What happens to system efficiency when debris is present on heat exchange surfaces?

When debris accumulates on heat exchange surfaces, it creates a barrier that impedes the transfer of heat between the surfaces and the fluid moving over them, thereby reducing the overall effectiveness of the heat exchanger. Heat transfer efficiency relies heavily on clean surfaces that provide maximum contact and minimal resistance for heat flow. The presence of debris acts as an insulator, causing the system to work harder to achieve the desired heating or cooling effect. This effectively results in decreased system efficiency, as more energy is expended without a corresponding increase in heat exchange effectiveness. In HVAC systems, maintaining clean heat exchange surfaces is critical to optimizing performance and energy consumption, making it evident that the efficiency will decline as debris builds up.