# unlimited water pump ?

Discussion in 'Shop Talk' started by fernando, Nov 21, 2005.

1. ### fernandoWell-Known Member

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I have a theoretical question. Suppose I want to put a closed-loop of pipe down an existing water well in order to utilize the constant water temp at the bottom. The well is 200' deep. Can I install a small pump on the "down" line and an identical small pump on the "up" line and not worry about the ability of the pumps supposed limitations of "lift" ?

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Well,...that falls under a thermodynamics law named the law of conservation of energy. basically you are going to lift and remove a certain amount of water..thats going to be work.. or its going to take horsepower to do it..

explain more about how you are going to make use of the water temperature (i'm guessing you are going to use a temperature differential and make use of more and less dense water?)

sorry miss read your post: your purpose is to extract heat?, not actually pump water? if so i appoligise in advance for the spelling...you need to do a balance of burnullies equation to find power needs. the main factors would be the friction of flow of the pipe, and the change in denisty of the water.

i suspect that if you could get enough heat exchanger in the down leg, you could get thermosophining to circulate the water with no pump.

tell more is its not top secret...

3. ### fernandoWell-Known Member

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No secret. I'm fortunate to have a drilled well that hit a strong flowing stream with water in the 50-60 degree range. I'm considering tapping that temperature with a submerged loop and cooling with it in the summer and perhaps supplementing a heat pump in the winter.

It would seem, theoretically, to be a logical idea that is not rocket science with short-term cost payback.

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Oh yeah, i think so, considering people in my area are trying to heat homes with heat pump using 15 degree air temperatures. little known secret to most heatpumps...electric heat strips.

5. ### rzrubekFlying Z

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Look up "Ground source heatpump" and see how the pros do it. That is all you are describing.

6. ### agmantooagmantooSupporter

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I have a geothermal heatpump and I use well water for the source of the heat/cool to be extracted. I just pump the water from the well and once through the heat exchanger the water is dumped back to the ground but not back into the well. You can elevate the temp of the well water and cause a growth of scum in the well casing by reintroducing heat.

7. ### michiganfarmerMaxSupporter

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I have thoght about burrying a 500 gallon tank in the ground, filling it with water, and pumping the cool water through a radiator with a fan on it to cool the house in the summer.

8. ### fernandoWell-Known Member

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You never know for sure unless you try something. With a buried tank, I would think bury depth would be a factor, along with a layer of foam insulation buried directly above the tank to keep out summer heat. Might also need to keep the soil around the tank a bit damp in order to assist with heat transfer.

9. ### John HillGrand Master

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Fernando

You would have a column of cold water balanced by a column of slightly warmer water. The cold column is the one you are trying to lift but it is more dense and will take effort of lift it, more than you get by the falling warm water.

A column of aerated water is lighter than a column of non-aerated water so one option to consider would be pumping compressed air down the well to be introduced into the bottom of your column of cold water. I think you would need more than 100 psi for that depth, I am sure someone can calculate this more accurately.

10. ### fernandoWell-Known Member

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Mr. Hill, I believe you are incorrect.

11. ### John HillGrand Master

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I may well be Mr Fernando, perhaps you can explain?

12. ### fernandoWell-Known Member

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I believe it is pretty much common knowledge that water is incompressable. If this is the case, how can there be any difference in density in this rather simple arrangement ?

13. ### John HillGrand Master

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Mr Fernando, we are talking about a closed system where the weight of the rising water is, to some extent, offset by the weight of descending water.

If one column of water contains air bubbles that column will weigh less than the pure water column, I trust you can see that?

14. ### Dan in WYWell-Known Member

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They call them "Swamp coolers" out here. Lots of people in Wyoming use them. They're plumbed with a constant water supply from the house and ducted into the house. I think they rely on evaporative cooling effect to some extent too.
When you get your cooler all figured out you gotta come build one for my house.

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Morning fellows,,,lots of ideas around .....the fellow is trying to (i think) remove heat from the well water...so the after temperature would be less than the inlet side.. yes, most liquids in their pure form are basically incompressable,,but their Volume will (in most cases) expand with an increase in temperature and conversely, decrease in volume with a loss of heat. so in his case(i think) the after leg will be more dense and tend to fall while water in his CLOSED loop "warm" will rise. Thermosophining. inducing air would lessen the density of that leg , but that would not be a closed loop system and therefore would not balance.

Like others have pointed out, using ground energy has been done for many years with heat pumps..

the swamp cooler thing is a totally different situtation...it uses evaporative cooling to reduce heat in air.....a system that does not work in my area where the average humidity is in the high 80's and in the mid to high 90's some months of summer.

well today is like a Friday for me and the kids...Happy Holidays fellows

16. ### fernandoWell-Known Member

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This thread is getting overly complicated. The original intent was to dump heat into the well during the summer and to pull heat from the well in the winter. This would seem to be quite simple. The question was directed to discover what pump requirements and limitations might be.
In the situation I am contemplating, thermosyphon action would probably be negligible since temperature differentials would be so minor. In any case, whatever difference might possibly occur in "density" would probably not be of much concern, nothing to exploit nor to compensate for but rather to ignore. Since I expect that a truly closed loop would complement pump efficiency, suggesting introduction of air into the loop would be a step backward.

Anyway guys, I surely do appreciate all the suggestions and comments.

17. ### John HillGrand Master

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If you say so, however if it were me I would think about it a bit as introducing air, thereby reducing the density of the rising column may do away with the need for pumps (other than the compressor).

On the other hand, if you keep your fully closed system a single pump is all you need.

18. ### agmantooagmantooSupporter

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Heat should not be reintroduced into the water in the well. This will create problems. I know this first hand!

19. ### fernandoWell-Known Member

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I think I would agree completely if my well was one that water only seeped into. However, I am blessed with a well that taps a year-round fast-moving stream. The down side is that I still have a great deal of sediment even after six years of usage. I guess the stream just carries the debris along continuously.

20. ### agmantooagmantooSupporter

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Shock treat your well with chlorine and see how long it takes for it to dissipate. You will find that the water is not moving at the rate you expect. If you are interested in spending some time plumbing and about \$125 for materials to get rid of the sediment I can help.