Composting To Create Hot Water

Want nature to supply you with 130-150 degree hot water? [Onestraw] shows you how to get just that by building a compost heap that heats water. Finding himself the proud owner of a dump truck of green wood chips [Onestraw] went about building his own version of Jean Pain’s thermal compost pile. The idea is to produce and store methane generated from the compost pile but in order to do so, the temperature must be kept fairly low. The microorganisms in the compost generate a lot of heat trying to break down that matter and running water through the system will keep the temperature low enough for the methane-producers to be happy. The side effect of this cooling system is hot water coming out the other end. [Onestraw] even has plans to use salvaged car radiators to turn the hot water into a heating system for his home. Granted you’re not going to add this to your apartment, but if you have space and waste plant matter and need hot water this is a great way to get it.

[Thanks Joel]

33 thoughts on “Composting To Create Hot Water

  1. Please guys, don’t spread false information. Your compost pile will not sponateously generate olfactory sensory organs, regardless of what rebar, barrels, or hose you thread through it. It’s a scientific fact.

  2. Interesting idea. However his plan to potentially use salvaged car radiators I wouldn’t do that. First off many still contain lead, plus other chemicals are in the radiator fluid, other debris, leeched metals, rubber particles amongst others. Companies make specialized heat exchangers for potable quality (read human consumption quality) water and I would use those even though they may not be as cheap as a salvaged car radiator but at least those wouldn’t make you sick in the process.

    1. Necro posting here, I realize. I just want to point out that he’s not using it for potable water heating. He’s making a water based heating system. The radiators are there to exchange the heat from the water with the air in the home. Central heating style.
      You know, in case some one reads the post and gets confused later on.

  3. I’d be curious to know the wattage heat output of the compost. That will let you know how much water per min you will need to heat. If it is too high, you are going to waste a lot of the heat just dumping it to keep the compost at the right temperature. If it is too low, you won’t have a useful supply of heated water to use for anything else. What this system needs is a second reservoir outside of the compost. Then you can add a radiator on the return line only (or that could be the house heating system).

  4. @Travas

    I was thinking of using a compost pit and make it so all that sticks out of the ground are the tops of the barrels. Plus my pool sits on a hill and I could put the compost down the hill out of sight and smell range. The hill side is facing the wrong direction for my solar panels so they sit by the pool obstructing the view.

  5. compost piles really don’t stink unless you’re right up putting your nose next to it. The annoying problem he’s going to have is that he won’t be able to keep the dirt there once it’s composted. I’m not sure how often he’ll need it to replace stuff in his yard, but my neighbor has a fairly large yard and a huge compost pile and it almost never gets used. So he’ll probably end up with a pile of loom produced from the compost and the compost itself. That would get annoying.

    What he should do it have it produce electricity and use the electricity to make an automatic dirt remover.

  6. You’re welcome!

    Guys, compost only stinks if you’re doing it wrong. Bad-smelling chemicals are only released by anaerobic composting; wood chips are great at maintaining air space, so the pile depicted here will smell like pine until it smells like good soil. If you don’t know how to compost, download “The Humanure Handbook” gratis…feel free to ignore the parts about human shit, it’s one of the best instruction manuals on how to compost I’ve seen at any price.

    Also, [Onestraw] is set up to use literally *tons* of compost. Making use of the finished product won’t be the problem, in fact part of the reason he wants to scale up is to meet his demand for humus.

    PPz, you want to maintain good airflow to the pile, but you’re right, there are lots more options to disguise it than there are for solar panels.

    1. A good way to avoid it is to maintain humidity inside/not allow to dry. In mine (made in wheely bin, i have fixel a plate under the lid, so the condensation drops everywhere back on top of the pile.
      i recommand the reading of The Compost Powered Water Heater book

  7. Another idea STOLEN from Mother Earth News. This idea was planned and performed by Mother Earth News in the late 70’s, early 80’s with success. They used copper pipe and water friendly materials to preheat water for the household hot water. The plans can be be bought at the MENS website.

  8. Is the idea STOLEN (sic) if he acknowledges their work, and talks about how his work differs from theirs?

    Read his earlier article if you’re curious, he’s exploring the importance of pre-soaking.

  9. This would be a GREAT idea if you have a pool… Have a pump run the water from the pool to the compose. Then you’re keeping your pool heated as wel as keeping your compost cool!

  10. you guys have your heads in the compost, the idea of composting to heat belongs, not to mother earth who borrowed it from a frenchman Jean Pain, they acknowledge tha, who uses a 4o ton pile of woodchip to generate hot water and methane and runs all his cars on that methane and when the pile is done composting he switches to his second pile and starts spreading his huge pile of compost on the garden. check it out and stop woffling on.

  11. This is basic geo thermal heating for your house, Geo thermal uses a ground loop to transfer the heat, the loop is buried in the ground and the refridgerant is pumped through the system.

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