When does a refrigerant give up heat?

A refrigerant gives up heat during the condensation process. This is when the refrigerant transitions from a vapor to a liquid state, releasing heat into the surrounding environment. This heat exchange is a crucial part of how refrigeration systems operate.

In a typical refrigeration cycle, after the refrigerant has absorbed heat from the space it is cooling and evaporated into a gas, it is then compressed and passed through condenser coils. Here, as the refrigerant condenses back into a liquid, it releases the heat it absorbed earlier. This is fundamental to the cooling process, as it allows for the continuous cycle of heat absorption and release that keeps the refrigerated space cold.

The other options do not effectively capture the scenario where heat is lost. Evaporation (the first option) involves the refrigerant absorbing heat to change into a vapor, while expansion refers to the refrigerant's decrease in pressure and temperature without necessarily transferring heat away. Cooling itself is a broader term that may imply a temperature reduction without specifying the process during which heat is released. Therefore, the choice regarding condensation accurately reflects the phase change and the corresponding heat transfer that occurs in a refrigerating system.