At extremely low evaporator temperatures, what happens to the compression ratio for a single-stage refrigeration system?

In a single-stage refrigeration system, the compression ratio is defined as the ratio of the pressure at the compressor discharge to the pressure at the evaporator. When the evaporator temperature is extremely low, the pressure in the evaporator decreases significantly, which directly affects the compression ratio. Since the discharge pressure remains relatively constant, a drop in evaporator pressure leads to an increase in the compression ratio.

As the compression ratio becomes too high, it can lead to inefficiencies in the system. The compressor has to work harder to compress the low-pressure vapor to the higher discharge pressure, which can result in excessive energy consumption, increased wear and tear on the compressor, and potential operational issues. In extreme cases, the system may struggle to function effectively, which could lead to overheating or even failure to operate entirely.

Understanding this relationship in a refrigeration system highlights the importance of maintaining appropriate evaporator temperatures to avoid excessively high compression ratios that could jeopardize system efficiency and longevity.