Why are economizers used on boilers?

Economizers are utilized in boiler systems primarily to heat feedwater, which is the water that is fed into the boiler to be turned into steam. By capturing and utilizing waste heat from flue gases that would otherwise escape into the atmosphere, economizers improve the overall efficiency of the boiler. This process effectively raises the temperature of the incoming feedwater, reducing the amount of fuel needed to reach the desired steam temperature. This leads to greater energy efficiency and lower operational costs, making it a vital component in many industrial and commercial boiler applications.

The other options do not accurately describe the primary function of economizers in boiler systems. Reducing noise is not a function associated with economizers, nor would they increase fuel consumption, as their purpose is, in fact, to optimize fuel usage. Additionally, while economizers might indirectly conserve water by improving efficiency, their main role is to heat the feedwater instead.