Simulation And Experimental Study On High Temperature Heat Pump System

In the trend of energy conservation and environment protection, heatpump technology is attracting more and more attentions among diverse industries.High temperature heat pump is the new trend of heat pump technology besidestraditional refrigeration. The key point to develop high temperature heat pump is tosearch a new working fluid that is appropriate for high temperature use. The thesisadopted the principle of matching working fluid with original heat pump system,built theoretic model and at last, analyzed the performance of new working fluid.In the system simulation, heat transfer models of each part of the heat pumpsystem named R134a used in this project were built. Programs for the evaporator andthe condenser were developed and compiled in FORTRAN. Then these two programswere called in the main program of the system as sub-program, so the wholesimulation program of the system was completed.Properties of many kinds of working fluid were studied and compared and sixnew kinds of mixed working fluid named S1~S6, respectively, were adopted as theworking fluid of the heat pump in this study. The simulation results indicate that, inthe stage of medium-high temperature (60~80℃), the total performance of S3and S4are better than others, while in the stage of high temperature (80~110℃), theadvantage of S4is obvious, making it the most appropriate working fluid for hightemperature heat pump. In the stage of medium-high temperature, the heatingcapacity per unit of mass of S3and S4are1.48and2times that of R134a,respectively and the COP of S3is higher than R134a’s by3%while the COP of S4islower than R134a’s by4%. In the stage of high temperature and the pressure lowerthan2.5MPa, the heating capacity per unit of mass and COP of S4are far more thanthat of R134a.A test system of the heat pump was built up, including the fabrication andcalibration of the thermocouple and the test program of temperature and voltage based on LabVIEW8.6. The status of the heat pump was monitored through this testsystem. The test result was compared with the theoretic calculation to verify thetheoretic result and system performances were analyzed according to the whole testdata.