How does a secondary heat exchanger differ from a primary heat exchanger?

A secondary heat exchanger is designed to transfer both sensible and latent heat, making it distinct from a primary heat exchanger, which typically focuses on transferring only sensible heat. In HVAC systems, the primary heat exchanger usually handles the direct transfer of heat between the refrigerant and air or water, functioning mainly during heating or cooling processes.

In contrast, the secondary heat exchanger often comes into play in more advanced heating systems, such as condensing boilers or HVAC units that utilize heat recovery. It allows for efficient energy exchange, capturing not only the temperature (sensible heat) but also the moisture content in the air (latent heat), which can contribute significantly to overall energy efficiency.

This capacity to handle both types of heat is crucial for optimizing energy use and improving system performance, especially in environments where humidity control is essential. By utilizing both forms of heat transfer, secondary heat exchangers enhance comfort and efficiency in way that primary heat exchangers alone may not achieve.