Using heat from gassifier hopper to heat house?

I rand the whole concept of producer gas by my friend, who deals in scrap metal. He's very interested in permaculture and getting off the grid. I ran it past him as a means of producing electricity, then he got the idea of maximizing efficiency. he wants to use some of the current from the alternator to produce HHO gas that would be fed back into the engine and use the heat from the hopper to warm a house.

The latter idea sounded terrific. Is there any way to sync some of the heat from the fuel barrel into a house. I was thinking, maybe you could somehow weld some piping and a radiator to the unit and install it inside a house to transfer the heat. Is this a good idea or bad idea? Has this been done before?

Producing H2 gas in this manner and "feeding" it to the engine can possibly increase net efficiency, but only by increasing combustion efficiency. In any case the gain would be minimal at best, and most likely it would reduce net efficiency. However, there is a lot of heat that can be harvested from the system. In particular, the heat from the engine exhaust should be used.

See the following link: http://www.powercubes.com/listers_12.html

I think Ken's system is admirable. However, I think there are shortcomings. If you're interesting in a discussion, then reply and I will discuss my thoughts.

Woodgasifiers need the heat for gas production but after it is produced you can get heat from cooling the gas, engine cooling is a heat source, and then the exhaust is a heat source you can get heat from that. each one will be a unique system in itself that would extract more energy from the wood consumed to provide rotational energy. The question then would be is this energy extracted be useable for what you need it for.