Evaluation of Flammable Refrigerants for Use in a Water-to-Water Residential Heat Pump.
Evaluation of Flammable Refrigerants for Use in a
Water-to-Water Residential Heat Pump.
Choi, D. K.; Domanski, P. A.; Didion, D. A.
International Institute of Refrigeration. Applications
for Natural Refrigerants. Proceedings. September 3-6,
1996, Aarhus, Denmark, 467-476 pp, 1996.
refrigerants; heat pumps; water; evaluation; cooling;
heating; test facilities
This paper evaluates the performance of R-22, R-290,
R-290/600a (70/30), and R-32/152a (50/50) for
application in a water-to-water residential heat pump
for space cooling and heating. The tests were performed
in a laboratory apparatus at different compressor speeds
to allow the comparison of refirgerants for the
constant-compressor-speed and the constant-capacity
criteria. Comparison of results for the same system
capacity showed R-32/152a to be the best performer due
to good glide matching in the heat exchangers and its
excellent thermodynamic and transport properties. The
hydrocarbon mixture, R-290/600a, had the highest
Coefficient of Performance (COP) at a given compressor
speed, but its COP at the constant-capacity criterion
was the lowest. This low COP was in disagreement with
an earlier simulation study where R-290/600a and
R-32/152a had a similar COP. The test data showed that
the low-volumetric-capacity R-290/600a had an excessive
pressure drop at the constant-capacity comparison. This
was related to the high compressor RPM needed for
R-290/600a to reach the target capacity. With an
optimized compressor and heat exchangers using larger
diameter tubes, R-290/600a should have a COP comparable
to that of R-32/152a. The study demonstrates the need
for both simulations and laboratory methods in
evaluating alternative refrigerants.