GLIDE MATCHING WITH BINARY AND TERNARY ZEOTROPIC REFRIGERANT MIXTURES .2. A COMPUTER-SIMULATION

The glide-matching study presented in Part 1 was a laboratory investigation which demonstrated the evaporator performance in detail. However, since it was not possible to instrument the condenser sufficiently, some computer simulation work was conducted using a semi-theoretical model CYCLE-11, which has been under continual development at NIST for the past five years. As in the experimental effort, R22, R142b, R22/142b, R23/22/142b and R23/142b working fluids were investigated, but the simulation work did not include heat pump operation with liquid-line/evaporator heat exchange. By utilizing the model to quantify entropy generation at various state points within the cycle, it was possible to locate the likelihood of temperature profile pinch points in both the condenser and evaporator. This information clarified the impact of non-linearities on the system performance.