Simulation of Heat Exchangers of a Window Air Conditioner Retrofitted With R-407C.
Simulation of Heat Exchangers of a Window Air
Conditioner Retrofitted With R-407C.
Devotta, S.; Padalkar, A. S.; Sane, N. K.; Domanski, P.
A.; Sawant, N. N.
International Congress of Refrigeration, 21st IIR.
Proceedings. August 17-22, 2003, Washington, DC, 1-8
heat exchanger; air conditioning; refrigerants;
evaporator; zeotropic mixtures; thermodynamics;
simulation; temperature profiles; pressure drop; air
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.