Blog

Wood stove heat exchanger, pretty hot


I  want to report some news about the integration of a wood stove heat exchanger into my brother’s shop, WerkHaus (see the project here), that I designed and built.
Yep, my brother has finally finished off the heating system with the help of Norm Walters, a radiant heating tech. Its kind of exciting because its the final product of a giant experiment started about 4 years ago. To get the overall picture of the scheme of the heating system, please see this pic first. Oh, and this one, too.  These diagrammatically say a lot about the general idea we had years ago.
Originally we started with radiant heat tubing in the concrete slab and Phil used a wood stove up until this fall to heat the building using the fan systems to move heat around the building. This really was lacking though because Phil has to work on cars while on a dolly on the slab, which is really kind of cold down at that level. So, he knew that getting the slab up and running as the heat source would be the ultimate solution.

Phil is on a budget, so a typical on the wall, on demand propane condensing boiler was out of the question, at least for now. Originally Phil and I came up with an idea…What if the wood stove came with a heat exchange manifold? Would this do the trick and provide enough heat to run the slab? Well the answer is yes, but it isn’t quite that simple. Norm Walters filled Phil in on the possible scenario that might make it all work. What it comes down to is you need a tank to store the heat and this tank it was decided needed to be well insulated and preferably do some heating, too. So a couple of years ago, Phil purchased this unit.
Then he had Norm hook up his wood stove, which came with a very simple heat exchange coil by using a typical manifold and pump system like this…. Well to make along story short, he got this hooked up to the slab with a typical manifold system and ran it straight off the wood stove, but guess what? It just wasn’t enough of a heat coil on the stove to make it work or run warm enough. So, he resorted to running off the electric hot water heater, and guess what? His electric bill went nuts. So, Norm found a copper coil from some old refrigerator unit and installed it on the top of Phil’s wood stove to increase the heat capturing capability of the stove and water tank. I am making this sound all quite simple but in reality, it took some fiddling and some pumps, and gauges, and sensors, thermostats, and electric meters to make it all work, along with some rather confusing diagrams…I can’t figure it out too much, but what I do know is that Phil is quite happy with the fact that he is running his concrete slab with the wood stove and looks to save some electricity this winter. He sounds kind of excited about it and I would have to say that makes me happy. With some work, it is possible to make these systems happen and it does help to have a radiant heat techy on hand like Norm.

See if you can figure it all out from the the pictures I provided. I understand the concepts, but am not really on top of the electrical and plumbing part.  I believe with the proper research, the integration of a wood stove heat exchanger into homes could save on the heating in your home, too.

3 Comments

  • mark on Jun 03, 2012 Reply

    Thanks for your input Kelly. Its a heating strategy that is just not giving enough consideration and effort here in the USA. Its been mostly a heating system for the hippies and counter culture types unfortunately. Kelly if you have any photos of your system please send them on to me and I will add them to this post to help others in considering this type of heating system…. if that is alright. mark@greenovision.com

  • Kelly G Rogers on Jun 02, 2012 Reply

    I bought one of these from ChimneyHeaters.com . I installed and it works fine. Heats my 2000
    square foot house. I have the pump connected to a UPS but I am not sure how long the pump will run if the electric goes out. I had it installed all winter and did not have to turn on my Electric heat once which saved me about 200 euro a month here in Romania.The Electric is not stable here so I had to rush to take out the fire a couple of times
    because the water pump had stopped and the pressure valves were going off. The UPS will
    solve that but I don’t know how long a UPS will keep my central pump going. I will attach a pic of what chimney heaters are in case you are not familiar with them. The pump is a Grundfos and has three speeds.

  • Wood Furnace Heat Exchangers on Jun 23, 2011 Reply

    great idea guys!

Leave Reply