Effect of Flash Gas Bypass on the Performance of R134a Mobile Air-Conditioning System with Microchannel Evaporator 2011-01-0139
This paper demonstrates that the implementation of Flash Gas Bypass method can improve the performance of conventional direct expansion R134a mobile air-conditioning system with a microchannel evaporator. This method uses flash gas tank after expansion valve to separate and bypass flash refrigerant vapor around the evaporator, and feed the evaporator with only liquid refrigerant. Pressure drop is reduced and refrigerant distribution is significantly improved, resulting in higher evaporator effectiveness and evaporation pressure. Both lower pressure drop and lifted evaporation pressure allows the compressor to work with lower pressure ratio, saving required compressor work. An experimental comparison of the direct expansion system shows that Flash Gas Bypass method increases the cooling capacity and COP at the same time by up to 16% and 11%, respectively. Thus, the implementation of this method is very promising for the system using a microchannel evaporator which is especially very sensitive to the refrigerant side maldistribution.
Citation: Tuo, H., Bielskus, A., and Hrnjak, P., "Effect of Flash Gas Bypass on the Performance of R134a Mobile Air-Conditioning System with Microchannel Evaporator," SAE Int. J. Mater. Manuf. 4(1):231-239, 2011, https://doi.org/10.4271/2011-01-0139. Download Citation
Hanfei Tuo, Algirdas Bielskus, Pega Hrnjak
Univ. of Illinois at Urbana-Champaign
SAE 2011 World Congress & Exhibition
SAE International Journal of Materials and Manufacturing-V120-5, SAE International Journal of Materials and Manufacturing-V120-5EJ