Optimizing Solar Hot Water Systems (Closed Systems) for Air-Conditioning Cycles in TRNSYS

摘要

Parallel and series solar hot water systems (closed systems) were simulated and optimized. The system is designed to supply the required heat for solar air-conditioning cycles such as heat generators in ejector cycle, absorption cycle generator, regenerator in liquid desiccant cycle and regenerating absorbent of the desiccant wheel, and solid desiccant cycle. A model of solar hot water system was simulated in TRNSYS and then, based on solar fraction, the components of the system were optimized. For optimization of the cycle, the dynamic performance of the system in supplying the required temperature for a cycle of Three Tons Refrigeration was analyzed under different situations. The results were compared with the experimental results to obtain consistency. The effects of the parameters of the system, supplied heat capacity, the energy used by the heater, and the effect of the environment were surveyed regarding feasibility of achieving higher solar energy. Finally, the solar hot water system was optimized for Bushehr city. The results showed that the optimization of the solar system is influenced by environmental parameters such as radiation intensity, dry bulb temperature, relative moisture; the way the system is utilized (residential and institutional); the term of operation of the system; and, most importantly, the set point of the auxiliary hot water system. The optimized system was featured as follows: solar fraction: 0.5, area of collector: 86 m~2, angle of collector: 31°, set point of the auxiliary hot water system: 75°C, capacity of tank: 4 m~3, solar collector discharge: 0.25 kg/s, and mass discharge rate of the thermal converter: 0.2 kg/s.