What type of heat transfer do recuperative air heaters utilize?

Recuperative air heaters utilize direct heat transfer, which occurs between two fluids without mixing them. In this case, the flue gases from the exhaust transfer heat directly to the incoming air through the walls of the heat exchanger. The efficiency of this process is crucial in industrial applications because it allows for a significant reduction in energy consumption by preheating the air before it enters the combustion chamber or process.

The choice represents a fundamental principle of heat exchanger design where heat flows from a hot medium (flue gas) to a colder one (incoming air) to enhance thermal efficiency. This direct exchange not only improves heating processes but also contributes to lower emissions and improved system performance.

Understanding the operation of recuperative air heaters is important for power engineers as it plays a crucial role in energy management, operational efficiency, and sustainability practices within heating systems.