What is a heat exchanger that transfers heat to a low pressure refrigerant liquid called?

A heat exchanger that transfers heat to a low-pressure refrigerant liquid is specifically referred to as an evaporator. In this context, the evaporator serves to absorb heat from the surrounding environment or a process fluid, causing the low-pressure refrigerant inside it to evaporate and change from a liquid to a vapor. This process is essential in refrigeration and air conditioning systems, as it allows heat to be removed from the space being cooled.

During its operation, the evaporator utilizes the principle of heat transfer, where the refrigerant evaporates by absorbing heat, thus providing cooling. It is distinct from other components like chillers and separators. A chiller is a broader system that can include various components working together to provide cooling, while a separator generally focuses on separating different phases of refrigerants rather than transferring heat.