Sectional view of a Convection Recuperator

Convection recuperators also referred to as "flue" or "canal" recuperators are tubular heat exchangers that utilize convection heat transfer to preheat combustion air or gas for the purpose of saving fuel. The heat is recovered from the hot waste gas exiting a furnace and transfer it to the combustion air feeding the burners, fuel usage can be reduced by an average of twenty-five percent (25%), and in many cases, greater savings are realized. Waste gas temperatures entering convection recuperators are usually in the 1500°F to 2000°F range, and combustion air preheat temperatures are usually in the 800°F to 1200°F range.