What cooling method involves the use of an air to air heat exchanger?

The correct answer is the Energy Recovery Ventilator (ERV). This cooling method utilizes an air-to-air heat exchanger to improve energy efficiency by transferring heat and moisture between incoming and outgoing air streams. The ERV works by pre-conditioning the incoming fresh air with the outgoing stale air. In cooling applications, it helps to reduce the load on the air conditioning system, thereby enhancing overall system efficiency and performance while maintaining indoor air quality.

Ductless systems may employ different cooling methods, but they do not specifically utilize an air-to-air heat exchanger. Evaporative cooling primarily relies on the process of water evaporation to cool the air, which is different from using a heat exchanger. Direct expansion cooling refers to a method in which refrigerant directly cools the air, without an intermediary heat exchange process like that found in an ERV.