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What is boiler efficiency and how is it calculated?

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97 views asked Aug 26, 2014 by Mepanet

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Boiler efficiency is defined in two ways:

Combustion efficiency

Input minus stack (chimney) loss, divided by input. This ranges from 75 to 94 percent.

Combustion efficiency = (Input- Stack loss)/Input

Overall efficiency 

Overall efficiency in gross output divided by input.

Overall efficiency = Output/Input


Input is the amount of energy used by boilers.
Output is the amount of energy boilers produce for heating systems.

Steam boilers are operated by boiler mounted, pressure-actuated controls which vary the input of fuel to the boiler. Hot-water boilers are operated by temperature-actuated controls that are usually mounted on the boiler.

Hot water temperatures for heating are usually 180℉ - 200℉ for supply and 140℉ - 160℉ for return. The temperature difference varies between 35℉ - 40℉.

answered Aug 26, 2014 by Mepanet

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