Evaporation and Condensation Heat Transfer Performance of Flammable Refrigerants in a Brazed Plate Heat Exchanger.
Evaporation and Condensation Heat Transfer Performance
of Flammable Refrigerants in a Brazed Plate Heat
Palmer, S. C.; Payne, W. V.; Domanski, P. A.
NISTIR 6541; 29 p. July 2000.
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refrigerants; evaporation; condensation; heat transfer;
brazed plate heat exchanger; flammable refrigerants;
Average Nusselt numbers were measured for R22, R290,
R290/600a, and R32/152a undergoing evaporation and
condensation in a brazed plate heat exchanger. The
refrigerants experienced wavy, stratified flow at low
heat and mass fluxes, 1.3 kW/m2 to 8.3 kW/m2 and 1.6
kg/m2s to 19 kg/m2s, respectively. Heat transfer
correlations from the literature for in-tube and channel
flow of refrigerants with similar heat and mass fluxes
were compared to the measured Nusselt numbers. The
agreement was found to be unsatisfactory. Evaporation
and condensation heat transfer correlations were
developed from the data for this study for the combined
data of R22, R290, and R290/600a and the data for
R32/152a. Separate correlations were needed because the
lubricant used for R32/152a was different than the
lubricant used for the other refrigerants.