Solar Community Energy and Storage Systems for Cold Climates
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SOLAR COMMUNITY ENERGY AND STORAGE SYSTEMS FOR COLD CLIMATES by Farzin Masoumi Rad Bachelor of Applied Science (Mechanical Engineering), Shiraz University, Iran, 1986 Master of Applied Science (Mechanical Engineering), Ryerson University, Toronto, Canada, 2009 A dissertation presented to Ryerson University in partial fulfilment of the requirements for degree of Doctor of Philosophy in the program of Mechanical and Industrial Engineering Toronto, Ontario, Canada, 2016 © Farzin M. Rad 2016 Author’s Declaration I hereby declare that I am the sole author of this dissertation. This is a true copy of the dissertation, including any required final revisions, as accepted by my examiners. I authorize Ryerson University to lend this thesis to other institutions or individuals for the purpose of scholarly research. I further authorize Ryerson University to reproduce this thesis by photocopying or by other means, at the request of other institutions or individuals for the purpose of scholarly research. I understand that my dissertation may be made electronically available to the public. ii SOLAR COMMUNITY ENERGY AND STORAGE SYSTEMS FOR COLD CLIMATES Farzin Masoumi Rad Doctor of Philosophy Department of Mechanical and Industrial Engineering Ryerson University, Toronto, Ontario, Canada, 2016 Abstract For a hypothetical solar community located in Toronto, Ontario, the viability of two separate combined heating and cooling systems were investigated. Four TRNSYS integrated models were developed for different cases. First, an existing heating only solar community was modeled and compared with published performance data as the base case with suggested improvements. The base case community was then used to develop a hypothetical solar community, located in Toronto, requiring both heating and cooling. In this second model an absorption chiller was added – Solar Thermal Chiller (STC) system. The chiller received its source heat from the solar thermal system with the supplemental heat from a natural gas boiler. The STC system was designed with two borehole thermal energy storage units (BTES). One was high-temperature BTES for the solar thermal energy storage, and another was medium-temperature BTES for the chillers’ heat rejection. The twenty year simulation results showed that by the fifth year in the heating season, the community operated with 100% solar fraction (SF). In the cooling season, the chiller received 18% of its required energy from the same number of solar collectors as the heating-only community system. The third model was based on the central heat pump system with borehole thermal storage for the heating and cooling, using a PV system as the heat pump power source - Heat Pump Photovoltaics (HPPV) system. The simulation results showed that the system operated favorably from the first year and did not have any significant performance degradation in 20 years. On average, the heat pumps performed with the seasonal COP of 3.3 in the heating mode and 5.9 in the cooling mode. The fourth system, Solar Thermal-Heat Pump Photovoltaics (ST-HPPV), a solar thermal system with borehole thermal energy storage as a iii supplemental heat source to the HPPV, was investigated. The simulation results showed that this system would be beneficial for a community with the annual heating and cooling difference of more than 75%. By adding a solar thermal system to the HPPV system, the heat pumps’ performance improved by 26% in the heating mode, and exhibited a negligible drop in the cooling mode. iv Acknowledgements I would like to express my great thankful and appreciation to my supervisor Dr. Alan Fung for his valuable suggestions and helpful support throughout the time and development of this research. Also, I would like to thank Dr. David Naylor and Dr. Wey Leong for their time and willingness to guide and provide the technical support. Without their motivation, immense help and interest, I would not be able to accomplish the dissertation successfully. My special thanks to Dr. Mark Rosen from UOIT for his supports and contributions on publishing a journal paper from Chapter 3 of this thesis. I would like to thank the Natural Sciences and Engineering Research Council (NSERC) of Canada and the NSERC Smart Net-Zero Energy Building Strategic Research Network (SNEBRN) for their financial support of this research. Lastly, but most importantly, I would like to thank my wife Roya for her encouragement and support during the production of this thesis. v Dedication My work is dedicated to my wife (Roya) and my daughters (Kathy, Kimia, and Kiana). vi Table of Contents Author’s Declaration ....................................................................................................................... ii Abstract .......................................................................................................................................... iii Acknowledgements ......................................................................................................................... v Dedication ...................................................................................................................................... vi List of Tables ................................................................................................................................. xi List of Figures .............................................................................................................................. xiii Nomenclature .............................................................................................................................. xvii Abbreviations ................................................................................................................................ xx Chapter 1 : Introduction .................................................................................................................. 1 1.1 Motivation ............................................................................................................................. 2 1.2 Purpose and goal of the research .......................................................................................... 3 1.3 Scope of work and approach to research .............................................................................. 3 Chapter 2 : Literature Review ......................................................................................................... 6 2.1 Solar communities with Seasonal Thermal Energy Storage (STES) .................................. 6 2.1.1 Underground seasonal thermal energy storage technologies .................................... 7 2.1.1.1 Hot water thermal energy storage (HWTES)...................................................... 8 2.1.1.2 Gravel-water thermal energy storage (GWTES) ................................................ 9 2.1.1.3 Aquifer thermal energy storage (ATES) ........................................................... 11 2.1.1.4 Borehole thermal energy storage (BTES) ......................................................... 12 2.1.1.5 Comparison of the storage concepts ................................................................. 13 2.1.2 BTES – high, medium, and low temperature design .............................................. 14 2.1.2.1 Field experiences with BTES............................................................................. 20 2.2 Solar communities with cooling systems .......................................................................... 22 2.2.1 Examples of installation of solar assisted cooling system ...................................... 25 vii 2.3 Literature Review Summary ............................................................................................. 28 Chapter 3 : Solar Community Heating System with Borehole Thermal Energy Storage ............. 29 3.1 System configuration and community thermal load ........................................................... 30 3.2 System major equipment configuration and model ............................................................ 34 3.2.1 Solar collectors............................................................................................................. 35 3.2.2 Borehole thermal storage (BTES) system.................................................................... 37 3.2.3 Short term storage tank (STST) ................................................................................... 43 3.2.4 Heat exchangers and pumps......................................................................................... 46 3.2.5 Backup boiler and climate data .................................................................................... 46 3.3 System simulation results ................................................................................................... 46 3.3.1 BTES performance....................................................................................................... 46 3.3.2 System energy and performance .................................................................................. 48 3.3.3 Results comparison ...................................................................................................... 50 3.4 System cost comparisons .................................................................................................... 52 3.5 Conclusion .......................................................................................................................... 52 Chapter 4 : Combined Heating and Cooling System for a Solar Community with Borehole