What is the function of an air preheater?

The function of an air preheater is to enhance combustion efficiency through warmed incoming air. By preheating the air that enters the combustion chamber of a boiler or furnace, the air preheater allows the fuel to burn more efficiently. Warmer air requires less energy to reach the necessary combustion temperatures, which can improve the overall efficiency of the combustion process. This results in better fuel utilization and reduces the amount of unburned fuel and emissions released into the environment.

Air preheaters play a critical role in energy conservation practices within power plants and industrial heating applications. By recovering waste heat from flue gases and using that heat to warm the incoming air, air preheaters improve the thermal efficiency of the system, ultimately leading to lower operational costs and reduced energy consumption.

The other options discuss cooling, filtering, or providing ventilation, which don't align with the primary function of air preheaters in optimizing the combustion process.