Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Combustion Processes and Combustion Efficiency

Typical furnace combustion efficiencies in fireplaces, space heaters, boilers and more

Sponsored Links

Combustion is an exothermic reaction between a fuel and an oxidant.

Combustion of carbon and oxygen to carbon dioxide can be expressed as:

C + O2 > CO2

Combustion of methane and oxygen to carbon dioxide and water can be expressed as:

CH4 + 2 O2 > CO2 + 2 H2O

Combustion of hydrogen and oxygen to water can be expressed as:

H2 + 1/2 O2 > H2O

Typical combustion process efficiency can be summarized to

  • home fireplace: 10 - 40 %
  • space heater: 50 - 80 %
  • residential gas furnace with low efficiency atmospheric burner: 70 - 80 %
  • oil burner heating system: 70 - 85 %
  • gas powered boiler: 75 - 85 %
  • high efficiency gas or oil condensing furnace: 85 - 95 % 

Furnace Performance Indices

The performance of a furnace is usually assessed by the following indices

Thermal Efficiency

μt = 100 Eo / Ei                (1)

where

μt = thermal efficiency

Eo = energy output (W, Btu/h)

Ei = fuel energy input (W, Btu/h)

Annual Fuel Utilization Efficiency - AFUE

AFUE measures the annual amount of heat actually delivered compared to the amount of fuel supplied to the furnace.

AFUE = 100 Eao / Eai (2)

where

AFUE = annual fuel utilization efficiency

Eao = annual energy output (W, Btu/h)

Eai = annual fuel energy input (W, Btu/h)

Steady-state Efficiency - SSE

Steady State Efficiency measures how efficiently a furnace converts fuel to heat once the furnace has warmed up and is running steadily and can be expressed as

SSE= 100 (Ei - El) / Ei (2)

where

SSE = steady-state efficiency

Ei = fuel energy input (W, Btu/h)

El = energy loss (W, Btu/h)

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Share

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Topics

Unit Converters

Temperature

oC
oF


Load Calculator!

Length

m
km
in
ft
yards
miles
naut miles


Load Calculator!

Area

m2
km2
in2
ft2
miles2
acres


Load Calculator!

Volume

m3
liters
in3
ft3
us gal


Load Calculator!

Weight

kgf
N
lbf


Load Calculator!

Velocity

m/s
km/h
ft/min
ft/s
mph
knots


Load Calculator!

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O


Load Calculator!

Flow

m3/s
m3/h
US gpm
cfm


Load Calculator!

5 9

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more