geothermal chiller

Ok, let me explain more in depth

The tank is 300g - UP to 10,000g tanks are available!!!
Cost is $200 on sale, $300 normally - how much is a chiller?
A 1200g tank is $600 - and yes I am considering getting one
I would store waste water in it or rain water & use it to water my lawn

My current setup - 125g show, 115g in the basement - which normally stays below 70 in the summer - hottest days it goes up to 73. The pump (1400gph) runs 24x7 cycling the water between the basement & show tank - not a lot of time for cooling
I have one fan on my tank with (3) 250w MH
I leave the back canopy open (viewable on three sides) during the summer while I am at work. I turn on the A/C in the house to keep the house below 80 in really hot weather
So, 115g of water at 68-70 is keeping my tank cool

Wouldn't 300g at 55 be a much better solution?

This will only be used in the summer - it will be pumped dry & cleaned out every fall. Then possibly used for waste water from RO/DI thru the winter

I'm still deciding how it will be connected. I'm thinking a small pump will be used to keep a small amount of water cycling between the show tank & the buried tank. When a controller indicates cooling is needed - a larger pump will kick on & pumep a larger quantity of water to the show tank
I do not anticipate it will call for cooling at night
I live in MA - with a stream beside my property - which keeps the ground at depth damp. Stream isn't really close enough to ise for colling - I thought of that

In spring time this tank would be refilled with NSW and the process would continue

I'm basing the way this will work on the success I have had with my current basement setup. This setup will soon be changed to a smaller pump (900gph), a larger sump (129g), a larger frag tank - 125g, and a summer cooling tank (75g)
Total system setup will be 180g show, cooled by 300g in the basement

The new 300g buried tank setup will be in my addition - show tank size undecided at this point - but most likely 300-500g
I considered the ground loop in the 24' x 36' garage floor - but they will be mechanically compacting the fill
I can imagine what that will do to thin wall tubing

If this were an untried theory, I might agree with everyone
But - it has worked for me on a smaller scale for 2 summers now
If I lived further South the results might be different

I run a solar heating system to heat my inground pool to 84
Without the solar heater it drops to mid -70's or lower
I'm increasing the solar heating setup on the pool from 80k to 320k this year

-Dave
 
Ha Doug, I know how you feel when you say "just one more thing ", so here's mine . . . . When we talk about 200 LF of piping it doesn't necessarily mean that the line has to be in a 200' trench. It could very well be coiled, laid parallel, or even stacked in lengths. In the coil and stacking scenarios you would want to make sure that there was SOME earth between the lines but with the thermal swings of typical tanks it wouldn't have't to be much.

Dave, it sounds like your current setup is working for you, why change it? If you have a basement that doesn't get above 70 degrees you'd think that a sump down there would satisfy your heat load.

I live in an area where summer temps reach 117 degrees and my sump and skimmer are located in a non-cooled garage so I am forced to do something. Earth cooling ain't free, but it's a lot closer than paying for a compressor. I might be doing this sooner rather than later, I was just hoping for a guinea pig.

Joe, I loved your post, you sound like the kind of guy that got his girl friend to do his homework. (Just like me) :rollface:
 
Thanks everyone that's participating here, this thread has been helpful. I've made some decisions and will be laying my loops Monday and Tuesday :smokin: (finally).
The whole discussion about material; copper vs, pvc vs, abs vs, pex was great and I was ready to go copper because of its heat transfer properties, pex was out on cost.....until I found something I think is the best of both worlds It's a Toro product called "Blue Stripe" What caught my eye about the is very very thin wall, it will kink pretty easy and will require some finesse on installation, I'll do a lot of back filling by hand to avoid issues caused by a machine dumping a yard or so at a time on it.
The loops (6@ 100'ea) will be outside the foundation.
I had 4" PVC sleeves installed on top of the footings at the base of the foundation walls, so coming through the foundation will be easy.
Next concern was working with the tubing during construction and during pouring the floor without damaging it, also running to and connect to the heat exchanger. I didn't want a material that would damage easy so ..Pex will run from the footing up through the floor and to the exchanger.
Right now I'm leaning toward Dougs SS gas lines as exchangers but for now I think this will be a good start with some flexibility.
 
Dave, it sounds like your current setup is working for you, why change it? If you have a basement that doesn't get above 70 degrees you'd think that a sump down there would satisfy your heat load.

That setup will stay - but I will increase the cooling water in the basement - since I am upgrading to a 180g show

The new setup with the 300g reservoir will be in the new addition for a new tank - size undecided. But I'd like a 10' tank
I'd actually like to bury 2 tanks - but I can always bury another one outside at some point if needed (or install it in the garage if that stays cool enough)

Yeah, the only thing that makes this feasible is MA location
Good thread
 
<

Joe, I loved your post, you sound like the kind of guy that got his girl friend to do his homework. (Just like me) :rollface: [/B]


C'mon, all you engineer brainiacs have to do is throw a delta T here and a flying wedge there and presto! there's the answer. Seriosly, an engineer or someone with HVAC experience is likely to have a much closer WAG than I. Just for the heck of it, my WAG is 81-82 F.

Anyway, good thread.
 
<a href=showthread.php?s=&postid=7405958#post7405958 target=_blank>Originally posted</a> by Marco67
:smokin: What caught my eye about the is very very thin wall, it will kink pretty easy and will require some finesse on installation, I'll do a lot of back filling by hand to avoid issues caused by a machine dumping a yard or so at a time on it.
The loops (6@ 100'ea) will be outside the foundation.
I had 4" PVC sleeves installed on top of the footings at the base of the foundation walls, so coming through the foundation will be easy.
Next concern was working with the tubing during construction and during pouring the floor without damaging it, also running to and connect to the heat exchanger. I didn't want a material that would damage easy so ..Pex will run from the footing up through the floor and to the exchanger.

Marco, I am excited to hear how this all goes. I would stay away from the blue stripe pipe but if you must . . . Put the pipe under 15 PSI pressure and put a gauge on the indoor portion (or at least the above ground portion). That way if you cause a leak during the backfill you will have a better chance of catching/fixing it.

You could also arrange the piping in a reverse return loop. That way you could equal the pressure drop through the sections and end up with a lower overall pressure drop.

Lastly, take pictures man! And share them with us. I am very excited to see you are moving forward with this idea. :rollface:
 
cuby.
i understand your 200' could be layed in layers. and i wasnt knocking it. my last house had about a 6x6 plot of bare ground. the rest was all concrete. city house. a walled in garden in the rear completly covered in concrete. it was really nice had no complaints. wild grapes grew up and over all the walls. very fragrant in the fall. but still only had about 6x6 in the front yard. much easier to dig one large hole in that case. now in my current house i would rent a ditch witch and run a couple trenches through the back yard. even easier.
 
<a href=showthread.php?s=&postid=7407248#post7407248 target=_blank>Originally posted</a> by Cuby2k
Marco, I am excited to hear how this all goes. I would stay away from the blue stripe pipe but if you must . . . Put the pipe under 15 PSI pressure and put a gauge on the indoor portion (or at least the above ground portion). That way if you cause a leak during the backfill you will have a better chance of catching/fixing it.

You could also arrange the piping in a reverse return loop. That way you could equal the pressure drop through the sections and end up with a lower overall pressure drop.

Lastly, take pictures man! And share them with us. I am very excited to see you are moving forward with this idea. :rollface:

I had some concerns on working with the blue stripe but in the end decided that the extra care needed in instalation would be worth the trade off for the better heat transfer.

Good Idea on monitoring presure during back fill, But I'm not sure it's going to be practical (not sure the excavator will have a real good sense of humor, with me in the ditch playing while he works :) )
We did back fill the first 2 feet by hand so as to go gentle and have control over line position. Worst case if one line is dammaged I'll still have the others.
Oh and I added one feature, I'm not sure it will make a difference or not but... hey .... Because we are near the beach here and the soil isn't dirt it's sand, I put a sheet of poly down first to help keep the sand in contact with the loops wet longer.
BTW they all ended up @ ~7feet below grade and the frost line here is at 32"....I did take pics and as soon as I resize I'll post, the bummer is that it's at least 2 months before I can take the next step in testing.
Marc
 
cool

cool

Finally, someone is taking the next step and building this. I have always wanted to do this, but never had the guts. I am definitely going to do this now, with energy prices nowadays. And my current chiller is on it last legs.

Just wanted to note, someone metioned to use a Grundfos pump for this application. IMO, I would discourage you on using that pump, since it heats up the water that its pumping. I have a old qiuet one pump which was a Grundfos with a plastic impeller cover, and man does it put heat in the system.

Question, how big of a ditch did you dig, Marco?

Waiting to hear results...
 
It seems to me that the best pump to use would be one that is designed for this type of application. Many pumps can't tolerate a lot of on/off cycles.

I saw some pumps at Johnstone Supply in the hydronics & pumps section that looked good. But I would not know which pump to choose.

Anyway, I'm just along for the ride. Thanks to everybody who contributed to this thread.

Joe
 
This is what I'm using, unfortunately, price went up since I purchased:

http://www.coleparmer.com/catalog/Product_view.asp?sku=7201210&pfx=

EW-72012-10
Centrifugal Magnetic Drive Polypropylene High-Head Pump, 4.6 GPM, 115 VAC

Power 115 VAC
Required hp 1/16 hp
Max flow rate 4.6 GPM
Max fluid temp 176F
Max system pressure 14.2 psi
Max head (ft) 36.1
Pump type Centrifugal
Duty cycle Continuous
Continuous duty Yes
Electric powered Yes
Leak-proof Yes
Reduced pulsation Yes
Pulseless flow Yes
Wetted materials PP, Ceramic, Viton, Teflon
Wetted parts (magnet) PP
Housing material PP
Dimensions 9 5/8"L x 4 3/4"W x 5 1/8"H
Connections outlet 5/8" Hose
inlet 5/8" Hose
Motor rpm 3400 rpm
VAC 115 VAC
Amps 1.00
hp 1/16 hp
 
Greg,
If that pump is rated for a continuous duty cycle, does that mean that constant on/off cycles might cause pump failure?

Joe
 
Marco,
Just for future reference here is a pic of a pressure testing manifold setup. I get a little freaked about burying pipe that is not under a positive pressure but this is just FYI anyway. Glad to see your progress!


http://reefcentral.com/gallery/data/500/119502Guitar_Shop_Basement_DSC02942.JPG

WaveFan, good point on the heat gain from the grundfoss pump, something I hadn't thought of. Just a bit more thought though, a pump that is cooled by the water will last longer than one that is not cooled. A 1/4 HP Grundfoss pump will use about 187 watts of power and not all of that heat will be put into the system. If your system is sized at 1/2 ton (6,000 BTUH) the capacity would be reduced by about 400 BTUH (A bit of a SWAG) so not all that much. If the system you are installing is a REAL closed loop (no exposure to ambient air) a grundfoss or similar pump will cost around $100. Compare that to a magnetic pump of the same capacity and there is a huge difference.
 
I do understand your point...and I do still have the excavator coming. So I guess the time to find out if there is a problem is now. I can easily drop a replacement loop before the floor is poured, or another outside if needed.
Marc
 
Well I finally got my geo thermal system up and running. It doesn’t get much easier than this. (assuming you have a well and a temperature controller)

I put a "T" on the cold water supply to my work sink behind my tank and ran it to a solenoid valve. The valve power is supplied by my temp controller so that it opens when the temp hits 81 degrees. The output of the valve goes to a heat exchanger grid that I made from a five foot piece of titanium pipe, which I put in my sump. (the pipe cost $20 a foot) The output of the pipe goes through about 25' of the 3/8" plastic tubing in my sump (I had some left over), and then it drains back into my work sink.


Works like a charm. The input temp is 57 degrees (ground water temp from my well), and the output to the drain is about 73 degrees. I set the flow to about 30GPH but it doesn't run for more than 10 or 15 mins before the temp drops to 80 and the valve shuts off the water supply.

I knew it was going to work as soon as I saw the condensation building up on the feed side of the exchanger an nothing on the output side.

Next I'm going to set up a 50 gal drum in my basement just to see how much water it actually uses in a day.

The whole thing cost me about $250 for the titanium pipe, the valve, and some plumbing supplies. I have my own well so the water only cost me the electricity to pump the water out of the well.

Beats the heck out of buying a $1000 plus chiller and then paying through the nose for electricity to run it.
 
<a href=showthread.php?s=&postid=7750136#post7750136 target=_blank>Originally posted</a> by nyvp
looser
Your my hero. WTG job well done

Pictures?

:) thanks!

No pictures yet. I've been a member here for awhile now any you would think I would have figured out how to post pictures by now but I havn't. I'll give it a try tomorrow.
 
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