Study On Thermal Performance Of New Refrigerant In Medium-high Temperature Water Source Heatpump

In the industrial production,a lot of water was wasted in 30~60?.This part of the waste heat can not be directly used that would be discharged,which results in waste of energy and environmental pollution.By using the technology of medium-high temperature heat pump,the recovered waste heat can be raised to more than 90 ?,which can bring significant energy saving and emission reduction effect.Commonly refrigerant,such as R22 and R134 a,can not meet the operating requirements of high temperature conditions.Mainly due to the condensing pressure and exhaust temperature and other conditions.It can only use the water below 30 ? and raise the temperature to about 60 ?.It can not recycle high temperature waste heat and meet the requirements of industrial water temperature.It is one of the main research directions to find a new working refrigerant for the high temperature working conditions of medium-high temperature heat pump.Based on the REFPROP working medium is established in the theoretical calculation model of high temperature water source heat pump.First of all,to conform to the principle of environmentally friendly pure working medium to carry on the preliminary screening,and then to screen out excellent pure refrigerant under the variable condition of the theoretical calculation,and further screen out R1234 ze,R152a and R245 fa which owe the cycle of good performance of four working pure medium.Through the theoretical calculation,I have chosen 3 groups of refrigerant with R152a/R245 fa,R134a/R245 fa and R1234ze/R245 fa.Using the calculating model of the mixture,through theoretical analysis,we compared three kinds of mixed refrigerant with R134 a and R245 fa,ultimately selected R134a/R245 fa as experimental new refrigerant.I have developed medium-high temperature water source heat pump,and used the R134a/R245 fa mixtures as the working fluid to optimize the experimental machine.The experimental machine equipped screw compressor with economizer and electronic expansion valve.At the same time,I have set up the system of medium-high temperature water source heat pump,which includes refrigerant circulation system,water circulation system,recycling and filling system,monitoring system and security system.Water cycle system uses air-cooled heat pump and cooling tower as auxiliary equipment,simulation of waste heat water supply and water by the user.Measurement and control system is mainly based on the LABVIEW software engineering control,edit control program,to realize the collection of test data and water side flow control.Based on the medium-high temperature water source heat pump system,the R134 a,R245fa and R134a/R245 fa were used as the experimental refrigerants.By comparison of the experimental data,the mixture of R134a/R245 fa can obtain the higher water temperature of the water outlet than the R134 a,which is based on the safe and stable operation of the unit.It also can obtain higher a higher pur volume of heat than the R245 fa,and COPh is appropriate.Theoretical and experimental studies have indicated that the R134a/R245 fa mixture has a great promise to be the optimum working medium of the high temperature heat pump.