How to Calculate ASME Boiler Efficiency

Maintaining optimum boiler efficiency is critical to minimizing carbon dioxide emissions, conserving fuel resources and lowering operating costs. Boiler efficiency should be monitored on a regular basis, especially if any changes are made to operating conditions or equipment.

Calculating boiler energy losses

Boiler efficiency includes two calculation methods:
Input-output (direct)
Heat loss (indirect)

With the input-output method, you calculate efficiency by dividing the boiler's Btu output by its Btu input and then multiplying this figure by 100. You determine the output and input through instrumentation, and the resulting data is used to calculate the efficiency value.

The heat loss method is designed to account for all of the boiler's heat losses. You subtract the total percentage of stack, radiation and convection losses from 100 percent as follows:
Efficiency = 100 percent — [(total heat losses / fuel heating value) X 100]

For natural gas systems, only four primary types of losses apply: dry flue gas losses (sensible heat), moisture losses (latent heat) from water formation by hydrogen combustion and water in fuel, as well as radiation and convection losses. Because the latter two are minimal, 0.1 percent is assumed for natural gas.

More information about how to calculate ASME boiler efficiency, please contact with our online customer service or Email zbgboiler@zzboiler.com or Call 86-371-86062323.