Preheating water

Is the well pump powerful enough to pump water as high as you want?
Also, a large demand of hot water would flow too quickly to gain any heat.

Good luck, I'm always in favor of making something work better.

If possible, you could always place a small storage tank up there too.

You can make use of check-valves, a back flow preventer, and the storage tank to eliminate
the back pressure of water working against your well pump.

I have fun trying to invent better ways of doing things too.

The actual cost of electric has more than doubled here in the last 2 years(electric hot water heater). I thought about rigging a storage tank from the ceiling directly above plenum of my wood furnace to preheat water .It's 90 - 110 on the surface of the plenum. I think your idea would work might want to insulate line coming down to your hot water tank.

As long as you don't have gas bubbles in the line, head loss isn't a big deal - what you lose on the way up you get back on the way down, so the only number that really matters is the net difference between the inlet and outlet points - i.e. what is the net difference between the pump and the faucets. Water friction in the pipe is a concern, but not a very big one as long as your pipes are properly sized to begin with.

However I would expect that unless you did something pretty significant to increase the heat exchange area that you would not get enough of a pre-heat effect to do you much good. (However what might be worth considering is a drain-back solar panel system hooked up to pre-heat your DHW tank, and a thermostatic mixing valve to keep the water temps steady.)

Gooserider

Per size, inches Volume in gallons per foot of pipe
1 0.04
1 ¼ 0.07
1 ½ 0.10
2 0.17
2 ½ 0.24
3 0.38
4 0.65


Can't format this properly, but the above table shows volume in gallons per foot of pipe size.

50 feet of 1 inch pipe holds 2 gallons of water! Was going to do what you want to do, and after I figured this out, came to the conclusion that it wasn't worth it.

JRP3 said:

Gooserider said:

As long as you don't have gas bubbles in the line, head loss isn't a big deal - what you lose on the way up you get back on the way down, so the only number that really matters is the net difference between the inlet and outlet points - i.e. what is the net difference between the pump and the faucets. Water friction in the pipe is a concern, but not a very big one as long as your pipes are properly sized to begin with.

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Do you think I could get away with smaller than 1 inch on the way up to reduce load on the pump? At what point does it get too small and create friction?

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Not sure, there are charts on pipe friction vs/ flow rates in the plumbing books, however pipe diameter as I understand it isn't a head load factor - pipe friction is. As a general rule the longer the distance or the higher the flow rate, the larger the pipe diameter should be (though not sure how much) in order to keep the pipe friction to a reasonable value. Excess friction increases the load on the pump, and can also lead to erosion of the pipes if the flow rate past a given point is to high.

However I would expect that unless you did something pretty significant to increase the heat exchange area that you would not get enough of a pre-heat effect to do you much good.

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I was thinking of doing some sort of manifold along the peak. Looking at the chart I could do 2 10 foot sections of 3inch pipe which would give me 7.6 gallons, plus whatever is in the feed and drain pipes. 12 hours overnight should heat that up, don't you think?

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It might heat up some, but not sure how much, or how much good it would do you. The water in that pipe section would not be the water that you showered with, only the make-up water that would go into your water heater tank as you shower. The largest part of a typical tank heater's energy consumption isn't in heating the incoming water initially, but rather in keeping it at temp while you aren't using it. Also the heat energy to bring water up from 40-80* is pretty negligible, so I don't think that even at the best theoretical transfer rate you'd gain all that much. What I've heard of that MIGHT work is a "Grey Water Heat Recovery" system - this is a heat exchanger that connects between your higher temperature grey water drains (shower, sink, dishwasher, etc) on one side and the DHW input line on the other, so that your hot water going down the drain would pre-heat the input water. I don't know how well these work in practice, or how easy it would be to retrofit them to an existing structure who's plumbing wasn't layed out with doing this in mind.

(However what might be worth considering is a drain-back solar panel system hooked up to pre-heat your DHW tank, and a thermostatic mixing valve to keep the water temps steady.)

Gooserider

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I live in the woods and don't get much solar, not to mention the nights can be freezing from Sept. to May around here.

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Lack of sun is a problem with solar - freezing weather isn't, or so the solar advocates claim... There seems to be two methods of doing freeze-proof solar, each has it's advantages and disadvantages. I prefer a "drain-back" system, where the panels are designed to self drain into a resevoir in the heated space when there isn't enough heating and the pump shuts off - you then don't care how cold the panel gets, and don't have to worry about glycol and it's hassles. The other approach is to fill the solar system with a glycol mix (there is a special blend for solar apps) so that you don't have to worry about freezing, but do have to do more with heat exchangers. Either way, the panels are equipped with sensors to only circulate if the net result is heating gain. (IMHO the best route would be to have a solar panel that powered the pump, so you have a natural throttling effect, and truly "free" heating) however neither approach would do you much good if you don't have any sunshine to begin with.

Gooserider

LEES WOOD-CO said:

The actual cost of electric has more than doubled here in the last 2 years(electric hot water heater). I thought about rigging a storage tank from the ceiling directly above plenum of my wood furnace to preheat water .It's 90 - 110 on the surface of the plenum. I think your idea would work might want to insulate line coming down to your hot water tank.

Click to expand...

My neighbor has just that suspended above his barrel stove in the basement. Its a 30 gallon old scrap water tank painted black and it feeds his super cell that common feeds to the oil boiler. He says its usually around 130* or so during the winter. Neat rig. Dirt cheap to boot.

think about the pipe sweating in the summer--you would not want your ceilings wet---just a thought
but you should check into this---pat

That is the simple beauty of an unfinished basement. No ceiling and concrete, let her drip no problem. His are like mine right out in the open where you can see and get at them. Function over beauty.