Then to add, if you are recovering heat while engine running then this heat will not be a constant. So you will still need a primary heat source while engine system is off and then add the complexity of controlling multiple systems to work together. If your thinking your going to run a gasifier to run an engine for both power and heat around the clock that is very inefficient and simply impractical. Make only the power you need and store that power in a battery bank. Store your heat in the wood itself and create that heat using better technology such as a good ole woodstove. You can doing your cooking on this as well. KISS.
An engine grade gasifier is good for one thing and that’s running an engine. Its not a good solution for heating or cooking. You can not run a gasifier indoors as hopper back drafting will be an issue and you will lose that 28%. in process heat as it will need to be outside. Not to mention that percent is actually a bit less in heat output as a portion of it is lost in exothermic process.
Yes I have ran liquid cooled heat exchangers and its not worth your efforts to harness this heat unless it is used to maintain a hot water heater, Actually thats not a good solution either as the purpose of your cooler is to extract that heat and cool the gas. A hot water heater is going to retain and return hot water and defeat the purpose of the chiller.