What energy recovery application is exempt from the prohibitions specified in NCMC 514.2?

The correct answer relates to applications recovering sensible heat using coil-type heat exchangers. The North Carolina Mechanical Code outlines certain prohibitions regarding energy recovery systems to ensure safety and efficiency within mechanical systems. However, among the energy recovery applications listed, those that utilize coil-type heat exchangers to recover sensible heat are specifically exempt from these prohibitions. This is significant because sensible heat recovery involves the transfer of heat without a change in moisture content and is often considered safer and more efficient for building environments.

Coil-type heat exchangers are widely used in HVAC systems and are recognized for their effectiveness and reliability in recovering heat from the air or fluid flow, which aligns with standard practices in the heating and cooling of spaces. When these systems are employed appropriately, they provide significant energy savings and improved indoor air quality while conforming to safety regulations, making them a practical choice within the code guidelines.

Other options represent types of energy recovery that may be subject to specific restrictions or design considerations to prevent potential issues, such as moisture buildup or contamination. Thus, the exemption for sensible heat recovery systems with coil-type heat exchangers showcases the code's understanding of practical HVAC applications that enhance system efficiency while adhering to safety standards.