What does a heat exchanger do in an HVAC system?

A heat exchanger plays a vital role in an HVAC system by transferring heat between two fluids without allowing them to mix. This process is essential in various applications, where the objective is to either absorb heat from a fluid (like air or water) and release it into another fluid or vice versa.

In heating systems, heat exchangers capture heat generated by a heating source, such as a furnace or boiler, and then transfer that heat to the air or water that will circulate through the home or building, thereby warming the space efficiently. In air conditioning systems, they perform the opposite function by transferring heat from the indoor air to the refrigerant, which then carries the heat outside, helping to cool the indoor environment.

The other options refer to different functions within an HVAC system. While filtering air is crucial for maintaining indoor air quality, it is the responsibility of air filters, not heat exchangers. Controlling humidity levels typically involves dehumidifiers or humidifiers that function separately from the heat exchange process. Similarly, regulating refrigerant flow is a task managed by components like expansion valves and compressors, rather than the heat exchanger itself. Thus, the primary function of a heat exchanger is indeed to transfer heat between two fluids.