How do non-condensables affect the heat exchange process within an HVAC system?

Non-condensables, such as air or other gases that do not condense under the operating conditions of the HVAC system, significantly impact the heat exchange process by blocking heat transfer. When non-condensables are present in the system, they occupy space within the condenser and heat exchanger. This prevents the refrigerant from coming into direct contact with the metal surfaces where heat exchange occurs.

The presence of non-condensables increases the pressure in the system, which lowers the overall efficiency of the heat exchange process. As a result, the refrigerant cannot absorb or release heat effectively, causing the system to operate under less than optimal conditions. This can lead to increased energy consumption, reduced cooling capacity, and ultimately, potential system failure if the issue persists. Addressing non-condensables is therefore critical for maintaining efficient and effective heat transfer in an HVAC system.