What is the main function of a heat exchanger?

The main function of a heat exchanger is to transfer heat between two or more fluids without allowing them to mix. This process is essential in various applications, such as heating and cooling systems, refrigeration, and industrial processes. By facilitating the exchange of thermal energy, heat exchangers can efficiently regulate temperatures and improve energy efficiency in systems that require heat management.

In many heating systems, such as boilers or heating, ventilation, and air conditioning (HVAC) units, heat exchangers play a pivotal role in transferring heat from the combustion gases to the water used for heating without letting the water come into direct contact with the combustion products. This separation is crucial for maintaining system integrity and ensuring safety, as it prevents contamination of the fluids involved.

The other options refer to functions that do not characterize a heat exchanger. While thermal energy storage can be a part of some systems that include heat exchangers, it is not the primary function of the heat exchanger itself. Releasing steam or cooling fluids before combustion may occur in specific contexts, but these actions do not define the overall purpose of a heat exchanger, which is strictly the transfer of heat between fluids without mixing.