What issue does oil trapped in an evaporator cause?

Oil trapped in an evaporator creates a significant issue by reducing the rate of heat transfer. The presence of oil can form a barrier on the heat exchange surfaces, impeding the efficient transfer of heat between the refrigerant and the air or liquid being cooled. This barrier can lead to lower heat absorption by the refrigerant, which ultimately means that the system has to work harder to achieve the desired cooling effect.

Additionally, when oil accumulates in the evaporator, it can increase the temperature of the refrigerant’s evaporating point. This happens because the refrigerant can't properly absorb heat due to the oil's interference, leading to a higher condensing temperature required to return to the compressor. In practice, this results in decreased efficiency of the refrigeration cycle, increasing energy consumption and potentially leading to system failures over time.

Understanding these consequences is crucial for maintaining the optimal operation of refrigeration and air conditioning systems. Regular maintenance practices that prevent oil buildup in the evaporator can enhance system performance and prolong its lifespan.