geothermal chiller
- Thread starter Frankie1
- Start date
The heat's gotta go someplace, it just doesn't "evaporate". :rollface:
ICURN, there has been a fair amount of discussion on the SS heat exchanger idea and it really boils down to a couple of things. How long do you want it to last, what type of stainless are you going to use, and . . .hmmm, well there were a couple of other ones. read back in this thread and a couple of others related and there are many differing opinions. I love the bow legged women comment.
My gut feel, if you use a high quality SS you will be ok. BUT if you are going to the trouble and expense of doing all this why not do it right and ante up for the ti?
Anyway, FWIW.
Giovanni
AKA Flippa
It is a quote from Jaws their first night out on the hunt. I just love that movie. Classic with tones of one liners.
Cuby2k I was planning on getting a cooling system up with SS then buying the Ti, but I wanted to try it with the less expensive stuff first. I have an oceanic 70 RR with 25 gallon sump. I was wondering if 1/4 inch line from my well water would do the job. My well water is about 58F and I have an unlimited amount. My well pump is 220v so it would be more effecient that a 120v pump and I could use the wast water to keep grass growing in the summer, which I do anyway. In the winter I most likely will not need it.
BTW: My wife is Bow legged and I will not swimm with a straight legged women again.
Cuby2k I was planning on getting a cooling system up with SS then buying the Ti, but I wanted to try it with the less expensive stuff first. I have an oceanic 70 RR with 25 gallon sump. I was wondering if 1/4 inch line from my well water would do the job. My well water is about 58F and I have an unlimited amount. My well pump is 220v so it would be more effecient that a 120v pump and I could use the wast water to keep grass growing in the summer, which I do anyway. In the winter I most likely will not need it.
BTW: My wife is Bow legged and I will not swimm with a straight legged women again.
Roughly speaking, the formula for determining GPM is BTUH/500 x delta T. The 500 number takes into account the density of the water and that number is for fresh water so it will vary slightly. I don't have time to look it up right now but that will get you in the ball park.
A 1/4 inch line won't move much water but let's assume you have a 3000 BTUH load which is about 900 watts. 3000/500 x 10 degrees = 0.6 GPM. Can you push .6 GPM thru a 1/4 inch line? You also need to take into account the inefficiencies for the heat exchanger and the temperatures of the waters.
A 1/4 inch line won't move much water but let's assume you have a 3000 BTUH load which is about 900 watts. 3000/500 x 10 degrees = 0.6 GPM. Can you push .6 GPM thru a 1/4 inch line? You also need to take into account the inefficiencies for the heat exchanger and the temperatures of the waters.
Giovanni
AKA Flippa
For at trial, I am putting 5' of 1/4 brake line in my sume and running water from the well then back to the bath tub. We will see how it does. I am sure that thin walled Ti will transfer heat better. Also, I think a longer coil will be needed. I figure it this works and I buy the Ti it can only get better. WDYT?
Geothermal cooling idea
Geothermal cooling idea
I posted this in a new thread but I figured with all the experts in this thread maybe I could get some solid help. Here it is:
I have read most of the DIY geothermal cooling threads and I need some help with this idea.
I live in Canada where the summers can get to 30 deg. C in the summer and -40 deg. C in winter. The summers are really humid so my current cooling fans don't do much when there is 80% humidy.
The house has radiant floor heating in the basement, and by my calulations there is about 3000 feet of pex tubing layed into the 6 inches of concrete.
Now my idea is to make an additional loop that would run from the manifold which directs the water flow into each of the rooms in the basement (which is conveniently located in the fish/sump room) to a high grade S/S or Ti coil submerged in my sump.
My question is will this be enough to cool my tank?
Specs:
Basement slab temperature in the summer 69-70 deg. F
Tank temperature at highest point before MH's shut off 81.5 deg. F
Total system volume is ~880 gal.
Heat load - 400 gal reef has 4 x 250watt DE HQI MH's, 2 Darts as CL, 2 x 6 foot VHO, 2 Tunze Streams
180 gal FOWLR has 2 x 175watt MH's, some powerheads.
System is run on 1 Hammerhead 360-380 watts.
Ideally I would like to get the ground loop to drop the system temp down to around 78-79 deg. F
Some more relevant info:
The basement air temp stays at 75 deg. F all summer.
Basement is about 9 feet below grade
Soil is Clay, so usually is always moist which should help transfer the heat away from the floor during the night.
Any help would be greatly appreciated.
Thanks
Geothermal cooling idea
I posted this in a new thread but I figured with all the experts in this thread maybe I could get some solid help. Here it is:
I have read most of the DIY geothermal cooling threads and I need some help with this idea.
I live in Canada where the summers can get to 30 deg. C in the summer and -40 deg. C in winter. The summers are really humid so my current cooling fans don't do much when there is 80% humidy.
The house has radiant floor heating in the basement, and by my calulations there is about 3000 feet of pex tubing layed into the 6 inches of concrete.
Now my idea is to make an additional loop that would run from the manifold which directs the water flow into each of the rooms in the basement (which is conveniently located in the fish/sump room) to a high grade S/S or Ti coil submerged in my sump.
My question is will this be enough to cool my tank?
Specs:
Basement slab temperature in the summer 69-70 deg. F
Tank temperature at highest point before MH's shut off 81.5 deg. F
Total system volume is ~880 gal.
Heat load - 400 gal reef has 4 x 250watt DE HQI MH's, 2 Darts as CL, 2 x 6 foot VHO, 2 Tunze Streams
180 gal FOWLR has 2 x 175watt MH's, some powerheads.
System is run on 1 Hammerhead 360-380 watts.
Ideally I would like to get the ground loop to drop the system temp down to around 78-79 deg. F
Some more relevant info:
The basement air temp stays at 75 deg. F all summer.
Basement is about 9 feet below grade
Soil is Clay, so usually is always moist which should help transfer the heat away from the floor during the night.
Any help would be greatly appreciated.
Thanks
looser
New member
nreefer - I tried to do all the math for my set up (well water through a titanium coil) and even with the help of the good folks here on RC my head was spinning ....so I just set it up and tried it. One thing is for sure, it will help, and whatever amount it helps will be more efficiant than running a chiller to get the same amount of cooling. So my suggestion is to give it a try and tweek it as you go. You can't lose.
nreefer - the only trouble that I see is that your basement slab is probably sitting on top of 2 inches (or more in Canada) of foam insulation and thus has very little direct heat transfer communication with the soil underneath.
But give it a try, it will be a quick and cheap experiment to setup.
But give it a try, it will be a quick and cheap experiment to setup.
Hmm, that is right about the foam. My hope is that the 3000 feet of pex will be more than enough to cool the tank and then during the night the slab will cool from all sides of the slab. Since the basement is pretty much all below grade there may be enough cooling coming from the basement walls etc. What do you think?
The other option is to build a larger swamp cooler and just vent all the exhust outside. Problem being that in the summer with the outside humidy at 80% the basement sump room gets to that point right away due to the HRV running constantly.
Reading the reports on the EcoChiller from Deltec it seems to do a good job in California anyway according to Moonpod's setup. So that maybe the ticket.
I don't really want to cut into the tubes of the basement manifold and get a new pump etc if there is no help in potential cooling.
The other option is to build a larger swamp cooler and just vent all the exhust outside. Problem being that in the summer with the outside humidy at 80% the basement sump room gets to that point right away due to the HRV running constantly.
Reading the reports on the EcoChiller from Deltec it seems to do a good job in California anyway according to Moonpod's setup. So that maybe the ticket.
I don't really want to cut into the tubes of the basement manifold and get a new pump etc if there is no help in potential cooling.
salty joe
Active member
I am finally going to break ground soon. I am thinking of installing Pex in the foundation hole before it is backfilled. Once around the house will be about 300’. I don’t have much of a feel for how many feet of Pex to use. I’m thinking 600’ is a reasonable starting point.
The soil here in NE Ohio is about 55 F once you get down a few feet. The tank will be an air driven, sunlit 450 gal. with about 600 gal. total system. I expect the tank to run at or slightly below the ambient temp., although I have no experience using sunlight for a tank.
We typically keep the AC at 85 when nobody is home and 76 when we are.
If anyone is interested, I can take a pic of the Pex in the foundation hole. The bad thing is, this tank wont be up and running for at least a year.
Any opinions would be appreciated.
Joe
The soil here in NE Ohio is about 55 F once you get down a few feet. The tank will be an air driven, sunlit 450 gal. with about 600 gal. total system. I expect the tank to run at or slightly below the ambient temp., although I have no experience using sunlight for a tank.
We typically keep the AC at 85 when nobody is home and 76 when we are.
If anyone is interested, I can take a pic of the Pex in the foundation hole. The bad thing is, this tank wont be up and running for at least a year.
Any opinions would be appreciated.
Joe
Ah Joe, this is good news. I am definitely interested in pics and because you asked I will offer my opinion. :wavehand:
I would try to keep the piping as deep and as far away from the foundation wall as you can.
Question; how did you determine the earth temp to be 55 deg? At what depth is this and at what time of year?
I think this type of system could potentially save much energy and I appreciate any sharing of info that you have. Don't worry about the time frame, I plan on being here for at least another year.
I would try to keep the piping as deep and as far away from the foundation wall as you can.
Question; how did you determine the earth temp to be 55 deg? At what depth is this and at what time of year?
I think this type of system could potentially save much energy and I appreciate any sharing of info that you have. Don't worry about the time frame, I plan on being here for at least another year.
salty joe
Active member
I'll get some pics, but it will be a few weeks. Then I'll have to figure out how to post them. My computer is pretty screwed up and I'm not exactly gifted when it comes to computers. But the pics will get posted.
As far as the ground being a steady 55 once you get down past 4-5 feet, it is something that is accepted as general knowledge around here. I never looked into it, but now I think the best thing to do is confirm it.
Not sure how far the edge of the hole will be from the foundation, but I will do the best I can to maximize the distance from Pex to foundation. Also, the foundation will have R-5 insulation installed and eventually the basement will be finished at which point the interior of the foundation wall will get additional insulation.
When the tank has water in it, I'll run the chiller nonstop for a day to check cooling capacity. Of course, that and any other info will get posted here.
Incidently, I'm not married to the idea of using 600' of 3/4" Pex. A different material, a different size, a different length,whatever. The one thing for sure is I have to make a decision soon.
Thanks,
Joe
As far as the ground being a steady 55 once you get down past 4-5 feet, it is something that is accepted as general knowledge around here. I never looked into it, but now I think the best thing to do is confirm it.
Not sure how far the edge of the hole will be from the foundation, but I will do the best I can to maximize the distance from Pex to foundation. Also, the foundation will have R-5 insulation installed and eventually the basement will be finished at which point the interior of the foundation wall will get additional insulation.
When the tank has water in it, I'll run the chiller nonstop for a day to check cooling capacity. Of course, that and any other info will get posted here.
Incidently, I'm not married to the idea of using 600' of 3/4" Pex. A different material, a different size, a different length,whatever. The one thing for sure is I have to make a decision soon.
Thanks,
Joe
Well I think PEX is the best solution. There are alternatives of course and some less expensive. I know the HDPE stuff is cheaper (I think) but it kinks easily and it punctures easily. What a bummer to install 600' of that stuff and find you have a leak after the backfill and start-up.
Copper is another solution with a much better heat transfer coefficient but the earth can't take the heat that fast because of it's relatively poor coefficient. Earth and PEX have similar coefficients.
I suggest one MUST DO; after you lay the pipe and secure it in several places with small piles of dirt or whatever, put a pressure gauge on the end where it rises from the ground and seal the other end. Put it under a ~60 PSI pressure and then monitor it throughout construction. If you see a drop you can relate it to progress on the site and hopefully pinpoint the leak. Small cost for piece of mind.
I think 600 feet is a good minimum. If you are able to install more ($$$ !) you might want to do a reverse return loop to minimize pressure drop. Similar to this . . .
Copper is another solution with a much better heat transfer coefficient but the earth can't take the heat that fast because of it's relatively poor coefficient. Earth and PEX have similar coefficients.
I suggest one MUST DO; after you lay the pipe and secure it in several places with small piles of dirt or whatever, put a pressure gauge on the end where it rises from the ground and seal the other end. Put it under a ~60 PSI pressure and then monitor it throughout construction. If you see a drop you can relate it to progress on the site and hopefully pinpoint the leak. Small cost for piece of mind.
I think 600 feet is a good minimum. If you are able to install more ($$$ !) you might want to do a reverse return loop to minimize pressure drop. Similar to this . . .
just a thought
just a thought
I have not read all the pages of this but rather than trench or dig, plow the smaller tubing in. You should be able to rent a cable plow in your area. Only draw back is if you have lots of roots and you can't get real deep with some models.
Just trench across the each end of the rows of pipe then start the plow behind the trench to get the tubing to full depth. You then use the trenchs to do your 180 loops or back to back 90s.
If you home is in a crawl space, you may be able to just lay the tubing on the ground under the house. Here is SC it gets in the 100s and it is usually 10 degrees or more cooler under the house.
Just some quick un thought out thoughts.
just a thought
I have not read all the pages of this but rather than trench or dig, plow the smaller tubing in. You should be able to rent a cable plow in your area. Only draw back is if you have lots of roots and you can't get real deep with some models.
Just trench across the each end of the rows of pipe then start the plow behind the trench to get the tubing to full depth. You then use the trenchs to do your 180 loops or back to back 90s.
If you home is in a crawl space, you may be able to just lay the tubing on the ground under the house. Here is SC it gets in the 100s and it is usually 10 degrees or more cooler under the house.
Just some quick un thought out thoughts.
Re: just a thought
Re: just a thought
Trenching might be a good way to go if you can get it deep enough. If the daytime temps get into the 100's I would venture that the temp at 3 feet is still to warm to do much good.
Laying piping open in a crawlspace would be the same thing only the heat transfer would be less. If the house is 78 adn assuming the air is 68 in the crawl space I don't think it would do much good. Even if the piping is buried it should be in the 50's before you'll see much effect.
Exceptions for sure but they would take much, much larger water volumes and larger heat exchangers.
I think an ideal situation would be to drill a vertical well to 300 feet then drop a line down so you'd end up with a 600 foot length. I know this is what we do for HVAC systems but drilling a well is a little spendy.
Best solution IMO is using a huge pit or hole that is being excavated for another purpose. i.e. a basement for a house. But like I said above try to keep it away from the foundation walls *** far as possible. AND insulating like saltyjoe is doing will help.
EDIT: I must have used a curse word in the post. Ah I meant to use "as" but used too many ess's.
Re: just a thought
Trenching might be a good way to go if you can get it deep enough. If the daytime temps get into the 100's I would venture that the temp at 3 feet is still to warm to do much good.
Laying piping open in a crawlspace would be the same thing only the heat transfer would be less. If the house is 78 adn assuming the air is 68 in the crawl space I don't think it would do much good. Even if the piping is buried it should be in the 50's before you'll see much effect.
Exceptions for sure but they would take much, much larger water volumes and larger heat exchangers.
I think an ideal situation would be to drill a vertical well to 300 feet then drop a line down so you'd end up with a 600 foot length. I know this is what we do for HVAC systems but drilling a well is a little spendy.
Best solution IMO is using a huge pit or hole that is being excavated for another purpose. i.e. a basement for a house. But like I said above try to keep it away from the foundation walls *** far as possible. AND insulating like saltyjoe is doing will help.
EDIT: I must have used a curse word in the post. Ah I meant to use "as" but used too many ess's.
