficiency and economic saving. 1 CHAPTER 1 INTRODUCTION 1.1. Background Introduction Currently, with the development of economy and growth of cities, an increasing number of buildings are constructed. The energy usage has become a concerning issue people focus on, because most of those building are operated inefficiently. The result of abuse of energy contributes to both fossil fuel depletion and global climate change. Nowadays, nonrenewable resources, such as oil, natural gas, coal, are widely used in America. Basically, using those nonrenewable resources is improper for the development of cities, and causes a high emission of greenhouse gas. The building sector consumes around 49% of the total energy consumed in the United States (EIA 2010), which is the aspect we need to pay particular attention to; the building sector is the key to addressing climate change. The success of climate bills depends on achieving huge energy consumption reduction and greenhouse gas reduction. Besides consuming 49% of the total energy in the US, the building sector is also responsible for 47% of annual greenhouse gas emission in the US and 74.5% of annual electricity consumption (EIA 2010). 2 Figure 1-1:U.S. energy consumption by sector (architecture2030 2010) Figure 1-2:U.S. CO2 emission by sector (architecture2030 2010) 3 Figure 1-3:U.S. electricity consumption by sector (architecture2030 2010) What‟s more, not only architects are concerned with this problem; society in general is paying more attention to climate change caused by abusing energy. President Obama called for an 83% reduction of U.S. greenhouse gas (GHG) emissions below 2005 levels by 2050. The 2030 challenge also aims to reduce the fossil fuel usage to zero by 2030. The following graph shows the 2030 challenge. Figure 1-4: The 2030 challenge (architecture2030 2010) 4 In order to address this target, looking for alternative energy to replace conventional fossil fuel energy is an optimal way. Before that, let us take a look at the energy usage in commercial building divided by different categories. Chart 1-1: Energy usage in commercial building (EPA 2008) Operating energy includes but is not limited to electrical lighting, electrical appliances and Heating, Ventilation and Air-Conditioning (HVAC) system. We can tell from the chart that space heat and cooling, which are provided by the HVAC system, contribute around 45% of total operational energy in commercial buildings. From that point of view, the largest energy saving can be realized in space heating and cooling. With today‟s market and technology, the most commonly used HVAC systems can be classified as combustion based systems and non-combustion based systems. Combustion based systems directly use energy sources such as oil, diesel fuel and natural gas, while non-combustion based systems use electricity to provide space cooling and heat. Even though non-combustion based system avoid the direct use of fossil fuel, electricity also 5 comes primarily from the combustion of fossil fuel. The Ground Source heat pump (GSHP), which does not require direct fuel consumption and which uses electricity with maximum effectiveness, is considered to be one of the most energy efficient and low greenhouse gas (GHG) emission systems. 1.2. Geothermal Heat Pump Introduction Ground Source Heat Pump (GSHP) is an advanced HVAC system which utilizes low status energy from a superficial layer of ground to transfer to high status energy to cool or heat space. The stored heat in a superficial layer of ground is tapped out; the temperature is raised by a heat pump and then is delivered to the indoor space in winter. In summer, the heat is extracted from the indoor space and transferred to the ground. The following chart compares the superficial layer and deep layer heat. Item superficial layer deep layer Same storage condition earth, rock source category renewable source Media earth, underground water Function energy efficiency, environment friendly utilize requirement bore hole, artificial recharge Different source from solar energy lava heat temperature range 10-25° C 90-150° C Depth <1000meter >1000meter utilization indirect exchange direct exchange bore hole superficial Deep Risk low High Renewable cycle fast Slow influence on ground water slight slight development fee low High Table 1-1: Comparison between superficial and deep layer 6 Figure 1-5: Schematic GSHP heating cycle (Oklahoma State University) Figure 1-6: Schematic GSHP cooling cycle (Oklahoma State University) 7 According to the International Ground Source Heat Pump Association, The GSHP is one of the most efficient heating and cooling systems available today, with heating efficiencies 50 to 70% higher than other heating systems and cooling efficiencies 20 to 40% higher than available air conditioners (IGSHPA). Also, GSHPs are durable and highly reliable. The GSHP contains fewer mechanical components, and all components are either buried in the ground or located inside the home, which protects them from outside conditions. The underground pipe carries up to a 50-year warranty and the heat pump can work for more than 30 years. Although the initial installation cost of GSHP is higher than conventional HVAC systems, it saves both operation and maintenance costs. From that point of view, it is crucial to conduct a life cycle assessment between GSHP and other HVAC systems. The life cycle cost is an important index which reflects the “cradle to grave” cost. 1.3. Building Background The Pudong natatorium is the biggest muti-purpose stadium in Pudong, Shanghai, China. The site footprint is 26,600 square meters and the building footprint is 22,000 square meters. It is a five story building with an expressive arched roof. The original HVAC system used chilled water plus a steam boiler. Currently, the building is changing its original system to a GSHP system, which means GSHP will provide both heating and cooling for the natatorium. This building serves as a case study building in this thesis to evaluate the energy and economic effect of GSHP. 8 Figure 1-7: Pudong natatorium, shanghai, China (temcor) 1.4. Objective This master‟s thesis is intended to demonstrate out the energy, environmental, and cost benefits of Ground Source Heat Pumps. For comparison the conventional model, chiller plus steam boiler, is defined as the baseline model. The energy consumption is predicted using computer program eQuest. The baseline results are compared with the alternative model, which is GSHP. From those two models, we can tell the benefits of GSHP. Also, in order to address conclusion‟s accuracy, the ASHARE GSHP model and CBECS (commercial building energy consumption survey) building code are brought into the comparison. Those two supporting documentation and model serve as the standard which gives an idea how this building‟s energy performance when compared with other buildings. With the help of Peter Simmonds, senor mechanical engineer of IBE, the relative costs of HVAC systems are estimated based on the market value. 9 1.5. Hypothesis 1.5.1. GSHP consumes less energy than conventional HVAC system The hypothesis is based on yearly cost, which means the yearly energy cost （YEC ） of Ground source heat pump is less than conventional HVAC system. The difference between two HVAC systems is the yearly energy saving (YES) YES GSHP (KWH/year) =YEC con (KWH/year)-YEC GSHP (KWH/year)>0 (equation1.1) Where YES GSHP stands for yearly energy saving through using GSHP YEC CON stands for yearly energy cost of conventional HVAC system YEC GSHP stands for yearly energy cost of GSHP system 1.5.2. GSHP reduces utility fee for the building owner This hypothesis contains two sub-hypothesis. One is that the life cycle cost of Ground source heat pump is less than conventional HVAC system. The other hypothesis is that the difference initial investment between GSHP and conventional HVAC system can be compensated through the yearly saved utility fee in less than ten years. First hypothesis: LCC CON ($)-LCC GSHP ($) >0 Where LCC GSHP stands life cycle cost of GSHP and is valued as $ LCC CON stands life cycle cost of conventional HVAC system and is valued as $ Second hypothesis: 10 DII (GSHP-CON) ($) <10x YES GSHP ($) Where DII (GSHP-CON) stands difference initial investment between GSHP and conventional HVAC system YES GSHP stands yearly energy saving through GSHP and is valued as ($) 11 CHAPTER 2 LITERATURE REVIEW 2.1. Development of Geothermal (Ground Source) Heat Pump In 1912, Swiss scientist Heinrich Zoelly proposed that people can utilize the superficial layer of the earth as a heat source for space heating. The technology was first introduced in England and America (P.J. Hughes). In the 1970s the technology flourished, boosted because of the energy crisis. With sales increasing of 10% annually over the last decade in more than 30 countries, Geothermal Heat Pump (GHP) – alternately Ground Source Heat Pump (GSHP) -- technology is one of the fastest growing uses of renewable resources in the world. The necessary operating condition, tapping heat from ground or ground water with temperature between 5 ℃ to 30 ℃, is easy to realize in almost all countries. The present world GHP/GSHP capacity is estimated 12,000 MWt, and the annual energy consumption (for heating) is around 20,000GWh (J. Lund 2004). From table 2-1, we can see most GSHPs are installed in North America and Europe. Country Installed Thermal capacity (MWt) Annual energy use (GWh/year) Installed numbers Austria 275 370 23000 Canada 435 600 36000 Germany 640 930 46400 Sweden 2300 9200 230000 Switzerland 525 780 30000 USA 6300 6300 600000 Table 2-1: Leading country using GSHP (J. Lund 2004) 12 2.1.1. Development of Ground Source Heat Pumps in the United States In the United States, the majority of GSHP units are designed for the peak cooling load and are oversized for heating load; because (except in the northern states) cooling loads generally exceed heating loads. By contrast, in Europe the design capacity generally is determined by the baseline heating load. If the load goes over the baseline requirement, fossil fuel compensates the exceeded part of energy. In the cooling cycle GSHP serves as a heat releasing function. GSHP is considered to be an efficient and environmentally friendly system when compared with conventional HVAC systems. In the US, the sales of ground source heat pump units have been steadily increasing, with a10% growth rate over the last 10 years. Most of this growth occurs in mid-western and eastern states. Today, approximately 80,000 GSHP single units are installed annually, of which 46% are vertical closed loop systems, 38% horizontal closed loops systems and 15% open loop systems (J. Lund 2004). The largest Geothermal Heat Pump system in the US is Galt House East Hotel in Louisville, Kentucky. It consists of 600 hotel rooms (750 square feet each), 100 apartments (Averaging 1800 square feet each), and an additional 120,000 square feet of public area. The GHSP serves the whole hotel for both cooling and heating requirements. Through using GHSPs, energy cost in the Galt House East is $25,000 less per month than the adjacent Galt House Hotel, which has an equal amount of space, but a conventional heating and cooling system (IGSHPA). 2.1.2. Development of Ground Source Heat Pump in Europe Generally, the climate in many Europe countries is winter dominated and so cold that GHSPs work most of the time in the heating cycle, which means air conditioning is rarely 13 used. However, this situation is changing gradually since an increasing number of large multi-purpose, commercial buildings are being built, which require both heating and cooling. The double use of GHP will become more popular and important in the future. Country All Heat Pumps( in 1000 units) Ground- Source Fraction% Number of GSHP systems(in 1000 units) Austria 22.2 11 2.42 Denmark 3.3 18 0.59 France 25 11 2.75 Germany 5.7 4 0.23 Netherlands 0.12 7 0.01 Norway 4 8 0.32 Sweden 42.3 28 11.8 Swizerland 15 40 6 Table 2-2: General Heat Pump (Total) and Ground-Source Heat Pump Systems (GSHP) Installed 1993- 1996 in Various European Countries (Burkhard Sanner 2000) Chart 2-1: General Heat Pump (Total) and Ground-Source Heat Pump Systems (GSHP) Installed 1993- 1996 in Various European Countries (Breembroek and Lazá ro 1999) From chart 2-1, Sweden has an extremely high number of heat pumps due to the large number of air-to-air heat pumps, but Sweden also has the highest number of GSHPs in 14 Europe. We can conclude from this chart the market occupancy of GSHP is still unsaturated over Europe except for Sweden and Switzerland. The following map diagram shows the BHE (borehole heat exchanger) systems in Switzerland. Figure 2-1: Location of BHE systems in Switzerland (Burkhard Sanner 2000) Tables 2-3 and chart 2-2 show the number of annual heat pump sales in Germany. Numbers of Heat Pump Sales in Germany Ground air water 1996 1519 518 273 1997 2307 691 582 1998 3156 564 647 1999 3408 774 537 2000 4149 993 595 2001 5415 1562 1238 2002 5360 1526 1439 Table 2-3: Number of annual heat pump sales in Germany (J. Lund 2004) 15 Chart 2-2: Number of annual heat pump sales in Germany (J. Lund 2004) As the above chart 2-2 illustrates, since 1996, the sales for heat pumps have increased steadily. Even though during 2001 and 2002 the construction shrank dramatically due to the poor economic situation, sales are still steady. Based on this performance there is ample reason to believe GSHP has a bright market perspective. 2.2. Types of Heat Pump There are three types of heat pump classified by which heat source/sink is used: air source heat pump, ground source heat pump and water source heat pump. An air source heat pump uses outside air as a heat source or heat sink. A compressor, condenser and refrigerant system is used to absorb heat at one place and release it at another. It uses the difference between outdoor air temperatures and indoor air temperatures to cool and heat indoor space. The air source heat pump can be energy 16 efficient but it only performs well under a moderate weather condition. Under cold weather condition, the air source heat pump has poor performance due to the frost built up on the evaporator when the surrounding temperature is near or below 0 ℃, which causes restriction of air flow across the outdoor coil. In order to address this issue, occupants have to switch to the air conditioning mode to move the heat from inside to melt the outside coil. The efficiency of air source heat pump is approximately 50% of ground source heat pump. Figure 2-2: Air-source heat pump (trademasteruk 2011) Both ground source heat pumps and water source heat pumps can be categorized as geothermal heat pumps. The different between the two types is the heat sink. The ground source heat pump uses earth as the heat sink, while water source heat pumps use ground water as the heat sink. Both utilize geothermal heat to heat the indoor space. They serve a 17 heat transfer function rather than providing heat derived from fossil fuel. Typically one unit of electrical energy input can lift three units of heat from geothermal. Figure 2-3 ：Ground source heat pump (gfbowman 2011) Figure 2-4: Water source heat pump (gfbowman 2011) 2.3. Terminology Explanation In this section, some terminology will be introduced in order to better understand geothermal (ground source) heat pumps. 18 Geothermal Heat Exchanger This term is used to refer to the direct exchange of heat between indoor space and underground. The Geothermal Heat Exchanger needs relatively high temperature of underground --between 100 ° F (38 C) and 300 ° F (149 ° C). Under that condition, heat can be extracted directly and sent to the indoor pace (Geo-Heat Center 2008). Geothermal Heat Pump Unlike the Geothermal Heat Exchanger using direct heat from underground, the term Geothermal Heat Pump applies when the underground temperature is not high enough. Under that condition, heat is tapped and a heat pump is used to raise the temperature: then utilized for heating. Generally, the ground temperature is between 40 ° F (4 ° C) and 100 ° F (38 ° C) (Geo-Heat Center 2008). Ground source heat pump This terminology refers to a given geothermal heat exchanger utilizing the heat from the earth itself rather than from ground water. The underground pipes can be arranged vertically in boreholes or horizontally in trenches based on project requirement and specification. The pipes serve as heat transfer to deliver the heat from underground to heat pump in heating condition, while in cooling condition, the circulation reverses. 2.4. Ground Source Heat Pump Overview Ground source heat pump (GSHP) is an electrically powered system that extracts the stored energy of the greatest solar collector in existence: the earth. The system uses the earth's relatively constant temperature to provide heating, cooling, and hot water for 19 homes and commercial buildings. Basically, GSHP uses the basic 4 components of mechanical heat pump systems: compressor, condenser, evaporator and expansion valve. GSHP can serve for both cooling and heating. In the heating cycle, because of the relatively high earth temperature in winter when compared with the outdoor temperature, the earth serves as the heat supplier to provide heat to indoor space. The refrigerant enters the compressor as saturated vapor at low temperature and low pressure. After being compressed the refrigerant leaves the compressor at high temperature and pressure as overheated vapor. Then the vapor goes through the coil of the condenser (indoor space). During this stage, the vapor is cooled down and condensed. The vapor releases heat to the indoor space and become liquid. After that, the liquid refrigerant goes through an expansion valve, where the refrigerant„s temperature and pressure drop dramatically due to throttling. Then the refrigerant enters the evaporator, located under the earth, and taps the heat stored in the earth. The refrigerant becomes vapor again because of absorbing heat. Then the low pressure, low temperature saturated vapor reenters the compressor and keeps circulating again and again. This process is illustrated in Figure 2-5. Figure 2-5: Heating cycle of ground source heat pump (Kongkun Charoenvisal 2009) 20 For the cooling cycle, the process is quite similar but in the reverse order, which means the evaporator is located in the indoor space, and condenser is located in the earth: which means the indoor space serves as the heat supply and the earth serves as the heat receiver. Because the indoor space has relatively higher temperature than the earth, the indoor air goes through the coils of the evaporator; during this phase the indoor air releases heat to the refrigerant and returns to the space at a cool temperature. In this stage the refrigerant absorbs the heat from the indoor air and becomes a saturated vapor which is suctioned into the compressor. After compression, the refrigerant leaves the compressor as an overheated vapor at high temperature and pressure. Then the hot vapor enters the condenser, which is located in the earth, and releases heat to the earth. The heat released contains energy both from indoor air and from the work input. After exchanging the heat, the refrigerant becomes a fluid. Finally, the refrigerant enters the expansion valve, where its temperature and pressure drop dramatically due to throttling. Then the refrigerant goes through the coils in the evaporator and absorbs heat from indoor air again. This is the full cooling cycle. It is illustrated in figure 2-6 Figure 2-6: Cooling cycle of ground source heat pump (Kongkun Charoenvisal 2009) 21 2.5. Principle and Performance of GSHP As a water pump lifts water from a lower level to a higher level, the heat pump serves a similar function: it transfers heat from lower temperature status to higher temperature status. The most obvious characteristic of the GSHP is that it utilizes a small proportion of electrical input to tap stored heat and lifts the heat status through a heat pump. Typically, electrical inputs to heat pump devices are less than one third of the total heat delivered into the heated space. As mentioned in section 2.4, a complete GSHP system contains the basic 4 components of mechanical air conditioning systems: Compressor, Condenser, Expansion Valve and Evaporator. We first consider the Compressor; the heart of the heat pump. It takes in refrigerant gas at low temperature and pressure, and then compresses the gas by the movement of a piston, which is driven by the electrical input. After that, the gas leaves the Compressor at high temperature and pressure. The second component is the Condenser, which serves as the heat output component. The Condenser gives off heat in the process of condensing the refrigerant gas into a liquid. This heat is given off into the room (heating cycle) or to the earth (cooling cycle.) The condensed liquid then passes through an Expansion Valve (Throttle Valve) into the Evaporator; in the process of evaporation it must take in heat in order to change phase. In this stage the room air is cooled (cooling cycle) or the earth is cooled (heating cycle). From the Evaporator the low pressure/low temperature refrigerant gas is returned to the Compressor and the cycle 22 repeats. In order to better understand the thermodynamic cycle of the heat pump, a schematic of vapor-compression refrigeration system is necessary. Figure 2-7: Schematic of vapor-compression refrigeration system Figure 2-8: Pressure-enthalpy diagram (ASHRAE 2005) 23 Figure 2-9: Pressure-enthalpy diagram (stage1-2) (ASHRAE 2005) In stage 1, the refrigerant is at low temperature and pressure saturated vapor status. After it is suctioned into the Compressor (stage 1-2), the refrigerant is heated and compressed by a piston. Because of that, the temperature and enthalpy are increased. The gas leaves the Compressor with high temperature and pressure at stage 2. The work input for the compressor is W. In stage 2; the superheated refrigerant has high pressure and a temperature which is higher than surrounding medium. According to the first law of thermodynamic, the energy balance can be presented as following equation 2-1: W = M (h2-h1) ------ equation 2-1 Where W is the work input M is the mass flow of refrigerant h2 is the refrigerant’s enthalpy in stage 2 h1 is the refrigerant’s enthalpy in stage 1 24 Figure 2-10: Pressure-enthalpy diagram (stage2-3) (ASHRAE 2005) During the second phase (2-3), the refrigerant leaves the Compressor and goes through the Condenser. Actually this is a constant-pressure, heat releasing process. The refrigerant goes into the Condenser as high temperature and superheated vapor and the vapor releases heat to the surrounding medium and becomes a saturated liquid. Although the pressure is the same before and after the refrigerant enters the Condenser the energy has been distributed to surrounding medium, which means the enthalpy declines after condensing. Equation 2-2 briefly introduces the heat balance in this phase. Q1 = M (h2-h3) ------ equation 2-2 Where Q1 is the released heat M is the mass flow of refrigerant h2 stands the refrigerant’s enthalpy in stage 2 h3 stands the refrigerant’s enthalpy in stage 3 25 Figure 2-11: Pressure-enthalpy diagram (stage3-4) (ASHRAE 2005) The third process is the expansion process. The liquid refrigerant expands in the expansion valve by throttling. Because of throttling, the refrigerant‟s pressure decreases with constant enthalpy. This phase can be presented as equation 2-3 h3 = h4 ------ equation 2-3 Where h3 stands the refrigerant’s enthalpy in stage 3 h4 stands the refrigerant’s enthalpy in stage 4 26 Figure 2-12: Pressure-enthalpy diagram (stage4-1) (ASHRAE 2005) The last process is the evaporation process, which is a consistent pressure heat absorption process. The refrigerant leaves the expansion valve at low temperature and pressure. In the evaporator, the refrigerant absorbs heat from the surroundings and becomes low temperature, low pressure saturated vapor. Then the saturated vapor enters the Compressor again. The above process can be summarized as equation 2-4 Q2 = M (h1-h4) ------ equation 2-4 Where Q2 is the absorbed heat M is the mass flow of refrigerant h1 is the refrigerant’s enthalpy in stage 1 h4 is the refrigerant’s enthalpy in stage 4 Finally, let us combine the 4 equations. The result would be Q1 = W +Q2------ equation 2-5 27 Basically, equation 2-2 can be explained differently for the heating and cooling cycles. In the heating cycle, Q1 stands for the heat delivered into space, W stands for the electrical input and Q2 is the heat extracted from earth. In the cooling cycle, the heat extracted from the indoor space is Q2, and the heat delivered into earth is Q1. W stands for the electrical input again. The switch between two cycles can be easily realized through reversing the valve. Since the Heat Pump is a mechanical system which requires electrical input, the efficiency of energy used must be considered. People always have high expectations for the efficiency of GSHP. The following table indicates the efficiency of different heating means. Efficiency of different heating ways Heating ways oil boiler electrical boiler solar thermal energy GSHP COP 0.70-0.90 1 0.80-0.95 >2.8 Table 2-4: The energy efficiency of different heating ways (Huang 2010) The COP (Coefficient of Performance ）for GSHP is the ratio between energy delivered to the space and work input. For a given ground source heat pump, the COP varies depending on heat pump design and characteristics of the heat pump. Basically, the COP is determined by the input refrigerant temperature to the Evaporator and output refrigerant temperature of the Condenser. Based on the four equations discussed above, equations 2-5 and 2-6 calculate GSHP‟s COP in cooling and heating cycle respectively. 28 COP cooling= input electrical space from removed heat = W Q 2 = 1 2 4 1 h h h h   equation 2-6 COP heating= input electrical space to in delivered heat = W Q 1 = 1 2 3 2 h h h h   =1+ 1 2 3 1 h h h h   equation 2-7 Where h3=h4 Therefore, COP heating=1+ 1 2 3 1 h h h h   =1+ 1 2 4 1 h h h h   =1+COPcooling equation 2-8 The COP in the cooling cycle is a positive quantity at least, which ensures the COP of heating cycle is greater than 1. The table above shows the COP of a typical heat pump is exceeding 2.8, while boiler COP is around 1. However, the actual COP of a heat pump or refrigeration cycle does not necessarily match the ideal cycle. The actual cycle operates less efficiently due to several factors. The first is fluid friction, which will cause a drop in pressure in the system. The second is heat losses in the system. In order to improve the performance of GSHP, it is necessary to introduce some crucial parameters involving the performance. Here are five most important factors on closed loop system: the soil thermal conductivity, the borehole thermal resistance, the undisturbed Earth temperature, the heat extraction (and rejection) rates, and the mass flow rate of the heat carrier fluid. 29 2.6. Types of GHP/GSHP Compared to the air source heat pump, geothermal/ground source heat pumps deal with a more stable underground temperature. As the depth increase, the temperature becomes more stable since limited interaction with the above-ground environment reduces variations. Figure 2-13: Variance in ground temperature with depth (H. Dowlatabadi and J. Hanova 2007) 30 Figure 2-14: Annual ground temperature range for different depths (H. Dowlatabadi and J. Hanova 2007) Figures 2-13 and 2-14 show the variation of ground temperature in Ottawa, Canada. In figure 2-13, depth below 10m usually has constant temperature with little or even no variation. The observation of figure 2-14 tells us the temperature various from 30F to 70F in 0.3m below ground, and 40F to 55F in 2m below ground. The temperature keeps stable when the depth is 5m. Based on that, the design depth of underground loop should exceed 10m below ground. In practice, the geothermal heat pump is a general term includes three types. Ground- coupled heat pump, ground water heat pump and surface water heat pump. 31 Ground-coupled heat pumps utilize the heat from earth; the heat is transferred through the water in the underground closed loop to the indoor heat pump system, by which it transfer the heat between earth and indoor space. In winter, the fluid takes heat from earth and delivers to required space, while the heats is absorbed and send to ground in summer. Ground-coupled heat pumps benefit the earth as a heating and cooling source, and have no effect on ground water -- which is a sustainable technology. Ground water heat pumps utilize ground water as the heat source. They pump out underground water through water well to heat or cool the required space; after heating or cooling, the water returns back to the ground. Although this technology has advantages, it still has some limitations. The first is location. Only a project located on the proper site can benefit from using a ground water heat pump. Also, the requirement for returning water to the ground is rigid. The flow rate should balance the extracted water flow ratio, otherwise underground water loss will occur. Also, if the water layer is deep underground, the investment and maintenance cost will increase. Surface water heat pumps use a relatively simple technology since there is no consideration involving underground. The system utilizes some amount of natural surface water as the heating or cooling source. Although it is an easy technology, it has restrictions. First, natural surface water is not considered as a stable source as it is easily 32 influenced by the weather or other factors. Also, it is next to impossible to locate every project adjacent to a natural water source. Figure 2-15: Ground coupled heat pump (Huang 2010) Figure 2-16: Ground water heat pump (Huang 2010) 33 Figure 2-17: Surface water heat pump (Huang 2010) 2.7 ． Current Research Situation Current research on GSHP focuses on three domains. First is the simulation model for the GSHP‟s performance and annual energy consumption. Those programs include: TRANSYS, Ground loop design, GS2000 and GLHEPRO etc. such programs perform calculations to determine or confirm the size of the underground pipe. The second is the hybrid ground source heat pump. In some multi-purpose and commercial building, the cooling load is higher than the heating load and the unbalanced heat load will cause fluctuation of ground temperature. In order to address this problem, a cooling tower or cooling pool is introduced to work with the heat pump so as to eliminate extra heat. The third area is research about heat resistance of underground pipe. 34 CHAPTER 3 METHODOLOGY 3.1. Methodology Overview Two major issues need to be addressed in this thesis. The first one is the relative energy performance of GSHP and conventional HVAC system in Pudong natatorium and the second is the relative economic performance of the two systems. In this research, a building simulation program eQUEST is used to estimate the energy usage of Pudong natatorium. The result from eQUEST can replicate the real building energy performance to a large extent. There will be three models in eQUEST. The first one is the baseline model, which is the real building with conventional system (chiller plus boiler), and the other two are alternative models. One of the alternative models is the real building with GSHP system applied in the building, while the other alternative model is the ASHRAE standard model with a GSHP system. The information coming from the baseline and alternative simulation models is used in the energy performance and economic comparison between GSHP and conventional HVAC system. After these results are achieved, CBECS (commercial building energy consumption survey) will be 35 used to compare the performance of this building and to verify the accuracy of the result from eQUEST. Subsequently, the results will be compared to the hypothesis. 3.2. ASHRAE and CBECS Introduction ASHRAE is the abbreviation of American Society of Heating, Refrigeration and Air- conditioning Engineers. ASHRAE fulfills its mission of advancing heating, ventilation, air conditioning and refrigeration to serve humanity and promote a sustainable world through research, standards writing, publishing and continuing education (ASHRAE 2011). For this mission, a series of building standards and guidelines have been developed by ASHRAE to help both ASHRAE members and other people concerned with mechanical processes and the design of indoor environments. ASHRAE 90.1-2010 and ASHRAE 62.1-2010 are two commonly used standards. The purpose of ASHRAE 90.1-2010 standard is to provide minimum requirements for the energy-efficient design of buildings except low-rise residential buildings (ASHRAE 90.1 2007). This standard provides minimum energy efficiency requirement of design and construction for both new and existing buildings. It addresses not only building envelope, but also systems and equipment such as heating, ventilation and air conditioning, water heating and lighting. The purpose of ASHRAE 60.1-2010 is to specify minimum ventilation rates and other measures intended to provide indoor air quality that is acceptable to human occupants and that minimizes adverse health effects (ASHRAE 62.1 2007). This standard also applies to both new and existing buildings. 36 The Commercial Buildings Energy Consumption Survey (CBECS) is provided by the US Energy Information Administration (EIA), which is an independent statistics and analysis organization. EIA collects, analyzes, and releases independent energy information to promote better policy decisions, efficient markets, and public understanding of energy and its interaction with the economy and the environment. Forecast & Analysis, Environment & Households, and Buildings & Industry are three topics under EIA. CBECS is a national sample survey that collects information on the stock of U.S. commercial buildings, their energy-related building characteristics, and their energy consumption and expenditures. Commercial buildings include all buildings in which at least half of the floor space is used for a purpose that is not residential, industrial, or agricultural, so they include building types that might not traditionally be considered "commercial," such as schools, correctional institutions, and buildings used for religious worship (CBECS 2011). 3.3. Simulation Tools and Energy Performance Simulation is a research method which is widely used in architecture and its related disciplines to predict real world energy performance and other factors. Simulation methods attempt to replicate relevant features of a building in a manipulable mathematical model. To the extent the simulation is successful results can be used to predict real world behavior; to the extent that variables can be easily manipulated it is possible to predict how changes will affect real world outcomes. 37 Prior to development of computer based simulations there were four different types of simulations available: iconic, analog, operational and mathematical models (Clipson 1993). An iconic model is a look-alike representation of some specific entity; it could be two- or three-dimensional. Analog models are representations of entities of a system by analog entities capable of dealing with dynamic simulation; these have been used for both actual and proposed projects. Operational models always deal with the human interaction in physical contexts. A mathematical model uses mathematical language – empirical equations -- to predict the performance of a real project. With the capabilities of current computers there is a tendency to merge the boundaries of these models and transform them to the operative level (Wang 2002). In order to achieve accurate replication of a real building accuracy and reliability of the simulation is quite important. There are many concerns for accuracy and reliability which range from the accuracy of replication and completeness of input data to cost and workability (Wang 2002). Once the decision has been made to use a particular simulation program the accuracy of the result is the vital issue; the prediction must closely simulate real building performance. It is very important that input data are well and fully collected and appropriately translated into usable form. The concern for cost and workability applies both to the data collection and input process and to the workings of the simulation program itself. Once accuracy and reliability of a simulation have been established 38 manipulation of variables can be an important tool for use in making design decisions affecting energy usage. 3.4. DOE2 and eQUEST There are several important considerations for energy performance simulations. First of all, the simulation should be able to be incorporated into the design process as early as possible. Improvement and modification of the simulation can occur during subsequent design. Second, the model in the simulation can be simplified while still containing the necessary information relating to the energy simulation; unnecessary details can be ignored in the simulation program. Also, the data must be complete; this is quite important for the accuracy of the result. Over the last 50 years, a number of building energy simulation tools have been developed, improved and applied to the question of building energy efficiency. In 2005 a research paper was published in DOE: Contrasting the Capabilities of Building Energy Performance Simulation Programs. In this paper the twenty most used simulation programs were compared in different aspects, which included zone loads, building envelope, daylighting and solar, ventilation and airflow, renewable energy system, electrical systems and equipment, HVAC systems and equipment, environmental emissions, climate data analysis, results reporting, validation, user interface and availability. Among those twenty programs, 9 programs enable users to perform high level GSHP systems simulation. Unfortunately, most of those programs are not free, 39 which means the program needs to be run under license. Only 2 programs can be run without licensing; eQUEST is one of these two and has been applied in this thesis. eQUEST is derived from DOE2, which is considered to be one of the most powerful simulation engines and is widely applied. Several programs are based on this engine, including eQUEST, DOE-2, Weather Data, Power DOE and LCC. The DOE-2 software itself was developed by James J. Hirsch & Associates (JJH) in collaboration with Lawrence Berkeley National Laboratory (LBNL). LBNL work for DOE2 was performed mostly using funding from the United States Department of Energy (USDOE) and other work was performed using funding from a wide range of industry organizations (DOE2 2011). eQUEST is a sophisticated energy simulation program which is valuable for all members of the design team. It was designed to allow users to perform detailed analysis of today‟s state-of-the-art building design technologies using today‟s most sophisticated building energy use simulation techniques but without requiring extensive experience in the "art" of building performance modeling (DOE2 2011). It is a combination of the DOE-2 engine, wizards and graphics. eQUEST is supported as a part of the Energy Design Resources program which is funded by California utility customers and administered by Pacific Gas and Electric Company, San Diego Gas & Electric, and Southern California Edison, under the auspices of the California Public Utilities Commission (DOE2 2011). 40 Figure 3-1: eQUEST screenshot 3.5. eQUEST Modeling Approach and Simulation Process With the support of the DOE-2 engine, eQUEST can perform hourly energy simulations throughout a year: 8,760 hours. DOE-2 calculates the hourly loads, the performance of various building components, and operation schedules. Besides the DOE-2 engine, wizards provide the capability to streamline modeling and simulation procedures. The easy-to-use wizards give users a clear path to input of key-information. Combined with building shape input, eQUEST provides a complete result on building energy performance and utility cost. There are six sections in the interface of eQUEST which include project&site, building shell, internal load, water-side HVAC, air-side HVAC and utility&economics. In the project&site section, building general information is input, such as weather data and 41 project name. For the building shell section the building shell can be built directly in eQUEST or imported from an external program, such as Revit or CAD. In the internal load section, both instantaneous load and space load are input and modified. The instantaneous loads are the heat gains from people, lighting and equipment. The space loads are considered as building heat gain or loss through building exterior envelope. After this information is input, mechanical equipment is defined in the HVAC section. Following the input stage the DOE-2 engine calculates a comprehensive result including building energy consumption and utility fees. In order to have confidence in the DOE2 engine‟s computation procedure, it is important to correctly determine space loads and the heat transfer through the building envelope since these directly influence the accuracy of the result. Basically, four types of heat transfer surfaces are determined in DOE2: exterior, interior, underground and light transmitting. The light transmission includes glass doors, curtain walls and windows. Roofs, exterior walls and exterior walls are considered as exterior surface, while interior walls include ceilings, floors and interior partitions. Basement floors, walls and slab are defined as underground surfaces (Kongkun 2008). 42 CHAPTER 4 SIMULATION MODELING PROCESS 4.1. Building Model Description Normally, eQUEST performs the building energy consumption through a virtual model which reflects the building itself as accurately as possible in thermodynamic aspects; but only energy related information is able to be manipulated in eQUEST. In the present research one baseline model and two alternative models were built and simulated in eQUEST. The baseline model is the existing building with its original conventional HVAC system, and the two alternative models are first, the existing building with the proposed with GSHP system and second, the ASHRAE GSHP model. Figure 4-1: Southwest view of Equest model of Pudong natatorium 43 Figure 4-2: Northeast view of eQUESTt model of the Pudong natatorium 4.2. Building Block Simulation Building site information and weather data This building is located in Shanghai, China. The weather in Shanghai is typical humid subtropical climate with four distinct seasons - a warm spring, a hot rainy summer, a cool autumn and an overcast cold winter. The hottest time in Shanghai comes in July and August, with more than 10 days of temperatures above 35 C (95 F). The coldest time is from late January to early February (Travelchina Guide 2011). 44 Climate data for Shanghai (1971−2000) Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Average high temp 8.1 9.2 12.8 19.1 24.1 27.6 31.8 31.3 27.2 22.6 17 11.1 20.2 Average low temp 1.1 2.2 5.6 10.9 16.1 20.8 25 24.9 20.6 15.1 9 3 12.9 Precipitation mm (inches) 51 57 99 89 102 170 156 158 137 63 46 37 1165 % Humidity 75 74 76 76 76 82 82 81 78 75 74 73 76.8 Avg. precipitation days (≥ 0.1 mm) 9.7 10.3 13.9 12.7 12.1 14.4 12 11.3 11 8.1 7 6.5 129 Sunshine hours 123 115.7 126 156 174 148 218 221 159 161 147 148 1895 Tablet 4-1: Climate data for Shanghai (1971-2000) (China Meteorological Administration) Table 4-2: Design related climate data (shanghai xiandai architecture) For this model, the weather file SHANGHAI.BIN was downloaded from DOE2 and applied into eQUEST for the baseline model and both alternative models. Building shell design parameter Although there are three models in this research, except for the ASHRAE model the baseline model and the alternative GSHP model are exactly same in all aspects except Heating design days （HDD18 ） 1691 Cooling design days （CDD26 ） 2847 Latitude North 31°10′ Longitude East 121°26′ Winter design dry bulb temperature -1.2 C Summer design dry/wet bulb temperature 34.6/28.2 C 45 HVAC system. For the baseline and alternative GSHP building, the material in the simulation program is in compliance with the original documentation from Xiandai Architecture design. For the ASHRAE model, the material settings are in compliance with ASHRAE 90.1-2007. The detailed settings for building shell are in appendix table A-1, and the settings for windows and glazing are in appendix table A-2. Building internal load The building internal load comes from lighting load, equipment and occupancy. The input information for baseline and alternative GSHP model are derived from MEP drawings from Xiandai Architecture. For the ASHRAE model, the input lighting, equipment and occupancy data come from ASHRAE 90.1-2007. The detail information is listed in appendix table A-3. Building schedule and operation There are two primary types of space in this natatorium: one is office and administration space and the other is natatorium, hospitality and public space. The schedules for those two types of spaces are different. Office and administration spaces are only occupied Monday through Friday, while the natatorium, hospitality and public spaces are occupied every day. It is necessary to differentiate these two types of space since occupancy schedules affect the final result directly. Because ASHRAE does not address a standard schedule, all of the three models use the same occupancy schedule, which is the actual building schedule. The detailed settings are available in appendix table A-4. 46 HVAC equipment and performance This section is the core of the modeling process, because the focus of the present research is the renovation of the HVAC system. Following are the tables of major parameters in conventional and GSHP systems. Chiller type Amount COP cooling capacity work input RTHB 2 4.8 1150kW （single capacity ） 240.0kW chilled water supply chilled water return mass flow 7℃ 12℃ 197.1m3/h cooling water supply(to cooling tower) cooling water return(from cooling tower) mass flow 37℃ 32℃ 234.54m3/h Table 4-3: Conventional HVAC system design parameter (Xiandai Architecture) Chiller type Amount COP cooling capacity work input RTHB 2 6.5 1150kW （single capacity ） 175.6kW chilled water supply(to room) chilled water return(from room) mass flow 7℃ 12℃ 197.1m3/h cooling water supply(to ground) cooling water return(from ground) mass flow 27℃ 22℃ 234.54m3/h Table 4-4: GSHP system design parameter (Xiandai Architecture) In these two systems, both use the same chiller since it‟s a renovation project which is improving the conventional system to a GSHP system. The detailed setting for 47 conventional and GSHP systems are given by Xiandai Architecture and manufacturer‟s website. Figure 4-3: Schematic conventional system (water side HVAC) Figure 4-4: Schematic GSHP system (water side HVAC) 48 Conventional system design parameter (Baseline model) Chiller specification in eQUEST: Chiller type Elec hermetic Centrifugal CHW loop chilled water loop CW loop condenser loop Elec input ratio 0.2083 Elec to condenser ratio 1 VSD drive used No Chiller capacity 3.9Mbtu/h Min ratio 0.1 design condition rated condition chilled water temp 44F chilled water temp 44F condenser temp 90F condenser temp 90F design/max capacity 0.92 condenser flow 3.0gpm/ton Table 4-5: Chiller specification in eQUEST Chilled water loop properties in eQUEST: loop type chilled water loop loop operation scheduled loop subtype Primary cooling schedule cooling schedule sizing option Secondary pump schedule Pump-fan schedule design CHW temp 44F loop minimum flow 0.05 loop design delta temp 9F loop sizing ratio 1 Avg circulate time 1.5min pipe head 21.6ft Cooling setpoint control Scheduled Table 4-6: Chilled water loop properties For cooling schedule and pump schedule, refer to appendix table A-4. For setpoint schedule, refer to appendix table A-4. 49 Condenser water loop properties in eQUEST: loop type chilled water loop loop operation scheduled loop subtype Primary cooling schedule cooling schedule sizing option Secondary pump schedule pump fan schedule design CHW temp 90F loop minimum flow 0.05 loop design delta temp 9F loop sizing ratio 1 Avg circulate time 1.5min pipe head 21.6ft Cooling setpoint control Scheduled Table 4-7: Chilled water loop properties For cooling schedule and pump schedule, refer to appendix table A-4. For setpoint schedule, refer to appendix table A-4 Heat rejection specification in eQUEST Heating rejection type open tower Design parameters wet bulb 78F number of cells 1 approach 12F cells controls minimum cells range 9F cell max flow 2(ratio) elec input ratio 0.0226 cell min flow 0.33(ratio) Fan control capacity control one-speed fan fan off flow 0.01(ratio) Table 4-8: Heat rejection specification in eQUEST 50 Pump properties for CHW loop and CW loop in eQUEST CHW loop pump CW loop pump Number 4 Number 4 Head(per pump) 72ft Head(per pump) 72ft Flow(per pump) 600gpm Flow(per pump) 600gpm Max pump ratio 1.3 Max pump ratio 1.3 Motor class high efficiency Motor class high efficiency Capacity control various speed Capacity control various speed Table 4-9: Pump properties for CHW loop and CW loop in eQUEST GSHP system design parameters (alternative I model) Ground loop heat exchanger properties in eQUEST GHX type vertical well field Ground Loop configuration Line 6 Pipe properties Vertical well field properties Outside diameter 1.20inch Depth 289ft Inside diameter 1.00inch Spacing 11.5ft Conductivity 5.0btu/hr-ft-f U-tube leg separation 2inch Numbers of identical Well Fields 288 Ground properties Loops attachments Undisturbed AVG ground temp 69F Flow control variable flow Ground thermal diffusivity 0.432ft2/hr Min flow 0.3(ratio) Ground thermal conductivity 1.127btu/h-ft-f Max flow 1.4(ratio) Table 4-10: Ground loop heat exchanger properties in eQUEST 51 Circulation loop properties in eQUEST. Loop type water loop HP Loop operation scheduled Loop subtype primary Cooling schedule cooling schedule Sizing option secondary Pump schedule pump fan schedule Design CHW temp 72F Loop minimum flow 0.05 Loop design delta temp 9F Loop sizing ratio 1 Avg circulate time 1.5min Pipe head 21.6ft Cooling setpoint control scheduled Heating setpoint control scheduled Table 4-11: Circulation loop properties in eQUEST For cooling schedule and pump schedule, refer to appendix table A-4. For setpoint schedule, refer to appendix table A-4. Pump properties for GSHP system in eQUEST GSHP pump Number 4 Head(per pump) 72ft Flow(per pump) 600gpm Max pump ratio 1.3 Motor class high efficiency Capacity control various speed Table 4-12: Pump properties for GSHP system in eQUEST 52 ASHRAE GSHP system design parameter (alternative II model) ASHRAE 90.1-2007 only addresses the minimum efficiency requirement for the HVAC zone. Because of that, the specification in this case for the ASHRAE model complies with alternative model I. For the ground loop heat exchanger properties for this model, refer to Table 4-10: Ground loop heat exchanger properties in eQUEST. For the circulation loop properties for this ASHRAE model, refer to Table 4-11: Circulation loop properties in eQUEST. For pump properties for this ASHRAE model, refer to Table 4-12: Pump properties for GSHP system in eQUEST. HVAC zoning design HVAC zoning design also influences the accuracy of the simulation result. HVAC zoning refers to the groups of conditioned spaces controlled by a single thermostat, where such spaces share similar load and usage characteristics (kongkun, 2008). eQUEST provides five types of zoning design. The first design is one zone/floor. The second and third designs are perimeter/core and perimeter/muti-core. The fourth design is zone selection by activity area. In the present research the fifth design: custom zoning, which is the last 53 type, is used because of the complexity of the project. In order to extract useful results from the three models, the same HVAC zoning design was used for each. The following are schematic HVAC zoning design layouts. The red hatched sections are the conditioned spaces. Also, the detailed zoning design parameters are listed in three charts, which are the zone load feature chart, the zone temperature control chart and the zone design flow rate chart. For the load schedule and Thermostat schedule, refer to appendix table A-4. Figure 4-5: Schematic HVAC zoning design for Pudong natatorium (basement plan) 54 Zone load feature (basement) Zone No. Zone Function Zone type Lighting schedule Equipment schedule Occupancy schedule 1 Kitchen conditioned lighting-1 equipment-1 occupancy-1 2 Dining area conditioned lighting-1 equipment-1 occupancy-1 3 other unconditioned lighting-2 equipment-2 occupancy-2 Table 4-13: Zone load feature (basement) Zone temperature control (basement) Zone No. Indoor design temperature(F) Thermostat schedule cooling heating cooling heating 1 78.8 68 cooling-1 heating-1 2 78.8 68 cooling-1 heating-1 3 N/A N/A N/A N/A Table 4-14: Zone temperature control (basement) Zone design flow rate (basement) Zone No. Area(ft2) Minimum design flow(cfm/ft2) Outdoor Air Flow/person (cfm) Minimum flow ratio Baseline and alternative I(GSHP) model Alternative II(ASHRAE) model 1 2068.5 0.5 29.5 7.5 1 2 2582.0 0.5 17.7 7.5 1 3 63140.2 N/A N/A N/A N/A Table 4-15: Zone design flow rate (basement) 55 Figure 4-6: Schematic HVAC zoning design for Pudong natatorium (1 st floor plan) 56 Zone load feature (1 st floor) Zone No. Zone Function Zone type Lighting schedule Equipment schedule Occupancy schedule 4 Athletes Lounge conditioned lighting-2 equipment-2 occupancy-2 5 Bathroom unconditioned lighting-2 equipment-2 occupancy-2 6 Swimming pool unconditioned lighting-2 equipment-2 occupancy-2 7 Dressing room unconditioned lighting-2 equipment-2 occupancy-2 8 Corridor conditioned lighting-2 equipment-2 occupancy-2 9 Dressing room unconditioned lighting-2 equipment-2 occupancy-2 10 Corridor conditioned lighting-2 equipment-2 occupancy-2 11 Clinic, Organizing committee room, Referee room conditioned lighting-1 equipment-1 occupancy-1 12 Clinic, Organizing committee room, Referee room conditioned lighting-1 equipment-1 occupancy-1 13 Bathroom unconditioned lighting-2 equipment-2 occupancy-2 14 Gym conditioned lighting-2 equipment-2 occupancy-2 15 Bathroom unconditioned lighting-2 equipment-2 occupancy-2 16 Corridor conditioned lighting-2 equipment-2 occupancy-2 17 Lobby conditioned lighting-2 equipment-2 occupancy-2 18 Other unconditioned lighting-1 equipment-1 occupancy-1 19 swimming hall conditioned lighting-2 equipment-2 occupancy-2 Table 4-16: Zone load feature (1 st floor) 57 Zone temperature control (1 st floor) Zone No. Indoor design temperature(F) Thermostat schedule cooling heating cooling heating 4 77 64.4 cooling-2 heating-2 5 N/A N/A N/A N/A 6 77 64.4 cooling-2 heating-2 7 N/A N/A N/A N/A 8 78.8 68 cooling-1 heating1 9 N/A N/A N/A N/A 10 78.8 68 cooling-1 heating-1 11 78.8 68 cooling-1 heating-1 12 78.8 68 cooling-1 heating-1 13 N/A N/A N/A N/A 14 77 64.4 cooling-2 heating-2 15 N/A N/A N/A N/A 16 78.8 68 cooling-1 heating-1 17 77 64.4 cooling-2 heating-2 18 N/A N/A N/A N/A 19 77 64.4 cooling-2 heating-2 Table 4-17: Zone temperature control (1 st floor) 58 Zone design flow rate (1 st floor) Zone No. Area(ft2) Minimum design flow(cfm/ft2) Outdoor Air Flow/person (cfm) Minimum flow ratio Baseline and alternative I(GSHP) model Alternative II(ASHRAE) model 4 4040 0.5 17.7 7.5 1 5 344 N/A N/A N/A N/A 6 10848 0.5 5.9 5 1 7 5605 N/A N/A N/A N/A 8 803 0.5 5.9 5 1 9 1453 N/A N/A N/A N/A 10 2312 0.5 5.9 5 1 11 2167 0.5 17.7 7.5 1 12 2684 0.5 17.7 7.5 1 13 70 N/A N/A N/A N/A 14 2929 0.5 41.29 10 1 15 783 N/A N/A N/A N/A 16 1101 0.5 5.9 5 1 17 784 0.5 5.9 5 1 18 174 N/A N/A N/A N/A 19 29895 0.5 29.5 7.5 1 Table 4-18: Zone design flow rate (1 st floor) 59 Figure 4-7: Schematic HVAC zoning design for Pudong natatorium (2 nd floor plan) 60 Zone load feature (2 nd floor) Zo ne No. Zone Function Zone type Lighting schedule Equipment schedule Occupancy schedule 20 Café bar conditioned lighting-2 equipment-2 occupancy-2 21 bathroom conditioned lighting-2 equipment-2 occupancy-2 22 Operation office conditioned lighting-1 equipment-1 occupancy-1 23 Lobby conditioned lighting-1 equipment-1 occupancy-1 24 Power distribution room unconditioned lighting-1 equipment-1 occupancy-1 25 lobby conditioned lighting-2 equipment-2 occupancy-2 26 gaming room conditioned lighting-2 equipment-2 occupancy-2 27 gaming room conditioned lighting-2 equipment-2 occupancy-2 28 Meeting room conditioned lighting-2 equipment-2 occupancy-2 29 Reception room conditioned lighting-1 equipment-1 occupancy-1 30 General office conditioned lighting-1 equipment-1 occupancy-1 31 corridor conditioned lighting-1 equipment-1 occupancy-1 32 bathroom conditioned lighting-1 equipment-1 occupancy-1 33 Auditorium box conditioned lighting-2 equipment-2 occupancy-2 34 other unconditioned lighting-2 equipment-2 occupancy-2 Table 4-19: Zone load feature (2 nd floor) 61 Zone temperature control (2 nd floor) Zone No. Indoor design temperature(F) Thermostat schedule cooling heating cooling heating 20 77 64.4 cooling-2 heating-2 21 78.8 68 cooling-1 heating-1 22 78.8 68 cooling-1 heating-1 23 78.8 68 cooling-1 heating-1 24 N/A N/A N/A N/A 25 77 64.4 cooling-2 heating-2 26 77 64.4 cooling-2 heating-2 27 77 64.4 cooling-2 heating-2 28 77 64.4 cooling-2 heating-2 29 78.8 68 cooling-1 heating-1 30 78.8 68 cooling-1 heating-1 31 78.8 68 cooling-1 heating-1 32 78.8 68 cooling-1 heating-1 33 77 64.4 cooling-2 heating-2 34 N/A N/A N/A N/A Table 4-20: Zone temperature control (2 nd floor) 62 Zone design flow rate (2 nd floor) Zone No. Area(ft2) Minimum design flow(cfm/ft2) Outdoor Air Flow/person (cfm) Minimum flow ratio baseline and alternative I(GSHP) model Alternative II(ASHRAE) model 20 5375 0.5 11.8 5 1 21 2659 0.5 17.7 7.5 1 22 1000 0.5 17.7 7.5 1 23 836 0.5 17.7 7.5 1 24 94 N/A N/A N/A N/A 25 7853 0.5 17.7 7.5 1 26 1460 0.5 17.7 7.5 1 27 1722 0.5 17.7 7.5 1 28 689 0.5 17.7 7.5 1 29 895 0.5 22.6 7.5 1 30 1785 0.5 17.7 7.5 1 31 920 0.5 5.9 5 1 32 189 0.5 17.7 7.5 1 33 2253 0.5 17.7 7.5 1 34 34780 N/A N/A N/A N/A Table 4-21: Zone design flow rate (2 nd floor) 63 Figure 4-8: Schematic HVAC zoning design for Pudong natatorium (3 rd floor plan) 64 Zone load feature (3 rd floor) Zone No. Zone Function Zone type Lighting schedule Equipment schedule Occupancy schedule 35 lounge conditioned lighting-2 equipment-2 occupancy-2 36 lobby conditioned lighting-2 equipment-2 occupancy-2 37 Power distribution room unconditioned lighting-1 equipment-1 occupancy-1 38 treatment room conditioned lighting-2 equipment-2 occupancy-2 39 lobby conditioned lighting-2 equipment-2 occupancy-2 40 Bathroom and dressing room unconditioned lighting-2 equipment-2 occupancy-2 41 corridor conditioned lighting-2 equipment-2 occupancy-2 42 bathroom unconditioned lighting-1 equipment-1 occupancy-1 43 treatment room conditioned lighting-2 equipment-2 occupancy-2 44 Lounge conditioned lighting-2 equipment-2 occupancy-2 45 Multi-function room conditioned lighting-1 equipment-1 occupancy-1 46 Auditorium box conditioned lighting-2 equipment-2 occupancy-2 47 bathroom unconditioned lighting-2 equipment-2 occupancy-2 48 other unconditioned lighting-2 equipment-2 occupancy-2 Table 4-22: Zone load feature (3 rd floor) 65 Zone temperature control (3 rd floor) Zone No. Indoor design temperature(F) Thermostat schedule cooling heating cooling heating 35 77 64.4 cooling-2 heating-2 36 77 64.4 cooling-2 heating-2 37 N/A N/A N/A N/A 38 77 64.4 cooling-2 heating-2 39 77 64.4 cooling-2 heating-2 40 N/A N/A N/A N/A 41 77 64.4 cooling-2 heating-2 42 N/A N/A N/A N/A 43 77 64.4 cooling-2 heating-2 44 77 64.4 cooling-2 heating-2 45 78.8 68 cooling-1 heating-1 46 77 64.4 cooling-2 heating-2 47 N/A N/A N/A N/A 48 N/A N/A N/A N/A Table 4-23: Zone temperature control (3 rd floor) 66 Zone design flow rate (3 rd floor) Zone No. Area(ft2) Minimum design flow(cfm/ft2) Outdoor Air Flow/person (cfm) Minimum flow ratio Baseline and alternative I(GSHP) model Alternative II(ASHRAE) model 35 4160 0.5 17.7 7.5 1 36 1352 0.5 17.7 7.5 1 37 272 N/A N/A N/A N/A 38 282 0.5 17.7 7.5 1 39 1523 0.5 17.7 7.5 1 40 3060 N/A N/A N/A N/A 41 936 0.5 5.9 5 1 42 290 N/A N/A N/A N/A 43 775 0.5 22.6 7.5 1 44 2127 0.5 22.6 7.5 1 45 4650 0.5 17.7 5 1 46 3069 0.5 17.7 5 1 47 464 N/A N/A N/A N/A 48 38648 N/A N/A N/A N/A Table 4-24: Zone design flow rate (3 rd floor) 67 Figure 4-9: Schematic HVAC zoning design for Pudong natatorium (4 th floor plan) 68 Zone load feature (4 th floor) Zone No. Zone Function Zone type Lighting schedule Equipment schedule Occupancy schedule 49 lobby conditioned lighting-2 equipment-2 occupancy-2 50 Entertainment room conditioned lighting-2 equipment-2 occupancy-2 51 Power distribution room unconditione d lighting-1 equipment-1 occupancy-1 52 corridor conditioned lighting-1 equipment-1 occupancy-1 53 corridor conditioned lighting-2 equipment-2 occupancy-2 54 bathroom unconditione d lighting-2 equipment-2 occupancy-2 55 other unconditione d lighting-2 equipment-2 occupancy-2 Table 4-25: Zone load feature (4 th floor) Zone temperature control (4 th floor) Zone No. Indoor design temperature(F) Thermostat schedule cooling heating cooling heating 49 77 64.4 cooling-2 heating-2 50 77 64.4 cooling-2 heating-2 51 N/A N/A N/A N/A 52 78.8 68 cooling-1 heating-1 53 77 64.4 cooling-2 heating-2 54 N/A N/A N/A N/A 55 N/A N/A N/A N/A Table 4-26: Zone temperature control (4 th floor) 69 Zone design flow rate (3 rd floor) Zone No. Area(ft2) Minimum design flow(cfm/ft2) Outdoor Air Flow/person (cfm) Minimum flow ratio Baseline and alternative I(GSHP) model Alternative II(ASHRAE) model 49 4095 0.5 17.7 7.5 1 50 13943 N/A N/A N/A N/A 51 272 N/A N/A N/A N/A 52 1342 0.5 17.7 7.5 1 53 1055 0.5 17.7 7.5 1 54 474 N/A N/A N/A N/A 55 32198 N/A N/A N/A N/A Table 4-27: Zone design flow rate (4 th floor) 70 CHAPTER 5 DATA RESULT 5.1. Baseline Model Result and Calibration The baseline model simulates the real building energy performance. The utility bills of Pudong Natatorium were monitored and collected by Shanghai Xiandai Architecture. The utility bills include three years‟ electric consumption bills (the gas consumption of the furnace is not included in these bills). The following table is the utility bill from Xiandai Architecture. Monthly electrical consumption bill(KWH) 2007 2008 2009 JAN 96765 100545 66360 FEB 74445 56235 71020 MAR 54810 53970 69105 APR 64210 60970 72910 MAY 51095 54645 56190 JUN 107070 95070 108540 JUL 236490 177030 232365 AUG 203250 179520 215025 SEP 107535 105765 132630 OCT 84380 75305 79105 NOV 69620 61055 70740 DEC 91275 72765 99780 TOTAL 1242952 1094883 1275779 Table 5-1 Pudong natatorium‟s utility bills from 2007 to 2009 71 Chart 5-1: Real monthly electrical consumption of Pudong natatorium From the chart above we can see the peak electrical demands for three years occur in July and August. This result is quite reasonable since July and August require the highest cooling load. The total electrical consumption for 2007 is 1,242,925 KWH, for 2008 1,094,883 KWH and for 2009 1,275,779 KWH. Chart 5-2: Comparison of yearly electrical consumption of Pudong natatorium 72 Let us take 2009 as the standard. The electrical consumption of 2008 is 85.8% of that of 2009, and the electrical consumption of 2007 is 97.4% of that of 2009. The following chart is the result coming from the virtual baseline model in eQUEST, which should replicate the real building as accurately as possible. The following is the table shows how much total electricity Pudong natatorium consumed in the eQUEST baseline model. Electrical consumption in eQUEST baseline model(KWH) JAN 57600 FEB 52400 MAR 57900 APR 55500 MAY 57000 JUN 141900 JUL 185800 AUG 180800 SEP 137400 OCT 56500 NOV 55000 DEC 58000 TOTAL 1095800 Table 5-2: Baseline model simulated electrical consumption of Pudong natatorium 73 Chart 5-3: Electrical consumption in eQUEST baseline model of Pudong natatorium In this chart, we can see that the peak electrical demand of the baseline model occurs in July, which is 185,800 KWH. Compared with the real building utility usage in 2009, the peak demand of the baseline model is around 80.0% of the actual 2009 utility bill. Chart 5-4; Monthly electrical consumption comparison between year 2009 and baseline model of Pudong natatorium 74 Chart 5-5: Yearly electrical consumption comparison of Pudong natatorium Chart 5-4 provides a calibration result for the eQUEST baseline model. The virtual baseline energy performance replicates the real energy performance reasonably closely. From this point of view, eQUEST is a workably reliable program and it will be appropriate to apply subsequent results coming from eQUEST to my thesis conclusion. 5.2. Detailed Result for Baseline, Alternative I and Alternative II model In this section, I will list the energy performance of all three virtual models in eQUEST, which includes the electrical consumption of different categories (cooling, heating, lighting, etc) for three models and gas consumption for conventional HVAC. Baseline model result The mechanical system of the baseline model is a conventional HVAC system which includes two chillers and one gas boiler. Because of that, the energy consumption consists two parts: one is electrical consumption and the other is gas consumption. 75 Because the chiller and boiler schedules rule the operation in summer and winter respectively, cooling electrical consumption only occurs from June to September, while heating gas consumption occurs in December, November and January. Baseline model electrical consumption(000KWH) Space cooling Heat rejection Ventilation fan Pump&Aux Misc Equipment Area Lighting Total Jan 0 0 14.6 1.1 5.8 36.1 57.6 Feb 0 0 13.2 0.9 5.6 32.7 52.4 Mar 0 0 14.6 0 6.7 36.6 57.9 Apr 0 0 14.1 0 6.1 35.2 55.4 May 0 0 14.6 0 6.1 36.3 57 Jun 61.8 8.5 14.1 15.6 6.4 35.4 141.8 Jul 98.1 15 14.6 16.3 5.8 36.1 185.9 Aug 92.9 13.8 14.6 16.2 6.7 36.6 180.8 Sep 59.1 7.3 14.1 15.6 6.1 35.2 137.4 Oct 0 0 14.6 0 5.8 36.1 56.5 Nov 0 0 14.1 0 5.8 35 54.9 Dec 0 0 14.6 1 6.1 36.3 58 Total 311.9 44.6 171.8 66.7 73 427.6 1095.6 Table 5-3: Baseline model electrical consumption 76 Baseline model gas consumption(000,000BTU) month space heating Jan 542.9 Feb 474.5 Mar 0 Apr 0 May 0 Jun 0 Jul 0 Aug 0 Sep 0 Oct 0 Nov 0 Dec 418.2 Total 1435.6 Table 5-4: Baseline model gas consumption 77 Chart 5-6: Baseline model electrical consumption The relative electrical consumption of area lighting, misc equipment and ventilation fan differs little over 12 months since those are not strongly influenced by weather changes. The heating and cooling consumption vary obviously as they are influenced by the weather change. The energy consumption of the baseline model includes electrical consumption and gas consumption. In order to compare the different energy performance of three models, it‟s necessary to convert gas consumption and electrical consumption into the same unit. The following is the conversion process. 78 1 BTU = 1.055 kilojoules. 1 joule per second = 1 watt, or 1 joule = 1 watt.sec. 1 kWh =1000 x 3600 watt.secs = 1000 x 3600 joules = 3600 kilojoules 1 kWh = 3600/1.055 BTU = 3412.3 BTU The reverse conversion is that 1 BTU = 0.000293 KWh Based on above conversion, the total gas consumption is 1435.6 million BTU, which is equal to 420.8 thousand KWh. (This conversion, based on equivalence of physical energy units, is convenient but does not reflect actual energy usage. A second conversion, based on energy costs, will be made below, but with the understanding that the cost conversion also does not reflect actual energy usage.) According to the above conversion, the total energy consumption of baseline model is 1516.4 thousand KWh. Baseline model total energy consumption(000KWH) month space cooling space heating heat rejection ventilation fan Pump& Aux Misc Equipment Area Lighting Jan 0 159.1 0 14.6 1.1 5.8 36.1 Feb 0 139.1 0 13.2 0.9 5.6 32.7 Mar 0 0 0 14.6 0 6.7 36.6 Apr 0 0 0 14.1 0 6.1 35.2 May 0 0 0 14.6 0 6.1 36.3 Jun 61.8 0 8.5 14.1 15.6 6.4 35.4 Jul 98.1 0 15 14.6 16.3 5.8 36.1 Aug 92.9 0 13.8 14.6 16.2 6.7 36.6 Sep 59.1 0 7.3 14.1 15.6 6.1 35.2 Oct 0 0 0 14.6 0 5.8 36.1 Nov 0 0 0 14.1 0 5.8 35 Dec 0 122.6 0 14.6 1 6.1 36.3 Total 311.9 420.8 44.6 171.8 66.7 73 427.6 Table 5-5: Baseline model total energy consumption (000KWH) 79 Chart 5-7: Baseline model electrical consumption (000KWH) As mentioned above, the conversion based on energy usage does not reflect the actual energy. Most people are familiar with site energy, which is the amount of energy (electricity, gas etc.) consumed by a building‟s operation. (In this thesis, “energy” refers to site energy; source energy will be named as “source energy”) Site energy usage can be observed in utility bills directly. Site energy can be divided into two types: primary and secondary energy. Primary energy is the raw fuel that is burned on site to create heat and electricity, such as natural gas or fuel oil used in onsite generation. Secondary energy is the energy product (heat or electricity) created elsewhere from a raw fuel, such as electricity purchased from the grid or heat received from a district steam system (Energy Star 2009). Because natural gas and electricity are types of primary and secondary energy, respectively, used in the baseline model, it is arbitrary to only use physical energy units 80 based on site energy to compare actual energy usage. The energy consumption in chart 5- 7 is only the site energy. Units of gas and electricity consumed at the site should not be compared directly because gas consumption represents the raw fuel while electricity consumption represents raw fuel converted elsewhere. Therefore, with two energy types in the baseline model, it is necessary to convert both natural gas and electricity into raw fuel consumed to compare actual energy usage. This is called source energy, which adds to site energy all related energy to generate and transport source energy to on-site use. No matter whether primary or secondary energy is used on site, the conversion to source energy has to account for the losses occurring in storage, production and transportation or transmission to the site. Actually, it is usually not practicable to calculate what percentage of source energy can be used as site energy with all the complications of different sources, distances, means of transportation and local policy. However, it is possible to provide a general ratio between source and site energy based on various types of fuels. Following is a table summarizing approximate source-site ratios for many fuels. Source-Site Ratios for all Portfolio Manager Fuels Fuel Type Source-Site Ratio Electricity(grid purchase) 3.34 Electricity (on-Site Solar or Wind Installation) 1 Natural Gas 1.047 Fuel Oil (1,2,4,5,6,Diesel, Kerosene) 1.01 Propane & Liquid Propane 1.01 District Steam 1.45 District Hot Water 1.35 District Chilled Water 1.05 Wood 1 Coal/Coke 1 Other 1 Table 5-6: Source-Site Ratios for all Portfolio Manager Fuels (Energy Star 2009) 81 Using this chart, we take 3.340 and 1.047 as the source-site ratio for electricity and gas. In the baseline model, the total actual site energy for gas and electricity are 420,800KWH and 1,095,600KWH, which require 440,578KWH and 3,659,304KWH of source energy. In this approximation the total source energy for the baseline model is 4,099,882KWH. When considering total energy consumption it is important to see the proportion of each end-use category to the total. This gives us a clear idea of how each category‟s proportion changes with different HVAC systems. The following is the detailed proportion for each end-use category in each month. Baseline model energy consumption end-use category proportion month space cooling space heating heat rejection Ventilati on fan Pump& Aux Misc Equipment Area Lighti ng Jan 0% 73% 0% 7% 1% 3% 17% Feb 0% 73% 0% 7% 0% 3% 17% Mar 0% 0% 0% 25% 0% 12% 63% Apr 0% 0% 0% 25% 0% 11% 64% May 0% 0% 0% 26% 0% 11% 64% Jun 44% 0% 6% 10% 11% 5% 25% Jul 53% 0% 8% 8% 9% 3% 19% Aug 51% 0% 8% 8% 9% 4% 20% Sep 43% 0% 5% 10% 11% 4% 26% Oct 0% 0% 0% 26% 0% 10% 64% Nov 0% 0% 0% 26% 0% 11% 64% Dec 0% 68% 0% 8% 1% 3% 20% Total 21% 28% 3% 11% 4% 5% 28% Table 5-7: Baseline model energy consumption end-use category proportion 82 From table 5-7, the total HVAC system consumes 67% of the energy of the Pudong natatorium in the baseline model: 1015.8 thousand KWh). The space heating energy consumption is a little higher than space cooling because the system uses a gas boiler to supply heat, which requires a large amount of gas. The ventilation fan is the second most influential part in the HVAC system, which account for 11% of the total energy consumption. The heat rejection and pump account for 3% and 4% respectively of the total energy consumption. Chart 5-8: Baseline model monthly energy consumption end–use category proportion In addition to the total energy consumption of the baseline model, the monthly peak demand can also be important (even though in China there is no demand charge.) In the United States, peak demand charges account for a large part of monthly utility fees. The following chart is the monthly peak demand by end-use categories. For this paper, energy demand charges will not be included in the life cycle cost (LCC) analysis but they do 83 serve as an index to show if annual utility fees of the baseline model would be higher or lower than for the alternative I model with electrical demand charges included. Baseline model monthly energy demand by end-use categories(KW) month space cooling space heating heat rejection ventilation fan Pump &Aux Misc Equipment Area Lighting Total max Jan 0 0 0 33.6 2.4 31.4 101.4 160.9 Feb 0 0 0 33.6 2.4 31.4 101.4 160.9 Mar 0 0 0 33.6 0 31.4 101.4 158.5 Apr 0 0 0 33.6 0 31.4 101.4 158.5 May 0 0 0 33.6 0 31.4 101.4 158.5 Jun 305.9 0 0 33.6 39 31.4 101.4 524.2 Jul 387.1 0 0 33.6 39 31.4 101.4 613.5 Aug 336.7 0 0 33.6 39 31.4 101.4 563.0 Sep 302.6 0 0 33.6 39 31.4 101.4 528.8 Oct 0 0 0 33.6 0 31.4 101.4 158.5 Nov 0 0 0 33.6 0 31.4 101.4 158.5 Dec 0 0 0 33.6 2.4 31.4 101.4 160.9 Total 1332.3 0 0 403.2 163.2 376.8 1216.8 3504.7 Table 5-8: Baseline model monthly energy demand by end-use categories (KW) 84 Baseline model monthly energy demand end-use categories proportion mont h space cooling space heating heat rejection ventilation fan Pump& Aux Misc Equipment Area Lighting Jan 0.00% 0.00% 0.00% 19.91% 1.42% 18.60% 60.07% Feb 0.00% 0.00% 0.00% 19.91% 1.42% 18.60% 60.07% Mar 0.00% 0.00% 0.00% 20.19% 0.00% 18.87% 60.94% Apr 0.00% 0.00% 0.00% 20.19% 0.00% 18.87% 60.94% May 0.00% 0.00% 0.00% 20.19% 0.00% 18.87% 60.94% Jun 59.83% 0.00% 0.00% 6.57% 7.63% 6.14% 19.83% Jul 65.33% 0.00% 0.00% 5.67% 6.58% 5.30% 17.11% Aug 62.11% 0.00% 0.00% 6.20% 7.19% 5.79% 18.71% Sep 59.57% 0.00% 0.00% 6.61% 7.68% 6.18% 19.96% Oct 0.00% 0.00% 0.00% 20.19% 0.00% 18.87% 60.94% Nov 0.00% 0.00% 0.00% 20.19% 0.00% 18.87% 60.94% Dec 0.00% 0.00% 0.00% 19.91% 1.42% 18.60% 60.07% Total 38.15% 0.00% 0.00% 11.55% 4.67% 10.79% 34.84% Table 5-9: Baseline model monthly energy demand end-use categories proportion Table 5-8 and table 5-9 are the summary of monthly energy demand by end-use categories. The highest demand for the baseline model occurs in July: 613.5 KW. Space cooling demand accounts for most of the demand in summer while, in other seasons, area lighting is a dominating category which almost contributes 60% of total energy demand. Becasuse of using the gas boiler to heat space, there is no space heating electrical demand in winter, which differs from the alternative I model. Chart 5-10 shows the proportion of each category for 12 months. In total area lighting and space cooling make up 73% of 85 electrical demand annually. Misc equipment, pump and ventilation account for the remaining 27% of electrical demand. The energy cost in the baseline model includes two parts: electrical cost and gas cost. The unit price for electrical cost is $0.12/KWH, while the unit price for natural gas is $0.48/M 3 . Because of the different units, a conversion is necessary to make the comparison. The heating value for gas is 7000, 000calorie/ m3. 1calorie is equal to 4.184 joules. 1000joules=0.0002778KWh 7000, 000calorie=8.05KWh Thus the unit price for natural gas is equivalent to $0.06/KWh. The simulation result summarized in the following chart shows that the highest cost happens in July ($22,308) while the lowest energy cost ($6,588) occurs in November. When compared with chart 5-7 and chart 5-9, it is interesting to find that, even though the energy consumption in January, November and December is higher than in June, July, August and September, the energy cost of those three months is lower because of the lower gas rate ($0.06 per equivalent KWh as compared to the electrical rate of $0.12 per KWh). The total energy cost for 12 months in the baseline model is $156,639, which includes electrical cost ($131,472) and gas cost ($25,167). 86 Base line model energy cost($) month electrical cost gas cost total Jan 6912 9465 16377 Feb 6288 8346 14634 Mar 6948 0 6948 Apr 6648 0 6648 May 6840 0 6840 Jun 17016 0 17016 Jul 22308 0 22308 Aug 21696 0 21696 Sep 16488 0 16488 Oct 6780 0 6780 Nov 6588 0 6588 Dec 6960 7356 14316 Total 131472 25167 156639 Table 5-10: Baseline model energy cost ($) 87 Chart 5-9: Baseline model energy cost ($) Alternative I model result The alternative I model is the retrofit building with Ground Source Heat Pump (GSHP) system. In this model, all building parameters and thermodynamic information are the same as for the baseline model except the HVAC system. The schedule of chiller operation is also the same as for the baseline model. 88 Alternative I model electrical consumption(000KWH) month space cooling space heating ventilation fan Pump&Aux Misc Equipment Area Lighting Total Jan 0.4 37.8 14 11 5.6 35.9 104.7 Feb 0.3 33.7 12.6 9.9 5.6 32.7 94.8 Mar 0 0 14 0 6.7 36.6 57.3 Apr 0 0 13.5 0 6.4 35.4 55.3 May 0 0 14 0 5.8 36.1 55.9 Jun 40.2 0 13.5 10.6 6.4 35.4 106.1 Jul 72.5 0 14 11 6.1 36.3 139.9 Aug 69.2 0 14 11 6.4 36.4 137 Sep 40.5 0 13.5 10.6 6.1 35.2 105.9 Oct 0 0 14 0 5.8 36.1 55.9 Nov 0 0 13.5 0 5.8 35 54.3 Dec 0.7 29.5 14 11 6.1 36.3 97.6 Total 223.8 101 164.6 75.1 72.8 427.4 1064.7 Table 5-11: Alternative I model electrical consumption 89 Chart 5-10: Alternative I model electrical consumption Based on table 5-11, the total electrical consumption is 1064.7 thousand KWh. Because of the GSHP HVAC system, there is no gas consumption in this model. The GSHP system only uses electrical input to drive the operation of the heat pump, which is its major advantage over the baseline model. Also, area lighting, misc equipment and ventilation fan consumption are roughly constant and almost the same as for the baseline model. The space cooling and space heating energy consumption are 233.8 thousand KWh and 101 thousand KWh. With the source-site ratio 3.340 for electricity, in order to generate 1,064,700KWH site energy, 3556098KWH source energy is consumed. Following is the end-use category proportion for alternative I model‟s energy consumption. 90 Alternative I model energy consumption end-use category proportion month space cooling space heating ventilation fan Pump&Aux Misc Equipment Area Lighting Jan 0% 36% 13% 11% 5% 34% Feb 0% 36% 13% 10% 6% 34% Mar 0% 0% 24% 0% 12% 64% Apr 0% 0% 24% 0% 12% 64% May 0% 0% 25% 0% 10% 65% Jun 38% 0% 13% 10% 6% 33% Jul 52% 0% 10% 8% 4% 26% Aug 51% 0% 10% 8% 5% 27% Sep 38% 0% 13% 10% 6% 33% Oct 0% 0% 25% 0% 10% 65% Nov 0% 0% 25% 0% 11% 64% Dec 1% 30% 14% 11% 6% 37% Total 21% 9% 15% 7% 7% 40% Table 5-12: Alternative I model monthly energy consumption end-use category proportion 91 Chart 5-11: Alternative I model energy consumption end-use category proportion The HVAC energy consumption in the alternative I model only amounts to 52% of total energy consumption in the base line model -- by taking benefit of the GSHP system. The cooling consumption accounts for 21% of the total energy and the heating consumption accounts for only 9% of total energy consumption. 15% and 7% of the total energy is accounted for by ventilation fans and pumps. For the alternative I model, the peak demand occurs in July as for the baseline model, but the value of peak demand is 448.2KW, which is lower than the baseline model (table 5-8). When we take the whole picture, the total electrical demand is 3428.6 KW, which is almost same as the baseline model (table 5-8). The reason for this is because, in the baseline model, space heating consumes gas rather than electricity; hence there is very little electrical demand for space heating. In this (alternative I) model, space heating is 92 provided by GSHP, which is powered by electricity. Therefore, even though the monthly peak electrical demand is reduced in this model, the total electrical demand for 12 months is almost the same. Alternative I model monthly energy demand end-use categories(KW) month space cooling space heating ventilation fan Pump& Aux Misc Equipment Area Lighting Total max Jan 11.2 151.9 32.2 25.2 31.4 101.4 315.0 Feb 7.9 160.9 32.2 25.2 31.4 101.4 324.1 Mar 0 0 32.2 0 31.4 101.4 157.1 Apr 0 0 32.2 0 31.4 101.4 157.1 May 0 0 32.2 0 31.4 101.4 157.1 Jun 241.8 5.2 32.2 25.2 31.4 101.4 390.2 Jul 280.4 0 32.2 25.2 31.4 101.4 448.2 Aug 263.5 0 32.2 25.2 31.4 101.4 426.7 Sep 246.2 0.3 32.2 25.2 31.4 101.4 416.4 Oct 0 0 32.2 0 31.4 101.4 157.1 Nov 0 0 32.2 0 31.4 101.4 157.1 Dec 24.8 159.4 32.2 25.2 31.4 101.4 322.5 Total 1075.8 477.7 386.4 176.4 376.8 1216.8 3428.6 Table 5-13: Alternative I model monthly energy demand by end-use categories (KW) The following it the summary of each category‟s proportion in the alternative I model. The heating demand and cooling demand dominate winter and summer season respectively in this model as in the baseline model. 93 Alternative I model monthly energy demand end-use categories proportion month space cooling space heating ventilation fan Pump&Aux Misc Equipment Area Lighting Jan 3.17% 42.99% 9.11% 7.13% 8.89% 28.70% Feb 2.20% 44.82% 8.97% 7.02% 8.75% 28.25% Mar 0.00% 0.00% 19.52% 0.00% 19.03% 61.45% Apr 0.00% 0.00% 19.52% 0.00% 19.03% 61.45% May 0.00% 0.00% 19.52% 0.00% 19.03% 61.45% Jun 55.31% 1.19% 7.37% 5.76% 7.18% 23.19% Jul 59.58% 0.00% 6.84% 5.35% 6.67% 21.55% Aug 58.08% 0.00% 7.10% 5.55% 6.92% 22.35% Sep 56.38% 0.07% 7.37% 5.77% 7.19% 23.22% Oct 0.00% 0.00% 19.52% 0.00% 19.03% 61.45% Nov 0.00% 0.00% 19.52% 0.00% 19.03% 61.45% Dec 6.62% 42.57% 8.60% 6.73% 8.39% 27.08% Total 29.00% 12.88% 10.42% 4.75% 10.16% 32.80% Table 5-14: Alternative I model monthly energy demand end-use categories proportion The energy cost of this model is entirely electrical cost since the GSHP uses electricity to generate space heating; there is no gas cost in this model. The electrical rate for this model should comply with the baseline model‟s electrical rate, which is $0.12/KWH. 94 Alternative I model energy cost($) month electrical cost gas cost total Jan 12564 0 12564 Feb 11376 0 11376 Mar 6876 0 6876 Apr 6636 0 6636 May 6708 0 6708 Jun 12732 0 12732 Jul 16788 0 16788 Aug 16440 0 16440 Sep 12708 0 12708 Oct 6708 0 6708 Nov 6516 0 6516 Dec 11712 0 11712 Total 127764 0 127764 Table 5-15: Alternative I model energy cost ($) 95 Chart 5-12: Alternative I model energy cost ($) For this alternative model, because the energy cost is all electrical, the cost for 12 months closely follows the energy consumption. The highest cost is still in July ($16,788) and the lowest is November ($6,515). The total energy cost for this model is $127,764. Alternative II model The alternative II model serves as comparison to the alternative I and baseline models. This model complies with ASHRAE standards and with Design Standards for Energy Efficiency of Public Buildings (DSEEPB.) The ASHRAE standards applied in this model are ASHRAE 90.1 and ASHRAE 62.7, which are two separate standards dealing with energy performance and ventilation. These two standards set forth minimum energy efficiency requirements for different types of buildings. The DSEEPB is a China energy 96 code. The main reason to use these two different energy codes is because neither of the two codes addresses all key information of the building. For example, the Misc equipment load is not addressed in ASHRAE 90.1 and 62.7, while the DSEEPB lists the Misc equipment load for different types of space. With the help of those two building codes the alternative II model has complete information. The basic principle used in this paper is that we comply with DSEEPB standards only when the information is not addressed in the ASHRAE standards. We would not expect the energy consumption from alternative I model to be less than the result from this model. The following is the summary of monthly electrical consumption. Alternative II model electrical consumption(000KWH) month space cooling space heating ventilation fan Pump&Aux Misc Equipment Area Lighting Total Jan 0.8 54.9 13.4 11.1 5.6 45 130.8 Feb 0.9 47.8 12.1 10 5.6 41.1 117.5 Mar 0 0 13.4 0 6.7 45.9 66 Apr 0 0 12.9 0 6.4 44.4 63.7 May 0 0 13.4 0 5.8 45.3 64.5 Jun 69.6 0 12.9 10.7 6.4 44.4 144 Jul 113.1 0 13.4 11.1 6.1 45.5 189.2 Aug 109.1 0 13.4 11.1 6.4 45.7 185.7 Sep 69.8 0 12.9 10.7 6.1 44.2 143.7 Oct 0 0 13.4 0 5.8 45.3 64.5 Nov 0 0 12.9 0 5.8 44 62.7 Dec 2.3 40.8 13.4 11.1 6.1 45.5 119.2 Total 365.6 143.5 157.5 75.8 72.8 536.3 1351.5 Table 5-15: Alternative II model electrical consumption 97 Chart 5-13: Alternative II model electrical consumption In the alternative II model, the total electrical consumption is 1351.9 thousand KWh. Because of the GSHP HVAC system, there is no gas consumption in this model. 98 Alternative II model energy consumption end-use category proportion mo nth space cooling space heating ventilation fan Pump&Aux Misc Equipment Area Lighting Jan 1% 42% 10% 8% 4% 34% Feb 1% 41% 10% 9% 5% 35% Mar 0% 0% 20% 0% 10% 70% Apr 0% 0% 20% 0% 10% 70% Ma y 0% 0% 21% 0% 9% 70% Jun 48% 0% 9% 7% 4% 31% Jul 60% 0% 7% 6% 3% 24% Aug 59% 0% 7% 6% 3% 25% Sep 49% 0% 9% 7% 4% 31% Oct 0% 0% 21% 0% 9% 70% Nov 0% 0% 21% 0% 9% 70% Dec 2% 34% 11% 9% 5% 38% Tot al 27% 11% 12% 6% 5% 40% Table 5-17: Alternative II model monthly energy consumption end-use category proportion 99 Chart 5-14: Alternative II model energy consumption end-use category proportion The above chart shows the proportion of each category for the alternative II model; the HVAC system accounts for 55% of total energy consumption. Space heating, space cooling and ventilation fans are the three major factors which consume most of the electricity in the HVAC category. The rest (6%) is consumed by pumps. Following is the monthly energy demand of alternative II model. The peak demand of alternative II model is 629.2KW and occurs in July. 100 Alternative II model monthly energy demand by end-use categories(KW) Month space cooling space heating ventilation fan Pump &Aux Misc Equipment Area Lighting Total Jan 17.1 248.7 30.8 25.6 31.4 126.7 430.9 Feb 12.1 261.9 30.8 25.6 31.4 126.7 444.6 Mar 0 0 30.8 0 31.4 126.7 180.5 Apr 0 0 30.8 0 31.4 126.7 180.5 May 0 0 30.8 0 31.4 126.7 180.5 Jun 358.7 8.5 30.8 25.6 31.4 126.7 532.8 Jul 414.7 0 30.8 25.6 31.4 126.7 610.4 Aug 398.1 0 30.8 25.6 31.4 126.7 580.3 Sep 374.4 0 30.8 25.6 31.4 126.7 564.3 Oct 0 0 30.8 0 31.4 126.7 180.6 Nov 0 0 30.8 0 31.4 126.7 180.6 Dec 52.3 257.3 30.8 25.6 31.4 126.7 440.9 Total 1627.4 776.4 369.6 179.2 376.8 1520.4 4506.9 Table 5-18: Alternative II model monthly energy demand by end-use categories (KW) 101 Alternative II model monthly energy demand end-use categories proportion Month space cooling space heating ventilation fan Pump&Aux Misc Equipment Area Lighting Jan 3.56% 51.78% 6.41% 5.33% 6.54% 26.38% Feb 2.48% 53.61% 6.31% 5.24% 6.43% 25.94% Mar 0.00% 0.00% 16.30% 0.00% 16.62% 67.07% Apr 0.00% 0.00% 16.30% 0.00% 16.62% 67.07% May 0.00% 0.00% 16.30% 0.00% 16.62% 67.07% Jun 61.66% 1.46% 5.29% 4.40% 5.40% 21.78% Jul 65.91% 0.00% 4.90% 4.07% 4.99% 20.14% Aug 64.99% 0.00% 5.03% 4.18% 5.13% 20.68% Sep 63.58% 0.00% 5.23% 4.35% 5.33% 21.51% Oct 0.00% 0.00% 16.30% 0.00% 16.62% 67.07% Nov 0.00% 0.00% 16.30% 0.00% 16.62% 67.07% Dec 9.98% 49.09% 5.88% 4.88% 5.99% 24.17% Total 33.56% 16.01% 7.62% 3.69% 7.77% 31.35% Table 5-19: Alternative II model monthly energy demand end-use categories proportion In the alternative II model, space cooling (33.56%) and area lighting (31.35%) are the two most dominant categories for total peak demand, followed by space heating (16.01%), ventilation (7.62%) and misc equipment (7.77%), with pump (3.69%) making up total peak demand. For the alternative II model it is not necessary to convert utility rates since it is being used to provide a criterion to determine whether baseline and alternative I models go 102 beyond the minimum energy efficiency requirement. The comparison between this model and the alternative I model can be limited to total energy usage rather than cost. 103 CHAPTER 6 RESULT ANALYSIS From the previous chapter, we already have a clear idea of how each of the three models (baseline, alternative I and alternative II) performs for energy consumption and energy demand, but we have not gathered for comparison among the models and between the models and actual energy consumption. In this chapter, we take the opportunity to make a comparison between the building‟s real energy performance and cost with three models‟ predicted energy performance and cost. 6.1. Comparison between Baseline Model and Real Building In Chapter 5 this thesis has already compared the detailed energy consumption for real energy performance and baseline model energy prediction. Generally, the prediction of the baseline model corresponds reasonably closely with the real building energy consumption. The total energy consumption for 2009 of the real building was 1,273,770KWH, while the baseline model predicts the total energy consumption to be 1,095,800KWH. The difference between those two is 177,970KWH, which is 13.9% of real energy consumption and 16.2% of baseline model. Based on the percentage of difference, the result from eQUEST model can be taken to predict the real operation of building with roughly accuracy. 104 Chart 6-1: Monthly electrical comparison between real building and baseline mode l(KWH) 6.2. Comparison between Baseline Model and Alternative I Model In this section, HVAC energy consumption, total energy consumption, total source energy consumption, end-use categories energy proportion, utility fees and energy demand from two models (baseline model and alternative I model) will be compared. HVAC energy consumption There are three parts of HVAC energy consumption in the baseline and alternative I models: space heating, space cooling and other (pump, ventilation and heat rejection). 105 HVAC energy consumption of baseline and alternative I model(thousand KWH) month space heating space cooling other baseline alternative I baseline alternative I baseline alternative I Jan 159.1 37.8 0 0.4 15.7 25 Feb 139.1 33.7 0 0.3 14.1 22.5 Mar 0 0 0 0 14.6 14 Apr 0 0 0 0 14.1 13.5 May 0 0 0 0 14.6 14 Jun 0 0 61.8 40.2 38.2 24.1 Jul 0 0 98.1 72.5 45.9 25 Aug 0 0 92.9 69.2 44.6 25 Sep 0 0 59.1 40.5 37 24.1 Oct 0 0 0 0 14.6 14 Nov 0 0 0 0 14.1 13.5 Dec 122.6 29.5 0 0.7 15.6 25 Total 420.8 101 311.9 223.8 283.1 239.7 Table 6-1: HVAC energy consumption of baseline and alternative I model 106 Chart 6-2: Space heating consumption of baseline and alternative I model The space heating energy decreases sharply from baseline model to alternative I model because of taking advantage of GSHP. The total space heating is 420,800KWH in the baseline model. In the alternative I model, the heating consumption is reduced to 101,000KWH, which is 24% of baseline model. 107 Chart 6-3: Space cooling consumption of baseline and alternative I model The difference of space cooling consumption between the two models is not as large as that for space heating. The total space cooling of the baseline and alternative I models are 311,900KWH and 223,800KWH, respectively. The space cooling of the alternative I model is 72% of baseline model. The rest of HVAC energy consumption comes from pump, ventilation fan and heat rejection, which are 283100KWH (baseline model) and 239700KWH (alternative I model). 108 Chart 6-4: Total HVAC energy consumption of baseline and alternative I model In each month, especially in winter and summer, the alternative I model consumes less energy than the baseline model. In total, the baseline model HVAC energy consumption is 1,015,800KWH, while the alternative I model consumes 564,500KWH: 56% of the baseline model. Total energy consumption comparison In addition to HVAC energy consumption, two more categories are added to calculate total energy consumption: Area lighting and Misc equipment. Those two categories are approximately invariant in energy consumption and constant for 12 months. With these two categories, total energy consumption is 1,516,400KWH for the baseline model. For 109 the alternative I model total energy consumption is 1,064,700KWH, which is 70% of baseline model. Total energy consumption of baseline and alternative I model (thousands KWH) month baseline model alternative I model Jan 216.7 104.7 Feb 191.5 94.8 Mar 57.9 57.3 Apr 55.4 55.3 May 57 55.9 Jun 141.8 106.1 Jul 185.9 139.9 Aug 180.8 137 Sep 137.4 105.9 Oct 56.5 55.9 Nov 54.9 54.3 Dec 180.6 97.6 Total 1516.4 1064.7 Table 6-2: Total energy consumption of baseline and alternative I model 110 Chart 6-5: Total energy consumption of baseline and alternative I model Total source energy consumption comparison The total source energy is 4,099,882KWH for the baseline model and 3,556,098KWH for the alternative I model. The source energy for the alternative I model is 86.7% of the baseline model; while comparing site energy in the previous section, the alternative I model consumes 70% site energy of baseline model. The reason for the 16.7%‟s difference is because natural gas is classified as primary energy and has much lower source-site ratio. 111 End-use categories energy proportion comparison In this section, total energy consumption is divided into five categories: space heating, space cooling, other HVAC consumption, misc equipment and area lighting. According to different HVAC systems, the proportion of each categories changes correspondingly. End-use category energy use proportion end-use category baseline model alternative I model Space heating 27.75% 9.49% Space cooling 20.57% 21.02% Other HVAC equipment 18.67% 22.51% Misc equipment 4.81% 6.84% Area lighting 28.20% 40.14% total 100.00% 100.00% Table 6-3: End-use category energy use proportion of baseline and alternative I model In the alternative I model, the HVAC system accounts for 53.02% of total energy usage versus 66.99% in the baseline model. 112 Utility fees comparison Annual energy cost for baseline and alternative I model ($) month base line model alternative I model electrical cost gas cost total electrical cost gas cost total Jan 6912 9465 16377 12564 0 12564 Feb 6288 8346 14634 11376 0 11376 Mar 6948 0 6948 6876 0 6876 Apr 6648 0 6648 6636 0 6636 May 6840 0 6840 6708 0 6708 Jun 17016 0 17016 12732 0 12732 Jul 22308 0 22308 16788 0 16788 Aug 21696 0 21696 16440 0 16440 Sep 16488 0 16488 12708 0 12708 Oct 6780 0 6780 6708 0 6708 Nov 6588 0 6588 6516 0 6516 Dec 6960 7356 14316 11712 0 11712 Total 131472 25167 156639 127764 0 12776 4 Table 6-4: Annual energy cost for baseline and alternative I model Two types of energy are used in the baseline model: electricity and gas. For convenience of comparison, both electrical cost and gas cost are listed in the table below even though the alternative I model only consumes electricity. Total energy cost is $156,639 for the baseline model and $127,764 for the alternative I model. Totally, $28,875 (18.4% of utility fees) is saved when using GSHP system instead of a conventional HVAC system. 113 Chart 6-6: Annual energy cost for baseline and alternative I model Energy demand comparison There are no energy demand charges for Pudong natatorium because of Chinese energy policy. However, in the United States demand charges account for a large proportion of monthly utility fees. Even though energy demand does not influence the conclusion of this thesis it demonstrates a potential additional advantage if the alternative I model can save more money where demand fees are charged. The highest demands for both models occur in July, which are 613.5KW and 448.2KW, respectively. The peak demand of the alternative I model is 73% of the baseline model. We note that the alternative I model has a higher demand than the baseline model in winter as a result of using electricity rather than gas for heating. As a result, the 114 aggregations of 12 months‟ peak demand for two models are roughly the same (alternative 1‟s aggregate peak demand is 98% of the baseline model). From this point of view, the demand charge appears to have a limited potential effect on annual utility fees saving in this particular case. Monthly peak demand of baseline and alternative I model (KW) month baseline model alternative I model Jan 160.9 315 Feb 160.9 324.1 Mar 158.5 157.1 Apr 158.5 157.1 May 158.5 157.1 Jun 524.2 390.2 Jul 613.5 448.2 Aug 563 426.7 Sep 528.8 416.4 Oct 158.5 157.1 Nov 158.5 157.1 Dec 160.9 322.5 Total 3504.7 3428.6 Table 6-5: Monthly peak demand of baseline and alternative I model 115 Chart 6-7: Monthly peak demand of baseline and alternative I model 6.3. Comparison between Alternative I model, Alternative II model and CBECS Database The alternative II model is the “standard model” of GSHP system. By applying ASHRAE standard and Design Standard for Energy Efficiency of Public Buildings, this model addresses the minimum energy efficiency requirement of Pudong natatorium. CBECS (Commercial Building Energy Consumption Survey) is published by the U.S. Energy Information Administration and is used as a standard of average building energy consumption for different types of buildings. Four sets of comparisons between the alternative I and alternative II models are made in this section: HVAC energy consumption, total energy consumption, end-use categories proportion and energy 116 demand. The electricity consumption is compared between the alternative I model and the CBECS database. HVAC energy consumption comparison HVAC energy consumption of alternative I and alternative II model(thousand KWH) month space heating space cooling other alternative I alternative II alternative I alternative II alternative I alternative II Jan 37.8 54.9 0.4 0.8 25 24.5 Feb 33.7 47.8 0.3 0.9 22.5 22.1 Mar 0 0 0 0 14 13.4 Apr 0 0 0 0 13.5 12.9 May 0 0 0 0 14 13.4 Jun 0 0 40.2 69.6 24.1 23.6 Jul 0 0 72.5 113.1 25 24.5 Aug 0 0 69.2 109.1 25 24.5 Sep 0 0 40.5 69.8 24.1 23.6 Oct 0 0 0 0 14 13.4 Nov 0 0 0 0 13.5 12.9 Dec 29.5 40.8 0.7 2.3 25 24.5 Total 101 143.5 223.8 365.6 239.7 233.3 Table 6-6: HVAC energy consumption of alternative I and alternative II model 117 Chart 6-8: Space heating consumption of alternative I and alternative II model Total space heating is 101,000KWH for the alternative I model and 143,500KWH for the alternative II model. The result shows that the alternative I model only consumes 70% energy of the alternative II model. 118 Chart 6-9: Space cooling consumption of alternative I and alternative II model Total space cooling energy consumption for the alternative I model is 223,800KWH, which is 61% of the alternative II model (365,600KWH). The rest of HVAC consumption comes from ventilation fan and pump, which are 239,700KWH (alternative I) and 233,300KWH (alternative II). The following is total HVAC energy consumption for two models. 119 Chart 6-10: Total HVAC energy consumption of alternative I and alternative II model In the aggregate, HVAC energy consumption in the alternative I model is 546,500KWH; HVAC energy consumption in the alternative II model is 742,400KWH, which means the alternative I model has better energy performance than the alternative II model and goes beyond the minimum requirement of energy efficiency. The Alternative I model‟s energy consumption is 73% of alternative II model. 120 Total energy consumption Total energy consumption of baseline and alternative I model(thousand KWH) month alternative I model alternative II model Jan 104.7 130.8 Feb 94.8 117.5 Mar 57.3 66 Apr 55.3 63.7 May 55.9 64.5 Jun 106.1 144 Jul 139.9 189.2 Aug 137 185.7 Sep 105.9 143.7 Oct 55.9 64.5 Nov 54.3 62.7 Dec 97.6 119.2 Total 1064.7 1351.5 Table 6-7: Total energy consumption of alternative and alternative II model 121 Chart 6-11: Total energy consumption of alternative I and alternative II model From a whole picture, the total energy consumption of the alternative I model is 1,064,700KWH, while the alternative II model consumes 1,351,500KWH energy. The alternative I model consumes 78% of the energy of the alternative II model, which means that, with the GHSP system, the Pudong natatorium will have better energy performance than the minimum energy efficiency required. Electricity consumption’s intensity comparison CBECS addresses the average energy consumption intensity in Table C21: Electricity Consumption and Conditional Energy Intensity by Building Size for Non-Mall Buildings, 2003. Following table is summary of table C21. 122 Total Electricity Consumption (billion kWh) Electricity Energy Intensity (kWh/square foot) Building size 1,001 to 10,000 Square Feet 10,001 to 100,000 Square Feet Over 100,000 Square Feet 1,001 to 10,000 Square Feet 10,001 to 100,000 Square Feet Over 100,000 Square Feet All buildings 190 341 360 15.1 11.8 16.4 Table 6-8: Summarized CBECS table C21 For Pudong natatorium, total area is 22,000 square meter, while the conditioned space accounts 46.8% of total area, which is 10296 square meter. 1 foot=0.3048 meter 1 square foot=0.092 square meter 1 square meter=10.84 square feet Based on area table 6-8, it divides buildings into three levels. According to the above conversion, 10296 square meters is equal to 111609 square feet, which falls into third level. Total electricity consumption of the alternative I model is 1064700KWH. The intensity of electrical consumption is 9.6KWH/square foot, which is 58% of 16.4KWH/square foot listed in table 6-8. The result tells us that, with the GSHP system, Pudong natatorium has greatly improved energy performance when compared with other buildings of similar size. 123 End-use categories proportion comparison End-use category energy use proportion end-use category alternative I model alternative II model Space heating 9.49% 10.62% Space cooling 21.02% 27.05% Other HVAC equipment 22.51% 17.26% Misc equipment 6.84% 5.39% Area lighting 40.14% 39.68% total 100.00% 100.00% Table 6-9: End-use category energy use proportion of alternative I and alternative II model There is no obvious difference between the two models in this respect; the space cooling percentage shrinks 6% in the alternative I model, while other HVAC equipment accounts for more percentage in the alternative I model than in the alternative II model. Energy demand comparison Monthly peak demand of alternative I and alternative II model month alternative I model alternative II model Jan 315 480.3 Feb 324.1 488.5 Mar 157.1 188.9 Apr 157.1 188.9 May 157.1 188.9 Jun 390.2 581.7 Jul 448.2 629.2 Aug 426.7 612.6 Sep 416.4 588.9 Oct 157.1 188.9 Nov 157.1 188.9 Dec 322.5 524.1 Total 3428.6 4849.8 Table 6-10: Monthly peak demand of alternative I and alternative II model 124 The peak demands for the alternative I and alternative II models both occur in July. The alternative I model‟s peak demand is 71% of the alternative II model. In the aggregate, the sum of peak demand of 12 months in alternative I model is 3428.6KW, which is also 71% of alternative II model. Chart 6-12: Monthly peak demand of alternative I and alternative II model 6.4. Life Cycle Cost Analysis After finding out the different utility bills between baseline model and alternative I model, it is possible to give a LCC (life cycle cost) analysis with the information of capital investment. Basically, both models use same chiller, which means the underground loop in alternative I model serves similar function as cooling tower in baseline model. According to Peter Simmonds‟ experience, the capital investment of conventional HVAC 125 system is $2000 per ton; while the capital investment of GSHP system is $1750 per ton plus $700,000 as the underground pipe cost. Because two 1150KW chillers are used in Pudong natatorium, the total cooling capacity is 2300KW, which is equivalent to 654ton. The life time of chiller and underground pipe are 15 years and 50 years. The project life is 50 years. Following table is the detailed economic factors for LCC analysis. Life-cycle costs analysis baseline model alternative I model Capital system cost $2,000/ton $1,750/ton Capital underground pipe cost 0 $700,000 Cooling capacity 654ton 654ton Annual utility fees $156,639 $127,764 Underground pipe life N/A 50 years Chiller life 15 years 15years Replacement cost (15 year) $1,308,000 $1,144,500 Table 6-11: Life cycle cost analysis table The annual utility fees‟ difference between two models is $28,875, which means alternative I model can save $28.875 each year. Regarding to capital cost of two models, alternative I model costs$ 546,500 more than baseline model. For first 15 years, because there is no replacement cost, In 50 year‟s life cycle, replacement will happen three times in 15 th , 30 th and 45 th year. Present value of baseline model in 50th year: $1,308,000*(15-5)/15=$872,000 Present value of alternative I model in 50th year: 126 $1,144,500*(15-5)/15+$700,000*(50-50)/50=$763000 Life cycle cost of baseline model: capital system cost + replacement cost + 50 years utility fees - present value: $1,308,000+3*$1,308,000+$156,630*50-$872,000=$12,191,500 Life cycle cost of alternative I model: capital system cost + capital underground pipe cost + replacement cost + 50 years utility fees – present value: $1,144,500+$700,000+3*$1,144,500+$127,764*50-$763,000=$10,903,200 The alternative I model‟s LCC cost is $10,903,200, which is $1,288,300 less than that of baseline model‟s LCC cost: $12,191,500. Besides the life cycle cost analysis, it is also important to see after how many years can alternative I model starts to save money when compared with baseline model. In order to address this problem, Break-even concept needs to be introduced. In economics, the break-even point (BEP) is the point at which cost or expenses and revenue are equal: there is no net loss or gain, and one has "broken even". In this case the brake-even is a time point. At this time point, the cost of baseline model equals to cost of alternative I model. Because the replacement happens in 15 th , 30 th and 45 th year, we can calculate break-even point based on different period of time, which are 1 st -15 th year,16 th -30 th year, 31 st -45 th year and 45 th -50 th year. 1 st -15 th year: assume Year A is the break-even point, (1<Year A<15) $1,308,000+$156,639*A=$1,144,500+$700,000+$127,764*A A=18.58, which is not qualified. 127 16 th -30 th year: assume year A is the break-even point, (15<Year A<30) $1,308,000+$1,308,000+$156,639*A=$1,144,500+$700,000+$1,144,500+$127,764*A A=12.9, which is not qualified. But we can notice that, the value of A in first equation is higher than requirement, while the value of A in second equation is lower than requirement. Actually, we notice that A should be a integer in this case. The two equations above omit only one year: 15, which should be the break-even year for this case. Let take a look at 14th year and 15th year. Following is the chart and table show total of 14 th and 15 th year from two models. Total cost at the end of 14th and 15th year for two models baseline model alternative I model 14th $3,500,946 $3,633,196 15th $4,965,585 $4,905,460 Table 6-12: Total cost at cost of two models in 14 th and 15 th year (replacement happens at beginning of 15 th year) Chart 6-13: Total cost at cost of two models in 14 th and 15 th year (replacement happens at beginning of 15 th year) $3,000,000 $4,000,000 $5,000,000 14th 15th Total cost at the end of 14th and 15th year for two models baseline model alternative I model 128 From the chart we can clearly see the brake-even point happens between 14 th and 15 th year, which means from 15 th year, the GSHP starts to save money when compared with conventional HVAC system is Pudong natatorium. 129 CHAPTER 7 CONCLUSION 7.1. Hypothesis Verification Hypothesis 1: GSHP consumes less energy than conventional HVAC system Hypothesis assumes GSHP system applied in Pudong natatorium consumes less energy that conventional HVAC system in Pudong natatorium. The result shows the alternative I model, which is GSHP model, consumes 1064.7 thousand KWH. In comparison, baseline model consumes 1516.4 thousand KWH. GSHP saves 29.7% energy every year for Pudong natatorium. YES GSHP =YEC CON -YEC GSHP =451.7 thousand KWH>0 Where YES GSHP stands for yearly energy saving through using GSHP YEC CON stands for yearly energy cost of conventional HVAC system YEC GSHP stands for yearly energy cost of GSHP system The result substantiates the hypothesis 1. Hypothesis 2.1: The life cycle cost of GSHP is less than conventional HVAC system The system‟s life cycle is 50 year since the underground pipe can operate around 50 years. The chiller‟s life time is around 15 years, which means the chiller needs to be replaced three times in 50 years. The alternative I model‟s life cycle cost is $10,903,200, which is $1,288,750 less than that of baseline model‟s life cycle cost: $12,191,950. 130 LCC CON ($)-LCC GSHP ($) =$12,191,950>0 Where LCC GSHP stands life cycle cost of GSHP and is valued as $ LCC CON stands life cycle cost of conventional HVAC system and is valued as $ The hypothesis 2.1 is also substantiated. Hypothesis 2.2 the difference initial investment between GSHP and conventional HVAC system can be compensated through the yearly saved utility fee in less than ten years. According to chapter6, after 15 years, the GSHP shows its economic benefits over conventional HVAC system. In 14 th year, the difference initial investment still cannot be compensated through 14 years‟ total utility fees saving, which means the difference initial investment between GSHP and conventional system will cost 15 year to cover. DII (GSHP-CON) ($) >14 x YES GSHP >10x YES GSHP Where DII (GSHP-CON) stands difference initial investment between GSHP and conventional HVAC system YES GSHP stands yearly energy saving through GSHP and is valued as ($) This hypothesis is rejected. 131 7.2 Future Work Based on result from this thesis, it is possible to spread further discussion on how GSHP performs on different locations. Although we know using GSHP to instead of conventional HVAC system is a good solution to save more energy, we still need to know under which kind of weather, GSHP has best performance. Because the heat change happens underground, the temperature difference between fluid in underground pipe and underground earth is the most important factor influence the performance of GSHP. According to different weather condition, we might be able to find four locations represent four different types of weather based on temperature in winter and summer ( cold winter and cool summer, cold winter and hot summer, warm winter and cool summer, warm winter and hot summer). After running of simulation tools, which is not limited to eQUEST, the four sets of result are compared with each other to see under which condition, GSHP has the best energy performance. Another research branch can be paid attention is how to balance the heat discharge and absorb underground. Follow is a chart of whole year ground temperature variation at well bore from alternative I model. The temperature variation underground does not balance well since ground temperature rises in most times. 132 Chart 7-1: Ground temperature variation at well bore of alternative I model The unbalanced heat transfer underground will trigger a serial environmental problem underground. How to balance the underground heat transfer is a important area we need to figure out. -4 -2 0 2 4 6 8 1 585 1169 1753 2337 2921 3505 4089 4673 5257 5841 6425 7009 7593 8177 Ground temperature variation at well bore(F) Ground temperature variation at well bore( ℃) 133 BIBLIOGRAPHY ANSI/ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality, Section I: purpose, American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Atlanta, GA, 2007 ANSI/ASHRAE/IESNA Standard 90.1-2007, Energy Standard for Buildings Except Low-Rise Residential Buildings, Section I: purpose, American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Atlanta, GA, 2007 Architecture 2030, Problem: The Building Sector, viewed 13 March, 2011 <http://architecture2030.org/the_problem/buildings_problem_why> ASHRAE, ASHRAE mission, viewed 15, March, 2011 < http://www.ashrae.org/aboutus/> ASHRAE.,Chapter 1: Thermodynamics and Refrigeration Cycles In 2005 Handbook Fundamental (I-P Edition), American Society of Heating, Refrigerating, and Air- Conditioning Engineers, Atlanta, GA, 2005 Breembroek, G. and F. Lazá ro, International Heat Pump Status and Policy Review. Part 1 – Analysis, Analysis Report No. HCP-AR7, IEA Heat Pump Cenre, Sittard/NL, Breembroek, G. and F. Lazá ro, 1998 Burkhard Sanner, GROUND-SOURCE HEAT PUMP SYSTEMS THE EUROPEAN EXPERIENCE, GHC BULLETIN pressed, North America, 2000 China Meteorological Administration, climate data for shanghai, China Meteorological Administration, China, 2009 Clipson, Colin, Simulation for Planning and Design, In Environmental Simulation, eds, by Robert W. Marans and Daniel Stokols, 30-34. New York: Plenum Press, 1993. DOE2, Introduction of DOE2, viewed 15, March, 2011 < http://www.doe2.com/> Energy Star, ENERGY STAR Performance Ratings Methodology for Incorporating Source Energy Us, Energy Star, Washington, DC, 2009 134 Geo-Heat Center, What is Geothermal, viewed 15, March, 2011 < http://geoheat.oit.edu/whatgeo.htm> Gfbowman, Geothermal systems, viewed 15, March, 2011 < http://www.gfbowman.com/geothermal> Huang Yuyu, ground-source heat pump system efficiency analysis, Master Thesis, Xi‟An University of Technology, China, 2010 H. Dowlatabadi and J. Hanova, Strategic GHG Reduction Through the use of Ground Source Heat Pump Technology, Institute for Resources, Environment and Sustainability, University of British Columbia,Canada,2007 International Ground Source Heat Pump Association (IGSHPA), Galt House East Hotel& Waterfront Offices Buildings Largest GHP System In The World, IGSHPA, Stillwater, OK: Oklahoma State University. International Ground Source Heat Pump Association (IGSHPA), How efficient is a GSHP, viewed 13 March, 2011 <http://www.igshpa.okstate.edu/geothermal/faq.htm> J. Lund, GEOTHERMAL (GROUND-SOURCE) HEAT PUMPS A WORLD OVERVIEW, GHC BULLETIN pressed, North America, 2004 Kongkun Charoenvisal, Energy Performance and Economic Evaluations of the Geothermal Heat Pump System used in the KnowledgeWorks I and II Buildings, Blacksburg, Virginia, Master Thesis, Virginia Polytechnic Institute and State University, Virginia, 2008 Oklahoma State University, Closed-Loop/Ground-Source Heat Pump Systems: Installation Guide, Stillwater, OK: Oklahoma State University, 1988. P.J. Hughes, Survey of water-source heat pump system configurations in current practice. ASHARE Transactions, 1990, 96(1B):121-1028 Shanghai Xiandai Architecture, Pudong natatorium simulation report, Shanghai Xiandai Architecture technical center, China, 2010 Temcor, Product Brochures: Shanghai Pudong Natatorium, viewed 12 March, 2011 <http://www.temcor.com/brochures.php> Trademasteruk, Renewable Energy: Ground Source Heat Pump, viewed 15, March, 2011 < http://trademasteruk.com/page3.htm> 135 Travelchina Guide, Shanghai Weather, viewed 15, March, 2011 < http://www.travelchinaguide.com/climate/shanghai.htm> U.S. Energy Information Administration (EIA), Commercial Buildings Energy Consumption Survey, viewed 15, March, 2011 < http://www.eia.doe.gov/emeu/cbecs/contents.html> U.S. Energy Information Administration (EIA), International Energy Outlook 2010 – Highlights, EIA, Washington, DC, 2010 United States Environmental Protection Agency (EPA), U.S.EPA’s 2008 Report on the Environment (Final Report), EPA, Washington, DC, 2008 Wang, David, Chapter 10: Simulation and Modeling Research, In Architectural Research Methods, by Linda Groat and David Wang, 275-300. New York: John Wiley & Sons, Inc., 2002. 136 APPENDIX Table A-1: Building Shell Design Parameter Building shell design(Real Building Model) Material Thickness(mm) Over all U value(btu/h-ft2-F) Exterior Wall cement mortar 20 0.36 brick 190 cement mortar 20 Roof cement mortar 20 0.42 cement swell perlite 60 reinforced concrete roof slab 120 Floor cement mortar 20 0.51 reinforced concrete 120 cement mortar 20 Basement Exterior Wall cement mortar 20 0.60 reinforced concrete 240 cement mortar 20 Ground Floor cement mortar 20 0.70 reinforced concrete 100 compacted clay 200 building shell design(ASHRAE Model) Location shanghai Climate Zone 3 Opaque element Assembly Maximum Exterior Wall Mass U-0.701 Roof Insulation Entirely Above Deck U-0.273 Floor Mass U-0.606 Basement Exterior Wall Below-Grade wall C-6.473 Ground Floor Unheated F-1.264 Table A-1: Building Shell Design Parameter 137 Table A-2: Window and glazing design parameter Type Height(ft) Width(ft) Shading Coefficient SHGC Real building ASHRAE model Real building ASHRAE model 1 19.0 20.0 0.93 0.52 0.81 0.45 2 19.0 16.0 0.93 0.52 0.81 0.45 3 15.6 16.0 0.93 0.52 0.81 0.45 4 15.2 27.0 0.93 0.52 0.81 0.45 5 15.2 15.6 0.93 0.52 0.81 0.45 6 15.2 32.0 0.93 0.52 0.81 0.45 7 15.2 14.0 0.93 0.52 0.81 0.45 8 15.2 18.0 0.93 0.52 0.81 0.45 9 15.2 6.0 0.93 0.52 0.81 0.45 10 15.2 20.0 0.93 0.52 0.81 0.45 11 7.8 6.6 0.93 0.52 0.81 0.45 12 7.8 9.0 0.93 0.52 0.81 0.45 13 6.9 8.0 0.93 0.52 0.81 0.45 14 6.9 3.2 0.93 0.52 0.81 0.45 15 6.9 4.0 0.93 0.52 0.81 0.45 16 5.9 20.0 0.93 0.52 0.81 0.45 17 5.6 3.0 0.93 0.52 0.81 0.45 18 4.9 6.6 0.93 0.52 0.81 0.45 19 3.0 20.0 0.93 0.52 0.81 0.45 Table A-2: Window and glazing design parameter 138 Table A-3: Building internal load Building Lighting and Equipment Load(real building) Space Name Lighting Power Density(w/sf2) Input Power Density(w/sf2) Mechanical room 0.37 0 Kitchen 0.56 0.56 Power Distribution Room 0.37 0 Gym 0.84 0.56 Bathroom 0.37 0 Clinic 0.84 0.56 Organizing Committee Room 0.84 2.22 Dining Room 1.21 0.56 Athletes Lounge 0.37 0.56 Dressing Room 0.37 0 Referee Room 0.84 0.56 Meeting Room 0.84 0.56 Café Bar 0.56 0.56 Lounge 0.84 0.56 Lobby 0.84 0.56 Entertainment Room 0.84 0.56 Gaming Room 0.84 0.56 Operation Office 0.84 2.22 Multi Function Room 0.84 2.22 Auditorium Box 0.84 0.56 Corridor 0.37 0 Reception Room 0.84 0.56 General Office 0.84 2.22 Treatment Room 0.37 0.56 Table A-3: Building internal load 139 Table A-3 continued Building Lighting and Equipment Load(ASHRAE building) Space Name Lighting Power Density(w/sf2) Input Power Density(w/sf2) Mechanical Room 1.49 0 Kitchen 1.21 0.56 Power Distribution Room 1.49 0 Gym 0.93 0.56 Bathroom 0.93 0 Clinic 0.93 0.56 Organizing Committee room 0.93 2.22 Dining Room 1.3 0.56 Athletes Lounge 1.21 0.56 Dressing Room 0.55 0 Referee Room 0.93 0.56 Meeting Room 0.93 0.56 Café Bar 0.9 0.56 Lounge 1.21 0.56 lobby 1.11 0.56 Entertainment Room 0.93 0.56 Gaming Room 0.93 0.56 Operation Office 1.11 2.22 Multi Function Room 1.3 2.22 Auditorium Box 0.93 0.56 Corridor 0.46 0 Reception Room 0.93 0.56 General Office 1.11 2.22 Treatment Room 0.93 0.56 140 Table A-3 continued Building Occupancy Load(real building) Space Name Area/person(ft2/person) Total Heat Gain(btu/h-person) Mechanical Room N/A N/A Kitchen 90 450 Power Distribution Room N/A N/A Gym 45 450 Bathroom 90 N/A Clinic 90 450 Organizing Committee Coom 18 450 Dining Room 22 450 Athletes Lounge 90 450 Dressing Room 90 450 Referee Room 18 450 Meeting Room 11 450 Café Rar 90 450 Lounge 90 450 lobby 90 450 Entertainment Room 90 450 Gaming Room 90 450 Operation Office 18 450 Multi Function Room 45 450 Auditorium Box 18 450 Corridor 220 450 Reception Room 90 450 general Office 45 450 Treatment Room 90 450 141 Table A-3 continued Building Occupancy Load(ASHRAE building) Space Name Area/person(ft2/person) Total Heat Gain(btu/h-person) Mechanical Room N/A N/A Kitchen 54 550 Power Distribution Room N/A N/A Gym 37 1800 Bathroom 90 N/A Clinic 107 450 Organizing Committee Room 43 450 Dining Room 15 550 Athletes Lounge 43 400 Dressing Room 90 450 Referee Room 43 450 Meeting Room 19 400 Café Bar 53 550 Lounge 43 400 Lobby 108 500 Entertainment Room 54 750 Gaming Room 54 750 Operation Office 19 450 Multi Function Room 10 450 Auditorium Box 32 400 Corridor 220 500 Reception Room 37 450 General Office 215 450 Treatment Room 107 450 142 Table A-4: Building schedule and operation On/Off Schedule for Lighting(%) Time Lighting Schedule-1(office) Lighting Schedule-2(public space) Business days Holidays All Year Round 0-1am 0 0% 10% 1-2am 0 0% 10% 2-3am 0 0% 10% 3-4am 0 0% 10% 4-5am 0 0% 10% 5-6am 0 0% 10% 6-7am 10% 0% 10% 7-8am 50% 0% 50% 8-9am 95% 0% 60% 9-10am 95% 0% 60% 10-11am 95% 0% 60% 11-noon 80% 0% 60% noon-1pm 80% 0% 60% 1-2pm 95% 0% 60% 2-3pm 95% 0% 60% 3-4pm 95% 0% 60% 4-5pm 95% 0% 80% 5-6pm 30% 0% 90% 6-7pm 30% 0% 100% 7-8pm 0% 0% 100% 8-9pm 0% 0% 100% 9-10pm 0% 0% 10% 10-11pm 0% 0% 10% 11pm-0 0% 0% 10% Table A-4: Building schedule and operation 143 Table A-4 continued Personal Availability by Time in Rooms(%) Time Occupancy Schedule-1(office) Occupancy Schedule-2(public space) Business days Holidays All Year Round 0-1am 0% 0% 0% 1-2am 0% 0% 0% 2-3am 0% 0% 0% 3-4am 0% 0% 0% 4-5am 0% 0% 0% 5-6am 0% 0% 0% 6-7am 10% 0% 0% 7-8am 50% 0% 20% 8-9am 95% 0% 50% 9-10am 95% 0% 80% 10-11am 95% 0% 80% 11-noon 80% 0% 80% noon-1pm 80% 0% 80% 1-2pm 95% 0% 80% 2-3pm 95% 0% 80% 3-4pm 95% 0% 80% 4-5pm 95% 0% 80% 5-6pm 30% 0% 80% 6-7pm 30% 0% 80% 7-8pm 0% 0% 70% 8-9pm 0% 0% 50% 9-10pm 0% 0% 0% 10-11pm 0% 0% 0% 11pm-0 0% 0% 0% 144 Table A-4 continued Rate of Utilization by Time for Electrical Equipment(%) Time Equipment Schedule-1(office) Equipment Schedule-2(public space) Business days Holidays All Year Round 0-1am 0% 0% 0% 1-2am 0% 0% 0% 2-3am 0% 0% 0% 3-4am 0% 0% 0% 4-5am 0% 0% 0% 5-6am 0% 0% 0% 6-7am 10% 0% 0% 7-8am 50% 0% 30% 8-9am 95% 0% 50% 9-10am 95% 0% 80% 10-11am 95% 0% 80% 11-noon 50% 0% 80% noon-1pm 50% 0% 80% 1-2pm 95% 0% 80% 2-3pm 95% 0% 80% 3-4pm 95% 0% 80% 4-5pm 95% 0% 80% 5-6pm 30% 0% 80% 6-7pm 30% 0% 80% 7-8pm 0% 0% 70% 8-9pm 0% 0% 50% 9-10pm 0% 0% 0% 10-11pm 0% 0% 0% 11pm-0 0% 0% 0% 145 Table A-4 continued Cooling Temperature Schedule Time Cooling-1(office) Cooling-2(public space) Business days Holidays All Year Round 0-1am 37 37 37 1-2am 37 37 37 2-3am 37 37 37 3-4am 37 37 37 4-5am 37 37 37 5-6am 37 37 37 6-7am 28 37 37 7-8am 26 37 28 8-9am 26 37 25 9-10am 26 37 25 10-11am 26 37 25 11-noon 26 37 25 noon-1pm 26 37 25 1-2pm 26 37 25 2-3pm 26 37 25 3-4pm 26 37 25 4-5pm 26 37 25 5-6pm 26 37 25 6-7pm 37 37 25 7-8pm 37 37 25 8-9pm 37 37 37 9-10pm 37 37 37 10-11pm 37 37 37 11pm-0 37 37 37 146 Table A-4 continued Heating Temperature Schedule Time Heating-1(office) Heating-2(public space) Business Days Holidays All Year Round 0-1am 12 12 12 1-2am 12 12 12 2-3am 12 12 12 3-4am 12 12 12 4-5am 12 12 12 5-6am 12 12 12 6-7am 12 12 12 7-8am 18 12 16 8-9am 20 12 18 9-10am 20 12 18 10-11am 20 12 18 11-noon 20 12 18 noon-1pm 20 12 18 1-2pm 20 12 18 2-3pm 20 12 18 3-4pm 20 12 18 4-5pm 20 12 18 5-6pm 20 12 18 6-7pm 12 12 18 7-8pm 12 12 18 8-9pm 12 12 12 9-10pm 12 12 12 10-11pm 12 12 12 11pm-0 12 12 12 147 Table A-4 continued GSHP System Operation Schedule Chiller Pump Fan Jan ON ON ON Feb ON ON ON Mar OFF OFF ON Apr OFF OFF ON May OFF OFF ON Jun ON ON ON Jul ON ON ON Aug ON ON ON Sep ON ON ON Oct OFF OFF ON Nov OFF OFF ON Dec ON ON ON Conventional System Operation Schedule Chiller Boiler Pump Fan Jan OFF ON ON ON Feb OFF ON ON ON Mar OFF OFF OFF ON Apr OFF OFF OFF ON May OFF OFF OFF ON Jun ON OFF ON ON Jul ON OFF ON ON Aug ON OFF ON ON Sep ON OFF ON ON Oct OFF OFF OFF ON Nov OFF OFF OFF ON Dec OFF ON ON ON

Abstract (if available)

Abstract The Heating, Ventilation and Air Conditioning system (HVAC) is one of the most important aspects of building energy efficiency. In order to enhance energy efficiency, design strategies always pay primary attention to the HVAC system design. The Ground Source Heat Pump is a relatively new system which has high performance with respect to energy efficiency and reduces carbon emissions correspondingly.

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Asset Metadata

Creator Yang, Shen (author)

Core Title Geothermal heat pump's energy effect and economical benefits

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Publication Date 05/03/2011

Defense Date 05/03/2011

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag energy efficiency,eQuest,GSHP,HVAC,OAI-PMH Harvest

Place Name China (countries), Shanghai (city or populated place)

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Woll, Edwin (committee chair), Simmonds, Peter (committee member), Xing, Tianxin (committee member)

Creator Email shenyang@usc.edu,wowogilbert@gmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-m3869

Unique identifier UC1335825

Identifier etd-Yang-4562 (filename),usctheses-m40 (legacy collection record id),usctheses-c127-461577 (legacy record id),usctheses-m3869 (legacy record id)

Legacy Identifier etd-Yang-4562.pdf

Dmrecord 461577

Document Type Thesis

Rights Yang, Shen

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Repository Name Libraries, University of Southern California

Repository Location Los Angeles, California

Repository Email cisadmin@lib.usc.edu