Development And Experimental Study Of High Temperature Water Source Heat Pump Prototype With R245fa As Working Fluid

There are a large number of low-temperature waste heat in industrial production,because these waste heat can not be used directly because of its low temperature.Direct discharge will cause energy waste and also cause thermal pollution to the environment.Utilizing high temperature heat pump to recycle this part of waste heat resources will bring great environmental and economic benefits.At present,the ordinary heat pump can not meet the needs of industrial production.In this paper,the new high temperature heat pump is studied theoretically and experimentally.The developed high temperature heat pump unit can make hot water at 106 C and has a good energy efficiency ratio.A theoretical cycle analysis method is used to study various types of high temperature heat pump refrigerants.The theoretical cycle of heat pump is calculated by using the thermophysical parameters of working fluids in REFPROP in MATLAB.The selection principle and method of new refrigerants for high temperature heat pump are put forward.By calculating a large number of working fluids,the pure refrigerant R245 fa and the non-azeotropic mixed refrigerant R1234ze/R245 fa are determined as new refrigerants with good comprehensive performance parameters.The new mixed refrigerant R1234ze/R245 fa has been optimized.The R245 fa has good high temperature characteristics and can achieve the outlet temperature of condensers above 130 degrees.Mixed refrigerant R1234 ze / R245 fa compensates for the shortage of pure refrigerant R245 fa unit volume heat production is small,suitable for high temperature heat pump at about 100 C.Compared with the same refrigerant studied at home and abroad,the new refrigerant presented in this paper has the best comprehensive performance parameters.Theoretical research shows that R245 fa is suitable for the application range of heat pump with higher temperature.Experimental research on R245 fa high temperature heat pump unit is carried out in this paper.Based on the thermophysical parameters of R245 fa,the condenser,evaporator,compressor and liquid storagesystem of high temperature heat pump unit were calculated,and the optimal design and selection were carried out.Aiming at the new material,the control mode of electronic expansion valve is put forward,and the control program is compiled.At the same time,the filling capacity is optimized,the lubricating oil is selected,and a new high temperature heat pump prototype for screw compressor unit is developed.The pressurization system of high temperature heat pump test bench was developed by ourselves,which can satisfy the heat pump experiment of effluent temperature about150 C.A new high temperature heat pump filling system is developed to achieve accurate control of the filling quantity of the new working fluid.The high and low temperature water mixing control system is developed.On the basis of improving the control accuracy,the experimental power consumption is saved.The experimental measurement and control system is developed to improve the accuracy and automation of the high temperature heat pump experiment.Experimental research on the new heat pump developed in this experimental system is carried out.The performance of low temperature heat source at 40-60 C was tested under various operating conditions.The outlet temperature of high temperature heat pump can reach 106 C.Under high temperature operating conditions,the condensation pressure and exhaust temperature of heat pump unit are still at a low level,and the potential of temperature rise is also available.At the same time,it has a good energy efficiency ratio.After a long period of high temperature operation,the unit has good stability and no obvious change in lubricating oil.The results show that the refrigeration unit developed in this paper can meet the needs of industrial high temperature waste heat recovery,and has a good application prospect.