A steady state distributed parameter model for the microchannel evaporator applied in a transcritical carbon dioxide air-conditioning system was established using the FEM method. Different models of heat transfer at the refrigerant-side were compared and analyzed
and a modified heat transfer correlation was proposed. Moreover
characteristics of heat transfer and flow were analyzed under both dry and wet conditions considering the pressure losses at the inlet and outlet of the header of the evaporator. The simulation results are in reasonable agreement with the experimental data. The average relative errors for cooling capacity and refrigerant-side pressure drop are less than 8.2% and 10%
respectively. It is likely that the present model may be used to analyze and design CO
2
microchannel evaporators.
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references
PETTERSEN J. Condensation in horizontal tubes: part 2 New heat transfer model based on flow regimes [J]. International Journal of Heat and Mass Transfer, 2003, 46(18):3365-3387.