What is a pre-heater?

The correct answer highlights that a pre-heater typically consists of tubes or plates with hot gases on one side. This describes a device that is integral to increasing the efficiency of heating systems, especially in power plants or industrial applications.

In a pre-heater, the hot gases flow through the tubes or over the plates, transferring heat to the incoming fluid, such as water or air, before it enters the primary heating equipment, like a boiler. This process maximizes energy usage by utilizing waste heat, reducing the amount of fuel needed to reach the desired temperature in the main heating system. Therefore, understanding the role and construction of a pre-heater is essential for effective energy management and system efficiency in stationary engineering contexts.