Maybe something as simple as coiled copper tubing inside the exhaust vents to heat water.
Furnace exhaust heat recovery.
There are four widely used methods.
It is a gas to gas heat exchanger placed on the stack of the furnace that preheats incoming air with exhaust gas.
Use of regenerative burners for reheating furnaces can provide significant energy savings.
The heat recovery system is connected to the off gas treatment system of the melting electric furnace.
Designs rely on tubes or plates to transfer heat from the exhaust gas to the combustion air and keep the streams from mixing.
Waste heat recovery elevates furnace efficiency to higher levels because it extracts energy from the exhaust gases and recycles it to the process.
This heat recovery process is accomplished in such a way that the stale air is never mixed with the fresh air.
Also if i try to steal the exhaust heat am i going to have to come up with some sort of induced draft fan.
In some cases such as industrial furnaces efficiency improvements resulting from waste heat recovery can improve energy efficiency by 10 to as much as 50.
Captured and reused waste heat is an emission free substitute for costly purchased fuels or electricity.
I know they sell heat recovery units for wood stoves with a 6 pipe i wonder if i could use one of those with my gas appiances.
A regenerative burner is with a heat recovery system that recovers the waste heat of the furnace exhaust gas to heat up the combustion air needed for the burning of the fuel at the burner.
This unit is equipped with a heat recovery core specifically designed to reduce ventilation costs by recovering the heat energy from the exhaust air and using that same heat energy to warm the fresh air being supplied.
A recuperator is a special purpose counter flow energy recovery heat exchanger positioned within the supply and exhaust air streams of an air handling system or in the exhaust gases of an industrial process in order to recover the waste heat.