Development Of A Technologic High Temperature Heat Pump Based On Component Optimization Analysis Of Mixed Refrigerant Under Variable Working Conditions

High temperature heat pump technology can use a large number of waste heat generated in the production process of different industries of petroleum chemical industry,agriculture,forestry and drying,textile,metallurgy,rubber and food.It can produce high temperature hot water or high temperature steam to meet the needs of the production process,and avoid the waste heat direct emissions caused by energy waste and environmental pollution.So it has a huge energy saving and emission reduction benefits.Selecting the refrigerants suitable for high temperature heat pump is the key of high temperature heat pump technology research.Because different production processes have different waste heat resources and heating requirements,it is difficult for a single component refrigerant to maintain a high performance in a wide temperature range,and it is difficult to develop a high temperature heat pump for each process to form large-scale production and application.In this paper,the optimization theory of mixed refrigerant components based on the "perfusion" application of high temperature heat pump under different working conditions is proposed.In different application conditions,by filling the corresponding ratio of mixed refrigerant without changing the heat pump unit,the heating demand can be realized,and has roughly the same heat production,exhaust pressure,etc.,which provides technical support for the realization of different production process requirements of high temperature heat pump scale production.In this paper,according to the demand for high temperature hot water in the production process of different industries,the condensation temperature is divided into three temperature ranges: 70-90℃,90-110℃ and 110-130℃.The theoretical cycle calculation and analysis of R134a/R245 fa R152a/R245 fa and R1234ze/R245 fa were carried out under variable working conditions to obtain the optimal composition ratio in different application temperature ranges.Aiming at the glyoxylic acid production system,the mixed refrigerant high temperature heat pump was developed to replace the gas boiler in the original production process.The waste heat of the cooling water in the production process was used to produce hot water at 80 ℃.The unit selected the semi-closed screw compressor and used the air injection enthalpy increasing heat pump to cycle.Through the optimization of the mixed refrigerant components,the matching design of evaporator condenser under the condition of temperature slip,and the control law of electronic expansion valve of the new working medium,the experimental prototype with the heating power of 120 k W was manufactured.At the same time,the high temperature water source heat pump test system was established,and the experimental research on the high temperature heat pump with mixed refrigerant was carried out.Under the working conditions of the inlet temperature of the evaporator 20-50℃ and the outlet temperature of the condenser 60-85℃,the variable working condition performance of the test prototype was tested and the continuous operation reliability experiment was conducted.The results show that the new high temperature heat pump with mixed refrigerant has good performance parameters,meets the requirements of production process,and has good effect of energy saving and emission reduction and economic benefits when running at high temperature.