DIY Grey Water Heat Recycling...

[Xringer]

Welcome aboard Tim..
It sounds like you have been on the DIY boat for a while.
I don't like doing plumbing, but the alternative is what motivates me to keep trying.
I've had 'expert' plumbers really drop the ball and what they charged me (high priced),
was nothing compared to the cost of hiring a welder to come in and repair my
poorly installed boiler.

So, my hats off to you for your 'no leaks' record. May it always stand!

About 20 minutes ago, my wife yelled from the kitchen, 'You've got water in here'!
I was in a panic! Was it the new food disposal, or the new sink faucets??
For an old guy, I got into the kitchen pretty fast. Where's the water??
She pointed and said, "it's in the microwave"!
I was dumbfounded for a couple of seconds, wondering HOW this could have happened!
Then, I realized she was referring to coffee cup of water I had just warmed up in the micro!!
It was done.. It was starting to cool off.. LOL!!
She was yelling because I've recently had a sudden-hearing-loss problem..

It sinks getting old!

Cheers,
Rich

[Xringer]

Originally Posted by NeilBlanchard

You can do this set up right at the shower drain, or at the dishwasher drain, and get a little more heat than at the waste invert.

Also, you if can do a heat pump exchange in the sewerpipe:

then you can heat a home with as little as 5' of sewer pipe.

I think my city sewer pipe is about 20 feet under the street..
But, I'm wondering if there is warm air inside that long downhill run
of PVC going to the street??
I have a 90 degree turn inside a man-hole beside the house in the back yard.
I could dig up the cover and scan it for heat!
It might not be too hard to drop a folded back line down into that PVC..
Haha! digging down to a BTU mine..

I can just picture a couple of 80 foot PEX lines with an exchanger payload
on the end, slowly descending downwards towards that warm city sewerage..

[Xringer]

I wonder if one of those Ebay flat plate exchanger would work for a shower drain (warming the cold input side).

50 Plate Outdoor Wood Furnace Heat Exchanger 1-1/4"Port - eBay (item 250586847892 end time Mar-26-10 22:34:19 PDT)

Might be a little tight in there..

Have to build in a back-flush valve to clean it out..

[Daox]

Yeah, I don't think that would work well at all. The clearance between plates is very small on those. It would get clogged rather quickly I think.

[Xringer]

I was picturing hair-balls and how to filter them before they got to the filter..

A screen filter on the gray input and a back-flow valve might be advisable on any kind of exchanger..

[Xringer]

Domestic Hot Water Heat Exchanger/Recover Green! $ave! - eBay (item 270311034829 end time Mar-25-10 18:03:33 PDT)




Those Ebay guys might be getting into the DIY mode..?.

[Daox]

Not a horrible idea (horribly overpriced though!). But not nearly as efficient as the vertical versions.

[Xringer]

Yeah, the price is NOT right..

But the 'idea' looks like someone has been surfing these postings!

I have to admit, my vision of the PVC unit had the gray water in the outer jacket.
Since it's at such low pressure, there would be minimal risk of a flooded basement.

I just believe in keeping the 70 PSI (plus Hammer peaks) city water inside of some good old copper..

[AC_Hacker]

Originally Posted by Xringer

Yeah, the price is NOT right..

But the 'idea' looks like someone has been surfing these postings!

I have to admit, my vision of the PVC unit had the gray water in the outer jacket.
Since it's at such low pressure, there would be minimal risk of a flooded basement.

I just believe in keeping the 70 PSI (plus Hammer peaks) city water inside of some good old copper..

As to price, it's really not so bad, even with shipping. Now, that's not to say we can't build it cheaper.

I rather like the idea of having the copper for the waste line, the larger diameter and straight-through design would be less likely to foul and if clean-out were called for, it would be easier to do.

As Xringer intimated, I'm wondering if the pressure couplings on the water jacket would hold up to city water + hammer pressure.

Although I think it's overkill, many states will not accept a heat exchanger that carries domestic water unless it's double-wall construction, which this device is not. The GTX device is.

And I think this guy is missing the boat, in that if he oriented it vertically, it would equal or beat the efficiency of the vertical tube & coil heat exchangers, since ALL the surface of the waste line would be heat-passing area... EAGRAHAM, are you listening?

But I think it is a very good sign that someone, whether they mined the idea from Ecorenovator or not, is actually doing it... He actually put the idea into action and is offering it for sale at a reasonable price.

An aside to eagraham:

eagraham, you really need to do your own testing and include the test results, and re-write the terrible copy you have, where you worm your way around not actually giving efficiency numbers of your design. You also NEED to include a statement that this is not a double-wall device and advise your potential customers accordingly. It will greatly enhance your credibility at the same time that it will offer some protection legally. Then, if someone wants to make an end-run around your warning, the onus is on them.

But, all-in-all, he has shown us how to build it.

Regards,

-AC_Hacker

[Piwoslaw]

On a larger scale, in Sweden heat is recovered from waste treatment plants and used for district heating. The temperature of water leaving the sewage treatment plant is between 7-22*C, large heat pumps extract heat, cooling it to 1*C before it is dumped into the sea. This can cover as much as 10% of a city's heating needs.

See the links at the bottom of my post Sweden - Oil independance through conservation and efficiency