Back to well water cooling / heating


  #1  
Old 09-19-04, 04:45 PM
energy_freak
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Back to well water cooling / heating

I didn't know where to post this so I assumed that this would be the most suitable forum. Please try to bear with me and my lack of knowledge on the area as I am not a specialist.

Here is what I have:

1. I have 4000 sq. ft residence in Chicago land with many glass windows facing west (this helps a lot in the winter and is absolutely miserable during summer)
2. Two older (10 years) Carrier or Bryant (who cares) A/C units 3 ton each per floor
3. Two considerably oversized 110000 Input BTU Carrier 80 plus forced air gas furnaces.
4. Two 50 Gal gas water heaters
5. Well water (private well) bringing very hard water from 250ft below at 53F all year around.
6. A retention pond outside the residence

Here is the list of known issues which I have to resolve before I embark on this project:

1. Ensure consistent supply of well water inside the house @ 30-40 GPM??!!
2. Provide adequate well water conditioning (canít use chemical water softener due to prohibitive cost and maintenance) in order to avoid any scaling and possible damage to extensive future plumbing set up, heat exchangers, etc.
3. Find very efficient water to air heat exchanger / coil which of course would be a function of size, material, GPM input and output T.
4. Find very efficient all electrical on-demand hot water boiler.
5. Install proper attic ventilation (Attic Fans)
6. Secure permit to dump water in retention pond.

Here is my plan of revamping the whole set-up: First of all, I am planning to use water as a main cooling and heating media. Secondly, I would like to use extensively smart ventilation in order to reduce heat/cooling load and conserve well water as much as I can (I know that I have a pretty strong well but still pulling 15-30 GPM to cool a house is a scary prospect).

While most concern is focused on home air tightness and size of the mechanical systems, proper ventilation of the home is often overlooked. Also, in terms of indoor air quality and pollution control, ventilation may be even more important. In my house, the only mechanical ventilation systems installed are 3 poorly made and noisy bathroom fans (two upstairs and one downstairs). These fans are seldom used for extended periods due to their high noise level, and are completely inadequate for ensuring proper ventilation to an entire house.

I would like also to conserve water table whenever it is possible; therefore, if the outside temperature is above 30F I would want to use an air/Freon setup (I will have build an intake duct to pump that air from outside) rather than water/ Freon. I am also planning to take the air from solar heated areas of the house (including the attic) and distribute it all around the house during the winter time. Obviously if the temperature drops below a certain point, such as 30F, I would have to cut off the air supply and turn on the water loop to increase energy efficiency of the future unit. Of course, I am not sure if those temperature cut off points are sensible at all in terms of energy consumption.

During the summer months, not even properly designed and engineered water to air heat exchange (I am not talking about various car evaporators) will be able to produce comfortable dry air in the hot and humid Chicago climate; therefore, I know that I have to add a dehumidification stage. I want to stress that I am not at all interested to buy a pre-packaged Water Furnace or an FHP geothermal heat pump because the only time I would need them is in the winter and I never found a dual system capable of working in both modes (water or air). So, the real question is, what do I do in winter time as I have heat sink coming to my house at 30-53F? Can I use a properly designed dehumidification stage to reverse it and heat the air? I can leave the current gas heaters but I hate to do that because NICOR is simply another mafia which is charging whatever they want for gas during the winter season (I hate mafiaís or monopolies in any shape or form not to forget absolutely uncontrolled spiraling cost of energy, so, it is a matter of principal if you will). I really want to get rid of gas utility all together and go electric. Talking to numerous people, I realize that I have to build the system without using pre-packaged solution unless somebody here can direct me to the right people who can help me to put it all together.
 
  #2  
Old 09-19-04, 05:31 PM
hvac4u's Avatar
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an interesting hybrid you describe.

geo thermal

with air to air backup

a few thoughts......
the u/s unit will have to be a split geothermal to keep water lines out of attic
use hrv's for ventilation
stage your heat for geo or air to air
tstat controlled fans to move heat from up to down
i have good luck with geothermal year round in georgia

it can be done, you will have to assemble it
 
  #3  
Old 09-22-04, 02:08 PM
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5. Well water (private well) bringing very hard water from 250ft below at 53F all year around.
We have hard water here also. So anything to do with water on heat and cool is a thing of the past. The cost to keep the pipes clean is out of this world. Just keep this in mind.

Ed
 
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Old 09-22-04, 03:50 PM
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I agree with Ed.
Forget about the well water. The maintenance will kill you not to mention the dissapointment if the well fails due to high flow rates.
Closed loop geothermal will give you the biggest bang for the buck.

The open loop heat pumps have been removed already and I will be removing the direct well water cooling next spring and installing direct expansion airconditioning at a local small casino.
Water leaks, pump problems, failing wells, frozen return well water line, risk of well water leaks in the building, etc all factor in to make well water not that good of a deal, even with free water.
 
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Old 09-29-04, 05:34 PM
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Originally Posted by GregH
I agree with Ed.
Forget about the well water. The maintenance will kill you not to mention the dissapointment if the well fails due to high flow rates.
Closed loop geothermal will give you the biggest bang for the buck.

The open loop heat pumps have been removed already and I will be removing the direct well water cooling next spring and installing direct expansion airconditioning at a local small casino.
Water leaks, pump problems, failing wells, frozen return well water line, risk of well water leaks in the building, etc all factor in to make well water not that good of a deal, even with free water.
Not trying to stir up an argument, but every negative you note there goes back to poor design.

Surely they did not circulate well water directly into the heat pumps in the building? Normal design's would use a plate and frame heat exchanger to extract/reject heat into the well water...therefore, well water would have no affect whatsoever on pumps. The wellfield would have it's own pumps, and since wellfield pumps have been in common use since, well, I don't know when, I cant see that as being much of a problem.

Frozen return line is due to either poor design or poor controls.

Water leaks...well, show me a commericial HVAC system that dosen't have a potential for leaks, and I'll...I dunno. I don't see how that can be blamed on the open loop design though. Think of the increased potential of leaks when you add some 300 feet or so of piping per ton of cooling capacity (think closed loop system)....

If you use a heat exchanger, you can just have the well lines come in the building, into the HEX, then right back out. Maybe 40 feet of wellfield piping in the building...is it really that great of a concern? And, who cares if well water gets in a building? It's certainly safer then having a bunch of glycol running around...

Failing wells, again, is a design problem. An essential part of the design process is to test the wells to make sure they don't ever fail!

Closed loop geothermal is far inferior to open loop, from a design standpoint. You guys are looking at it from an installers standpoint (which makes sense). I work on the design side. I can tell you that open loop provides much more bang for the buck (65 degree water versus 90 degree water for cooling...which is going to be more efficient?). The only drawback is you have to replace the plates in your heat exchanger often (annually from what I've seen). It's simply a matter of getting the design right!
 
  #6  
Old 09-30-04, 07:51 AM
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I take it you have not had to deal with well water for heating or cooling All I can say is dont do it. You can think about DX Geo and forget the water and the pumps and all the work with it. Still have the inground heat pump and AC and hot water. Just one compressor and one fan thats all

Try www.amgeo.com

ED
 

Last edited by Ed Imeduc; 09-30-04 at 09:55 AM.
 

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