This paper presents the results of simulation of heat exchangers of an HCFC-22 window air conditioner retrofitted with R-407C. The test conditions considered are as per the Indian Standard IS 1391 (1992) for unitary air conditioners. The simulation has been 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) has been selected for the study. The performance of heat exchangers with R-407C is compared with the baseline performance with HCFC-22. The simulated results are validated by comparing with experimental results of window air conditioner retrofitted with R-407C. The assessment parameters considered are temperatures of refrigerant and air, and pressures with pressure drop in the refrigerant flow. 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 the refrigerants. The exit temperatures of R-407C are lower in the range 1.9°C to 5.2°C in the condenser and are higher in the range 3.2°C to 3.8°C in the evaporator compared to HCFC-22. The evaporating pressures of R-407C are higher in the range 4.5% to 5.3% than HCFC-22. The condensing pressures of R-407C are higher in the range 10.3% to 14.1% than HCFC-22. The pressure drop of R-407C is lower in both evaporator and condenser than HCFC-22. The outlet temperatures of air for HCFC-22 and R-407C in both the heat exchangers are almost similar.
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