Translated Abstract
In this thesis, the transcritical heat pump water heater (HPWP) using CO2, a natural refrigerant, as the work refrigerant has been researched theoretically and experimentally. Aiming to provide reliable data for the marketization of transcritical CO2 heat pump water heater (HPWH), type selection and calculation of critical components is instruducted. Also, influence of external condition on CO2 HPWH system has been studied on the experimental platform.The conception and formation of optimal pressure is explained. Influences of evaporation temperature, suction superheat of compressor and outlet temperature of gas cooler on performance of the system are computed using the refrigeration professional software Coolpack.The performance of CO2 HPWH in some typical operating conditions is studied in the laboratory. On the premise of keeping the outlet temperature of hot water constant and system operating under optimal pressure as well, the heating COP and heating capacity show the same variation trend.In low temperature condition(7℃DB/6℃WB), intermediate temperature condition(20℃DB/15℃WB)and high temperature conditon(35℃DB/29℃WB) the heating COP is 2.30, 3.01, 3.69 and heating capacity is 39.36kW, 52.64 kW and 70.88 kW respectively.Based on the experimental results, effect of water outlet temperatures and ambient temperatures on the optimal discharge pressure and system COP was illustrated, and with change of water outlet temperatures and ambient temperatures, variation of heating COP, heating capacity, evaporating temperatures and other cycle variables was presented and interpreted. At fixed water inlet temperature and certain ambient temperature, rise of water outlet temperatures leads to increase of the optimal discharge pressure at the optimum status, while has negligible effect on evaporating temperatures.
Translated Keyword
[Transcritical Cycle Carbon DioxideHeat Pump Water HeaterHeating Capacity]
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