Comparative Analysis of Heat Transfer Characteristics for C02 and Conventional Refrigerants
The obvious characteristics of transcritical CO2 cycle are that the heat rejection process takes place in the supercritical region (about 8-12Mpa). The heat transfer features of CO2 under supercritical pressure are different from those of the conventional refrigerants. And the heat transfer performances comparison study for supercritical CO2 fluid and the conventional refrigerants are carried out by means of thermophysical properties analog analysis and experimental results quantitative comparison. The special properties variation of supercritical CO2 fluid makes its heat transfer performance different from the conventional fluids. From the view of properties analysis and quantitative comparison, the heat transfer performance of supercritical CO2 is equivalent to the condensation heat transfer of conventional refrigerants. Although the condensation coefficient is very large since there is phase-change and latent heat variation in the condensation process, there is liquid film thermal resistance. While in the supercritical CO2 cooling process, there is no liquid film in existence and the thickness of the boundary layer is very thin. The heat transfer temperature difference is very large, so the heat transfer performance in the supercritical CO2 cooling process is equivalent to that of the condensation heat transfer.
supercritical CO2 fluid heat transfer performance conventional refrigerants comparative analysis
YANG Junlan MA Yitai LI Minxia
Department of Energy and Mechanical Engineering, Tianjin Institute of Urban Construction, 300384 Tia Thermal Energy Research Institute, Tianjin University, 300072 Tianjin, Peoples Republic of China
国际会议
合肥
英文
1306-1309
2011-09-23（万方平台首次上网日期，不代表论文的发表时间）