Geothermal heat pump

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Jdoll42

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What is the approximate cost of your system?

Installation or operational? Complete install in a new house was around $26k. (See posts above).

As to the operational costs, I'd have to look at my bill for the exact kWh cost. I can tell you that my parents house is half the size of mine, has gas heat, gas hot water, and gas dryer, and their power bill is twice mine. (My house is 100% electric.) Their house is only 18 years old, so it's not like it's a 200 year old house with no insulation.
 

Jadnashua

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NH's nickname is the granite state...wells here are a major pain. They may end up deep, and then when you do get water, you may find it is full of radon gas, which isn't the nicest thing to have spraying out the showerhead (the heat releases it, and you suck it deep into your lungs, giving the radiation maximum detrimental effect!). that would be a multiple day affair here. Still, the local schools are thinking about doing it for an upgrade to the heating/cooling system as we have some of the highest utility rates in the country.
 

Gear Junkie

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A customer of mine has a 4000 sq ft home and his electric bill was close to 250 a month. After he got geothermal, it dropped to 100 a month. I'm definently going to have it in my home and lots of government facilities are already starting to plan for it's use.
 

Jadnashua

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I use about 600KwH per month, and my bill runs about $85. My guess is that the electric rates there are a lot lower than mine! Ground source heat pumps are good. Around here, though, you find it hard to drill down, or have enough soil to bury them (even if you do have the acerage you want to tear up to install it that way).
 

Jdoll42

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I use about 600KwH per month, and my bill runs about $85.

I just checked my last bill. My usage for Jan. was 3598kWh. The first 2000kWh was at 0.08715 and the last 1598kWh was at 0.06272. My kWh charge totaled $274.53. I know it's not New England or anything, but we've been getting down to the teens most night and maybe breaking freezing during the day. Add the wind to that (I'm in the middle of an old horse pasture with no defenses from the wind) and my system seems to be chugging along pretty well most of the time. With that said, it RARELY hits second stage and I don't know if it ever touches the electric strip heaters inside the unit.

Looking at my historical usage, my worst months are Jan-Mar. However, in the summer my kWh usage barely exceeds 1200kWh, if even that much. That's trying to cool down 90-100F air with between 70-90% humidity down to about 72F.
 

Bill Arden

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I've been trying to convince a directional drilling company to try what I call a "Star" configuration, but most charge by the foot based on drilling a few feet.

The concept is simple in that you make a pit and turn the machine in a circle drilling down at a angle with it set to curve upwards. You then use a back reamer to pull a pair of pipes back with a U at the end. You pull the far ends down below the frost line and then tie them together in the pit to make a series of radial fingers.
 

Bill Arden

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I have the summary from the power utility. Since I use mostly baseboard electric the kWh follows heating.

kWh total for year =35,685
$ total for year = $2,442

Highest month = February
kWh = 6,590
$ = $397

So this shows that a heat pump would save me a bit of money.
I've found a used unit cheep and plan on using a "pump-n-dump" system using a shallow well and dumping the water in the yard.
 
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Speedbump

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Be aware that some shallow wells have large amounts of iron. The tubing that exchanges the heat can become useless when clogged with iron. I know this first hand with the GWHP that I had about 12 years ago. It was a major pain. If you have pristine water or are going to recirculate clean water, this wouldn't be a problem.

bob...
 

Bill Arden

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The water has iron... I am not far from the "iron range"

I just plan on cleaning it out using vinegar like others do.

It's a stepping stone to a closed system.
 

crater

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just wanted to add my 2 cents in also jdoll, I haven't got my Geo all in yet but it is going to be 1- 300' well "Pump n' dump system", the idea is that the return water that is returned at the 300' depth will be moved away by the aquafur before it could be pumped back up. The submersible pump will be set at 150' at least 100' away from the return. Here in Iowa they have had some problems with the return water freezing the well in the winter, so they also dig a return pit and fill it with rock just in case the weather would stay cold for weeks on end. then at a predertrimened water temp a valve that automactically switches over to the pit would be turned on to avoid a freezing problem. Sounds like alot of crap that could potentially go bad or fail over time (High maintence) but for a $30ish heating bill I guess I can't complain. My system also costs about the same. mine is estimated to come in for $21K well and pumps included.
 

Bill Arden

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the idea is that the return water that is returned at the 300' depth will be moved away by the aquafur before it could be pumped back up.

Here in MN it's illegal to pump water back down a well.

I've not heard of water freezing problems as most systems I've seen use a sloped drain pipe that drains when the system turns the water off.

The snow on the ground insulate the ground and keep it thawed out.

Anther problem is that removing deep water can cause problems since that will draw contaminants down into the aquifer.

So the consensus is that "Pump n' dump" systems should use shallow wells.
 

boze62

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boze62

I will agree with some of the posts, geothermal units are high maintenance machinery. I have a well to well system (open loop) installed in 1992 in a new home construction. I was living in a 962 sq ft home with elctric baseboard heat averaging $125/month in cost (no A/C). Then I moved up to a 1500 sq ft home with heat and A/C and kept it slightly warmer, and my average that year was the same!

About $3000 extra cost for the system, $3500 to drill a 290 ft well to supply (used the old well as return well or likely would have been another $1500, it is a 120 ft well which handles the return flow). I know I am ahead of the game, but maybe only by a small margin after replacing the pump once, redoing the soleniod shut off and in home supply and a couple of other things. These guys are not cheap.
 

crater

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Yea Bill I'm kind-of leary about pumping back down my well also, but it is not against the law here in IA, I know a couple a people that have the same system and love it, however they both pump back to surface (Pond,creek), I just talked to my HVAC guy, he said that this was the only year he has ever had a problem with the freezing of the well, the return water is around 6d colder going back down than suppied. anyway they have a sollution for it, the discharge pit (French Drain)
BTY I have heard some rummor's that the state DNR is going to be looking into the pump n' dump systems, so it probaly won't be long before the outlawed here also, especially since neighboring states have already have banished them.
 

CWinAZ

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Would like to use a cistern as my water source for GSHP

Greetings! I am new to this forum, my first post. I have a question and have been searching for an answer. I live in Metro Phoenix, AZ and want to install an open loop GSHP system using a cistern for water source and return. My home is a 2 story and currently has 2-3 ton air to air HP's. Reading from several sources I would need about 18 gpm of water. How many gallon capacity buried fiberglass cistern would I need? I plan to use the water to irrigate a small area in the back yard and collect water from the roof to add to the cistern when available. Not allowed to drill a well in the neighborhood and am on city water and sewer.
 

bartman99

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Returning water back to well

just wanted to add my 2 cents in also jdoll, I haven't got my Geo all in yet but it is going to be 1- 300' well "Pump n' dump system", the idea is that the return water that is returned at the 300' depth will be moved away by the aquafur before it could be pumped back up. The submersible pump will be set at 150' at least 100' away from the return. Here in Iowa they have had some problems with the return water freezing the well in the winter, so they also dig a return pit and fill it with rock just in case the weather would stay cold for weeks on end. then at a predertrimened water temp a valve that automactically switches over to the pit would be turned on to avoid a freezing problem. Sounds like alot of crap that could potentially go bad or fail over time (High maintence) but for a $30ish heating bill I guess I can't complain. My system also costs about the same. mine is estimated to come in for $21K well and pumps included.

Hi Crater,

I just found your post. I was wondering how your system turned out? I am contemplating the same thing. We live in Virginia and have a 400' well (12gpm).

Does your well also supply potable drinking water? That is what we are contemplating too. Any specs on how the water temp in the well is affected by the heat pump return water? One fear is that the aquifer will not be able to handle the temps and will eventually reach a steady state with the HP (ie become too warm or too cold to be effective). Have you or any of your neighbors had a problem with this?

Thanks in advance,

BM
 

Bill Arden

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Metro Phoenix, AZ ... open loop GSHP system using a cistern for water source and return.

Ouch.

It's not just the flow rate. you need to figure out how the water is going to be cooled back off again.

I would suggest you start with a closed loop drilled well system. to save costs you could start with cooling only using a water "A" coil or some other water to air radiator.

The closed loop wells last "almost" forever so in your case it is a good way to start.

Edit:
"almost forever" in this case is defined as the life expectancy of burred black plastic pipe.
I believe it's in the 100's of years so it can be considered a gift to future generations since heat pumps are likely to be used more and more in the future.
 
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Statjunk

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Theoretical question. How far down would you have to dig a well so that when water is dropped down it will return as steam to power a turbine?

Couldn't you theoretically power a place for virtually free with a deep enough well?

Does this make any sense?

Tom
 

Jadnashua

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Geothermal steam very much depends on where you live. In Iceland, they generate nearly all of their electricity that way, but then the island is essentially an old volcano. In some places, it is feasible, in others, it isn't, and unless very near the surface, unlikely to be useful on an individual level. Now, if you live near Yellowstone, maybe it would be fairly easy to tap a hot spring.
 
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