Is there any simple equation for estimating furnace efficiency only by excess air (oxygen) and flue gas temperature?
Paul J. Martin, RPCServices, email@example.com
A very good rule of thumb is the following:
Furnace Efficiency = 100 - (%Oxygene)/2 - (Flue Gas Temperature)/20
Despite of the fact that radiation section efficiency is not taken into account in this formula, this will give you an efficiency a little bit lower than the one calculated by loss method.
Typically, efficiency is the one calculated plus 0,5 -1,5 %.