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I visited a house years back that captured back hot water heat from the shower drain. Hot water going down the drain went through a pipe wrapped with a spiral p
by rossjudson 7y ago
I visited a house years back that captured back hot water heat from the shower drain. Hot water going down the drain went through a pipe wrapped with a spiral pattern of other pipe (and fresh water from the hot water tank circulated through there). Don't know how efficient it was, but it was pretty cool to see as a working system.
- ants_a 7y agoApproximately 50%.
- Cerium 7y agoThe keyword is "drain water heat recovery". I don't know the efficiency, but you can buy one for about $600.
- abiogenesis 7y agoNice, a turbocharged shower.
- theluketaylor 7y agoHere in Canada recovering heat from the drain can be used as part of energy efficiency code requirements in new builds. They can recover quite a bit of heat, around 50% depending in inlet and outlet temperatures. Pretty good for a fully passive technology that has no maintenance or moving parts. It does require a lot of copper, so the parts are about $1000 but it's a really easy install.
- frosted-flakes 7y agoThose things are neat. I always wondered why they were wrapped around vertical pipes rather than horizontal, because intuitively it seems like horizontal would be better, but that's not the case. I looked it up and it's because falling water in a vertical pipe will cling to the pipe wall, while in a horizontal pipe it will just sit in the bottom. It's obvious in hindsight, but I've never thought about the physics of water in a vertical drain pipe.
- willvarfar 7y agoThis, and blockages...
- twic 7y agoI've seen a design which exploits this by having the waste pipe flare out enormously - imagine two squat cones joined at their circular faces. You get loads of surface area for heat exchange, with slower flow across it, and no chance of blockage.
- twic 7y agoThis seems like easily the biggest win available to most homes, at least in the UK. Modern building regulations mean that new homes have to be so well-insulated that heating requirements are small. We have a lot of old housing that was not built to those regulations; some of that has been refitted with insulation, and the rest should be. Whereas the heat that goes into hot water just goes down the drain, even in the most modern homes!