【作者】 刘兵；

【导师】 杨昭； 马海云；

【作者基本信息】 天津大学 ， 工程（专业学位）， 2022， 硕士

【摘要】 全球变暖对全球发展和人类文明进步造成重大威胁,控制全球温室气体的排放迫在眉睫。制冷行业作为中国达成“双碳”目标的重要战场,寻找新型环境友好型制冷剂已成为制冷行业的研究热点。本文以一种新型三元混合制冷剂为研究对象,从理论分析和实验测试两个角度验证其作为R134a在水水热泵系统中的替代品的可行性。新型环保制冷剂RGT2是一种低GWP(GWP=560)近共沸混合制冷剂。根据热物性分析,制冷剂RGT2具有与R134a相近的热物理性质。制冷剂RGT2的标准沸点和临界条件与R134a相近,且具有优异的换热性能和传输特性;同时RGT2是一种不可燃、无毒的制冷剂,并且与常用的冷冻机油具有良好互溶性。将RGT2和其余6种R134a的典型替代制冷剂进行理论循环性能分析,结果表明RGT2的综合性能优异且具有良好的制冷和制热能力。基于水水热泵系统,对R134a,R513A和RGT2这三种制冷剂的典型工况和部分负荷工况性能进行实验测试对比。结果表明,在名义和最大负荷工况,RGT2比R134a平均多提供0.1%的系统制冷量和1.8%的系统制热量,同时制冷性能系数(EER)和制热性能系数(COP)比R134a平均低4%和1.7%。部分负荷工况条件下的RGT2的综合部分负荷性能系数(IPLV)比R134a低2.1%。针对三种制冷剂在变工况条件下的循环性能差异进行了测试和对比。结果表明,在制冷变工况(蒸发侧水温12℃,冷凝侧水温24～36℃),RGT2的系统制冷量比R134a平均高0.4%,系统EER值比R134a平均低3.8%;在制热变工况(蒸发侧水温20/18/15℃,冷凝侧水温40～55℃),RGT2的系统制热量比R134a平均高2.1%,热泵系统的COP比R134a平均低3.5%。针对压缩机的性能监测显示,制冷剂RGT2和R513A的压缩机排气温度和压比始终低于R134a。但RGT2的管路压力要略高于R134a,需进一步加强对热泵系统的压力监测。结合天津全年气象参数数据,针对三种制冷剂的季节能效性能进行了综合性评价。根据实验所得的制冷剂循环性能数据,分别对三种制冷剂的制冷季节能效、制热季节能效和全年季节能效进行了对比。结果表明制冷剂RGT2的季节能效略低于R134a和R513A,在实际应用过程中,具有作为R134a替代制冷剂的应用前景。更多还原

【Abstract】 Global warming poses a major threat to global development and human civilization progress.It is urgent to control global greenhouse gas emissions.Refrigeration industry is an important battlefield for China to achieve the goal of "double carbon",and it has become a research hotspot to find new environmentally friendly refrigerants.This paper takes a new ternary mixed refrigerant as the research object,and verifies its feasibility as a substitute for R134 a in water-water heat pump system from theoretical analysis and experimental test.The new environment-friendly refrigerant RGT2 is a low GWP(GWP=560)near azeotropic mixture.According to thermophysical properties analysis,the refrigerant RGT2 has similar thermophysical properties to R134 a.The standard boiling point and critical conditions of refrigerant RGT2 are similar to those of R134 a,and it has excellent heat transfer performance and transmission characteristics.At the same time,RGT2 is a non-flammable and non-toxic refrigerant,and well intersolubility with common refrigerated oils.The theoretical cycle performance analysis of RGT2 and other six typical alternative refrigerant R134 a shows that RGT2 has excellent comprehensive performance and better cooling and heating capacity.Based on the built water-water heat pump system,the performance of R134 a,R513A and RGT2 refrigerants in typical working conditions and partial load conditions was tested and compared.The results show that RGT2 provides 0.1% more system cooling capacity and 1.8% more system heating capacity on average than R134 a under nominal and maximum load conditions,and the refrigeration performance coefficient(EER)and heating performance coefficient(COP)are 4% and 1.7% lower than R134 a on average.The comprehensive partial load performance coefficient(IPLV)of RGT2 under partial load condition is 2.1% lower than that of R134 a.The cyclic performance of the three refrigerants in the cooling/heating variable conditions was tested respectively.The results show that RGT2 has an average cooling capacity 0.4% higher than R134 a,and an average EER value 3.8% lower than R134 a under different cooling conditions(the water temperature of evaporation side is 12℃,and the water temperature of condensation side is 24～36 ℃).In the heating variable condition(the water temperature of evaporation side is 20/18/15℃,and the water temperature of condensation side is 40～55 ℃),the average heat production capacity of RGT2 system is 2.1% higher than that of R134 a,and the average COP of heat pump system is 3.5% lower than that of R134 a.The performance monitoring of the compressor shows that the compressor exhaust temperature and pressure ratio of refrigerant RGT2 and R513 A are always lower than that of R134 a,but the pipeline pressure of RGT2 is slightly higher than that of R134 a,so it is necessary to further strengthen the pressure monitoring of the heat pump system.Combined with the annual meteorological data of Tianjin,the seasonal energy efficiency of the three refrigerants was comprehensively evaluated.According to the refrigerant cycle performance data obtained in the experiment,the energy efficiency of the refrigeration season,heating season and annual season of the three refrigerants were compared.The results show that the seasonal energy efficiency of refrigerant RGT2 is slightly lower than that of R134 a and R513 A,and it has a promising application prospect as a substitute for refrigerant R134 a in practical application.更多还原