Re: Grey water heat exchanger GFX

 


If we pump for 1 minute and use 100/60 = 1.67 Wh
and recover 10x8.33(95-55)/3.412 = 977 Wh,
that's 586 times more energy.

Nick

 

In alt.solar.thermal nicksanspam@ece.villanova.edu wrote:

I thought I had a four foot vertical drop in my blackwater line, but I
forgot that there's over two feet of slope in the sewage line from one end
of the house to the other.

Given the high energy recovery noted above, I might do well to install a
pump just for the shower, to raise that greywater to a point above the
laundry room, and run that pump only for showers.  
I could join the shower water at that point with the washing machine
output, which is not as hot, but is already elevated, and near the water
heater, and make economic sense of this.

The dishwashing machine could be plumbed in as well, since it also has a
high standpipe for anti-siphon purposes, and hot exit water, but that's not
conveniently located.

The idea of using the thermal recapture in two or three spots also would
allow use of the smaller, much cheaper GFX units, maybe totaling less cost
than one 4" installation.

Your example, above, is only calculating energy expended during the
recapture of hot waste water, but the original example would have been
pumping all waste in the house, hot and cold, which I don't think makes as
much sense.

I have always thought that greywater should be plumbed separately anyway,
allowing it to be used as desired for toilets and gardening.

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Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5

 



<snip>

I think in some areas there are plumbing code issues.

But I knew a retired engineer in Michigan that when he built his retirement
home, he had black water and grey water drains separated.  Ran the black
water to a conventional septic system, and the greywater to a less involved
drywell/drain field.

After ten years, the septic system installer offered to open up the tank for
the 'ten-year warranty' inspection.  When they did, it was remarkably
'clean' in that it did not have much silt or other 'non-degradables' in the
tank.  Of course, the septic tank had a pretty low flow rate with just a
retired couple and no greywater.

I too have often thought this is a good idea.  Especially when not on city
mains sewage.

daestrom