water well pipe and geothermal potential
 

I have a water well, a 2" inch pipe deep in the ground( I don't know how deep), that's hooked to a small pump and tank which is used for gardening and other non potable water uses.

I know that my water table is high--we live between two rivers and the sump pump has water running year round, and it runs regularly.

How does one determine the extent to which this existing water pipe could be used for a small geothermal system-- perhaps to heat the basement or first floor.

I stumbled into this site, and am still catching up on a lot of information.

I have read about open and closed loop systems, but have found very little info on my type of water wells. My guess is that it's too small, but since it's there I am curious to know its potential.

thanks in advance
tc

So far, most of the interest on this site has been on Air Source Heat Pumps and on closed loop GSHPs.

There is a site, IGSHP that has very good manuals. The are expensive, too expensive in my opinion, but I know of no other source of information as good as these. In part, the reason for this blog is to make that kind of information freely available. If you are interested, you can become part of this effort.

You might email IGSHP and ask what manual they would suggest for you. I think that their original manual has information you are seeking.

If you are motivated, the 'homade heat pump manifesto' thread has enough info that you could build your own GSHP and then you could test the resources you have.

-AC_Hacker

Note:
I'm no expert.. But, I have read up on open loop systems a bit.
I wanted to know about freeze prevention etc. My 'knowledge' is pretty general..

A 2 inch, 100 foot pipe does not hold a lot of water. Under 10 gallons, I think.
Dipping a closed loop of copper down into the well isn't likely to be a good transfer source.

Unless the well walls are very porous to some moving ground water,
this looks like an open-loop app.

So, you need to find out what kind of flow you can get out of the well, during sustained pumping.

If you could get a lot of water out of the well without problem,
and, had another 'well' some distance away, to dump the water back into..

You might be able to harvest a usable amount of heat.. :)


The 'Dump' well needs to be a fair distance away from the source well,
so the water that's recycled, has a change to regain the ground water temperature.

I guess it all depends on the ground water level, and it's movement.
If it's stagnate / the ground isn't real porous..?.
Maybe a pump-out test will tell. It would be interesting to see if you could
learn about underground flow, by lowering a temperature sensor into the well.
If the water temp is higher than expected, that might mean the 'two rivers'
are influencing your well.. Which would a good thing!!
(If/when water temp of the rivers is actually higher than ground water).

Keep us posted.. I have high ground water and have been thinking about
all that 60deg F water sitting down there, a few feet under my basement.
It sure seems a waste not to tap it..

Cheers,
Rich

A rule of thumb for GSHP is 2 gallons per minute per ton of heat. Before my heat pump was installed, the installer ran all the water sources in my house (faucets, showers, etc) for half an house to see if pressure dropped at all. It didn't, so I have a 3.5 ton unit, uses about 7 gals per minute when running, which can be more than 50% of the time on a cold day.

Wow! That's going to be up around 5,000 gallons after 12 hours.. That's a truckload of H20!!
http://www.trucktanks.com/img/waste/wo006-01.jpg

The outflow keeps my 300,000 gallon pond/pool full so I can stock it with yellow perch. The overflow from that irrigates my plants, then goes back into my sandy soil.

So, 5,000 gallons is 1/60 of your pond.. A drop in the bucket so to speak.. :)

When I was a kid in south Texas, I recall eating a lot of perch.. (with a lot of bones).
It was danged good eatin too.. But I came to love Catfish later on and wouldn't
even consider perch if catfish was available.. :)

How's Yellow Perch? Good eating??

Very nutrition. Most fish fries in the midwest use perch. Here in Indiana we have the largest perch farm in the world. By raising my own from well water, it is probably largely free of pesticides and other chemicals in most lake water. Cheaper than buying them too. Fishing for them is an added benefit, but I can net them as well. Fun for the kids too.

]Wow! That's going to be up around 5,000 gallons after 12 hours.. That's a truckload of H20!!
:thumbup:
it would be 5000 gallons if you never shut off the system.. but since gshp are very efficient I would be surprised to see many of them running more than .25 of the time or 6 hours over the course of day

I plan to get an energy monitoring system that can monitor individual circuits so I know how much it runs. The installer said it would run 50% of the time, but I don't think it runs that much, and that is only when it is in the single digits outside. I spend about $1200 a year to heat my house, definitely cheaper than propane, my previous heat source.

a couple of things that come to mind.. the ground temp should stay within a few degrees in a properly designed system.. so even during the winter.. should not get much below 50 degrees.. which is considerably warmer than outside air on a freezing day. so the amount of time the system should run is much reduced...

The other thing is that normally gshp are sized a lot more correctly than a lot of air source hp..

Do you know this to actually be true, or is this a guess?

Both GSHP and ASHP are classified as low temperature heating. They are more efficient than oil, gas or electrical resistance, but their duty cycle (the ratio of on-time to off-time) is higher than heating with fossil fuels.

My ASHP runs pretty much all the time, but it is extraordinarily efficient.

-AC

an air source heatpump has a thermostat that cuts the unit off at 37 degrees. beyond that as the temp drops.. the return of heat drops off dramatically.. at this point back up heat comes on.. which if you have electric strip.. you can watch your meter spin and spin and spin.. if you are fortunate to have dual fuel.. where the back up is gas.. you will come out far ahead of strip heating.. This is why gshp is so much more efficient.. some of the newer units are claiming over 27 SEER .. general rule is that one can suck enough heat out of the ground that it provides 4 times the BTU for the draw on the power to run the pump.

the systems have to be sized correctly.. often multiple smaller units.. which are closer to actual heat loads as figured by "j" loading schedule.

But as I am fond of saying.. Conservation is alway a better alternative to running the meter.. Insulation over 20 years is cheap cheap cheap.. and power bills will only be going up up up in Obama keeps up his carbon cr*p which is nothing more than a giant power and money grab enforced by the EPA

My little unit is good to below 17F... I have watched it. Some of the newer ones are good to 5F.

I believe this is referred to as COP (Coefficient Of Performance).

COP = (energy-out) divided by (energy-in)

My homemade unit had a COP of between 3 and 7, depending on the source temperture (where the heat was coming from) and the sink temperature (where the heat was going to).

Regarding energy issues, you might want to check out a web site called The Oil Drum

Very useful information about what's going on behind the scenes.

-AC

ASHP at low ave temps are pretty good
 

My Sanyo 24KHS72 units work down to about 8F before sucking down excessive KWs.

During the heating season, on the average day, both of the systems go into idle mode a lot.
Of course, I over-sized them. (Just in case I move to a really big house). ;)

Here in MA, north of Boston, the weather isn't very severe. Must be too close to the sea..
http://pics2.city-data.com/w1q/lhaq11355.png
http://pics2.city-data.com/w2q/humq11355.png

This heating season was so mild (so far), we never had to use back-up.
I had it set to come on a couple of times, but the low temps never
effected the indoor temp enough to hit the set-point.
When it was down around 4F, I was asleep, but I'll bet each Sanyo
was using at least 1kw for a few hours.

an air source heat pump using 410a may continue pulling heat but you will find that it is greatly diminished beyond 37 degrees. There is always latent heat in the air.. how much power it takes to gather it.. is another thing. manufacturers are always trying to push that envelope. With todays prices on NG falling.. to $2.4 or less per million btu it really does not make much sense to run the compressor..

There are 1000 Cubic Feet per MCF or about 1,020,000 BTU's

Do you have any numbers to back this up?

It is just a guess?

Have you actually logged the performance to come up with this statement?

-AC

It is even worse. your wondering about my comments.. I used to sell HVAC equipment including GSHP.. ( fhp) so I spent a lot of time reading manufacturers literature. Cannot sell it to the professional if you cant tell the pros and cons

Ashp they do play some serious games.. with tiny compressors that dont have much capacity (did you ever wonder why there are so many different compressors all rated the same? Then they put in huge condenser coils and huge evap coils. If one goes to big.. the ability to remove humidity from the air.. drops dramatically.. but you will have cold air. but the dry bulb will be well over 55%

How long ago was this?

-AC

410a was just coming online

OK, that explains a lot.

There has been quite a lot of progress in the state of the art since then.

The new Mini-splits from Asia are quite advanced now.

You might want to look into a couple of them, Mitsubishi's Mr Slim is one and the Fujitsu Halcyon is another. Both pretty good. Xringer has a Sanyo that is a couple of years old, mine (also Sanyo) is maybe a year older than his, they've both been by-passed by new developments.

The developments have been in greater efficiency (COP) and also their ability to efficiently extract heat from colder air.

Most of the regular folks on this blog are pretty up to speed with the latest technology.

For your information, the current crop of ASHP is just about as efficient as prior technology GSHP.

For some reason, there has been quite a delay in applying the new technology to GSHPs, which will surely push them well out in front, efficiency-wise.

It is an efficiency race that we can all benefit from.

American designed equipment is just not keeping up with developments from Asia. They have a huge advantage with good engineering talent, steadily developing better equipment.

We're simply falling behind.

The energy situation is also changing pretty fast. The link I posted before is reliable.

-AC

pretty amazing what they are doing with the inverter run dc compressors.. can slow them down and let them chug along as super slow speed .. but they are small units.. hard pressed to find ones over 3 tons. Most being 1 -2 ton units.. some having multiple evap cores.

Think part of the reason that we have not seen applications coming from domestic producers.. is that they have not been pushed .. mini splits are still not common here.. to many ding bat installers afraid to mess with them.. What part of simple and easier to install ??? I have not really figured that one out..

Yes I see lots of ashp with seer around 17 and cop right up there between 2 and 3.

My bottom line is conservation is still a much better solution than running the watt meter on the side of the house.

Mini-Splits are solutions designed by Asia for the Asian market. Smaller homes and energy at least twice the price.

Also we graduate 70,000 engineers per year and half of them are working on war-related projects. So, 35,000 are available for problems affecting the civilian sector.

India graduates 350,000 engineers per year and China graduates 600,000 per year.

We are out-gunned 27 to 1

Do you still think our problem is ding bat installers?

The Fujitsu Halcion has a COP of 3.5

Much better.

-AC

We still have installers all over the place who will connect a tank to an A/C unit turn it on and load it with their hand over around the suction line. I think the major issue is that in order to make decent profit they can't install a mini-split and have the customer happy. Often people don't know, at least up north that a heat pump even exists. I've tried to mention it to some people and they go, "wait an air conditioner running backwards? you are an idiot"

For mini-splits, I always get a 'why would I want something on my wall', or 'wait it costs over a grand for just the unit and so I'd have to get a bunch?'

It's not necessarily cheaper or easier to install when a house has ductwork and they connect it to one point in a furnace. In my house, I'm lucky by design, the occupied bedroom and space used for office type stuff is upstairs and the warm air seems to share well with the level below so I could heat my bedroom and the heat stays upstairs and circulates well and its a little cooler down a level but convection does magic while I can leave the downstairs cooler. In the summer, the heat rises so I can cool the upstairs and the whole house gets the benefit. House design makes a difference.

You could check out the Carrier Greenspeed system, central heat pump system that gets 20 SEER and 13HSPF and does a great job of producing heating down to very cold temperatures.

"My bottom line is conservation is still a much better solution than running the watt meter on the side of the house."

Not sure what you are trying to say here because to me conservation has three parts. Using less, including using a temperature that demands less, energy efficient equipment, and energy efficient design.

I've got some old equipment in my house that is far from energy star apart from my computer equipment. I've got a refrigerator that chews power and minimum efficiency nat. gas furnace and air conditioner.

Yearly natural gas is under $300 and electricity under $400, 36% of that are fixed fees like connection fees and city fees to have the service, the rest is usage. By August my trailing energy usage subtracting the fixed fees will be under $400 for electricity and natural gas combined. My $100 energy audit and using this website already paid itself off in sealing up the place.

Not quite true. There are larger efficient ones. Toshiba RAV-SP420AT2-UL can cool and heat at 4 tons. 11HSPF and 18.8 SEER. 28600 output at 17f 44500 at 47f

The problem with this is that its not designed for ductwork so you would need to have somewhere to put that BTU output and would either need to run your furnace blower or a bunch of fans in your house and blow your COP or have a very open floor plan.

I've seen a few installations (and a bunch on youtube) that didn't really
take much labor at all.

I've heard from a few people that were turned off mini-splits because
they researched them on the web and saw the prices and the amount
of labor needed for a standard install.

Once they got their estimate, and saw the labor cost, they lost interest real fast.
'How could labor cost more than the hardware'?

Maybe if the tripled the cost of the units?? Then the labor cost wouldn't seem so bad.?.