I am looking for ideas for hydronic heating & domestic hot water so I'll do my best to lay out my situation.
We live on the coast of Maine where the temperature occasionally drops to the negative numbers (Fahrenheit) for a week at a time. More commonly the winter temperatures are in the teens or twenties (Fahrenheit). We would use this heater during the late fall, winter and early spring. The rest of the season, we'll rely on solar for our domestic hot water.
I have access to lot's of cheap firewood that I cut myself. For this reason, the heater needs to use wood.
Our home is a duplex and is basically two houses that are only attached in one corner. We live in one half and rent out the other half. Renter's insurance prevents us from having any type of wood heat, including a RMH in the rental side. A full basement (connected) is under both sides. We have access to the basement and the tenants do not. It would be possible to have a heater that we control in the basement. There is a conventional propane furnace and hot water heater (tank type) in the basement. I'd like to get off of propane entirely, except for use as a back up and cooking. Currently, we both use the propane based domestic hot water. Our side of the house is heated exclusively with a wood stove and we burn about 2 to 3 cords of wood per year. The furnace heats the tenants side. Both sides have a footprint of 900 sq' for a total footprint of 1800 sq'. Both sides have an upstairs that relies upon rising heat. Both sides are equipped with baseboards
I'd like to only add fuel once or twice a day. This may be a necessity if I have to leave for the day for work or other obligations. I need to have a fossil fuel back up in case we need to go away for a while. I'm looking for a solution that doesn't cost a lot of money.
I'd like to build an exterior RMH that heats water that I pump into the house, but I'm worried about inefficiencies as the mass heats the outdoors. Perhaps there might be a way of super insulating the RMH so that heat loss is minimal. Ideas? I'm also unclear about the best way to extract the heat from the RMH. I've thought of coils or fins through the riser and barrel assembly, but I'm not sure on how to do this. I could conceivably run the exhaust through the foundation wall and into the basement where it could put some heat into the basement before exiting via a basement window some distance away.
Any ideas or suggestions would be greatly appreciated. Thanks, River.
