Can you heat your house using compost?

Question

I know that there is a significant amount of heat that builds up under a compost pile. It would seem logical that this heat could somehow be harnessed and used to heat your house, water, etc. Are there any working models already out there?

Answer 1

In principle I don't see why not, although it may not be your idea of a compost pile but on the basis of a Permaculture Chicken system I think it could be possible. It would depend on many factors including the size of your home and the required level of heat so it may be a very ineffective way of heating (require more human energy than it produces)

You would first have to look very carefully at heat retention (fixing drafts, insulation, etc) then at heat storage. You would increase your heat storage  through increasing biomass in your home such as placing stone flags up the wall and around heat sources ie the fire. Then you would need to plant trees around your home as  plants with high biomass (eg trees) store heat in their mass and slowly release it when it is cold. Large trees shade the house in summer keeping it cool, so you don't need to use other non renewable sources. Water and stone around the outside of the home are great heat storers too so are bodies of water such as ponds. A pond near your house, for example, would store the sun's heat during the day and release it at night.  A stone wall stores the heat from the sun over night and protects your tender crops too.

Check out the Thermoguy link below, he is also on my contact list. This link shows visual evidence through thermal imaging  the (wasted and excess build up of) energy within/around a house and the incredible difference in temperatures when trees are planted around the house.

In Permaculture we talk about relative location, that is, each  element is a part of a functioning whole rather than seen in isolation. We are careful to put each element that makes up the design in the right place in a design. By doing this we create an energy efficient system.

So in your example your compost that you need is the waste from another system (the farm) but a yield in yours (produces heat), it takes a lot of effort wheelbarrowing your compost around, energy transporting it, turning it to ensure it stays warm, moving it again when it is spent.

In Permaculture we aim to ensure that the yields and wastes of each individual part fulfil the needs of other elements within that system. All parts are in the system so a Permaculture system would look like this:

If you used relative location to site your greenhouse you would  place it on the south side of the house. The sun heats the rest of the house and the house wall acts as a heat store releasing warmth back into the greenhouse at night. So now your food production from your greenhouse is next to your kitchen so it is easily to hand and as it is in zone 0 (see link below for explanation) you will remember to water your plants, you will see the exact time to harvest and water your crops.

Now it is heat you are after, right, it is winter and you are cold, you garden in spring and summer. But you are a budding Permaculturist so lets follow the story through and you will see my line of thinking.

At the end of summer, when you have collected the last of your greenhouse crops there is a lot of work to do before next season. So get chickens in to do the pest control, weeding, fertilizing and heat generating for you. In the autumn put the chickens in the greenhouse. In the spring you can let them out when they have done all that work and your greenhouse soil will be ready for planting.

What's this got to do with heating my house? In Permaculture we say each element has many functions so we look for as many yields as possible from each element  (see link below for explanation) Always look for multiple yields. Chickens are really useful to Permaculturists producing eggs and meat, which is particularly useful for storing summer veg calories for humans to eat in winter when vegs are not as available. Chickens are self populating, eat kitchen waste and garden weeds, scratch, weed, plant seeds, control pests, fertilize the soil, give off heat, produce manure which gives off heat and produce carbon dioxide for your winter greenhouse veggies.

So build a slotted wooden false floor in your greenhouse with manure collecting containers underneath which you can pull out in spring and use on the garden. Take advantage of the Chicken's heat and it's manure's heat in the winter and all the other benefits listed above.

Then in spring when they have prepared your soil for planting in your greenhouse put them in chicken tractors to clear your other veg beds outside (see links below for explanation of chicken tractors). When they have cleared your outside beds, feed your chickens the seeds you want to planted in the rest of the garden. Some of them will grow without any effort from you.

So yes, theoretically, I believe it is possible to heat your house using compost (well chickens and chicken manure) using Permaculture methods. HOWEVER:

I am a Vegan, I am a PERMACULTURIST and am developing a Deep Ecology view of the world so this is not the way I would do it personally.

Me? I prefer the no heat option. Insulate and don't have any heat on except in the most sever months of the year. No heat is much more effective than any form of heating in terms of cost, pollution, Greenhouse gases, human energy input needed and impact on the environment.  When it gets too cold to be just wearing jumpers, hats etc and adding hotwater bottles and blankets then we heat only the one main living room with waste wood in a wood burning stove. When that is no longer available in the future then our fuel will come from bio-mass willows we planted on our land.

Permies don't like wasting resources, time or energy lol.

Answer 2

i think you'd need a lot of compost. but you can probably heat up something small, but not a house. its a good concept though!

Answer 3

This is a good idea, but in order to make good compost the internal temperature has to maintain a certain level for the bacterias to digest. So to get that energy out of the pile would mean to run heat collectors in the pile, but to make a good compost you have to turn around the pile periodically to give it oxygen.

First problem is how do you distribute these collectors in the pile knowing that you have to turn the compost, second problem is that if you remove heat from the pile the lower temperatures will not make compost !

Am i clear ?

Answer 4

Excellent concept but practical applications are limited as to date with green house growers. They virtually supply them self's with their own energy source. It is one area of biomass heat distribution that is currently being explored. Others consist of using lake water as a heating and cooling process. I do heat my green house during the winter months with compost, but it's a tediuos process that works.

Answer 5

Home composting wouldn't work, but larger commercial compost might make a go of it.  

The link below was the closest I could find, but I like the idea.  Make it so!

Answer 6

i think you would need way more compost than the average house and garden produce! also, the bulk of it would be produced in the summer, you would need some way of stopping it heating up to save it for the winter...

you can make a hot bed, but we are only talking a few square metres there.

http://www.the-gardeners-calendar.co.uk/...

you can use one of those to keep a greenhouse above freezing, that's about it.

an better idea would to have a giant rainwater storage tank (a.k.a. swimming pool ;-) ) and run the coils of a ground source heat pump through it.

the cogs whirred a few minutes and i remembered i did see something on these lines in a permaculture magazine once! a bit of a search gave this (not the article i read but i think the same people)

http://www.motherearthnews.com/Modern-Ho...

Answer 7

There are lots of older houses with stables in the basement.

It would have lent a barnyard smell to the houses though.