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Effects of Non-Uniform Refrigerant and Air Flow Distributions on Finned-Tube Evaporator Performance.


pdf icon Effects of Non-Uniform Refrigerant and Air Flow Distributions on Finned-Tube Evaporator Performance. (198 K)
Choi, J. M.; Payne, W. V.; Domanski, P. A.

ICR0040;

Refrigeration International Congress, 21st IIR. (IRC2003). 10th Technical Session "Energy-Efficient Heating and Cooling Systems for Buildings. Proceedings. August 17-22, 2003, Washington, DC, 2004.

Keywords:

refrigerants; refrigeration; degradation; air flow

Abstract:

An experimental investigation was implemented to determine the capacity degradation due to non-uniform refrigerant and air flow distributions, and to assess the potential to recover the lost capacity via controlling refrigerant distribution between individual refrigerant circuits. The tests were performed on a three-circuit, three-depth-row, finned-tube evaporator. Refrigerant inlet quality, exit saturation temperature, and exit superheats for the individual circuit were controlled. The study showed that capacity degradation due to refrigerant maldistribution can be as much as 30%, even when the overall evaporator superheat is kept at the target 5.6DGC. Experimental data indicate that part of this capacity degradation was caused by the internal heat transfer within the evaporator assembly. For the coil and air maldistributions studied, he maximum capacity degradation was found to be 8.7%. A 4.0% capacity recovery was obtained by controlling refrigerant distribution to obtain the target 5.6DGC at each circuit exit.