A heat exchanger would be a problem, but if the plughole had an integrated pump like in the sump of a dishwasher, feeding into a temperature-regulating valve to feed more hot water in, it could work ok. You'd have a switch to turn on the pump (so you could disable it to have a pee), and could turn down the hot (replacement) water volume at the tap.
Clifford Heath.
me
s a common drain. I just don't see it in a single family residence, especia lly when these heat exchangers sell for $450 apiece, and you would need a l ot of them.
o get a realistic diy construction cost.
r appliances, clothes washers and dishwashers, which also minimize water us age, flow limiters on shower heads I think are 2.5 GPM, which is plenty, th ey should come out ahead. I think the commonly available and cheap 99% effi ciency electric water heater, at my $0.11 rate, estimates at $400 for an en tire year for a family of four.
ower & hot water heater you'd save $100 a year. If it's there for 20-30 yea rs that's 2-3k saved. Not bad for under $100.
So you have this possibly long cold water feed to the shower fixture. You n ow need to run the cold water-> heat exchanger->shower mixing valve. I don' t see running a second cold water feed all the way back to the hot water fe ed cold water inlet.
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drain-waste piping leaves the house.
00144734Your sewage should drop down a vertical into an exit pipe under the floor i n the basement. You can install it in the vertical.
We've been fine for 25 years now. That little rubber flapper thing wouldn't last that long. Looks like a good place for crud to build up too.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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.Horizontal certainly needs to be larger, as you don't get the film effect n or water flowing over as much of the surface. I came up with around 10' lon g 1.25" diameter copper pipe, around which snaked 4 microbores in parallel for the cold water. The microbores are soldered around the bottom but space d away round the top to allow for differential expansion. The drain pipe is folded into a U so it fits under a standard bath.
If they're going to see wide adoption they need to be practical in the aver age home, and the perception that you have to pay some ripoff outfit 10x th eir cost needs to be seen through.
There are other approaches too, eg a tank with a spiral hose in, giving som e heat storage to enable harvesting of eg washing machine drain water, whic h doesn't leave at the same time the machine is refilling. Making that safe adds complications.
NT
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emes a common drain. I just don't see it in a single family residence, espec ially when these heat exchangers sell for $450 apiece, and you would need a lot of them.
to get a realistic diy construction cost.
tar appliances, clothes washers and dishwashers, which also minimize water usage, flow limiters on shower heads I think are 2.5 GPM, which is plenty, they should come out ahead. I think the commonly available and cheap 99% ef ficiency electric water heater, at my $0.11 rate, estimates at $400 for an entire year for a family of four.
shower & hot water heater you'd save $100 a year. If it's there for 20-30 y ears that's 2-3k saved. Not bad for under $100.
now need to run the cold water-> heat exchanger->shower mixing valve. I do n't see running a second cold water feed all the way back to the hot water feed cold water inlet.
In my case I was assessing an exchanger that would just reuse shower heat, so it warmed the cold feed into the shower. If you wanted to recover heat f rom other things you'd run the incoming cold feed via your heat exchanger t o the HW cylinder/boiler. Whether that would add no or lots of pipe depends on house layout.
NT
This has been done for at least a decade in many places all over the world.
Are you letting out the fatbergs directly into the lake or sea ?
In reality, the heat exchanger is after the cleaning process.
There's a very simple way of doing that *if* your drain run allows - and I have heard of someone in the UK doing this:
About a yard of 1 1/2" +/- copper pipe spliced into the drain from the shower;
Helically wrap a number of microbore (1/4 - 3/8" ish) soft copper pipes around the large pipe.
Solder the 2 together.
Pass cold water on the way to the electric shower or gas boiler in one end of the microbore pipes (at the outfall end of the drain) and then onto the water heater.
Very simple, passive... But does require access to a suitable run of drain, which doesn't work if the shower drain drops straight into the ground or out of an outside wall.
-- Email does not work
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That offers no easy cleaning, and a yard isn't enough. Turning that into a
5' run along the bath and a 5' run back can solve both issues. Also deal wi th differential expansion.NT
How about a false floor in the shower. The 'old' floor has a zig-zag of channels leading to the drain, in which are laid the cold water feed pipes. Maybe some weirs to keep the level up. The false floor drains the shower into the start of the run.
Easy to clean by lifting the false floor.
Cheers
-- Clive
that's more or less what I came up with years ago, but I chose a very shallow dome shape to get the water to spread out. It gives better flow & easier cleaning than a zigzag. But there is a better option for cleanability.
NT
most of the heat is given up by the time the water hits the floor drain.
m
Here are some of the temps I recorded in September:
39C at shower head 34C where jet hits tray 19C room temp at end of shower outdoor temp apx 15C at apx 1pm Inlet water temp 5CSo the water is heated from 5C upto, once mixed, 39C, a rise of 34C. The he at exchanger has available to it 34 to 5C = 29C. Thus 29/34= 85% of the heat is available to the exchanger. If you were desperate to get more out you could use a closed or less ventilated shower area, this one was wide op en.
NT
Given up to what? My body runs at about 37'C and most of the water runs down that. An acrylic shower base only takes a few seconds to heat up.
Take a thermometer in with you next Christmas.
Cheers
-- Clive
Forty years ago, I had a summer job building thermal solar collectors. They were pretty snazzy--flashing copper fins with type K copper tube soldered to a groove rolled into the fin, painted with some sort of Dupont selective-absorber paint.
The best use of them was for heating swimming pools, but some folks got them in nice insulated frames covered with stretched Teflon film and tranlucent corrugated fibreglass (coated with UV-absorbing Tedlar to prevent the epoxy from yellowing). They were used to preheat a separate tank upstream from the inlet of the normal hot water tank. Completely mental. And this was in Vancouver, which is nearly as cloudy as England.
You could do a lot better with a heat exchanger in the gas flue, which is much higher-quality heat and has zero fatbergs.
What frustrates me about this sort of stuff is the opportunity cost of not doing something more intelligent.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
that the water leaving our homes and offices?specifically, warm and hot wastewater?is an astoundingly powerful source of energy. One e stimate is that Americans flush 350 billion kilowatt-hours of energy into t he sewers each year?roughly enough to power 30 million U.S. homes. Cities are taking notice, and taking steps to install sewage heat recovery systems to get a piece of that energy resource.
ee heat exchangers might get tricky dealing with raw sewage though.
heat-recovery/
'This sort of stuff' can sometimes be made to give 50% or more ROI - not ba d if someone has time on their hands. And plenty aren't capable of anything better. Of course if bought as steeply priced commercial systems it's not going to pay well. Solarthermal collectors are one of the easiest techs to make pay back.
Energy cost is going up. Material costs are coming down. Computing costs ar e falling. I suspect one day kit with good ROI will be widespread - but we' re not there yet.
Gas flues with condensing boilers, which most are now, only reach 60-80C, o nly run a limited percentage of the time, and are gas not water, with corre spondingly less heat density. If you wanted to eke the last of the heat out , an exchanger that sends warmed water from that bottom end to the bottom o f the hot water cylinder, or for instant systems to a radiator would work. At current prices the payback - well I've not calculated it, but am not esp ecially optimistic. I'd expect more at lower cost from a 'hot harry' solar preheater.
NT
We have big cast-iron drain pipes. Soldering would be tough.
The added copper tubes carry clean water so should last forever. There would be no expansion problem. But all that work would take a zillion years to pay off.
Most people mix hot and cold water when they adjust their shower temperature. That's inefficient.
(We rarely have electric point-of-use electric water heating here, as some europeans seem to have.)
-- John Larkin Highland Technology, Inc lunatic fringe electronics
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comes a common drain. I just don't see it in a single family residence, esp ecially when these heat exchangers sell for $450 apiece, and you would need a lot of them.
8 to get a realistic diy construction cost.star appliances, clothes washers and dishwashers, which also minimize wate r usage, flow limiters on shower heads I think are 2.5 GPM, which is plenty , they should come out ahead. I think the commonly available and cheap 99% efficiency electric water heater, at my $0.11 rate, estimates at $400 for a n entire year for a family of four.
e shower & hot water heater you'd save $100 a year. If it's there for 20-30 years that's 2-3k saved. Not bad for under $100.
ou now need to run the cold water-> heat exchanger->shower mixing valve. I don't see running a second cold water feed all the way back to the hot wate r feed cold water inlet.
, so it warmed the cold feed into the shower. If you wanted to recover heat from other things you'd run the incoming cold feed via your heat exchanger to the HW cylinder/boiler. Whether that would add no or lots of pipe depen ds on house layout. Returning it to the hot water tank will be pricey. Your return water will b e at lower pressure and therefore will not enter the tank. The return pipin g would need a one way flow valve, and then you would either need to shut d own the cold water street feed to the tank via another valve or use a boost er pump of some kind to overcome street pressure to get the water into the tank. Those kinds of components are not cheap. The shower heads in my area are flow limited to 1 GPM, and my average showe r duration is 5 minutes, making for just 5 gallons of water total, of which maybe 3 gallons may come out of the hot water heater. It just doesn't seem like all that trouble is worth it.
g that the water leaving our homes and offices?specifically, warm a nd hot wastewater?is an astoundingly powerful source of energy. One estimate is that Americans flush 350 billion kilowatt-hours of energy into the sewers each year?roughly enough to power 30 million U.S. homes . Cities are taking notice, and taking steps to install sewage heat recover y systems to get a piece of that energy resource.
free heat exchangers might get tricky dealing with raw sewage though.
e-heat-recovery/
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bad if someone has time on their hands. And plenty aren't capable of anythi ng better. Of course if bought as steeply priced commercial systems it's no t going to pay well. Solarthermal collectors are one of the easiest techs t o make pay back.
are falling. I suspect one day kit with good ROI will be widespread - but w e're not there yet.
only run a limited percentage of the time, and are gas not water, with cor respondingly less heat density. If you wanted to eke the last of the heat o ut, an exchanger that sends warmed water from that bottom end to the bottom of the hot water cylinder, or for instant systems to a radiator would work . At current prices the payback - well I've not calculated it, but am not e specially optimistic. I'd expect more at lower cost from a 'hot harry' sola r preheater.
Solar thermal panels are expensive. They use vaccuum insulation technology and it needs to have very rugged construction to withstand hail and constan t beating from UV. The panel itself will contain a phase change medium that is valved through a heat exchanger through which your potable water is pum ped. Then there have to be provisions for draining the water out of its pip ing as temperatures approach freezing, and almost every system requires an additional hot water storage tank with large thermal heat storage mass, usu ally stone. By the time you're through buying and installing all those part s, even a small system is $4000, which is a decade payback time. This is wh y you don't see a whole lot of them.
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it would be if you change the design to use cast iron :) Plastic waste pipe is universal indoors here. Either way replacing a bit is part of the plan
a 5' run along the bath and a 5' run back can solve both issues. Also deal with differential expansion.
I can't find the figures I did, but I think it came out at about 50% pa ROI
NT
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