| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 97 === The focuses of this study were to develop a generic multi-purpose heat pump capable of providing cold water, cold air, hot water and warm air at the same time, as well as to investigate on the impacts to the coefficient of performance of the system and the compressor due to various operating conditions in either high pressure and/or low pressure side of the refrigeration cycle, including on/off of the second stage heat exchangers and steady or transient state of water flow through water-air heat exchangers. This generic system consists of compressor, pressure accumulator, plate-type heat exchangers, air-water heat exchangers, dual pipe heat exchanger, capillary tube, thermal-controlled expansion valve and gas-liquid separator.
The components selected for this generic design are as follows: capacity of the compressor is 1.5 USRT, power of fans of the air-water heat exchangers are 60 W, amount of water in the hot and cold water tanks are 40 L and 150 L, respectively, and the flow rate of the water re-circulating in both plate-type heat exchangers is 1160 L/hr. Subject to the components previously selected, other corresponding components were under investigation in order to reach highest COP, the selected components are: pressure accumulator at the capacity of 0.77 L, plate-type heat exchanger with the heat exchange area of 0.432 m2 at the cold (low pressure) side, and 0.421 m2 at the hot (high pressure) side, capillary tube at the length of 45 cm and amount of refrigerant R22 charged in to the cycle at the weight of 1.5 kg. With such combinations, the high pressure side of the COP of the system and compressor is 2.87 and 3.38, respectively, the low pressure side of the COP of the
system and compressor is 2.86 and 3.29, respectively and the total COP of the system and compressor is 5.21and 6.53, respectively when the water temperature is to be raised from 20 C to 50 degree C.
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