What is an economizer's role in boiler efficiency?

An economizer plays a crucial role in enhancing boiler efficiency by capturing waste heat from flue gases that would otherwise be released into the atmosphere. By utilizing this waste heat, the economizer preheats the boiler feedwater before it enters the boiler. This process reduces the energy required to bring the feedwater up to the necessary temperature for steam generation, which in turn lowers fuel consumption and operating costs. The implementation of an economizer can lead to significant improvements in overall system efficiency, making it a valuable component in modern boiler systems.

The other options revolve around functions that do not pertain specifically to the economizer’s purpose. Cooling steam is not part of its function, nor does it serve to filter water or increase steam pressure. The economizer's primary focus is on recovering usable energy from the exhaust gases to improve the overall thermal efficiency of the boiler system.