Using deep well water fro cooling / heating & other ideas

[energy_freak]

I tried to post this in USA, but I could not find any intelligent response to the issues I brought up. It looks like most of Americans operate on the "if it ain't broken do not fix it" principle, comes from proper upbringing and excellent educational system. Please try to bear with me and my lack of knowledge on the subject as I am not a specialist in this particular field.

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 2 forced air gas heaters
4. Two 50 Gal gas water heaters
5. Well water (private well) bringing very hard water at 53F all year
6. A retention pond outside the residence where I can hopefully discharge processed water.

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 (can't 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.. I heard that there was a new development in water treatment by Honeywell available only in Europe.
3. Find very efficient water/air and air/air heat exchangers 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, I am open to all suggestions from your guys because this technology is light years ahead in Europe.
5. Install proper attic ventilation (Attic Fans)

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 builders 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. For instance, 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 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, during summer I would like to use strategically installed exhaust fans to pull very hot and humid air from those areas of the house were I have high vaulted ceilings. However in this particular case I am not sure what size heat exhaust fans I need as well as how to deal with the problem of creating negative air pressure when system is not running.

I also decided to implement forced air ventilation where I can bring an ample quantity of fresh outside air to keep my house under comfortable temperature condition when keeping the windows open is not really an option due to heavy rain or those situations when open windows pose some serious security concerns. In addition to forced air ventilation, I would like to use the same delivery mechanism for air/air heat exchange instead of water/air as another alternative to well water when the outside temperature is good enough to completely shut off the well water supply. I would also like to conserve the water table whenever it is possible; therefore, if the outside temperature is close to 50F I would want to use an air/air heat exchange rather than a water/air one. Obviously, if the temperature drops below a certain point, such as 40F (I leave the decision of that optimal temperature to those professionals who are more knowledgeable than myself), I would have to cut off the air supply and turn on the water loop to increase energy efficiency of the future unit.

I am also planning to use heat pipe technology, if you are not familiar with them you can visit their site at

and learn about their products and technology behind it. So in very simplified view my future system 1st stage will consist of a heat pipe and two heat exchanges (water/air and air/air between them). During the summer months, not even properly designed 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 am sure that I have to add a dehumidification stage. It looks like I have to design the future system (2nd stage) with a refrigeration circuit with Freon line being cooled with the same water leaving water exchange. I want to stress that I am not at all interested to buy a pre-packaged Water Furnace or Florida Heat Pump 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). Now you probably see all my reasons why I have not even slightest interest in installing a Geothermal Heat Pump operating with an Open Loop as it provides me with no flexibility whatsoever.

So, the real question is, what do I do in winter time as I have a heat sink coming to my house at 48-53F? 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 local Gas Utility is simply another monopoly which is charging whatever they want for gas during the winter season (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.

And the last wish, I would appreciate any input, constructive criticism even flame regarding my proposed ideas and design, but please spare me from any suggestions on other geothermal alternatives, including closed loop systems as well as any single function commercially available units.

[Pete C]

Hi,

You may be able to adapt a split air conditioner/heat pump to use your well water as a source, are you dead set against using a heat pump?

Whether a heat pump is better than gas for winter heating depends largely on the relative cost of electricity to gas. How do they compare in your area?

cheers, Pete.

[energy_freak]

Yes, I am against using a heat pump for all those good reasons I mentioned in my post and I have no interest in split air conditioner/heat pump either.

Definetely not in favor of gas as the cost of Natural gas is absolutely out of reach during winter season.

[N. Thornton]

you definitely need to post this to alt.solar.thermal. The expertise there is well beyond what it is here on this topic.

thats doable if you discharge the well water back into the well. Water tends to stratify, so discharge warmed water to the top, and take cold from the bottom.

Dont overloook earth pipes as well, theyre simple and will give you lots of extra capacity. You can heat exchange the pipe output to avoid any damp issues.

Might be more logical to keep the well water to a separate circuit and design it to work with the scaling and corrosion issues. Ie avoid iron and steel, use an air separator, and add valves to enable you to flush the system with acid if its ever needed. Plastic plumbing is not so pricey.

All electric heaters are 100% efficient. I missed why you wanted to use one though.

For cooling, good. I would look at earth pipes as well though.

absolutely the way to go, had great success with that. Proper control is all important though, you need to monitor temps on each side and have it controlled automatically for it to work well.

not if the water goes back to the well. I doubt theres any real hope of it supplying enough if you discharge it elsewhere.

I quite agree, it affects health and comfort signficantly.

yup, but always use a differential stat, otherwise its little good.

?

Good. Monitor temp and RH on both sides, and ventilate plentifully when doing so will keep the house within your chosen temperature comfort zone, and not make it damp. You can either fan vent, or use a larger area of natural venting, with iron bars and mesh across it for security. Of course this eats way less energy than a big fan, but it is more work to put in. Use a motorised vent.

I think with returning water to the well, which will be necessary, and using a earth pipe, the above should not be an issue. It will come more down to which takes less energy to run, and whether you ened to run one or both.

lost me there.

You might just be able to use the cold well water for that, I dont know. Probably not.

Obviously you dont want to bring the cold well water in in winter. So far youve not mentioned solar flat plate space heating: this can pay back at 25% pa and run in winter nicely.

you could, but whether thats really the right move is another question. I would far rather see flat plate solar thermal, it would be way better.

Well I've got one that makes lots of difference to summer cooling: shade the whole house. White paint is far from 100% reflective, the sun heat load on a house in summer is enormous, so shade makes a great difference. A separate metal frame with climbing plants is ideal, or putting climbers direct on the house is cheap.

I would also add the suggestion of temperature comfort zones and thermal storage. Ie your night time whole house fan should continue to run until youre at the low end of your comfort zone, then you have lots of coolth stored in teh structuer for automatic daytime cooling. Thats if your house is brick/block.crete, if its timber then youve got no significant thermal storage there.

Regards, NT

[Pete C]

Okaaay! You can provide cooling with chilled water, this may also provide dehumidification if the water temperature is below the dewpoint of the cooled air.

It would be worth doing some trials to see how much cooling and dehumdification a water/air exchanger will give.

If you can get some quite cheaply it should be doable. You may not get scale deposits in them for cooling but the pH of the water needs to be checked.

For minimising solar gain, as well as shading consider solar/blackout blinds, and as well as attic ventilation consider a radiant barrier such as foil stapled to the roof rafters.

In that case you would be better off with electric heating. For 'on demand' heating there should be electic showers and washroom heaters that can do the job. If gas is a lot cheaper the rest of the year a 'multipoint' gas heater could be worth having too.

cheers, Pete.