With the limited production and use of R245fa,environmentally friendly refrigerant has attracted the attention of researchers.Due to the similar thermal characteristics,R1233zd(E)is considered to be an ideal substitut...With the limited production and use of R245fa,environmentally friendly refrigerant has attracted the attention of researchers.Due to the similar thermal characteristics,R1233zd(E)is considered to be an ideal substitute for R245fa in heat pump systems.In this study,the performance and economic analysis of heat pump systems with R245fa and R1233zd(E)as refrigerants are carried out.The results show that the total cost of R1233zd(E)system is more than 10%higher than that of R245fa system under the same heating load.With the increase of condensation temperature,the heating capacity of both systems decreases,and with the increase of evaporation temperature,the heating capacity increases.The variation trend of coefficient of performance(COP)of the two systems is similar to that of heating capacity.Under the same operating conditions,the COP of R1233zd(E)system is 19.2%higher than that of R245fa system,and the volumetric heat capacity of R1233zd(E)is 9.0%–13.9%lower than that of R245fa.The economic analysis results show that the investment cost of R1233zd(E)system is low under the same heat load.展开更多
Numerical simulation on R245fa condensation inside an inner diameter of 8 mm horizontal tube is researched in this paper. The effect of variation in velocity, condensation temperature and superheat of inlet steam and ...Numerical simulation on R245fa condensation inside an inner diameter of 8 mm horizontal tube is researched in this paper. The effect of variation in velocity, condensation temperature and superheat of inlet steam and variation in cooling water temperature on heat transfer coefficient are investigated as a parametric study. Condensation process of steam has been successfully modeled by applying a user defined function (UDF) added to the commercial computational fluid dynamics (CFD) package. By analyzing the corresponding condensate contours and the curves of local heat transfer coefficient, the relationships between condensation heat transfer coefficient and various parameters of R245fa inside horizontal tube are obtained. It shows that the heat transfer coefficient increases by the increase in velocity, condensation temperature and superheat of inlet steam and the decrease in cooling water temperature. The errors between the heat transfer coefficient of simulation result and model of Wang and Shah are within ±30%. The parametric study will provide the basis for designing efficient heat exchangers of R245fa.展开更多
基金Project(51606162)supported by the National Natural Science Foundation of ChinaProject(2018JJ2399)supported by the Natural Science Foundation of Hunan Province,China
基金supported by theKorea Institute of Energy Technology Evaluationand Planning (KETEP) grant funded by the Korean Government (MOTIE) (No. 20202020900060,The development and application of operational technology in smart farm utilizing waste heat fromparticulates reduced smokestack).
文摘With the limited production and use of R245fa,environmentally friendly refrigerant has attracted the attention of researchers.Due to the similar thermal characteristics,R1233zd(E)is considered to be an ideal substitute for R245fa in heat pump systems.In this study,the performance and economic analysis of heat pump systems with R245fa and R1233zd(E)as refrigerants are carried out.The results show that the total cost of R1233zd(E)system is more than 10%higher than that of R245fa system under the same heating load.With the increase of condensation temperature,the heating capacity of both systems decreases,and with the increase of evaporation temperature,the heating capacity increases.The variation trend of coefficient of performance(COP)of the two systems is similar to that of heating capacity.Under the same operating conditions,the COP of R1233zd(E)system is 19.2%higher than that of R245fa system,and the volumetric heat capacity of R1233zd(E)is 9.0%–13.9%lower than that of R245fa.The economic analysis results show that the investment cost of R1233zd(E)system is low under the same heat load.
文摘Numerical simulation on R245fa condensation inside an inner diameter of 8 mm horizontal tube is researched in this paper. The effect of variation in velocity, condensation temperature and superheat of inlet steam and variation in cooling water temperature on heat transfer coefficient are investigated as a parametric study. Condensation process of steam has been successfully modeled by applying a user defined function (UDF) added to the commercial computational fluid dynamics (CFD) package. By analyzing the corresponding condensate contours and the curves of local heat transfer coefficient, the relationships between condensation heat transfer coefficient and various parameters of R245fa inside horizontal tube are obtained. It shows that the heat transfer coefficient increases by the increase in velocity, condensation temperature and superheat of inlet steam and the decrease in cooling water temperature. The errors between the heat transfer coefficient of simulation result and model of Wang and Shah are within ±30%. The parametric study will provide the basis for designing efficient heat exchangers of R245fa.
