| Heat pump water heater is an application that heat pump technology applied in the heating. It is more energy saving and environmental protection. With increasing demand of high temperature hot water in heating, chemical, electroplating areas and the prominent of global energy crisis, environmental pollution problems, high temperature heat pump water heater has become the main research direction in recent years. In this paper, air source and water source high temperature heat pump water heater unit are studied to provide technical data for the improvement and application of high temperature heat pump water heater.Experiments and thermal properties analysis of the three kinds of refrigerant R22, R134 a, R406 a used in the heat pump water heater have been done. The results show that R134 and R22 are all have potential in medium high temperature heat pump water heater.To improve the conventional air source heat pump water heater, fluid injection and refilling and enthalpy increasing devices are respectively equipped on the units. Experiment results show that,for the air source heat pump units, at 20℃ /15℃ and 7℃/6℃ working conditions, the discharge temperature of the supplement-compressing system and fluid injection system were reduced. Furthermore, in nominal operating conditions, the fluid injection system is more effective than the supplement-compressing system. In low temperature condition, the effective is contrary.In water source heat pump water heater unit, compared with the system without fluid injection device, the discharge temperature of fluid injection system reduces about 8℃ to 10℃, when the water temperature is 80℃. The discharge temperature can effective reduced by fluid refrigerant injection device. The direct heating cycle system always runs in a certain high temperature and high pressure condition which will damage the compressor easily. Therefore, the cycle heating is more suitable for the high temperature heat pump water heater. |
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