I think there’s two ways to do that.
- A simple heat exchanger from the drain to the cold water running to the shower. A thermostat on the shower reduces the amount of hot water you use as the cold water gets warmer.
- Recovering water from the drain to go into the shower again, probably via reverse osmosis.
Second option requires maintenance and a bunch of engineering. Unless there’s a massive lack of water where you live and you have lots of money.
First option… Well, it requires more piping and that the drain pipe is a heat exchanging pipe - a pipe within a pipe where the cold water is in the outermost pipe, running in the opposite direction of the drain water. I’m not sure how much heat you would recover. The floor of the shower might need to be a bit higher than otherwise. And if you have hard water then I wouldn’t do it. When you heat cold, hard water the calcium carbonate precipitates and you get limescale. To avoid reducing heat exchange efficiency and avoid clogs you would have to descale regularly and it’s just not very accessible. With normal descaling you can remove a lot mechanically but here it would have to be all chemical. And how would you even get the descaler into those pipes?
Tl;dr don’t do option 1, only do option 2 if you have very soft water.
PoliteDudeInTheMood@lemmy.ca 2 days ago
rainstickshower.com
ivanafterall@lemmy.world 1 day ago
Damn, that’s cool.
Damn, that’s expensive.
CannonFodder@lemmy.world 1 day ago
But what if you puss in the shower? Or worse …
PoliteDudeInTheMood@lemmy.ca 1 day ago
It goes on at length about how the myriad filters remove everything. I hadn’t thought about that, but I don’t think it would clean the water THAT good.
ryedaft@sh.itjust.works 1 day ago
If it’s reverse osmosis literally only water can pass through.