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Boiler efficiency formula

Boiler efficiency formula

Boiler efficiency formula

(OP)
Does anyone know how to calculate the efficiency of a boiler? I know how to calculate the efficiency of turbines and compressors, but I can't find a formula for boiler efficiency? Thank you.

RE: Boiler efficiency formula

HI SeaSexEngineer

The formula for boiler efficiency is:-

boiler eff= energy gained by fluid/energy in to boiler


regards desertfox

RE: Boiler efficiency formula

The official means of calculation is defined in the ASME power test code PTC 4.0.  It can be calculated either on basis of  HHV ( higher heating value of fuel) or LHV ( lower heating value of fuel) , and via input/output or loss methods

RE: Boiler efficiency formula

SexSeaEngineer,

There are two methods to calculate the boiler efficiency.
You may refer to ASME PTC 4-1998.

AOBJR

RE: Boiler efficiency formula

The formula presented by DesertFox is concise and accurate but it is not easy to measure efficiency of a running boiler that is why the ASME power test code was developed.

RE: Boiler efficiency formula

For a simple method, try

eff.= Heat energy transfered to water & Steam
      --------------------------------------
      Heat energy supplied by fuel


eff. = mass of steam(kg/hr)* (h(s)enthalpy of Steam -      
                              h(w)enthalpy of feed water)
       ---------------------------------------------------
       mass of fuel (kg/hr) * calorific Value Mj/kg

N.B. Enthalpy obtained from steam tables

RE: Boiler efficiency formula

Cleaver-Brooks has a 21-page file on Boiler Efficiency:
http://www.speci-fire.com/EmmisEffic/boiler_efficiency_facts.pdf
It covers the different methods of calculating efficiency as well as the factors (excess air, type of fuel and H/C ratio, no. of passes, ambient temperature) affecting the efficiency.
Tables give stack losses as f(flue gas T) and fuel consumption as f(efficiency).

An example is given of their preferred Fuel-to-Steam efficiency calculation.  It uses actual measurements of flue gas T, CO2 or O2 concentration, ambient T, and tabulated “Hays charts” of flue losses by fuel type and “Radiation and Convection” losses.

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