Effects Of Internal Heat Exchanger On Performance Of R1234yf Heat Pump Cycle

As global warming increases and energy crisis intensifies, the energy conservation and emissions is urgent. However, today, substance HCFC and substance HFC, which has higher GWP, are more often used in air conditioning heat pump industry. EU countries had passed legislation that refrigerant which GWP is larger than 150 is not allowed to use in new designed automotive air conditioning since 2011, so refrigerant replacement brooks no delay. R1234 yf stands out from numerous alternative refrigerants, becoming a strong competitor.R1234yf heat pump system with internal heat exchanger were analyzed in theory. The result showed that effective superheat was favorable for refrigerating capacity per unit of swept volume and coefficient of refrigeration of R1234 yf heat pump system. Therefore, adding internal heat exchanger in R1234 yf heat pump system could improve systematic refrigerating capacity and COP.According to the orthogonal test, three factors and three levels orthogonal experiment table were designed. By using FLUENT software, the nine state of internal heat exchanger numerical simulation were carried out under different velocity. The research showed that capacity of internal heat exchanger would rise with the increase of velocity, and when the velocity was small, there existed a linear relationship between the two. Nine outlet temperature of the regenerator were compared, the simulation results showed that the same situation in other conditions, the largest outlet temperature of the internal heat exchanger was 9.Orthogonal test was analyzed. The research showed that length, pitch of fins and external diameter had influence on capacity of internal heat exchanger, length was the biggest, pitch of fins is the second, external diameter was the minimum. It was concluded that the factors across the superheat and COP of the system through calculation and analysis.