Geothermal Heating Systems

you understand that geothermal is just a heat pump.

I gathered as much. Frankly, I am not concerned with what it is.

I'm an M.E. I have no attachment to process. Only the result.

Hello Laughing Jaguar,

I'd been contemplating the same question and this the result.

If I use radiant heat be it in-floor or using radiators; I prefer the latter. If I use electric tank-less water heaters placed in the heated zones; I.E. not in the basement. Then I could realize a fuel savings similar to geothermal in that I would heat water from about 74° to 110°F. There would be the added benefit of avoiding the $20K fee for Geo for the apx $700 per unit + $300 for PEX and fittings per floor + about $700 labor.

I did the math and realizing the Geo system efficiency is nil when pulling -10°F or below air temp through the unit. I've decided that barring the rare event I'd need begin heating from below 40°F the radiant system would be cost effective to a point the Geo would never catch up.

EditorGBAnalysts wrote:

"Geothermal Energy extraction is not possible everywhere."

I agree. I am not, however, looking for, nor do I need the high temperatures used in New Zealand to achieve the result.

A friend has a 50,000 gallon swimming pool whose temperature in the winter is only 5 to 6 degrees warmer than ambient, often higher.

The number of BTU's present in this temperature differential is enormous. His system captures it quite effectively to keep his very large home comfortably warm in all but the most extreme winter temperatures.

Electrically heated baseboards are available to supplement the heat extracted from the pool. He claims that he has not needed to turn them on but once in the last 4 winters.

I realize that his is not geothermal. It is, however, a good example of what might be possible if I can tap into the warmer temperatures that I know exist 4 to 6 meters below the surface of my property which is too small to allow for a swimming pool.

Thanks for the link.

L.J.

Bwise wrote:

"If I use radiant heat be it in-floor or using radiators; I prefer the latter."

50 years ago a friend of mine built a home using copper pipes embedded in a cast cement floor. It was fully zoned so that each room's heating system could be adjusted to suit the activity of the day. To this day, it continues to provide the most uniform temperatures I have ever experienced in any heating system. Were I to build a home from scratch, I would not hesitate to replicate such a system using more modern materials.

However, I am constrained by the current baseboard heating system so this pursuit is limited to the source of the heat not how it is distributed.

I must admit that I have dismissed electricity as a heat source without further study. Historically, heating with electricity has proven to be very expensive in this region and is shunned by many. The cost of heating that way is many time higher than other more conventional methods such as fuel oil, in spite of government subsidies.

With energy costs escalating at such a dramatic rate, the use of electricity portends an even frightfully higher cost heat medium in the future than now.

My intention is to heat my home for as close to nothing as is possible beyond the investment needed to install new equipment and thus liberate myself from the tyranny of rising energy costs.

I appreciate your concerns over the initial cost of modernization. However, it stands to reason that any home that costs nothing to heat in the winter, will command a higher price when sold, thus returning the initial investment.

Thanks for the response.

L.J.

I don't recall the specifics but there have been recent uses of geothermal in Vermont. If I remember correctly they were using vertical coring @ 800'-1500' depth rather than horizontal due the rocky soil conditions. It would seem a similar approach could attain a reasonable outcome upon a small property. The depth would be determined by thermal integrity of the dwelling.

I strongly suggest you consider solar collection...several very informative threads have been posted.

Del the cat and AndyGermany have very interesting designs for the DIYer

Bwire wrote: "I strongly suggest you consider solar collection. . . "

A neighbor, a commercial electrician, has started a separate company for the purpose of selling and installing solar electric panels that will, presumably, put electricity back into the regions grid.

The irony is that neither he nor I can install these systems because both of our roofs are in the shade for the entire day! If my roof won't support electric panels, it's highly unlikely that they will work any better when used to provide heated water.

Another negative factor is that while not as warm as direct sunlight, geothermal is a constant stream of energy, 24 hours a day. Sunlight is not and if a weather system with sustained clouds should pass through the area, it could be many days before any energy from sunlight might be available.

Many government incentives exist for the purpose of encouraging people such as we, to stick our toes in the water. It would appear that the financial commitment may not be as high as it would appear at first blush.

Laughing Jaguar wrote:The irony is that neither he nor I can install these systems because both of our roofs are in the shade for the entire day! If my roof won't support electric panels, it's highly unlikely that they will work any better when used to provide heated water.

I didn't specify a roof mounted solar array though it is the form most often thought of, vertical wall hung is favorable as is ground placement.

I am surprised your roof has full shade in winter though.

Laughing Jaguar wrote: Another negative factor is that while not as warm as direct sunlight, geothermal is a constant stream of energy, 24 hours a day.

Use of 3-sheets plywood, 40' of PVC schedule 40 and some lexan could significantly contribute to the energy savings of geothermal too.

Laughing Jaguar,

You will find this very interesting:

http://www.darwin.bth.rwth-aachen.de/opus3/volltexte/2008/2372/pdf/Hartman_Andreas.pdf

http://www1.eere.energy.gov/femp/financing/superespcs_ghpresources.html

Geothermal Basics

Drill a hole in the ground and take the temperature at the deepest depth you can afford. Check the mean annual temperature for the site. If the hole temp is less than 15\OF of the aver.temp. forget it, If >15\OF you have a chance - preferrably +15\O if you are going to warm. If it is close to mean annual you may be able to use it but you need more calcs to see how much of the warming can be done before you ADD heating elements.

If you get to groundwater - or you know you are on a flood plain - XY ft above the water level in the river during the winter then you will go to a "recirculating pumped" system...need to check local City or County Engineer as to permits...for either a closed loop heat exchanger or an open loop with discharge to a NOT-freezing pond for recharging or a series of septic tank like infiltration galleries.

Go to Long Island and check with any of the HVAC installers as Long Island has used Hydro-Geo-Thermal systems for >50years - primarily for cooling but in the winter getting rooms up to 60OF before you add heat helps a lot.

Need to know location, how big of structure...you got a swimming pool?? and a solar roof heater?? which can be incorporated using the pool as your storage - still need several pumps and a control system...but you are an ME.

Also see if you can use it for AC during the summer...depending on location and slope-exposure-orientation.

Tom

Thanks Tom. You've given me lot to work with.

"Need to know location" Delaware River Valley, Western New Jersey. bordering Pennsylvania. I'm about about 2 hours west of Verrazano, South shore, Long Beach Island, JFK, etc.

"How big of structure..." Insulated Wood Framed. Eastern half of a duplex. 1500 square feet

"You got a swimming pool" Nope! Not enough room for one.

"...a solar roof heater?" Slope and orientation of roof wrong for solar.

Contemplating such a system for another purpose I was advised
by two very experienced consultants not to waste my money on
trying to heat the house from ground sources.

They explained, yes, initially some heat could be extracted, however
the ground very quickly became frozen, (around the pipes) or certainly
became too low a temperature to extract any further heat.

They also advised that the best source (of heat) is from water; i.e
lakes, ponds, etc - providing they were of sufficient size, and obviously
were not prone to freeze. (not many of these around in winter)

Sorry to pour "cold water" on your idea, but better now than after
spending a load of money on it. How about a new fur coat?

jt.

When you find the answer, please tell us all, thank you.

Dear Laughing Jaguar,

There is an publication that may or may not be of interest to you:

Technical Note TN 18/99 Ground Source Heat Pumps - A Technology Review

If you google that then you may find some useful answers, if not then sorry for wasting your time.

Kind Regards

Mr. W.A. Snow

I looked into Geo-thernal heat pumps also. The only issue I had with it was the cost. You need to drill a series of holes approx. 15-30 ft deep the average cost was about $25,000 just for the drilling. The rest of the package wasn't to bad ~$15,000 for a two zone system. The premiss of the system is that transfer oil or a type of anti-freeze in tubes is dropped down in the holes and circulated drawing heat from the earth. Since you ground temp is at a constant temp well above freezing it is much more efficient then standard heat pumps. If you are just building it the way to go it's much easier to write it into the cost.

Hi John!

The cost for most any heating system is high these days. Fortunately, there are many government incentive programs, available right now, that encourage us to invest in modern energy efficient or environmentally friendly systems. Some are driven by a desire for energy independence. Others as response to the global hysteria over climate change.

Frankly, I think that Al Gore and the his crew of fear mongers are wrong. The news is out: the temperatures of every planet in our solar system rose at the same time ours did, following in lock-step the cyclical temperatures of the sun. There are probably a dozen valid reasons why we should make cleaner use of carbon based fuels or elliminate them completely. Global warming isn't one of them. Over 5,000 members of one scientific community are raising hell over the use of garbage can science to promote a conclusion that simply isn't supported by the facts.

I'm studying this alternative simply because I can't afford to pay out $1,500 to $2,000 for heating oil this winter!

From your description, it appears that each hole contains pipes that form a closed loop, recirculating system. Simple enough in principle.

Thanks

Art

I was just looking to have a more efficient system that would help lower my electric bill. The heat pumps I have become totally inefficient as soon as it drops below 32-30 degrees then the heating coils turn on and my electric meter goes crazy.

Luckily our winters have been pretty mild lately.

Move the heat pump inside the envelope and install return air.

You would benefit by the pmp's in put temp being within the thermometer setting.

This year I am moving my heat source into the envelope as my chum's have and experience significant energy advantage.

You mean move the pumps into my basement. That's an interesting idea.

With the air return won't that bring call air into the system?

The return air system I'm referring to is a system within a system or a separate system. It would bring fresh air into the envelope but at a minimal rate intermittently.

It is not fed directly to the heat source.

You mean move the pumps into my basement

Into the heated area, yes.

My basement isn't heated but does stay a constant temp. all year long so it should work like a geo-thermal without the drilling and new systems.

Cool.

Insulate and heat the basement and be $ ahead

Jag

Demand Side

Do you have a basement...high crawl space???

You can insulation your floor easily - easiest - rugs, especially along the exterior wall corner with the floor (after caulking). Remember rugs can be drawn back during the summer, because a cool floor helps during the summer, unless you AC and the basement is warmer than your living room.

Supply

Ample basement - think 4-6in boring horizontal collectors (yes watch out for water coming down along the foundation line, etc.) then a simple half diameter pipe with small fan into the basement. (expensive but allows for some variety and backup)

TOM

My winter project this year is to dry lock the walls. We had water issues for the past 8 years because of poor landscaping by the builder. I finally got that straightened out no more water in the basement. So now I can fix it up it will make a nice 1500 sq ft living space.

Another quick question if I put the unit in the basement won't it be noisy?

Natural Heaters (Coolers)

Once you have established your source - trenched or drilled - you need to concentrate on insulating the entire system, make sure you have insulation even over the soil of a trenched system - wood chips/mulch. Header can be insulated and all pipe work anywhere exposed to anything other than soil.

If you can get the source into groundwater - makes it even better - heat capacity and some circulation. ALSO remember if you have a trenched-piped system keep the soil irrigated during the summer and the heat capacity is improved while bigger tree canopy may provide too much shade for your shaded roof.

When you get your pipe works together - simple light bulb "heater" can help alot, remember any heat into the pipe comes to you.

On the demand side (everything you do for AC applies HV side), insulate/caulk are the key, double-windows, and double entry doors/heavy plastic strips sheeting/heated air screens all do a lot.

Staircases are also a problem as the warm air goes UP.

Small 5amp fans for through the walls - about 6in below the ceiling line really do a wonder to get the high hot air down to the floor.

Oh by the way, have you checked the $ efficiencies - insulation, caulk, double windows, and door controls are usually more immediate, no permits, and less costly; by the way this will help in the summer tooooo. For costing, ask your utilities regarding peak month pricing if they have one on your property, then you may pick up some benefit.

WATER Side

Do you have room for a borehole or trenches???

Problem with groundwater is the regulatory requirements from City/County, maybe even state...especially in NE as the LongIsland situation was widely circulated...too many pumping groundwater and putting the warm effluent back into the ground and the neighbor sucking in the warm effluent...during winter that may be OK but not for AC.

If you pump out groundwater and do a single pass open loop, your discharge may be regulated to storm drain - yes you can put it through your toilet/santiary lines and maybe no one will catch it. As long as not everyone is doing it, "everything" is OK.

Lakes are very different unless YOU own the whole thing - need permits and expensive construction - maybe even the Corps of Engineers 401/404 permits. But (if geology supports) the easier way is pumping shoreline wells or horizontal trench "wells" and discharge back to the lake or to a trench recharge gallery at some distance.

TOM

....and no expensive and deep holes (in the Bank account too!) either.....

There are always people around willing to part you from your money.....

Everything needs to be well thought through and the costs and the returns calculated and if at the end of the day you have to add a little fossil energy into the equation, using equipment that is already built in, well that can be arranged!

http://www.econar.com/products/hydronic.htm

This website has some basic info on geothermal systems.

Hope this helps.

Thanks Burt.

Econar has several reps in the area with many successful installations. They are sending me literature and I will be visiting an installation soon.

L.J.

http://www.thermia.com/

These are a Swedish supplier of heat pumps. Not sure if they have suppliers state side but they are very good heat pumps. These typically provide your domestic hot water aswell. These can be controlled over the internet and have many other features.

I have one of these in my house and they do work well, however where I live we do not get the extreme temperatures that they get in Sweden or in the States. My house has no oil or gas (apart from the gas cooker) and my electricity bills are relatively low when compared to my neighbours.

In order to run the model of heat pump that I have there is 300 feet of pipe running in the garden (1 meter under ground). I had the option of drilling but this was more expensive.

Regards

Mr. W.A Snow

I've been contemplating the same thing and also live in upper NW New Jersey. Since I live on a decent sized lake my question is:

a. Will my running either a closed or open loop system off the bottom of a 550 Acre, 45 foot deep (where I can hit it) lake negatively effect the lake's eco system?

b. If not, what would happen if a number of my neighbors do the same thing?

Thanks for all the other information both here & other strings!

Hello AAndy,

It would seem you have optimal geothermal available, you and your neighbor's may be able to become geothermal thermal providers which may be non-profit

I think I think you could could configure a closed or open loop system without effecting the ecosystem though a closed loop may present fewer maintenance issues.

Google: lake heat sink

Here's a previous thread: http://cr4.globalspec.com/thread/11487/Ground-source-heat-pump

I used to have a ground source system, and was happy with it. It is certainly more economical than heating oil, and,when I installed it, it was also slightly more economical than using natural gas. (The central air conditioning was also more efficient than standard central air.)

I'd recommend doing as much of the system design as you feel comfortable with, yourself. It seems that some contractors charge a large premium for a full installation. It's worth evaluating the cost of trenching vs drilling wells, etc. and contracting out the drilling yourself. The systems are inherently fairly simple, given that a single unit is handling both heating and cooling (whereas with gas heating and central air you've got a large portion of the system that is idle half the year). In my case, I don't think the overall cost was any more that I would have paid for gas heat and central air.

EXCELLENT INFORMATION... Thanks

My main consern is if many of my neighbors also start doing this that it might cause a thermal problem of some sort. We are very protective of our lake... you can drink the water with no problems (except for occasional algae) most of the year.

You may want to contact your version of the Department of Environmental Protection and your Fish and boat service in case the require permits. You never know whats on their books.

It is unlikely that the overall average temperature of the lake would be changed measurably, but local temps around the return pipes would be about 10 degrees warmer. I used to live in Ithaca, NY, where Cornell University installed a system that uses Cayuga lake as the heat sink (and maybe heat source in winter -- I don't remember). If you google you could probably find details on their system.

In any lake that forms ice, the bottom of the lake must be 34 degrees for the top to be 32. At 32 degrees the lake is no longer a very good heat source. So if you are thinking about drawing water from the lake, I think that would not work well. If you are thinking of a closed loop system, I think the likelihood of warming the ground enough to affect the lake would be very very slight.

The first thing to consider is that your home needs an efficient insulation envelope for any type heat source to perform effectively.

Last year one neigboor used 260 gallons of soy oil to heat his house 1500 sq ft, the entire season. 260 gallons x $4 = $1040 per season of enviromentally friendly fuel. Compare to geo @ $20k +; 20000 / 1040 = 19.3 years.

The deeper I dig into this, the more apparent it becomes how effective the system can be, provided I follow the KISS principle and plan it carefully.

Yes, a well insulated home is paramount. I didn't say that but simply took it as a given regardless of the heat source.

I live about 200 yards from the Eastern banks of the Delaware River. East of me is a tall mountain which almost certainly effects the ground table I live on top of. Yet a 6 Inch hole drilled 200 feet into the rocky terrain below should be immune to major effects by either. That's well within the capability and costs of conventional water wells but would require a submersible pump. No big deal.

The systems I've studied thus far employ low boiling point refrigerants above ground to capture the heat brought up from below ground. Nothing but water gets circulated in the underground loop so there is no threat to the environment.

At the risk of being overly optimistic, I believe I can design and build this puppy myself, except for drilling the well.

Already I have found some free money as a result of this inquiry!

While following the trail of web sites, I uncovered the fact that my new washing machine is one of the most energy efficient around, is Energy Star compliant and that I can get a $75 rebate check for having chosen it!

Neat huh?

L.J.

Jag

Always start with the simplest - make sure - especially caulking and rugging along the exterior walls/floors.

Double Windows, Drapes, Entry Controls, and Ceiling Vertical/Horizontal fans take the simple to the next level.

Basement/Crawl Space is important for both HV and AC.

By the way, put a heat exchanger on the washing machine and shower drains.

Rebates and cost saving also from the Refrigerator and TVs - but then you lose a heat source (good for AC).

We have the same problem but in AC here in LA, we are conserving lower 25%ile of users so we can save very much. Utilities won't buy the PV electricity so I need AC and plug-in to make a PV panel worthwhile. Plenty of sublight - so we are reinstalling a solar water heater.

TOM

"By the way, put a heat exchanger on the washing machine and shower drains."

My daughter got married and moved. That ended the era of 45 minute showers! I don't use enough hot water to recover the expense of heat exchangers on the washing machine or drains. I do agree with you in principle however and made a recovery system for the gas fired clothes dryer.

Remarkably easy to do.

I modified a hot air heating system floor vent slightly. I cut a small rectangular hole in the floor of the kitchen immediately above the basement laundry room. Dropped the vent in place, screwed it down and then simply attached the hose from the exhaust side of the dryer. A six dollar PVC valve from Home Depot allows me to direct the flow out doors when appropriate. Originally I simply exhausted the hot air into the basement but stopped when I saw that moisture was condensing on shop tools

Directed upstairs instead, the heat helps warm the house and the humidity is elevated in winter allowing a level of comfort at cooler temps.

The whole mod cost me three hours, most of it spent cutting through to the basement and about $25 in materials.

If you had bought (next time eh?) a CONDENSER dryer, you would not have that problem. I will never go back to the ordinary dryer ever again....

You also get gallons of distilled water for free too!! (Whether it is clean enough for batteries I could not say as there might be small pieces of cloth caught up in it, but it fills the steam iron a treat!!!)

www.hud.gov/energystar/home.cfm#new

At the risk of being overly optimistic, I believe I can design and build this puppy myself, except for drilling the well.

I agree, and if you shop around, you should I think be able to find a reasonably priced ground source unit. If it were not for volume and desirability, the ground source units should be less expensive (per btu) than an air source unit, because the water/refrigerant heat exchanger can be much smaller. *

When I installed mine, I was on my own partly by choice, and partly because there weren't a lot of people who were familiar with installing them.

*Incidentally, installing these units requires only the water piping to go large distances. A standard air source unit often has many feet of refrigerant piping between the evaporator and condenser. I find water piping much easier to work with than refrigerant piping -- and if you have a pinhole leak somewhere in the water piping outside the house it is of little consequence. Not so with refrigerant.

Burt gave me a link to Econar. Soon I found myself speaking to the sales engineer for this region. One of the things he emphasised was that the refrigerant is of a low volume and tightly contained within the evaporator-condenser circuit in the house. The only thing that goes into the ground (and back) is water.

However, the municipality I live in provides a municipal water supply and thus has an ordinance specifically forbidding private wells.

Tomorrow I will visit the municipal clerks office and ask to see the book of local codes so I might read the specific language. If the language is sloppy and too broadly written (which is common) it could be so loosely worded as to forbid any well, including one for geothermal applications.

L.J.

However, the municipality I live in provides a municipal water supply and thus has an ordinance specifically forbidding private wells.

Ouch. You'd have to check with a lawyer, but if the intent of the law is to prohibit wells for domestic water supply, then, even if the specific wording seems to prohibit any vertical hole in the ground, you can usually get away with acting according to the intent (I think...).

I was once the Zoning Officer for this borough. I've a reminder to call the Civil Engineering company that is under contract to the community and which oversees applications for construction.

I know the Chief Engineer. He's knows his stuff and is a straight shooter. If he is in when I call on Wednesday, I may have the answer by afternoon.

I agree that the language of the ordinance may be specific to drinking water supplies only. If it can be shown that drilling for geothermal purposes is outside the scope and intent of the ordinance, then my activity is beyond their control, at least insofar as THAT ordinance is concerned.

However, I was also a member of the both the Planning Board and Board of adjustments and I know from experience that if they can find a way to say "No", they will do so just to play it safe.

Stay tuned!

L.J.

Hanging loose

What you will be doing does not qualify as digging/drilling a well.

Though what may be found in the ground water may not be to your liking nor healthy.

I been to sites in NJ where no birds twittered, the streams had no aeration no life forms, nothing. Eerie places, don't drink the water

LJ; are you not drilling a hole in which to put your closed loop of water tubing? perry

I was unable to even find soy flour in the store last visit. I wonder if biofuel was why.

"I was unable to even find soy flour in the store last visit. I wonder if biofuel was why."

Yesterday I went food shopping. Went to buy fresh corn. They wanted a dollar a piece!

Same time, last year, fresh corn was selling for $3 for a dozen!

They wanted ethonol? They got it and drove up the cost of feeding farm animals too. But that's a whole other angry conversation. Why do we continue to elect those people?

L.J.

I hate to be a wet blanket, and I hope you can crow eventually and tell me I am totally wrong, but I am VERY sceptical as to whether this will work in such a manner as to actually save you money......or say get a payback within 3 years.....

I personally feel that there are better ways to cut your heating costs that are far cheaper and will have a much shorter payback time......but at this time, I do not have the time to correctly and fully investigate as to whether my thoughts are just that or something better.....

Please cost it all out first and make sure that you are on the right road.......

I certainly wish you 101% success and do keep us posted. I am very interested in being proven wrong (hopefully!)

Andy wrote: "I hate to be a wet blanket, and I hope you can crow eventually and tell me I am totally wrong, but I am VERY sceptical."

Well intended scepticism is a gift Andy. I welcome your skepticism without angst.

I'd sooner surround myself with a thousand sceptics like you than a single cynic whose underlying purpose is to destroy initiative and the creative spirit. Sceptics allow for the possibility of being mistaken. Cynics haven't got that kind of courage.

Many of my creative pursuits have not turned out as I would have liked. Still they were fun. For me the joy is in being engaged, active in a pursuit of a goal. The results are simply consequential..

Thanks.

L.J.

Great answer... from both the philosophical and pragmatic perspectives.

Ken wrote: "Great answer... from both the philosophical and pragmatic perspectives."

Thank you Ken!

Thanks from me too....

with all the discussion about the prohibitively expensive nature of the general Geothermal install... what with the need for either digging up your entire backyard to lay a series of groundloop piping, or the drilling of wells (obviously provided you don't have direct access to a farm pond/stream/lake/etc)... have you considered some of the high-efficiency, cold-temperature air-source units on the market today? Now, obviously i am a little biased, as i used to work for a company here in Bangor Maine making such a unit... but the air-source technology DOES work... www.gotohallowell.com and is FAR cheaper than a geothermal install. even though the efficiencies are still lower than a geo, they are still very high, and the payback is much better! It's getting to the point where these units have become economically feasible even here in the northeast US, where we are paying $.18/kWh... with oil at $4.50ish/gal...

so, take it as you will, again, i might be a little biased, having worked for the company for a while, but the systems work.. no joke!

I spoke to the Water Commissioner for our municipality today and was pleased to learn that the town laws say that I must hook up to the municipal water supply for obtaining domestic water. There is no law specifically forbidding drilling.

I will continue to and make sure that there isn't some other regulation that might bite me but it appears that I can now investigate the cost of sinking not just one but several holes.

I haven't a clue what optimum depth is or what advantage, if any exists in drilling down 250 feet vs 200.

I'm also calling state agencies and investigating government grant programs to see what if any state or Federal money there might be as an incentive.

Geothermal literature is starting to pour in. However, I suspect that nothing will happen in time to help with this winter's heating bill.

I'll stay in touch. Thanks all for your suggestions and support

L.J.

LJ; here in Minnesota in 1953 a large mall was heated by ground water pumped from one depth, returned to another depth, this cooled water was used for air conditioning & the warmer water for heating, some homes were using pump & dump where is was possible, swamp, pond,etc, NOTE; the 3/4 inch pipe from heat pump should change over to a 3 inch pipe that is dumping the water to pond..( won't freeze shut). the 50 story IDS building has over 500 heat pumps to control HVAC in the building, for homes the closed loop used 1000 feet of buried tubing per ton of cooling, typically sized 4 ton units, 4000 feet, a local church had 21,000 feet slinky style buried on it's property for heating & cooling. I would look into ELECTRIC THERMAL STORAGE of peak heating to save money, look on web for steffes.com perry