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Simulation of Heat Exchangers of a Window Air Conditioner Retrofitted With R-407C.


pdf icon Simulation of Heat Exchangers of a Window Air Conditioner Retrofitted With R-407C. (222 K)
Devotta, S.; Padalkar, A. S.; Sane, N. K.; Domanski, P. A.; Sawant, N. N.

IRC0048;

International Congress of Refrigeration, 21st IIR. Proceedings. August 17-22, 2003, Washington, DC, 1-8 pp, 2003.

Keywords:

heat exchanger; air conditioning; refrigerants; evaporator; zeotropic mixtures; thermodynamics; simulation; temperature profiles; pressure drop; air temperature

Abstract:

This paper presents simulation results for the heat exchangers of an HCFC-22 window air conditioner retrofitted with R-407C. The test conditions are per the Indian Standard IS 1391 (1992) for unitary air conditioners. The simulation was carried out using EVAP-COND, a heat exchanger model developed by NIST. A typical Indian window air conditioner of capacity 5.13 kW (1.5 TR) was selected for the study. The performance of the heat exchangers with R-407C is compared with the baseline performance with HCFC-22. The simulation results are validated by comparing to experimental data for a window air conditioner retrofitted with R-407C. The assessment parameters are temperatures of refrigerant and air, and refrigerant pressures and pressure drops. The simulated evaporator capacity with R-407C is lower by 3.3% for the lower outdoor conditions and 6% lower for the higher outdoor conditions with respect to HCFC-22. R-407C has 6.1% lower condenser capacity for the lower outdoor conditions and 10.6% lower for the higher outdoor conditions with respect to HCFC-22. The simulated evaporator capacities are within - 3% of the experimentally measured cooling capacities for both refrigerants. The exit temperatures of R-407C are lower by 1.9 DGC to 5.2 DGC in the condenser and are higher by 3.2 DGC to 3.8 DGC in the evaporator as compared to HCFC-22. The evaporating pressures of R-407C are higher by 4.5% to 5.3% as compared to HCFC-22. The condensing pressures of R-407C are higher by 10.3% to 14.1% as compared to HCFC-22. The pressure drop of R-407C is lower in both the evaporator and the condenser as compared to HCFC-22. The outlet temperatures of air for HCFC-22 and R-407C in both heat exchangers are nearly the same.