drain water heat recovery

[Daox]

Has anyone used or know about drain water heat recovery? I am incredibly interested and am most likely going to try this out.

http://gfxtechnology.com/

[bennelson]

Hmmm - right on that web page, it shows a couple of installations and says where they are. Including one at a Dartmouth College Dorm.

Too bad we don't know anyone on this forum who is a Dartmouth student who could go take a look at it!

(And by this, I mean SVOboy. I did get the right school, didn't I?)

-Ben

[Tony Raine]

huh, so its basically running your cold water through some copper pipe wrapped around a copper drain pipe from your shower?

good idea, and it sounds easy enough to build yourself........

[Daox]

Originally Posted by Tony Raine

good idea, and it sounds easy enough to build yourself........

Thats exactly my thought on it!

Since they install them vertically, the water going down the drain clings to the sides of the pipe creating a thin film and thus a great amount of surface area to sap the heat out of it.

Yeah, it would be nice if SVOboy could get us some actual info. He just moved back the other day.

[dremd]

a buddy of mine has been talking about doing that forevor, must help . . . .

I bet it would be killer for a kitchen with a big dishwasher, or someplace like a dorm where there is heavy use per shower.

[SVOboy]

I'll send out some emails to "the right people" and see if they can either tell me or connect me with someone in the sustainability office or facilities, operations, and management to talk about the heat recovery.

[mopo3]

I'm a chemical engineering student at georgia tech, and this is basically a simple energy balance. I have an excel sheet that you can use to calculate the economics.

spreadsheet (for calculations)
http://sites.google.com/site/showerh...attredirects=0

Diagram
http://sites.google.com/site/showerh...attredirects=0

Description (open in openoffice)
http://sites.google.com/site/showerh...attredirects=0

[Daox]

I just checked out your spreadsheet for calculations. What efficiency does the sheet use for the heat exchanger? There is a pretty large variance between the different models avaliable.

Here are also two more companies that make them.

RenewABILITY Energy, Inc.

ReTherm™ - Drain Water Heat Recovery Solutions

[Daox]

I found another maker of these things. It appears that this one can be installed horizontally or vertically. The website doesn't say much about how it operates though.

EcoDrain | high performance shower heat exchange

[knowbodies]

Originally Posted by Daox

I found another maker of these things. It appears that this one can be installed horizontally or vertically. The website doesn't say much about how it operates though.

EcoDrain | high performance shower heat exchange

From what I understand of the diagram they have on How does it work? | EcoDrain, they use the waste heat from the water going down the shower drain to preheat the cold water line to the shower. Depending on the length of the pipes involved, I've probably finished my shower before the heat can make it's way around that circuit. I can only see it being useful in a location where many showers take place (the next person taking a shower will get the benefit of the waste heat from your shower). In a home like mine (the wife is up at 5:30am, I'm up at 7:00am, the kids bathe in the evening) the benefit would be very very minimal.

You could run the shower water underneath the floor in front of the shower and have a nice warm place for your feet when you get out but I wouldn't want to try and clean the hair out that kind of drain.