Preheating water by running pipes through attic?

All of our pipes are in the attic in So Fla and I don't see any condensation but the water isn't really that cold. I can attest that you do get a little burst of very hot water out of that pipe in the summer

Reply to
gfretwell
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Heh!

Use the entire attic as a giant collector for solar water heating?

You could get by with a 3x4 box-like thingy.

Reply to
HeyBub

I am working on doing this myself. I will use CPVC which can stand the heat. I've placed a remote thermometer in my attic and it gets to be 125 degrees on a day when it is in the 80's outside.

I am going to run say 2" CPVC back and forth in the attic the entire length of the house. With larger pipe, the water will flow more slowly and have a longer period to heat-up.

Then I am going to get a solar water heater circulation pump, controller, and electric solar panel to power it. This will circulate the water into my hot water heater, but it will sense the temperature of the water from the attic as well as in the tank and only circulate the water when the attic water is warmer.

The reason I am using CPVC is I will have to drain the pipes before the 1st freeze and I don' want any rust. So plastic.

Also I will need to run the pipes so all the water can drain out. And I will need to install an air escape to get the air out when filling the pipes in the spring.

So basically the pipes will run back and forth attached to the underside of the rafters and going higher and higher with a gentle slope (for draining). Then air release pipe at the top.

And valves for all this to by-pass in winter, drain, and let air escape.

Also CPVC will expand with heat, so need plastic fasteners which allow the pipe to move back and forth.

Water heater tanks hold heat for a long time. So I am predicting that this will provide all the hot water I will need. I will basically turn off my hot water heater and will be able to turn it on only as needed. FYI - I've noticed that I am happy with shower water being about 102 degrees.

Reply to
Bill

I would suggest that you will need a tempering tank up there, and for that I would suggest you may also require some structural re- enforcement to make it safe. Only the water in the attic would be heated and it would need to sit in the pipes for some time to actually warm up. Even then you would not be absorbing much heat.

Frankly I doubt if it would be worth the bother, cost and risks involved, even assuming there would be some reduction to the amount of heat going into the home in the summer reducing the cooling expense.

How about ground thermal? Do they have that option?

Reply to
jmeehan

If they were putting in as many energy saving things as they could they wouldnt need the utility co, it would be solar.

Reply to
ransley

don't forget the consider the weight . when you're hanging it and what not.

s

Reply to
Steve Barker DLT

What is the reference to HOA rules?

Do you mean in this day and age with energy prices rising, oil at over $100 per barrel, gasoline at at $3 to $5 US per gallon, water shortages (which will influence the costs of hydro generated electricity etc.) and other problems there is a rule which says 'Don't use solar panels' ??????? Make about as much sense as using cedar shingles or thatching on a roof in fire prone California, doesn't it?

Been raining for several days here; so reluctantly drying clothes in the dryer, instead of hanging them out on the line. Gather even that is not allowed in some places!

BTW was reading recently about some ergonomically designed homes in Germany that while they are connected to the electricity grid to meet peak moments of demand are, on average, making and returning more electricity to the grid than they use! This helps defray the cost of solar panels and the equipment to convert the electrcity thus produced to 'mains type' electrical current.

Those homes (Freyburg I think was mentioned) are in area where the government has legislated that electric utilities 'must' receive back and pay the householder for electric energy returned or fed into the grid. Way to go, eh? A negative power bill! With the electric meter running backwards!

My grown up son has been looking at building a smaller home, people get married much later and have much smaller families now. We feel by hanging onto enough land we can use a ground loop heat pump system. If we could generate in this 'not very sunny' climate some of the electricity to run the heat pump system that would be great as well!

Hoping the cost of solar panels which on our existing roof would be just about invisible from the road will come down greatly. Guess they wouldn't work well with some inches of snow on them though!

Reply to
terry

Sure, they could get lots of heat from the attic. Around here hot water heating costs about $200 a year for a big house and they may save half that. Done at the time of construction the system additions might cost from $1000 to $1500 so the payback is more than 10 years, maybe 20 years. Not great but not bad and it is a green approach.

Use polyethylene (PE) tubing which can stand being frozen without bursting in case they get one of those every 10 year cold days. Never have to drain it. PE pipe is very leakproof IF it is heat welded so it must be installed by someone who knows how to do it properly. There are mechanical fastners for PE but it is a very slippery material compared to other plumbing pipe and mechanical connections should not be trusted for this application. If all joints are professionally heat welded and pass a pressure test then it is better than any other system.

Use about 100 feet of 1/2 inch or 3/4 inch tubing. Have it air pressure tested before turning on the water - standard plumbing practice. Insulate all the hot water system lines that are not in the attic, even the ones not in the circulating loop. Pipe insulation should be minimum

1/2 inch - thicker adds a bit of benefit but not much so only get it if it is readily available. Don't insulate the attic pipes since they are supposed to transfer energy as efficiently as possible. Make the runs as long as possible with a minimum of bends.

Use a Grundfos UP-10 circulating pump like I have in my house for circulating the hot water. It is a 25 watt pump with a thermostat and a timer - maybe $2/month to run. Dead quiet. You set the thermostat to shut off if the returning water reaches a certain temperature to prevent running while the water heater is heating and also prevent over-heating. Maybe set the timer to only run during the day so you aren't cooling off the water at night. Summer temps may be such that there would be benefits to running at night - bound to be warmer in the attic than in the ground. Timer is simple to set.

This pump, and most circulating pumps, won't make enough pressure to lift water from a basement to a roof. It doesn't have to since you install it inline with the house pressure system. It pumps from the storage tank and back into the storage tank. So it only adds enough energy to this loop to make it flow in a circle. It can be located anywhere as long as it draws from the bottom of the tank and returns to the top of the tank. Bottom connection will likely need a special fitting so it can function as both a drain and a loop connection. Mine has a tee with a tap at the bottom. There has to be a valve at the top of the loop to allow air out while the loop is filled. You open this valve while filling the house hot water system for the first time. The house pressure will flow up both sides of the loop and purge the air. Run a hose from this valve to a drain so it can be opened and water run out for a good long while to ensure all air is purged. Don't use any check valves in the loop - run out from and back into the storage tank so no check valves needed. Use only a high quality bronze valve - plastic won't do. Special adaptors are required to install a valve in a PE system.

Must add a storage tank before the main tank, without electrodes. Only the storage tank should be in the circulating system loop to the attic. The main tank has a permanent hot water layer near the top which would defeat the idea because this water would get cooled not heated. Storage tank also increases the amount of hot water kept on hand.

Cold water in the attic would create a condensation problem with water dripping off the pipes before it gets heated and perhaps on cool days or at night. Plastic half-pipe drainage system would solve this. A solvent glued PVC collector system would not leak. Drain pipes must be at least an inch below the PE pipes - can't be touching or condensation occurs on the outside of that pipe and defeats the purpose. Use spacers to hold the circulating pipe about an inch or two above the drain pipe. Slope all the drain pipes so they drain towards an exit point - just make one end of the lengthwise runs lower than the other by 6 to 12 inches. Make sure the valve is within the drain pipe so any slow leakage would just drain away.

Inspect the loop every few months so any leakage is spotted before it becomes serious. With a proper installation it should be

Reply to
Reno

They should consider on demand, at the place of need, tankLESS water heaters. A bit pricey at purchase but quickly pay for themselves with the savings in water and energy. There is no need to keep 30 or more gallons of water hot all the time or run the water until it's warm at the faucet.

Reply to
Phulltillt via HomeKB.com

might consider PEX with basically no joints, little chance for leaks, easy to install, just spool out.

add disconnect so you can blow compressed air thru lines each winter before freezing, no sloping of lines necessary, plus PEX is basically freeze proof.

Reply to
hallerb

remember theres lots of downsides to tankless. just look at other threads on that subject.

Reply to
hallerb

Not unless you like it hot. PHUCCK a bunch of tankle$$ junk.

s

Reply to
Steve Barker DLT

Hell, really for the application, it could be left coiled up.

s

might consider PEX with basically no joints, little chance for leaks, easy to install, just spool out.

add disconnect so you can blow compressed air thru lines each winter before freezing, no sloping of lines necessary, plus PEX is basically freeze proof.

Reply to
Steve Barker DLT

yep way less work, no joints to leak, and check home depot, PEX is dirt cheap

Reply to
hallerb

USE PEX, its cheap!

Cheap, but has poor heat transfer properties compared to copper.

Reply to
Edwin Pawlowski

I don't know if I would want all that water in my attic.

Reply to
metspitzer

I don't know whether design/construction practices in UK have changed over the decades, but the houses there with which I was familiar all had storage tanks -- insulated to some degree -- in the attic. The only "tap" ("faucet" to LeftPondians) fed directly from the incoming water supply was one over the kitchen sink for drinking water. The storage tank fed the other cold-water faucets and the water heater. Open top -- or maybe with a loose cover -- and a float valve. I'm guessing that they held 40 gallons or so -- real gallons, not the four-fifths-sized US ones.

Perce

Reply to
Percival P. Cassidy

87@uwe...

This is a good example of the false benefits generally attributed to the miracle tankless. Unless you have multiple tankless close to every point of use, which greatly increases the cost and complexity, you actually have a LONGER wait for hot water with a single whole house tankless. The water still comes from the same place and you have the slight additional delay for the tankless to sense the water usage and fire up.

Reply to
trader4

Obviously that leaves you out Stormy. Bubba

Reply to
Bubba

You're better off with point of use electric demand water heaters. They are only$150 and only run when you actually use the hot water. One under the kitchen sink and one under the bathroom sink and shower. Will work fine in the shower if you are not a water hog and use super saver shower head with reduction valve. Not recommended for tub or spa bathers or other water wasting devices. As far as preheating you can put a large cold water holding tank in your furnace room or in a closet in the living area. That will keep your water at room temperature.

Reply to
Blattus Slafaly

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