Drain Water Heat Recovery (DWHR)

tbone52

Anyone have any experience with some of the DWHR products?

bill_105

Just saw one

It's a great idea. Installing in an existing structure can be a project though, like crawl space misery.I think all new buildings ought to have them. It's just so simple.

Charlie from wmass

The ones that work best

need to be installed on a vertical pipe. This is one of the big issues with being able to install them.

meplumber

Check with local AHJ

Up here, there are a few systems in use that I am aware of.  The catch is that they are not fully approved by codes yet.  The systems that I have seen are all engineered by a Professional Engineer (licensed) to allow the exception to the adopted codes.



Your local code may already allow them.  If not, then you may have to have a system designed, stamped and then pre approved.



Good Luck.

tbone52

why vertical?

Why vertical, seems like one would work better in the horz - warm water moving slower.

tbone52

why vertical?

Why vertical, seems like one would work better in the horz - warm water moving slower.

Mark Eatherton

GFX Technology....

The GFX stands for Gravity Effects. In the vertical mode, it can recover up to 50% of the exiting drain waste heat, and THAT is substantial, in a parallel use load, i.e. showering. It is NOT as effective with dump load uses, i.e. dishwashers, clothes washing and such because the heated water doesn't go down the drain until after the load is done...



In an effort to over come thiis shortcoming, I installed a receiver and a sump pump. It too recovered 50 % of the thermal, but by the time you account for the additional pump parasitic draw it ends up around 25 to 30%, which in my estimation is a worthwhile effort...



I drive my DHW loads at the cabin because of the GFX. Without it, the best I could hope for would be tepid water unless we were willing (not) to eat more out of our time to achieve big differentials. Where this conservation effort has the biggest impact is on the sizing of the solar DHW system. It means 40 square feet of solar panel (2 each 3 x 7's) will carry all of my DHW load, and whatevers left can go to the space heating needs, Keeping the place warm for free is FUN (or so I'm told:-))



I personally think waste heat recovery of ALL publicly owned/maintained buildings should be MANDATORY if it can be proven that the installed cost would be recovered within the lifetime of the device. Especially if its MY dollars going to the debt. At least THAT investment would show SOME return on the investment... And we'd be doing Ma Nature a solid.



ME

Charlie from wmass

Mark one thing came to my mind

What about legionella as the water will only be luke warm sitting in the heat exchanger?

Mark Eatherton

Copper tubing...

suppresses bacterial growth. My GFX is a 3" copper drain with a 1/2" soft copper tube tightly wrapped around the 3" and the whole shebang is insulated with R 19 FG insulation.



That coupled with the fact that it then goes to the final heat exchanger which blasts it up to 130 degrees F pretty much alleviates any large colonies of bacteria.



But you are right with your concerns. This is where I contracted LD from, so I know for a fact that it is in the water...



ME