Numerical Simulation And Experimental Study Of CO₂ Transcritical Water-Water Heat Pump

The development of refrigerant standards is elaborated based on the developm ent of the refrigerant, and the environmental and security performance of the refrigerant is elaborated. A kind of new refrigerant comprehensive perform ance evaluation method-natural degree is put forward, and the refrigerant natural degree is also quantitative analyzed.The research in this paper mainly focuses on the nature refrigerant CO₂, moreover, the computer simulation is carried out and the e xperiment study on the application of heat pump is also conducted.The simulation model of CO₂ transcritical water to water heat pump is developed in consid eration of the extern al pa rameters of the system, which contains cooling water flow flux, cooling water temperature, chilled water flow flux, chilled water temperature. The calcu lated results show the high pressure changing with th e variation of system eva porating pressure. The condensing pressure and discharging temperature decrease w ith the increasing of the condensing pressure. A nd the flow flux will also incre ase with the in creasing of the evapora ting tem perature, but the cooling water tem perature decreases. The influence of superheat on the system performance is small, and with the increase of superheat degree, system heat and COP increase slightly.The CO₂ water-water heat pump system is developed. The components of system, research goal, researching content and expe riment methods are introduced in this paper. The experim ental results indict there existing an optim um high pressure correspinding to the optim um system pe rformance. The optim um high is around 8.5MPa. Cooling water flow rate and the inle t temperature have a great effect on the system performance. With the in creasing of cooling water flow rate, the heating and cooling cap acity of th e system increas ed and also the heating C OPh and the refrigeration COPc. But in order to increas ing the hot water outle t temperature, the cooling water flow rate s hould be reduced, however th e corresponding cooling water flow rate is very sm all wh ile the hot water is beyond 65 ?. It is p ositive of the influence of flow rate and chilled water inlet temperature on th e performance of the system. W ith the increasing of flow rate and inle t water tem perature, the system heating and cooling capacity, heating COPh and refrigeration COPc increase.