Anybody have an information on doing a ground source heat pump using a lake?
What kind of water depth is needed? What is used for an heat exchanger, etc?
This will be in the Kansas city area.
Anybody have an information on doing a ground source heat pump using a lake?
What kind of water depth is needed? What is used for an heat exchanger, etc?
This will be in the Kansas city area.
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Replies
I saw this once and i don't know how well it worked but the guy who had it said it was there when he got there and he thought it kept his cooling bills down...
small electric pump sucked water from about 30ft down in a lake where the water is pretty cool a 30ft... deposited it in a concrete tub where the central a/c coil was submerged... the water spilled over the tuband out a small hole in the bottom and down a man made "creek" back to the lake...
i asked about the small hole in the bottom... he said the pump was controlled by the thermostat and the small hole in the bottom would drain the tub just in case he ever forgot to drain it before it got cool and would freeze up... and that the compressor was on a 3 min delay to give the incoming water enough time to cover the coils when it called for it...
pony
i know it wasn't what you asked but i just happen to remember it and wonder if his system really worked...
I think that my area is too cold for that kind of setup. You could probably get by with it 95% of the time.But when you needed heat the worse it would freeze up.But I know of someone that just put the condenser coil in the lake. That was about 25-30 years ago.I could not get by with that where I am, even if I trusted it.
A friend had a house north of Toronto that used this system. He had a quarter acre spring fed pond. He could pull enough heat out of it all through the winter to heat his large house, garage and shop etc. All new construction and well insulated.An ex-boat builder treading water!
I would call this geothermal.
I've looked into it and for a 2800 sq ft house it ran about $24,000.
you can use the following for the geothermal part:
Water or antifreeze is pumped through a pipe in the ground, well or lake, and the "heat pump" unit either takes in heat or gives off heat depending on the time of year. (not a real good description, but you should be able to find a better description searching on geothermal).
hope this helps.
Roger,
That's about the best short description of geothermal I've seen.
SamT
I know what geothermal is.And yes there is lots of information about it.But my question is specifically about using lakes. That is as very specialized application.
I have a friend who has a setup like that. Don't know a lot of details. I do recall him saying that his HVAC guy said he needed an 8' deep pond for the thing to work effectively. He had a special pond built, then hoped like heck it would fill up before he needed it in the winter. (It did, but just barely)Haven't seen the guy for a while, but I might be able to get some info from him. Is there something specific you're looking for?
Seen it all, done it all, can't remember most of it.
Well the 8ft is one of the things that I am interested in.The other is some idea of the size of the coil or what whatever was used and how it is "mounted".In my case the lake is full so it would have to be sunk rather that installed in place.
I inspected one house a couple of months ago under construction being set up to do that.
It did not give the appearnace of being an inexpensive install.
If you like, I'll dig up some of the photos.
(FWIW< for that sort of odd-ball thing I tell them to get an expert - I'm a generalist!)
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Sojourners: Christians for Justice and Peace
If you have them I would like to see them.The new issue of JLC came yesterday and they have an article on Direct Exchange Geothermal Technology.They don't use water for heat transfer, but directly burry, or put into wells, copper carrying the refigerant.It list too companies ECR Tech (http://www.erctech.com) with EarthLink brand.And American Geothermal, http://www.amgeo.com But all I could find on their web site was for industrial processing and heat recovery.
4 shots attached:
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Sojourners: Christians for Justice and Peace
Is that lake source or regular ground contact?Do you know any more details of how it works?1) it appears that those are water and not freon lines into the AH. that implies that water/freon heat exchanger, compressor and evaporator coil are all in that one space. Or is is hydro-air with compressor and heat exchangers elsewhere?2. Is that hot water setup just for potable water or does it run radiant also?3. That is a Rheem Marathon electric water heater (gray tank) that is plastic and a convential steel electric water. Looks like they are going to be in series, but hard to tell.But it could be a "solar heat exchanger/heater/storage" http://www.rheem.com/consumer/catalogRes_detail.asp?id=26&brand=RuudThat would make more sense. With the HP also provide hot water.But the connections that I see from the "furance" appear to tap in at the top (cold water supply?) and the drain. So that would make it a regular tank and hot a heat exchanger.
I'm 90% certain it was running to a man-made lake close to the house.Beyond that, I don't know much - I was there for a partial inspection of some spectacularly crappy brick facade work, and ran across the unit in tha basement and snapped some quick shots.
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Sojourners: Christians for Justice and Peace
Bill, I'm speaking from about 7 years ago when I had mine installed - but not into a lake.
They run the plastic pipe into the lake and back buried below the frost line as someone else said. You may or may not run into enviromental issues. You may need some protection from accidental damage from a boat anchor or such.
If the pipe gets buried natually over time, no big deal. It still functions. Commonly the installers give some huge warranty like 50 years or more on the installed pipe.
Everything is in one unit - save for the seperate control panels monitoring the circulation pipes - you see them on the back wall - just above the valve assemblies of the pipes. Lots of insulation on the pipes.
The hot water setup involves extra heat available from the cooling phase of the refrigerant. It's passed thru what's called a "desuperheater" or something similar. The extra heat withdrawn at this point is used to preheat the incoming cold water for the DHW. This stepup enhances the existing heater's capacity and allows the contractor to sell another feature - unlimited hot water (some of the time). They do feed a pipe into the bottom of the tank where the drain tap is.
As far as radiant, I dunno. But it would seem to be philosophilically in conflict with the one system one box concept. They like to have some form of backup heat available for the unit should something fail or demand calls (commonly electric). Using the excess tap for radiant seems to be contrary to the backup issue. Although I bet there's some bright guy that's thought it out.
Bill,
Strange how it happens, I just met a pro guy minutes before reading your question. He is the director of an energy utility, and has a lake-sourced heat pump at his home. He described me the general layout, but we didn't discuss too much in detail. This guy is your perfect source for more info. And, by the way, he's located in Toronto (Canada), which is most certainly a colder place than yours. If it works there, it will work for you too. For obvious reasons I can't post his contact info on the forum, but if you give me your contact I can either ask this guy to call you, or give you his phone/e-mail.
Here in Canada we don't understand the big fuss about freezing. A lake never freezes below 3 ft depth; same with the ground: you bury your pipes under the frost line. If you absolutely have to go above ground, you just make sure that you have water flowing fast through the pipe, and that the pipe drains fast when you have to stop the flow. Simple, and it works; if it didn't, we wouldn't have drinking water in our homes...
Let me know if you're interested in talking to this person.
ThanksI have bookmarked this. From what I have gotten here and over at HVAC-TALK I have the basic infomation that I need.
Cannot say about ground source, but I once built a home on a lake where we used an open-loop geothermal arrangement, using well water, and discharging into the lake.
It was an excellent arrangement, but you need a good well to do this.
Bill,
My last house that I lived in had a ground source heat pump. One of the contractors that I had give me a bid had a ground source hooked through a pond on his own property. I believe he said the water depth was 9 to 10 feet (central Iowa). He claimed that it worked excellent and that the length of pipe and loops are the same as what is needed in a vertical loop setup. For my own install I ended up going with the vertical loop setup, for every ton of compressor compacity that we had (3 ton) we needed one loop 185' deep. The pipe size is 3/4 black poly pipe geothermal grade and all it had was a street L and a 90 degree elbow thermal welded at the end to form a loop. Environmentally friendly antifreeze is circulated through the loops, 80/20 mixture. The exchanger is built into the unit. Hope this helps!
Although I had a nice pond on my lot, I choose to go to a pump and dump because I knew within 5 to 10 years, I'd be redredging the pond. Them rural ponds have a way of filling in over time.
The way I understand you have to have a fairly decent water quality to use that method.
To add to my last post, just one more thing...the contractor I was telling you about said the lake source was the cheapest way to go. Because basically you excavate up to the edge of the lake and into the water a touch and sink the loops.