Experimental Evaluation of a Triple-State Sorption Chiller

Abstract

Globally, residential electricity consumption for space cooling is projected to increase by a factor of 40 over the course of the 21 st century. Given that 66.8% of worldwide electricity is generated from the combustion of fossil fuels, a surge in air conditioning of this magnitude would add millions of tonnes of carbon dioxide to the atmosphere annually. The extent of these emissions can be reduced by upgrading the energy efficiency of the existing air conditioner stock, by employing more stringent building energy codes, and by implementing energy conservation programs. However, the most effective mitigation strategy may be the widespread adoption of alternative cooling technologies that consume considerably less electrical energy. One such technology is the sorption chiller, which can be driven by lowgrade heat provided by solar thermal collectors. Although residential solar-driven sorption chillers have gained popularity during the past decade, there exist approximately only 1000 worldwide installations today. The unique nature of each system (i.e., local climate, solar collector size/type/orientation, utilization of thermal storage, operating strategy) makes it difficult to extend the performance of existing installations to future projects. Therefore, before widespread implementation of this technology can occur, more work is required to adequately model the performance of the current generation of commercially available sorption chillers over their full range of operating conditions. This thesis presents the experimental testing results of a novel triple-state sorption chiller with integrated cold storage. The performance of the chiller was measured for hot water inlet temperatures between 65°C and 95°C, heat rejection inlet temperatures between 15°C and 35°C, and chilled water inlet temperatures between 10°C and 25°C. The performance data collected ii during these tests were then used to develop a Microsoft Excel-based model for implementation in the TRNSYS simulation software. The output of the model was then compared to the results of a five hour experimental charge test in which the inlet temperatures were varied throughout the experiment, resulting in a 0.7% error in the heat input energy and a 1.3% error in the heat rejection energy.iii Acknowledgements I would like to thank my supervisor, Dr. Cynthia Cruickshank, for the guidance, patience, and unwavering encouragement she has provided over the past two years. I would also like to thank my colleagues within the