3296 (RP-479) -- Performance Comparison of Refrigerants R-134a and R-12 in a Residential Exhaust Air Heat Pump PDF

Performance comparison tests were carried out on R-134a, which is being considered as a substitute refrigerant to replace R-12. The two refrigerants were tested in a smallprototype exhaust airheatpump (EAHP) designed for R-12. For the R-134a tests, a special compressor lubricating oil was used.

t~oth refrigerants were tested over the same range of air temperatures supplied to the EAHR From the test data, graphs were plotted to compare performance of the unit as a function of outdoor air temperature. In this paper, comparisons are presented of refrigerant evaporating~ condensing temperatures and pressures, heating capacities, compressor powerequirements, coefficients of performance (COPs), etc. Thermostatic expansion valve behavior is also described, including the internal orifice changes that were necessary to provide satisfactory control in the R-134a tests.