geothermal chiller experts wanted

Giovanni · #1 05/15/2007, 09:28 PM

Want to replace my 1/3HP chiller with a geothermal system. I have well water and a front yard that needs watering. My chiller is a 1/3hp coralife unit. It runs a total of about 2.5 hours a day. My water volume is around 120 gallons. I would like a geothermal setup that will coll my system if the chiller was running 5 hours a day.

Can someone who has done this before help me design a system?
Thanks

smcdonn · #2 05/15/2007, 09:57 PM

No offense but if you looking at this from an economic standpoint, it only cost you roughly $27/year to run that chiller. So don't think your going to re coupe that cost if that's what your looking to do. Now if your wanting to do it for other reasons, I am sure some people here will be more than helpful.

Giovanni · #3 05/15/2007, 10:07 PM

None taken. I will be watering the lawn in the summer anyway. I might as well use the water to cool my tank? Also the noise of the chiller makes me want to stick a fork in my eye! LOL

Thanks for the cost analysis though. I will use the sale of the chiller to fund the Ti coil part of the system.

I will just tap off my well water system where is comes under the foundation rout it to the coil then rout it to the front yard sprinkler. In the winter I do not need to water the yard or cool the tank.

Giovanni · #4 05/17/2007, 05:04 PM

Anyone?

douggiestyle · #5 05/17/2007, 05:24 PM

your plan will require a very large coil. you will want to put as much heat into the well water as possible before it goes to the lawn.

Giovanni · #6 05/17/2007, 05:49 PM

When you say large, do you mean larger than some other method, and what size do you mean? How did you arrive at this determination? Thanks

douggiestyle · #7 05/17/2007, 06:10 PM

when using a system that recirculates the idea is to maintain a large dT. more flow means more go (heat that is). there is a point where it all converges to give the best efficiency. but you are going to throw the water away when done. so you would do better to try and remove as much heat as possible before dumping it. so that would require a large HE coil.

Giovanni · #8 05/17/2007, 06:25 PM

douggiestyle,

Can you tell me how many BTUs I am removing now and help me design a system that will pull twice that many with well water that is ~60F? Can I use a coil with a 3/8" ID? If not what formula did you use to get that answer and what size is needed per that formula? Where can I buy the coil needed? Thanks

douggiestyle · #9 05/17/2007, 06:36 PM

http://archive.reefcentral.com/forum...hreadid=817756

douggiestyle · #10 05/17/2007, 06:50 PM

Quote:

Originally posted by Giovanni
douggiestyle,

Can you tell me how many BTUs I am removing now and help me design a system that will pull twice that many with well water that is ~60F? Can I use a coil with a 3/8" ID? If not what formula did you use to get that answer and what size is needed per that formula? Where can I buy the coil needed? Thanks

thats asking an awful lot

im not using any formulas, just quoting basic thermodynamic laws. laws that i do understand btw.

youve got all sorts of variables involved. there is no right answer just better answers. the more efficiency, the more varibles and their accuracy and precision that are required. so the common choice is "oversize it".

but lets go with coil id... wall thickness is needed and material thermal conductivity. then some sort of answer could be had.

so i would suggest to oversize it. as i stated earlier use a large HE coil and get the most bang for the buck.

douggiestyle · #11 05/17/2007, 06:59 PM

maybe thermodynamics isnt the right word, laws of thermal conduction would be better.

Giovanni · #12 05/17/2007, 06:59 PM

I did not ask for help to start a debate. I have not called into question your knowledge. You are being very vague. You keep saying large but that is a relative term. So far you have not given me any help other than go large. I get that suggestion at McDonald's every time I eat there. Thanks for that suggestion. What other advice do you have to offer?

douggiestyle · #13 05/17/2007, 07:08 PM

Quote:

Originally posted by Giovanni
I did not ask for help to start a debate. I have not called into question your knowledge. You are being very vague. You keep saying large but that is a relative term. So far you have not given me any help other than go large. I get that suggestion at McDonald's every time I eat there. Thanks for that suggestion. What other advice do you have to offer?

????????

read the thread i linked. become knowledgeable on the subject (do some research on your own first) then come back and repost your question.

Giovanni · #14 05/17/2007, 07:14 PM

So I guess the answer to my last question is NONE. Please don't bother wasting my time if I do post another thread. Thanks.

douggiestyle · #15 05/17/2007, 07:30 PM

well flippa, i tried to be helpful.... enjoy your project.

BruiseAndy · #16 05/17/2007, 08:16 PM

Only thing I'm thinking is you plan on watering the lawn everytime you need to cool tank??I made a pretty simple HX out of Ti but if you aren't doing direct expansion you will need quite a bit of tubing. Won't get much help with the snippity remarks btw, from what I read douggie was being helpful.

woz9683 · #17 05/17/2007, 10:09 PM

I was wondering the same thing. How is that going to keep your system cool at the right times when you water your yard for maybe a half an hour a day?

That is, unless you're talking about running a coil through the actual well?

Giovanni · #18 05/17/2007, 10:18 PM

I have a large yard and plan on 8 sprinklers. I Intended on running only one sprinkler at a time for say 1/2 3/4 hour each. I have been looking at an automated sprinkler system anyway. I currently have a roaming sprinkler that follows a length of hose and takes 4 hours to water 200ft of yard I could even just have the output of the cooling system run to a hydrant that the roaming system hooks to. It does not take much pressure to run so the loss of the cooling system would not be an issue.

manderx · #19 05/17/2007, 11:35 PM

i did this in my old house and it worked wonderfully. i really miss it in my current apartment, especially since my new 3x3 has 4x250w over it.

my wellwater was ~60 in the summer. i used 1/4" poly for the whole thing. i tapped into the cold water line, to the sump, through a 25' coil (sure Ti conducts heat better, but with 25' it does just fine, especially since it's really just a dribble going through it). it turned on and off by a solenoid hooked to a temp controller. then another 100' or so to get out to the garden.

i wouldn't worry about trying to tie it into a sprinkler. it's simply not enough flow. <100ml/min will probably do you just fine. think more of a drip irrigator or soak-hose.

the biggest problem is condensation on the cold side. i insulated mine up until the coil with some ~1/2" vinyl hose.

Alto · #20 05/18/2007, 02:20 AM

Thats kind of what I was thinking, running water through a coil as fast as you would need to run a sprinkler efficiently isnt going to cool your tank efficiently. You want a long contact time with the water and the "chiller coil". I would recommend getting a sample piece of whatever material you plan on making your coil out of and see how long in minutes it takes to raise the water inside to the same level as the tank water outside, thats the best efficiency you can achieve. If that takes, for example, 10 mins then you know you need to balance the length of the coil and the speed of the water to achieve a 10 min contact time. Hope that makes sense.

redox · #21 05/18/2007, 06:01 AM

dump it into a goldfish pond. That is exactly what my friend has done. It works great and in the winter the water doesnt freeze over

or you could run the water through something like this[IMG]

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webbstock · #22 05/18/2007, 07:26 AM

Just my 2 cents...
As a home brewer (yea beer!) I use a similar device to cool the wort (hot beer juice) from boiling to about 70F. For a five gallon batch of beer 30 feet of tubing with tap water running through it will cool the wort in about 10 minutes.

I don't know how cold your tap water is in kentucky, but mine is pretty cold. I honestly think that during the summer your idea will work fine to chill the tank. Since you are planning on watering the lawn for about 5 hours that gives you a pretty large chunk of time to allow for heat exchange. As for tubing, I would get the smallest diameter tubing that still allows reasonable flow (smaller diameter= more surface area= better heat exchange) and also as long as you can afford/find/fit in tank.

Giovanni · #23 05/18/2007, 08:29 PM

Maybe I will try the 1/4 line. It is inexpensive and I have a 30gal trash can as a secondary sump I could sink it in. If is does not work, No big deal as it is cheap anyway. In fact I have about 100 ft in the shop so I do not have to run to town every time I need a little. I will let you know how it goes.

manderx · #24 05/18/2007, 09:10 PM

just make sure there is at least some flow around the coil. if you end up needing more cooling power than i did (though i doubt this is the case if you don't need chilling all year), then you might need a longer coil to handle the higher flow rate (if you care about max efficiency and not wasting any water). just measure the temp coming out of the coil to see how far off it is from tank temp.

Giovanni · #25 05/24/2007, 02:19 PM

I finally got about 100 ft of 1/4 line in my sump and it is working great. Cools my tank about 1 degree in about 20 min when lights are off. We will see how it does with the lights on in a few days. I will buy a rainbyrd valve to controll it with and put it on the ACIII. The 1/4 tube is about 7 cents a foot so very inexpensive. Anyone need a 1/3 HP chiller? HEHE