What does a heat exchanger in a compression refrigerating system transfer heat to?

In a compression refrigerating system, a heat exchanger plays a critical role in transferring heat from one substance to another. In this context, the heat exchanger specifically transfers heat from the hot vapor that comes from the evaporator.

As the refrigerant vapor is compressed in the compressor, its temperature and pressure rise. The vapor, now at a higher energy state, flows into the heat exchanger, which is typically functioning as a condenser in this scenario. The purpose here is to reject heat from the refrigerant vapor to the surrounding medium, which is often ambient air or water, allowing the refrigerant to cool down and condense into a liquid state. This heat removal is essential for the cycle to continue efficiently and maintain the cooling process.

Considering the other options, the cold air from the evaporator is not where heat is being transferred but rather a product of the refrigeration process. The liquid refrigerant output is the result of condensation and does not actively participate in heat transfer in this phase of the cycle. Ambient temperature air could be the medium to which heat is rejected, but it is the hot vapor that actually carries the heat being transferred in the heat exchanger.