The Study Of High Temperature Heat Pump System With R245fa

Experimental performance of high temperature heat pump has important significance in energy conservation and environmental protection,which is based on the previous experience of the normal temperature heat pump.It becomes an important means in waste heat recovery and utilization,and enlarges the application field of heat pump technology.Nowadays,it is extremely necessary to look for excellent environmental and cycle performance of working medium in high temperature heat pump.In the recent,many researchers have carried out a large number of theoretical analyses of high temperature heat pump in the R22 heat pump system in the world.And some comparative experimental evaluation has been researched.The paper shows the original R22 test system is re-designed and transformed as a high temperature heat pump system,which use R245 fa as working refrigerant.The optimal filling quantity of refrigerant is studied in the system,firstly.Then,high temperature performance experiment is systematically examined on the optimal refrigerant charge.After the filling quantity experiment,the optimal refrigerant charge is 1100 g.At the same time,this paper respectively puts 45 ℃,50 ℃ and 55 ℃ constant temperature water as cold reservoir to study some temperature rise tests in high temperature heat source.Temperature rise test is carried out at 75 ~ 90 ℃,75 ~ 95 ℃ and 75 ~ 100 ℃ in high reservoir,successively.The experiment shows that when the temperature of cold reservoir and hot reservoir is 55 ℃ and 100 ℃,the condensing pressure of the system is only 1.22 MPa.Meanwhile,the operation condition has higher safety performance.When the temperature of cold reservoir is constant,rising time of the constant temperature difference increases with the temperature rise of heat reservoir.And the heat utilization factor of high temperature heat pump system is decline,gradually.When high temperature heat source end temperature reaches 97 ℃ or above,some of the heat will be converted into the heat of vaporization of hot water because of physical properties of water.The character results in the decrease of actual heating efficiency.Considering the requirements of high temperature and heating efficiency,the performance was superior when the low temperature heat source was 55℃ and high temperature heat source end temperature was 95 ~ 97 ℃ in the paper.The system of heating utilization factor is at around 2.6 and the water temperature is relatively higher.