I've written before about how to make a hot compost heap, and I've been known to explore navy showers as a way to lessen your environmental impact too. But what if you could combine the two? Specifically, what if you could heat your water using the excess energy produced by a hot compost pile? It turns out you can.Composting Water Heaters Not New
Inspired by a Frenchman called Jean Pain, it turns out that using compost for heating your water is not new, nor is it particularly high-tech. I've seen a few examples of Jean Pain-style composting/heating systems on various permaculture projects before—most notably the one being used at green t-shirt printers' TS Designs headquarters to heat their biodiesel brewing process.
Small-Scale Jean Pain Composting Water Heater
What I'd never seen, however, was a compost/water heating system that was quite as small as the one in the video below (Pain's original was 6m in diameter and 3m in height). Introduced by permaculture teacher Darren Doherty, this particular system is only 2m x 2m in size.
Used in conjunction with a tankless solar water heating system, Doherty says they can get 40 gallons of hot water at one time. Of course the green zealots out there might argue that that's way too much for a single shower—but it looks like Doherty is also following the best green shower advice of all—never shower alone.
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