Electricity from the calories of a compost!

[xboxman4]

Here, I came up with the idea of ​​something that seems feasible to me: recovering the heat from composts in order to make electricity, notably thanks to the Stirling engine.

I do not think the return is huge but hey, it can be worth the cost anyway right?

[Gregconstruct]

It would take a nice big pile of compost, right?

[Ahmed]

I understand your approach, unfortunately, amha, it is based on a poor appreciation of the reality of the phenomenon.

There is confusion between the amount of heat present in a heap of organic matter in fermentation and the heat production capacity.

To make it simpler, it is to confuse the stock and the flow.
The "stock" is considerable, which explains the error, but the production remains very modest.
Why? There are few heat losses in a heap worthy of the name for mathematical reasons: the volume grows much faster than the exchange surface. So, for a sufficient volume, the quantity of thermogenic bacteria is important while the losses are minimal.

If, now, we want to intervene to take calories, we at the same time break this balance. However, the consequence is not just physical, but also biological.
These bacteria, which I have frequented quite a bit (excuse me a little!), Are large chills, and cooling them is not the best plan to obtain heat from them in return ...

In my opinion, the only way to validly use the heat of a compost is in an application that takes into account the above. Cad a use valuing a modest flow, as did the warm layers of gardeners of yesteryear, eg.
Another possible and more current application: maintaining the temperature around a methanization tank.

[xboxman4]

ok, thank you for your explanations!

[renaud67]

Happy,
try to find out about the jean-pain method (not the grinders)
http://www.onpeutlefaire.com/ilslontfait/ilof-jean-pain-broussaille.php

[xboxman4]

thanks for the info!

[greg]

I spoke to a heating engineer who had mounted a heat pump whose sensor was sunk in the slab of the manure.
it can correspond to a modest flow, right?
greg

[Ahmed]

@Greg;
The heat pump is a system which is, if I may say so, a kind of thermal lever arm (at least, in theory). The idea is that with a modest flow of electricity you can get a greater amount of calories in the final (that's true under certain conditions).
In the present case, the CAP serves to make up for a logical flaw. If the manure / compost pile had the ability to generate a suitable amount of heat on a sustained basis, there was no need for a heat pump. As it is not the case, the CAP makes it possible to extract calories from a medium which functions badly by the very fact of these punctures. Where a conventional exchanger would stop, the heat pump continues to take calories, because it exploits a small temperature differential.