geothermal chiller
- Thread starter Frankie1
- Start date
You will need AT LEAST 1.5 GPM and depending on the area where you live that might be for 12 hours perday = 1080 Gallons. I would check to see how much your well pump has to operate to get that much water but I remember doing a study years ago to determine the life cycle of a well for taking the heat from a heat pump and it turned out to be VERY expensive, especially compared to an air type condenser.
looser
New member
Thanks Cudy2k .. Wow... thats a lot more than I thought. I live in MA. I was thinking that I could use this as my only means of cooling vs. setting up the usual array of fans that I set up in the hallway behind my tank each summer (my wife loves that. . . not). Sounds like I might need to do some type of hybred fan/coil system to keep the water flow to a minimum. Just curious....how did you determine that amount of flow?
looser
New member
ok... I just did a LITTLE bit of research and I know that a little bit of knowledge can be dangerous, but maybe somebody can tell me where I'm going wrong. I found that it takes 8.3 btu to raise the temp of a gallon of water 1 degree. So using the 5000 btu requirement specified by chiller manufactures, and assuming I use a coil big enough to extract 20 degrees of temp from the ground water (55 on the input, 75 on the out). I would need 5000/8.3/20=30GPH during peak cooling.
looser
New member
So 5C is about 40F which is basically impossible to do without a compressor to chill the water even further or letting my tank overheat. If its 55 degrees coming out of the ground and best case its 80 leaving the coil thatââ"šÂ¬Ã¢"žÂ¢s only a 30 degree temp spread, so I would need much greater flow to equate to the 7,000 btu noted above.
I give up. I really do. Thanks eveyone for the help. I really do appreciate it, but my eyes are starting to glaze over. I'm just going buy the bigest coil that will fit in my sump, hook it up, and give it a try. Hell....we have so much water on the ground up here in New England now anyway, whats a few thousand gallons more going to hurt.
I'll be sure to post how it all works out after getting past some of the dog days of summer. Thanks again.
looser
New member
ok thats much better. thanks. So my flow rate could be much less if I can get good utilization of the cold water.
BTW I just got a quote for a titanium coil from a company in Canada called SEC heat exchangers. $1050 US. What!
Forgeting the price for a minute, the quote specifies 55 degree water on the input side and 76.96 on the output with a flow rate of .5 GPM. That was for 7,000 BTU. They specified some type type of titanium plate material. So given the 5000 btu is supposed to me more than enough for my set up worse case my output should be around 20 GPH. Sounds great, but not for over a grand. I'll keep looking.
douggiestyle
New member
looser. you could use a ss coil. cheaper and easier to find. sure the ss will eventually rot out but very slowly if completely submerged. seeing that you are using pure water at low pressures, if a leak occurred it would not cause any problems other than the need to replace the coil. you could use a stainless flex gas connector. available at most local hardware stores. get a long one. flexible means easy to bend. and it is ribbed for better transfer. crack the brass nuts off the thing and trim off the flair. then use an all plastic compression fitting that way the entire thing can be submerged.
looser
New member
Marco67 - Thanks I did check out the ebay listing earlier but he dosn't offer just the coil without the inline casing. I also sent a note to another company asking if the would sell me just the coil.
douggiestyle - Man that sounds like a plan, but wouldn't the rotting ss cause toxins to leach into the tank?
douggiestyle - Man that sounds like a plan, but wouldn't the rotting ss cause toxins to leach into the tank?
I know what you mean about information overload looser so I almost hate to bring this up . . .but . . . when you lower the flow rate to 20 GPH or there abouts I seriously doubt the transfer rate they are quoting. The problem is the water flow becomes laminar and there is not enough turbulence in the flow to cause heat transfer. It is a very real problem. AND if they have done their homework correctly, in order to keep the water velocity up to reduce the laminarity the tube sizes will have to be very small and then there is the risk of clogging them. At any rate you MUST provide a good strainer before allowing the well water to enter the tubing. Crud buildup inside of the tubing will kill all of your investment.
I know as we start looking at the costs of all this stuff it is easy to get discouraged as well. At least it is for me, I just try to not think about it. :rollface:
I would not poopoo Doug's idea on the stainless steel heat exchanger just yet, I think there is some merit there.
I do appreciate your posts and input, it's cool to actually see that someone is going to give this a shot. I just hope that you can 'cipher through all the banana info and get to the meat. Whatever you do PLEASE keep document your results and keep us posted. there is much to be gained from all of this.
BTW, to calculate GPM: BTUH/500 X Delta T
Bill Wann
In Memoriam
Ive been reading this post and thou I would chim in
I have been using a Ti heat exchanger cooled with well water for over 3 years . Iam not sure of th eflow but its minimal at best . Iam using it to cool a 1500 gall display and 3000 galls total . It works great with no other cooling . Ive never had to clean my coils inside just the outside with a little Hydorcloric acid .
Good luck
Bill.
I have been using a Ti heat exchanger cooled with well water for over 3 years . Iam not sure of th eflow but its minimal at best . Iam using it to cool a 1500 gall display and 3000 galls total . It works great with no other cooling . Ive never had to clean my coils inside just the outside with a little Hydorcloric acid .
Good luck
Bill.
I have worked in the piping/plumbing trade for 20+ years now and have experience in about every type tube/pipe and what they contain, that you can think of. Stainless is perfectly fine for saltwater if you get the correct type of stainless, there is many grades of stainless tubing available. The 2 most common grades of stainless for anti-corrosiveness is 304L and 316L, 316L being the best grade and the one I would use. In fact the metals used in making stainless 316L is as follows, Chromium-Nickel-Molybdenum-Mananese-Silicon-Carbon-Sulfur. And as far as I see most of those are already in seawater.
Also I don't exactly understand this idea that to get better heat exchange the faster the flow has to be, when I know for fact the opposite is true. The longer you have contact with whatever your exchanging the heat with, the more the exchange. I understand the reasoning behind the temp. difference idea the greater the better the heat exchange, but in truth it doesn't matter if its 50 degrees difference or 5 degrees, exchange will happen at the same rate. In fact the faster the flow the worst the exchange gets,( I won't get into detail but it has to do with water dragging on the surface of the piping). The only way i would say faster would help if you had only a small temp. difference between the ground temp and your tank temp. Geothermal cooling works well, but you have to take in consideration several things, depth of pipe, soil density(denser/tighter packed soil will conduct better), surface area of exchange, ect.
Also water is a very good conductor of heat, in fact water conducts 33 times better than air. Adding anti-freeze actually decreases its ability to conduct(tho only a very small amount), anti-freeze is only added for the exact reason for what its called, anit-freeze/anti-boil.
Also I don't exactly understand this idea that to get better heat exchange the faster the flow has to be, when I know for fact the opposite is true. The longer you have contact with whatever your exchanging the heat with, the more the exchange. I understand the reasoning behind the temp. difference idea the greater the better the heat exchange, but in truth it doesn't matter if its 50 degrees difference or 5 degrees, exchange will happen at the same rate. In fact the faster the flow the worst the exchange gets,( I won't get into detail but it has to do with water dragging on the surface of the piping). The only way i would say faster would help if you had only a small temp. difference between the ground temp and your tank temp. Geothermal cooling works well, but you have to take in consideration several things, depth of pipe, soil density(denser/tighter packed soil will conduct better), surface area of exchange, ect.
Also water is a very good conductor of heat, in fact water conducts 33 times better than air. Adding anti-freeze actually decreases its ability to conduct(tho only a very small amount), anti-freeze is only added for the exact reason for what its called, anit-freeze/anti-boil.
Bill Wann
In Memoriam
I agree with Alfinus
I run my otlet water from my heat exchanger to waste at the same as the tank temp so as to not waste any water running it too fast and to get complete heat exchange .
Like I said befor it is a very small amout of water . alot of things look good on paper or in a book but things dont alays work that way in real life . I speak from experiance and I think Alfinus does too .
I run my otlet water from my heat exchanger to waste at the same as the tank temp so as to not waste any water running it too fast and to get complete heat exchange .
Like I said befor it is a very small amout of water . alot of things look good on paper or in a book but things dont alays work that way in real life . I speak from experiance and I think Alfinus does too .
