What type of heat can be recovered without limitation according to the exception for energy recovery ventilation equipment?

The correct answer pertains to sensible heat, which refers to the heat that causes a change in temperature of a substance without a change in its phase. Energy recovery ventilation (ERV) systems are designed to reclaim heat from the exhaust air and utilize it to pre-condition incoming outdoor air. This process is crucial for enhancing the efficiency of heating, ventilation, and air conditioning (HVAC) systems.

Sensible heat can be recovered without limitation because it is directly associated with the temperature of the air and does not involve phase changes. In contrast, latent heat is associated with phase changes, such as the transition of water from liquid to vapor, and it can be subject to limitations based on the system design and operational conditions. Residual heat and combustive heat aren't recognized in the standard definitions related to energy recovery in the same way. Therefore, the focus on sensible heat recovery aligns with the principles governing energy efficiency in HVAC systems, making it the suitable choice in this context.