Summary:

Experiments have been conducted to determine the range of pressure differentials i.e., condensing temperatures for a constant evaporating temperatures, over which a refrigerating system can be successfully operated. It has been confirmed that the characteristics of the expansion valve limits this useful range because of instability at part

load and high condensing temperature conditions.

The effect of pressure drop in the liquid line leading to the occurrence of flash gas has been investigated both theoretically and experimentally. The theory agrees well with the experimental results. It is shown that flash gas reduces refrigeration capacity when condensing temperature is low and the expansion valve is fully open. In addition it is shown that flash gas can be eliminated by using a subcooler or LPA but, when the operating conditions require a fully open expansion valve, the refrigerating capacity can only be restored to the value when no flash gas was present if a LPA is used.

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