What system does a thermal wheel operate similarly to?

A thermal wheel operates similarly to a run-around system because both are used for energy recovery and typically involve the transfer of thermal energy between two air streams. In a run-around system, fluid circulates between two coils—one where it picks up heat and another where it releases it. Similarly, a thermal wheel exchanges heat or moisture between incoming and outgoing air as it rotates, transferring energy from one side to the other.

The operational principle is based on the movement and exchange of heat through a medium, which in the case of a thermal wheel is a material that retains and re-releases thermal energy as it rotates. This design is especially efficient for enhancing the energy performance of ventilation systems, making the run-around system analogy fitting.

In contrast, options like a heat exchanger represent a broader category where different methods of heat transfer can occur but do not specifically involve the rotating mechanism characteristic of a thermal wheel. An evaporator system focuses on refrigerants and their phase changes rather than air and thermal energy recovery. Lastly, the refrigeration cycle pertains to a broader process of cooling using refrigerants and does not directly resemble the function of a thermal wheel in the context of air handling and energy exchange.