A study to compare the performance of several types and makes of reversing valves as used in heat pump systems is presented. The study includes the definition of characterizing parameters based on first princlples and results of an uncertainty analysis of the computed parameters based on experimental data. An example of the use of the coefficients is presented as well.

The parameters address: (1) mass leakage from the discharge, (2) (high pressure) to the suction side (low pressure), (3) internal heat loss and exnernal heat loss from the body of the reversing valve to the ambient, and (4) pressure drops. Tests were performed in two different setups: one used to measure mass leakage and the other for heat losses and pressure drops.

Analysis of test results demonstrates that proposed coefflcients are proper characterizing parameters, and in some cases effects of reversing valve on heat Dump performance are not unsignificant.

Units: I-P