| The greenhouse effect is intensified and the extreme climate is frequent.Environmental problems are still not optimistic.Greenhouse gas emissions are important reasons.Specific to the energy consumption of the whole society in a relatively large field of building energy,high-efficiency,energy saving,emission reduction significant heat pump technology has received widespread attention.However,the refrigerants used in the traditional heat pump system have large greenhouse effect values,even destroy the atmospheric ozone layer(ODP>0),and find new alternative refrigerants have become the interest of the researchers.R1234ze is non-toxic,nonflammable,ODP is 0,GWP is lower than R22,R32 and R134 a are regarded as the new favorite of refrigerants.However,the latent heat of R1234 ze vaporization is low,and the thermodynamic properties of the heat pump system are not ideal,and most of the HFC type refrigerants have excellent thermodynamic properties.The two element mixed refrigerants are composed of R1234 ze based and HFC refrigerants,and the heat pump working fluids with good thermodynamic properties are expected.Based on this,the theoretical analysis and analysis are carried out in this paper.The cycle performance of two element mixture R1234ze/HFCs water source heat pump system is studied by experimental research.The main contents are as follows:(1)On the basis of the analysis of the thermal properties of refrigerants,a new type of environment-friendly refrigerant HFO-1234 ze and three kinds of HFCs refrigerants(R125,R32,R134a)are composed of two elements,and the thermodynamic analysis of heat pump cycle is carried out respectively.It is found that R1234ze/R32 has a high coefficient of thermal performance in the mass ratio of 10/90-30/70(mass percentage,the same below),which reaches the maximum value at 20/80.Under this ratio,the condensation pressure of the system is larger than that of R134 a,which is 28% and 17% lower than that of R32 and R125;the exhaust temperature is higher than the R125 and R134 a exhaust temperature,and the exhaust temperature of R32 system is lower than that of the R32 system;the COP value is 17.88% and 4.53% higher than that of R134 a and R32,respectively.(2)The experiment bench was reformed and built,and the optimal filling and filling experiment of the experimental system was carried out with the reference of pure R32.The results showed that the heat pump system had the maximum thermal performance coefficient of 2.95 when the filling amount was 1.9kg,which laid the foundation for the selection of the optimum working condition point of the mixed refrigerant heat pump system.(3)Under the condition of R32 charge 1.7kg-2.1kg,the heat pump performance test of mixed refrigerant R1234ze/R32 with different mass ratio(10/90-30/70)is carried out,and the experimental results are obtained.At R32 filling quantity 1.9kg and mixed refrigerant ratio 20/80,the mixed refrigerant heat pump system achieves the maximum thermal performance coefficient 3.24,9.8% higher than that of the R32 system,the condensation pressure is 12% lower than that of the R32 system,the system heat is 8.62 kw and 31.8% is higher than the R32 system.Under the same heat production,the filling quantity of the mixed medium is reduced,which reduces the quality of the working material.The danger of leaking;The power consumption of the system is 2.66 kw,which is 11.6% lower than that of the R32 system,and the pressure ratio in the whole system is low,which is beneficial to the efficient operation of the compressor.The reduction of the condensing pressure and the decrease of the filling quantity of the working fluid ensure the safe and stable operation of the system.The research shows that with the increase of R1234 ze mass ratio(10/90-30/70),the COP of mixed refrigerant R1234ze/R32 heat pump system first increases and then decreases.When the mass ratio of R1234ze/R32 reaches 20/80,the maximum thermal performance coefficient is higher than that of pure R32.This paper provides a reference for the application of a new type of environment-friendly refrigerant R1234 ze and HFC type refrigerants in the heat pump system,and the hybrid refrigerant R1234ze/R32(20/80)is expected to be a new substitute. |
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