Author Topic: underground air cooling system diagram  (Read 11746 times)

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framistan

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underground air cooling system diagram
« on: November 03, 2007, 05:04:02 AM »
Thank you for all the thoughtfull comments on Part 1 of

my Underground Air Cooling system.  Here is a more detailed

simplified schematic of the system.  


1.  Starting at item one, the SUBMERSABLE PUMP.( The kind used

    everywhere in those small water garden fountains). It is a very

    small 4-watt/ 66gallon per hour/ten dollar waterpump.  This

    pump only has a "lift" of 16 inches. But almost NO LIFT at all

    is needed to move the water from resivoir 1 over to resivoir 2.


2.  Water spews into the 2nd resivoir. The water must maintain an

    equal level throughout the system, so the water goes down the pipe.



  1.  Warmed water flows down the pipe into the TOP of heat exchanger.
  2.  Warmest water will rise to top of heat exchanger, coolest to bottom.





5.  At the bottom of the heat exchanger, water should be coldest because:

          A. Hot water rises in the pipe, cool water falls down.

          B. Heat rises in the mud, ABOVE the pipes.


6.  Cooled water begins its trip back up.  Notice the "UP" pipe is located

    UNDER the 4" heat exchanger - not above it!... thats because we dont

    want to REWARM the cooled water on its way back up.


7.  Would be a good idea to INSULATE the pipe on its way up, As suggested

    by one readers comments in part 1 of this article.


8.  Cool 60 degree water enters radiator at the BOTTOM.  Water warms

    as it passes through radiator.


9.  Warm air at the ceiling of the room enters the top of the radiator.

    As air cools it falls down through radiator. Because we are trying to

    cool with only 60 degree water, a larger than usual radiator would be

    needed.  


10. Warmed water enters RESIVOIR one... to be pumped again... back to step 1.


In this way,  No freon is needed... No compressor.... No complex electronics

And very little electricity!   Notice though, for the system to work right,

the PUMP must pump water towards the TOP of the underground heat exchanger.  

Also the BOTTOM of the radiator pipe must connect to the BOTTOM of the heat

exchanger.  Be sure to mark them before you bury the heat exchanger or you

won't know which is which.  This system is a PROTOTYPE and not proven to

actually work yet.  If you build one, please hold yourself responsible for

all safety issues and blame if it doesn't work.  My system is still under

development and not working yet.  This is submitted for your consideration,

comments and suggestions. thanks from FRAMISTAN

 

« Last Edit: November 03, 2007, 05:04:02 AM by (unknown) »

wpowokal

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Re: underground air cooling system diagram
« Reply #1 on: November 03, 2007, 02:14:59 AM »
I have not read all the last post but one point seems to be overlooked, earth is a good insulator, therefore the earth around your heat exchanger pipe will soon be at or near the water temp.


The theory around earth cooling/heating is sound but one is dealing with very low grade heat/cool. But at least from your efforts you may expand to a workable system, good luck.


allan down under

« Last Edit: November 03, 2007, 02:14:59 AM by wpowokal »
A gentleman is man who can disagree without being disagreeable.

Old F

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Re: underground air cooling system diagram
« Reply #2 on: November 03, 2007, 03:33:13 AM »
Here a site you mite find interesting

http://mb-soft.com/solar/saving.html


Old F

 

« Last Edit: November 03, 2007, 03:33:13 AM by Old F »
Having so much fun it should be illegal

drdongle

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Re: underground air cooling system diagram
« Reply #3 on: November 03, 2007, 07:53:12 AM »
Actually it's not so much an insulator as it's temp changes very slowly in relationship to ambiant air temp. But because it changes slowly you can end up with a zone around the ground heat exchanger that equalizes with the exchangers temp. You end up need a lot of in ground exchanger surface area.
« Last Edit: November 03, 2007, 07:53:12 AM by drdongle »

rippersoftware

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Re: underground air cooling system diagram
« Reply #4 on: November 03, 2007, 08:11:15 AM »
There is a house in Fairfield Iowa that uses a large pipe (conduit) buried roughly 20 feet underground with a opening up to outside air and an opening up into the house.  Natural air flow within the house to an exit at a peak on the roof "pulls" air through the tube and into the house.


In the summertime this air coming in from 20 feet underground can be very cool compared to 95 degrees outside air temp.


RipperSoftware

« Last Edit: November 03, 2007, 08:11:15 AM by rippersoftware »

wdyasq

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Re: underground air cooling system diagram
« Reply #5 on: November 03, 2007, 09:22:40 AM »
Several things need to happen for a scheme such as this to work. As Allan pointed out earth IS an insulator (well, copper is to just a very poor one) and the earth WILL eventually heat up.


David states he has a 15C difference between ambient and ground temperature he will get effective cooling only until the mass of earth heats. The system will gradually degrade to useless. Unless, there is a moving ground water source under the piece of dirt he is on. A lot of this is covered simply in the link 'Old F' posted.


There are a lot of things that may be done. A plenum chamber with the radiator at the top would allow the cool air to drop, pulling air through the radiator at low or no energy costs.


Systems such as this work only when a lot of factors come in line. The best of these systems will still have the possibility of mold infestation and the need for extreme heat exchange areas. This is a result of the low 'delta T'. I doubt anyone can be found  who is smart enough who will design such a system at low or no charge. If the systems DID work effectively one would see companies in the business of building this age old idea. The fact it is not happening, and there are no 'scam' artists exploiting the concept should be an indication of some kind.


Ron

« Last Edit: November 03, 2007, 09:22:40 AM by wdyasq »
"I like the Honey, but kill the bees"

spinningmagnets

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Re: underground air cooling system diagram
« Reply #6 on: November 03, 2007, 10:53:26 PM »
Most of the car radiators I have seen have plastic side caps, and an aluminum tube-and-fin core. I have seen large all-aluminum turbocharger intercoolers from 18-wheel trucks get crushed for their scrap weight. A truck had rolled and insurance was buying a new one. Although the original was only slightly bent, the mechanic didn't want to risk it having a crack (easily brazed) when a new one was included at no extra charge.


I think one of these might work slightly better than two car rads equaling roughly the same size (if one could be found at a reasonable price). I would mount the heat exchanger(s) flat and parallel to the ground with the warm air flowing over the top face.


Assuming you are mounting the reservoirs in the attic of your small garage, I would suggest placing them next to the wall in a tray that allows leaks to drain to the outside. I would recommend putting the heat exchanger(s) and fan inside the insulated room.


Your design allows the pump to push volume instead of pressure (small pumps such as these are cheap, and in your configuration they're easily replaced) and you also allow for the systems fluid expansion and contraction. A cup of chlorine bleach per 100 gallons should keep the biology experiments to a minimum.


The more wells you add, the slower each individual well will flow, so I very much encourage you to insulate all the cool up-tubes all the way to the heat exchanger. Slow uninsulated up-flow through the warmed higher soil will rob half your efforts.


Even with the heavy wall insulation you mentioned before, I would encourage you to shade the two sunniest outer walls. Five months a year I stapled loose weave burlap cloth (dark green and plastic fiber from "Home Depot") onto my southern eaves. It only hung down halfway, but shaded 3/4ths of the wall (plus windows) because of the angle of the sun, and it noticeable helped.


Running a small pump and a small fan will probably only draw as much as two light bulbs. Other people have done something similar with great success, but the ones I have seen are much larger and much more expensive. This is a great design!


This will sound crazy, but after you complete the system and get it working, one option is converting your pump to a DC motor (trash treadmill or Amatek?) and constructing an "Archemedian screw", shown here as a Vitruvian water screw (the tube and screw are attached, and turn together)


http://en.wikipedia.org/wiki/Vitruvius


I have seen them made from a coiled copper tube around a plastic pipe, lifting water from one tank to a higher one at about a 30-degree angle.


The lowlands of Holland were pumped dry past earthen sea-dikes to reclaim many acres of land with windmills turning these tube-screws (high volume/low lift). When there's sun, a PV panel can turn the water pump and the inside fan. If the DC pump motor has a shaft output at both ends, you can later hook up a small VAWT to it, so when there's wind, the pump will draw even fewer amps to turn.

« Last Edit: November 03, 2007, 10:53:26 PM by spinningmagnets »

Capt Slog

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Re: underground air cooling system diagram
« Reply #7 on: November 05, 2007, 02:41:26 AM »
Why do you have two reservoirs? why not just attach the pump outlet to the down pipe?


I agree with the other comments about the ground warming up around your heat exchanger.

« Last Edit: November 05, 2007, 02:41:26 AM by Capt Slog »

BigBreaker

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Re: underground air cooling system diagram
« Reply #8 on: November 05, 2007, 09:24:55 AM »
I beg to differ.  Soil has pretty low specific heat compared to its thermal conductivity.  That is why it changes temperature slowly.


Stone will also change temperature slowly, but that is because of high specific heat compared to its thermal conductivity.  Stone is a poor insulator over the long term.  Enough stone will average a daily temperature cycle but that's different.  In the winter a stone house will get REALLY cold.


----


You will want a lot of smaller tubes, not a single bigger one.  The smaller tubes can have similiar surface area, but will "see" a larger volume of soil.  Each tube will set up a thermal gradient in the surrounding soil and at the soil / tube interface there will be a discontinuity (a delta T).  That thermal gradient is a decaying exponential just like a capacitor discharging over time but the thermal gradient is over space.  Far enough away, the temperature is constant and cold.  Closer to the tube the heat is dispersing into the soil and that soil is thereforewarmer.


A good example of this, and a good natural experiment is the thermal gradient of your soil in the late summer.  From the surface to a depth of about six feet the temperature will drop from summertime hot to a cool and essentially constant annual average.  That causes me to think that tubes should be spaced about 12 feet from each other to avoid the tubes "seeing" each other over a cooling season.  I guess that sub-surface soil is denser and therefore has higher conductivity, so twelve feet is maybe a lower bound for spacing.


The thermal "power" you can extract or push will be determined by the surface area of your tubes and the "delta" T of the soil to tube interface.  The thermal "energy" will have to do with the soil volume accessible by your tubes.  That is a volume integral (yes calculus) of the this radial gradient times the length of the tubes.  These thermal gradients will overlap a bit with multiple tubes, but assuming the tubes are sufficently spaced, it will be a small error.  A decent estimate is to simply assume the tubes access soil in the surrounding ~6 feet and add that up.


Figure out the cooling energy you need in a summer and divide that by the specific heat of your soil and then the difference in temperature between the soil and room temperature in celcius.  That will give you the amount of soil you need to push that heat into.  You may be surprised how much it that is....

« Last Edit: November 05, 2007, 09:24:55 AM by BigBreaker »

framistan

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Re: underground air cooling system diagram
« Reply #9 on: November 05, 2007, 06:51:35 PM »
The reason I show 2 resivoirs is..... when i constructed my

first radiator, (see part 1 and picture of big yellow radiator),

I had problems INITIALLY  filling the pipes to the TOP using

one resivoir, and also problems with AIR BUBBLES getting into

the pipes. The resivoirs allow airbubbles to go out the top.

When I actually build my next radiator, I will have

one water tank separated by a plastic barrier, essentially making

it two tanks in one.  I drew-it-up that way so people new to the concept

can see what I am talking about easier. Lots of people spend 3 minutes

looking at what I have drawn, and jump to conclusions pretty

quick on something I have worked on for years..  I am aware of

 SOME of the problems many people have

listed such as the dirt not being a good conductor of cold/heat. For that,

I have also placed a WATER SOAKER PIPE alongside my heat exchanger. but

I didn't mention it  in the articles. You picked up on it quick though.

This should make the ground wet around the heat exchanger and

make it work better. DIRT is a bad conductor, but MUD is wonderfull.

I very much appreciate everyones comments

though.  I have gotten some really good ideas from all of you.

My purpose was to give a good overview of the system and generate

comments and ideas from others who look at things different than

I do.  And wanted others to have U.G.A.C. idea for free just in case

I can't finish it, others may pickup where I left it and may make

it work.  I find it FASCINATING how well things work on paper, but

when you actually start construction, it just doesn't work out like

you thought it would.  Too much thinking and designing leads to not

enough hammering and sawdust.  
« Last Edit: November 05, 2007, 06:51:35 PM by framistan »

spinningmagnets

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Re: underground air cooling system diagram
« Reply #10 on: November 05, 2007, 08:15:35 PM »
I measured the inter-cooler and the radiator on my truck this morning, in case you're interested, because they are much larger than a cars. They're from a '96 Kenworth 18-wheeler.


The IC is 2" thick and the tube-and-fin face (minus end caps) is 28" X 30"


The rad is 3-1/2" thick, and 35" X 30"


The IC tubes are as thick as my little finger (very low restriction), and the radiator tubes are smaller, but about twice as thick as my cars. If you could find either at a reasonable price I'm certain they would work well for your small one-car shop.

« Last Edit: November 05, 2007, 08:15:35 PM by spinningmagnets »

Kevin L

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Re: underground air cooling system diagram
« Reply #11 on: December 19, 2007, 07:50:33 PM »
To give you some referance of the cooling area required, my 2600 sq ft home geothermal system requires 1200 linear ft of 1" pvc water line buried 7' deep and spread out over 1/2 acre.  The lines are spaced a minimum of 15' apart because the soil will heat/cool 5-6' away from the water lines.  
« Last Edit: December 19, 2007, 07:50:33 PM by Kevin L »