Anyone here use a geothermal heat pump?
 

If so, how do you like it? Would you care to share the install price and/or monthly heating/cooling bills? These sound like great systems.

I looked into it last spring when we got our air to air pump. When I asked for a quote the salesman laughed. He then let me know that he has only priced one out for residential once and since it was about 8 times the price of the air to air, he has yet to see one. Considering my air to air cost about $12k with a fairly extensive electrical update I figure it'd have been at least $50k probably more.

But I can report my air to air with AC is has lowered my electric bill by about $75 a month (no more window units--no more space heaters in some areas). Also considering that I don't have to buy oil anymore I'm guessing replacing my heating and cooling system is saving me about $1000-1500 a year.

Sounds like its worth it. Thats a lotta dough to save per year!

I guess I'm not familiar with the air to air pump systems. Care to explain?

A friend of mine instaled an air to water system at his place,
wich is hooked up to his floor heating. He's still heavily remodeling the house, so he can't yet comment on how effective the system is.i haven't seen the setup but the exterior hardware looks like an AC. he said the system could still derive energy from the air as low as -15 degrees celcius that 5 degrees farenheid and for every watt of electricity it delivers 4watts of heatenergy. the downside is it costs about twise as much as a conventional natural gass boilers and it's more suited for pasive houses with limited additional heating required. still i'll be looking into this system when i'll have to decide how to heat my place

Why would a conventional heat pump not work if immersed in water?

Suppose you have a house on a lake or river, or ground water at easy depth.

If using such water source as a medium, simply immerse the heat exchanger portion of the heat pump. That way, you could dispense with the air fan and its associated operating costs.

After all, the freon inside the heat exchanger does not know or care what medium (air or water) is on the outside of the heat exchanger.

All it knows is that its temperature is changed as it flows through the heat exchanger.

And, since water is ~800 times denser than air, and since groundwater in the US is generally >50 degrees vs. <30 degree ambient air in the wintertime, that >50 degree groundwater has a whole lot more heat to extract, at much lower effort, than if the heat pump were struggling to heat your house from <30 degree air. Especially in a cold snap. Ditto the relative efficiency for summer cooling.

That's what I've been trying to figure out.
See thread http://ecorenovator.org/forum/geothe...thermal-c.html

Well, I asked my brother about this. because he's taken some airconditioning/heat pump, freon classes, and got some sort of basic certification in that stuff. Not a seasoned veteran of the HVAC business, but a bright guy who wanted to learn more about this to help with maintenance of his various properties.

Anyhow, he says a plain old heat pump, if its heat exchanger were immersed in ground water, or any other liquid medium of moderate temperature, would work just fine. After all, the freon or other working fluid inside the heat exchanger does not know or care what's on the other side of the metal membrane that it exchanges heat with.

So, why not put your heat pump down the water well, or whatever?

Re geothermal, I spent a lot of time composing a msg which got dumped before I could send it. -- Two ways generaly to go: drilling, and trench with coils. I like drilling But without expensive equipment you have a development problem.


See this item on ebay: Build A Water Well or Geothermal Drill Drilling Rig - eBay (item 220413261413 end time May-22-09 04:01:51 PDT)


For $40, plans to build a well driller capable of being operated with either a tractor or bobcat. Requires a welder and a few standard tools. Interesting descriptive material here. Suggests a possibility for building a low cost well driller which if not useful as a final tool for geothermal drilling could be justfiied just on the basis of gaining experience.

You might look at the archives of NATIONAL DRILLER. One guy there slant drills holes from a shallow hole 6-ft square. Appears to me the above plans might be adaptable for slant drilling, and you could operate the driller with the hydraulic system of any medium size tractor or Bobcat.

Anybody thinking along these lines?

Glenn Ellis
glenne1949@aol.com

My roommate works for a HVAC company that specializes in geothermal installations. Next time he is home I will try and get him to post some information regarding costs, capabilities and efficiencies.

Off hand I seem to remember most installations running from 10-18k depending on the situation. The systems run around 5:1 efficiency for AC. This means for every one watt of electricity used to run the system you get the equivalent of 5 watts of cooling. I believe it is even more efficient for heating, but I don't recall for sure.

Anyone know a good source to find detailed info on making a geo heat pump? would be awesome if i could cool/heat my house without the high costs.