Hi,
Just thought I’d throw out some ideas used the CCGT building:
Using a ground source heating/cooling system. Just a few feet below ground, the temperature remains a constant 54 degrees. The system loops water through sealed pipes underground to take advantage of this constant temperature. In the winter, water warms up and returns to the building, augmenting the heating system. In the summer, the water flowing through the system is cooled by the ground and provides air conditioning.
Replies
Actually, the geoexchange is a heat pump operation.
In a "normal" type of heat pump rejects heat during the cooling mode to the outside air, typically at 95 degrees and extracts heat out of the inside air. In the heating mode, heat is extracted from the outside air and "rejected" to the inside air.
In a geo exchange, the ground loops use some of the stored energy in the ground to offset the ineeficiencies of using ambient air. During a long summer, the fluid coming out of the ground loops will rise to 85 to 90 degrees. The "undisturbed" ground temperature may be 54 degrees or there abouts. In the winter, thetemperatures will be well below freezing.
Tim, Thanks for the good input...just trying to get some ideas going here...:-)
By undisterbed you mean below the frost line where the system would be installed. The temperature of the ground where the system is installed will never be below zero. Most locations except the artic will have accessible ground area below the frost line - 4 feet is typical. If you were up in the Canadian Artic then the 1500 foot frost line will cost quite a bit to overcome but other areas should be non-issues. At most you'd have to do vertical bore shafts at 300 foot depths - expensive but not un-doable - depending on your location it can often be the only way to put in a geothermal pump where you don't have 400 feet of space for horizontal installations. http://en.wikipedia.org/wiki/Geothermal_exchange_heat_pumpThe Earth below the frost line remains at a relatively constant temperature year round, usually between 7-21 degrees Celsius (45-70 degrees Fahrenheit) depending on geographical location. Becauses this temperature remains constant, geothermal heat pumps perform with far greater efficiency and in a far larger range of extreme temperatures than conventional air conditioners and furnaces.
The Earth below the frost line remains at a relatively constant temperature year round, usually between 7-21 degrees Celsius (45-70 degrees Fahrenheit) depending on geographical location.
You've got to go a long way below frost line to have an almost constant temperature. Think about it: dirt just below is going to stay toasty when it's frozen a few inches, or feet above?
Takes about 20' deep, depending on local conditions. Why 20'? That's the distance heat will move, unaided, through dirt in half a year. Add moving groundwater and things change, a lot.PAHS Designer/Builder- Bury it!
Here you go:
"Passive Annual Heat Storage" by John Hait, 1983. ISBN 0-915207-00-1
PAHS Designer/Builder- Bury it!
Edited 11/3/2006 9:18 am ET by VaTom
Thanks for the post and diagram. I think what it shows and what you are saying make sense. It does seem to show more of a flucuation than I'd consider relatively constant perhaps they are implying the temperature is relatively constant compared to air temperature. From what I've read before I wouldn't expect that diagram to be applicable on a broad scale as soil types, water content, and ambiant air temperature is all going to make a difference. The diagram looks like it is calibrated to a frost line of 10 feet - that seems quite deep; I thought 4 feet was fairly typical - but even given that, I am suprised to see how much further down from the frost line you have to go to get to the more constant 7/45 degrees. How deep should you bury a horizontal loop relative to the frost line? Surely not 20 feet, 400 foot long trench at 20 feet deep would cost more to setup than to do a 300 foot vertical bore shaft.Thanks for the discussion!
Hait did his work in Missoula, 8125 heating degree-days, in conjunction with The Rocky Mountain Research Center. Clearly geology, and particularly ground water, will influence ground temps. Like most things, you get great moderation with some earth cover, but diminishing returns when you go to great depth.
How deep should you bury a horizontal loop relative to the frost line? Surely not 20 feet, 400 foot long trench at 20 feet deep would cost more to setup than to do a 300 foot vertical bore shaft.
I'm not the guy to ask. Looked into ground source heat pumps for a client once and was shocked at the cost. A friend recently had a large complicated system installed, depth here was about 5' (frost depth 18"). Shallow burial clearly works, just not as well as deeper would. Cost/benefit?
Hait, and I, go the other way. Place the house where you get that almost constant temp, make the temp comfortable, and forget about the heat pump and plumbing. Going down 20' isn't any more practical for a house than a loop, so we insulate above whatever earth cover we choose to pay for, going out 20' from the perimeter. If ground loop installers insulated above their installations they'd get better efficiency due to approaching annual heat storage.
I don't know enough about the systems. Cost wouldn't be very great. Pretty sure you'll get some very peculiar looks if you ask. My friend had great difficulty finding an HVAC guy who knew anything at all about ventilation. Insulation was not brought up.
You chose an appropriate name. Something we all should be. If you do learn anything about insulating above ground loops, please post. As I said, sounds reasonable, but I don't know enough. PAHS Designer/Builder- Bury it!
I wonder if those hortizontal drilling rigs have merit in placing ground source loops?
I'm in the process of getting two projects going, both using geothermal with vertical ground closed loops. System for a 2400sq' 3 zoned house is around 28,000 bucks.14,000 for a 1600sq' 2 zone addition.Since space is limited, both systems use deep wells 300-450' in the driveways.HVAC guy sent me to:http://www.geoexchange.com/At least I know how to get the lines in the house now<G> "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
Any idea what the cost breakdown would be in terms of drilling the holes and everything else? How do you get the lines in the house?I've wondered about just digging below the drain tile on a newly poured foundation and wrapping pipe around the house several times to provide for the adquate piping and whether that would be effective enough give that you place some amount of dirt in between each layer. The ground below the footing would be wet dirt/clay and should conduct the ground heat into the piping easily enough.
The 2400 sq' two story is getting 2 300' vertical holes 2 1" loops in each. Grouted with bentonite clay. All the lines are fused, so apparently, no way they can leak. They are running through two sleeves in the foundation, 12" below grade. $8400 for the wells, grout, and the lines to the house. "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
I'm considering a slightly different twist on the ground loop. I have a spring that is a source of constant temperature water. I'm considering running a line from the spring (syphon flow, 30' elevation difference) to a concrete 1500 gallon tank buried 6' under ground. Copper coils in the tank would take the place of the ground loop. The tank would also be used for house water with RO for drinking water. An overflow line would be run off to a nearby creek. The water flow from the spring is about the same as needed by the heat pump. The coils and the line from the spring would be at the bottom of the tank with the overflow line at the top.
The Water Furnace company recommends that a ground loop be buried 6' deep. In southern states that depth would be at pretty much the same temp all year. Don't know about northern states.
I've also talked to 3 different people that have geothermal heat pumps in their houses. They all said their electric bill have been cut in half for both the summer and the winter. They all had all-electric houses and were out in the country where propane would be their only other choice for heating (or wood).
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
Edited 11/10/2006 12:13 am by PlaneWood
My buddy who just had a traditional ground source installed had a similar dream. Even wanted to use the spring for continual water source for the swimming pool. He scrapped the plan when it became prohibitively expensive.
Don't know the details, but his installer wanted a lot more money for using the spring.PAHS Designer/Builder- Bury it!
Well, it may be a dream right now. But, I can bury the tank and run the line from the spring for about $1200. That includes the price of the tank. My only other alternative for water is to drill a well and that costs $1500, minimum, with a 1/3rd chance of getting good water. Does not include the price of a pressure tank and pump which I would use for either approach.
The spring is there and has flowed forever, i guess, (at least 150 years) and the water is clean, clear, and cold.
This is on 60 acres out in the country. The only water there now comes from a hand dug well 40' deep and 6' diameter. After pumping about 100 gallons, you have to wait 24 hrs for it to recharge. My former renters did run a surface line from the spring to alleviate that problem.
I just recently had dozers in to clear the timber. After building a new house, the old house will be demolished.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
Mike, I wasn't suggesting that it was an unrealistic dream, just that my buddy didn't find anyone to do it. You know, hire the expert and you're going to do things his way. Go counter to prevailing practice and it's more difficult.
Amazing that you can get a well drilled for $1500. Easily twice that here. Nothing against spring water, but you'd find the health dept here unhelpful. Not one in the state that has the required coliform level. I considered developing a spring, bought a drilling rig instead ($2k).
Looks like you have a nice area. Medain home of only $162k, 50" annual rainfall, Jan low of 41º, July high of 94º, 1399 heating degree-days, and 3010 cooling degree-days. Nice mild climate which will make it very easy for you to figure out a low-energy house. http://www.homeinsight.com/home-value/TX/katy.asp
I certainly wouldn't bother with a heat pump there <G> but it'll work. If you're paying a high premium for ground source, looks to me that you'd do very well with air source, considering your air extremes.
Hope you're gonna post about the house.PAHS Designer/Builder- Bury it!
Tom, tangent. Someone on another site asked about PAHS. I gave some answers based on what I've learned from you. He wanted more info, sent requests to some places found through Google, got no response. Is there a reliable source of info where someone can go and get questions answered?
The short answer is: no. PAHS, if you don't know me, is pretty obscure.
http://paccs.fugadeideas.org/paccsforum/viewforum.php?f=3&sid=da9f2b1f9698c693d09ba862e21bdd0d is a moribund forum ostensibly on the subject. The originator now seems to think that active geo-solar systems are a better solution, not that he has any experience. I wish I knew more about them (annualized geo-solar, AGS) but the Pacific NW guy responsible for the term isn't interested in providing details. At least not to those who don't employ him.
Where did your acquaintance send info requests? If it was Hait (the author) or Rocky Mountain Research Center, they aren't overly interested in conversation. There's an engineer in the Denver area who offered to do modelling for me, Joe Anderson, who's listed at the end of the best excerpt http://www.axwoodfarm.com/PAHS/UmbrellaHouse.html.
Joe's also been involved with tire bale houses with a similar heating/cooling system. I don't know him or his expertise, but he's interested/interesting.
I've posted more here on BT about PAHS than anywhere else I know, based on both my experiences and heat/loss gain calcs. Amazing, the amount of email I've gotten from that one web page the PAACS guy put up about our place. A stalwart from the ferrocement list found it and tried (unsuccessfully) to get me to go for more commercialism.
PAHS Designer/Builder- Bury it!
Thanks, Tom.
Tom -
This place is up in eastern Oklahoma. The house will be a 2nd house for recreation for my wife and I and our children and grand children.
I will use an RO system for drinking water. However, people have been drinking this spring water for it's entire history. The watershed covers about a 5 sq mile area of rugged hills with virtually no inhabitants and no cattle. Nearest house is 2 miles away. I have made a concrete collection basin for the spring and the whole thing will be covered and protected from surface water.
I am an engineer by training and the heat flow calculations for the heat pump were fairly easy. There will be some temperature rise in the concrete tank on a hot day, but it will stay within design limits of the heat pump. WaterFurnace has all the technical data on their web site. I should average a SEER of about 15 - 18 for cooling.
Actually, it was a WaterFurnace retailer/installer in Arkansas that suggested the concrete tank. He said that he had installed several that way to take advantage of springs in Arkansas. Though my spring is small as they go in my area, it should do the job. Neighbor a few miles away has one that flows about 10 GPM. He also installed a 1500 gallon tank for it.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
For interest- have geothermal up and running in NH - Used Climate Master 3 ton system top of the line Tranquility. Unit cost about $5500. Installation of air ducts etc about $4k. Using well water and recircing to the well. So the well is no extra cost. House is about 1250 sqft. System works like a champ. Figure the system cost close to oil fired heat (by the time the oil tank and stack is installed.
That's a very reasonable sounding system...did you do a self-install? "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
Using well water and recircing to the well.
Whaaatt?
Please describe that a bit. From where I'm from, that'll get you hung.
That's how our geothermal system works. Works well too but I wonder abou the wear on our pump and the energy used to raise the water to house level plus another 40 PSI.
Semipro
"Using well water and recircing to the well.
Whaaatt?
Please describe that a bit. From where I'm from, that'll get you hung."
I'm referring to a potential contamination of the aquafier.
Yes, you've got a closed system, but there is always the potential for something being introduced as it goes thru the equipment and back into the well.
My past experience with GSHP involved a pump and dump method. Whatever was pumped out of the well and thru the equipment was then simply dumped over the hill and it flowed back into the wetlands. They were quite against re-injecting the waste back into another well.
this is a question for the people who claim that they heat their superinsulated house with a wallmart heater: have you ever had a real heat loss calc done? if so, does the calculated figure jive with your actual btu usage? how do you keep the temp consistant throughout the house-does your erv provide enough air movement for that? also, please include some details such as sq ft conditioned, construction/insulation, # of people, solar gain etc.
i have run across some articles suggesting that elaborate heating systems are overkill in tight efficient houses; icf, sips, spryed foam etc. anybody have experiences?
frank
I was told by the WaterFurnace people that you'd need at least a 300' column of water in a well with a 6" pipe for that to work. That would only be about 470 gallons of water in the entire column. They did not recommend that approach.
I guess if the fresh water was entering the column fairly high up and the pickup pump was at the bottom of the column, it could work.
And, as a matter of fact, many low producing wells are completed that way. That gives enough buffer to prevent the water level from getting below the pump. It would also prevent the pressure head from the returned water from forcing water back into the producing formation. I think a 3 ton unit would be pushing it though, for a low producing, 300' deep well. 2 or 2.5 ton probably would work under the right conditions. Lot of dependencies here.
Since your returning the same water that came from the well back to the well, I see no environmental problems with that approach.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
"Place the house where you get that almost constant temp,..."
Tom - Do you mean locate the house in a certain geographical region?
"Place the house where you get that almost constant temp,..."
Tom - Do you mean locate the house in a certain geographical region?
Absolutely not. The design I followed originated in Missoula. What Hait (and I) did was to create a dirt situation around the house where the temp is almost constant. Far as I know, it can be created about anywhere that's not underwater.
Haven't had an opportunity to test, but I'm quite certain I know how to create a dirt mass for a cooling-only climate. Somewhere in these archives, if Prospero would cooperate, is that conversation. David (Alaskan, whose surname escapes me) once opined that PAHS was applicable in Alaska with a heating-only climate.
It's a matter of doing heat loss/gain calculations and tweaking the dirt temp accordingly. We could do a lot better here, if I bothered. Our house temp annual swing is almost twice Hait's. PAHS Designer/Builder- Bury it!
As to the question "how deep should you bury a horizontal loop relative to the frost line", the answer is the same as "how deep and on what spacing do you have to drill vertcal bores?". The answer is, it depends on the site soils test. BTW, horizontal loop fields are seldom used in anything other than resdiential jobs, because the control of the "bore" is impossible, and the only way to be sure that it will work is to grossly oversize them. Vertical bores are more consistent, 100 times easier to grout, and obviously take up a whole lot less real estate. When involving professionals, the cost difference is minimal.
"The temperature of the ground where the system is installed will never be below zero."
Which is why I was refering to the liquid used in the system, not the ground. The system affects the ground temperature. If you have 300 foot deep vetical bores on 15 ft centers, you will take the temperature of the gound below freezing in the winter. Below zero was a misstatement on my part.
"Becauses this temperature remains constant, geothermal heat pumps perform with far greater efficiency and in a far larger range of extreme temperatures than conventional air conditioners and furnaces." That statement is a fallacy. The term "undisturbed" has to be applied to "the ground" for that statement to be true. Once you have installed a series of heat exchanging loops in that ground, the constant temperature no longer applies. In the summer, when heat is rejected to the earth, it heats up. In the winter, as heat is extracted from the ground in the loop field, the tempearture drops. This is simple basic thermodynamics, laws of physics. In the reality of economically viable systems, i.e. those in which the loops are as close as possible and still far apart enough to still work, the ground is affetced by the process.
there's a couple other things about ground-water source heat pumps:
they have a high initial cost
the ground loops have a high cost
if you have moving ground water , the source will be more efficient
.. as the system is used it will effect the ambient temp around the ground loops
OR, it will raise the temp in the vertical shaft.. thru a short circuit.. if you use an intake shaft & a discharge shaft
the ground source heat pump is high tech and high maintenance... the companies that make them do not have a long life.. most do not stay in business as long as the terms on their warranties.. a lot of this has to do with a lack of sales volume.... tehy keep inventing better equipment , but the sales do not support the investment
you know how hard it is to get a plumber when you need one... now think about getting a refrigeration tech who knows heat pumps, refrigeration, water pumps , electronic differential control systems, etc...
all this for a residential application...
been there , done that, bought the tee shirtMike Smith Rhode Island : Design / Build / Repair / Restore
"the companies that make them do not have a long life.. "
Trane and McQuay have had (and I'll venture will continue to have) quite a long life.
Some of the lesser known companies such as WaterFurnace and ClimateMaster may be relatively new. I don't know their history.
These are the only ones I have dealt with personally.
Ground loops typically run around $3500 to 5000 / ton, in my area of northern IL and southern WI, drilled and grouted.
For a residence? I wouldn't.
Tim, why not for a residence? I just sold two clients on it, and I'm grinding down another...shoud I go back to wall units?<G> "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
The real payback on a residential system is about the life of a lot of the components, if not more than. I like the systems and push for them in commercial applications whenever possible. I am in the process of retofitting a school for geoexchange. Large savings to be had in this scale of system, where the diffence in cost, usage and actual energy savings doesn't provide good justification for the complication and expense of installing a 4 or 5 ton system for an average house. Regardless of what you use for your sales, the numbers are not there.
I'm not trying to be argumentative, just trying to understand.The systems I'm seeing here are not much more complicated than an air source heat pump. I'm being told that the systems are well suited to our hot weather. The 5 people I know that have these are very happy with them.I know they're not cheap, but a 16SEER air source system for the same 2400sq' house would cost 17 grand. I see air source units that have gone bad all to frequently.I'm also told that there's about a 12 1/2% return per year on the tax dollars spent...I know both you and Mike are from colder climates...does that have any bearing on the geo performance/reliability? "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
I am only familiar with closed ground loop systems. The sizing criteria, even in northern IL and southern WI is still cooling demand, at least in commercial applications. In residences, which I have very limited experience engineering HVAC systems (people just don't want to pay for a well designed system in their McMansions), but in this area, the system sized for cooling, has a lot longer of a payback in a residence. Again, I am not well versed in the costs or effectiveness of either open systems or with the "trench" method of closed ground loops.
Air source heat pumps in this environment are not common, for good reason. You spend most of the winter on secondary/supplemental heat. (You don't get much heat out of -10 degree air)
I will ammend my statement about a residence. I would pay to put one in my house. I live in the country and propane is the only viable fossil fuel available, which is quite a bit more costly than NG, usually. I could also live with a marginally (not conservatively which I would have to provide in a commercial or school application) sized system. On those 100 degree days, so it doesn't get to 70 inside. Or when it's -15 out, might have to have a little supplemental heat.
I know how I operate my AC system vs how a commercial building operates their AC, and that is where I see the payback as limited. As the saying goes, your mileage may vary...
Good points.
I had a Carrier GSHP in my last house - it worked well, only cost 7K or so since I did my own ducts and dug my own lines...and the lines are guaranteed 50 years...
but...
After I sold the house the lines lost pressure (no problem, I knew how to add a little water, and did twice in 7 years) but the original contractor wasn't around anymore, and fixing the lines meant a lot of digging. The last time I drove by I saw a new heatpump unit sitting outside - they must have given up.
I think dollar for dollar, insulation is a better investment (as VaTom would argue)
I'm in ICFs now and heating the house with a $15 walmart heater. To me that seems "greener".
Treat every person you meet like you will know them the rest of your life - you just might!
i guess that wound up as my bottom line too... we used to distribute Water -to-Air heat pumps ( geo-thermal ----Vaughn Corp ), wholesale & retail
great concept... lousy life-cycle cost
insulation makes heating and cooling a no-brain lo-tech problem
heating ? : 20 couples dancing... or a small propane water heater....your choice..
cooling ? a couple window shakers or a thru-wall sleeved unit
it breaks ? get a new one at wal-mart for $80
super insulation ... hard to argue withMike Smith Rhode Island : Design / Build / Repair / Restore
Hey Mike, I'm curious about your equipment poo-poos. The fellow I'm hiring has been doing this for over 25 years...really seems to know his stuff. He's using a Florida Heat Pump: 2-stage, variable speed R-410 horizontal packaged w/1 2-pump purging/pumping station...guess I'd better check out if Ralph knows 'em?<G>Anyway, he says the equipment lasts much longer than air source pumps, because they're inside, out of the weather...and he's been touting their incredibly low maintenance...I know the upfront cost is high, but it sure does seem like a lot of folks think it's the way to go.Edumacate me brother<G> "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
I'm not Mike, but I will comment on something you stated in the last post:
"The lines are fused....apparently can't leak."
Sure., it makes a lot of sense, but if they do leak, they'll need to be pulled (the well arrangement makes this easier than the trench way) Mine were fused, and somehow leaked (even though they were buried in stone dust), and the installer was very experienced and fastidious.
One other comment - people thought I was experimenting with new technology...havent GSHPs been around for 30 years?
I personally found low-tech/high insulation to be more appropriate in my application.
Your mileage may vary.
Treat every person you meet like you will know them the rest of your life - you just might!
Could you figure out why or how they leaked? I'll definitley be finding out about the warrantee<G> "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
snort... i'm just not a high-tech guy.. i 've tried a lot of the hi-tech solutions and they don't last around home -owners
we got involved with water -to-air heat pumps in the mid -70's... i even got a $10K grant from HUD for a Solar-heatpump system
liquid collectors, 10K gal concrete storage, water -to-air heat pump for heating and cooling .. with the 10K water reservoir as the heat sink
first time the home owner need a techy to service the heat pump.. he balked at the hourly rate
had them disconnect and installed an oil fired furnace
another one .. water-to-air heat pump with solar collectors heating an indoor swimming pool.....
owner got tired of servicing the equipment... too high tech
equipment is only as good as the service company that keeps it going..
insulation is forever
think refigerator... you buy it , it runs for thirty years , then it shids the bed...
that's the level of reliability people expect... they tire quickly of dealing with HVAC techs servicing black-box water-to-air heat pumps
i don't want to deal with techies ... and ther is nothing more technical than a ground source heatpump system... NASA engineers might like it... but not me
i think we sold about 20 systems in the '70's with water -to -air heat pumps
i can't think of a single one that is still running.....
but the low tech stuff is still chugging awayMike Smith Rhode Island : Design / Build / Repair / Restore
Wow, I can't believe I've finally become a modern kinda guy...I might have to try those frosted shredded wheat things!<G> "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
>He's using a Florida Heat PumpSnort, I have FHP in my house. It's just been chugging along. Get the lines purged of air every few years. Had a compressor replaced under warranty. Runs fine, low noise, low maintenance. To me it's just the 3' x 3' x 2' gray box in the basement that purrs along and gives me heat in the winter and cool in the summer.We have a vertical loop. They're more risky in that any problem is all or nothing. You're likely not gonna locate and fix a leak, so you'll be drilling a new well. My installer prefers the horizontal...charges less be/c they're easier. We didn't have a choice.To put Mike's comments into context, he just discovered music comes on 8-tracks. :)
Cloud and Tim...I just read that there is some vertical closed loop pipe (since that's what we're all talking about) that has a 50 year warranty...I've got a call in to see if that's what the well driller is using...Cloud, did you use the FHP because you wanted it, or because that's what's available? Did the compressor go out in the 1st year? Know why?Do you find the heat and air to be as even as advertised?We should get Sphere to send Mike the Wayne Newton Collection on reel-to-reel for his birthday..."Donkey shane, my darlin'..."ha,ha,ha "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003
Our pipe is HDPE--high density polyethylene--described to me as similar stuff as milk jugs, but thicker. It was thick, hard to move and bend, black. The tool for making joints was a dual-sided iron. One side melted the male component, while the other side melted the female at the same time. Pull them off the iron at the same time, line them up and jam them together in no more than a second or two, and hope you seated it right or you're cutting it out and starting over.The compressor was about 5 years old.Used FHP be/c that's what the contractor ordered, and he's done many, many installations throughout the mountains and Piedmont (based out of Hickory).The output of the unit measures about .5-1 ton above its rating.In terms of evenness, that's a function of the distribution part of the hvac system (RFH and Hi-velocity AC for me) and not the source (GSHP). The source provides what we demand, with capacity reached (as planned) as we exceed design temp. Like any other system, sizing the system per the load is important.>I've got a call in to see if that's what the well driller is usingbtw, my well driller just drilled the well. The gshp contractor was the one who prepared the pipe and dropped it down the hole, which itself is a story worthy of Great Moments in Homebuilding.
Edited 11/10/2006 1:36 pm ET by CloudHidden
The HVAC man told if the well driller dug a dry one, don't let him fill it in!Water wells run abour $9.50/' here (without casing)...that bentonite, extra pipe, and fusing, would sure look good in a dry hole<G> "I am the master of low expectations." Georgie Boy, aboard Air Force One, June 4, 2003