<a href=showthread.php?s=&postid=11898816#post11898816 target=_blank>Originally posted</a> by demonsp
My vet has a 500 gallon reef with another 300 gallons sunk in the ground for constant temp of 78. Many do and makes sence.
never thought about it for the reef
until read this thread
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1312010&perpage=25&pagenumber=1
wondering why more people arent using these ???
seems like a few hundred dollars upfront then the cost of running a simple pump after that - makes this not only an eco friendly option but can also save alot of money in the long run!
that is *** if *** its effective
here is what appears to be very simple instructions for making one... taken from above listed thread
Liveforphysics (RC member)
Due to having plans to be running plumbing outside, you could use a more eco friendly option. This is something you may want to try.
Buy a stick of 20ft 3/8" Ti tubing. Take it to someone with a pipe bender, who will take his time and make a nice bend in the bottom so you are left with a 10ft long U-bend. Hire a fence crew or a foundation crew to dig you a single hole in your backyard (somewhere near where you are routing plumbing) about 10ft deep with a hole digger. They will have to have a 4ft extension shaft on a 5ft auger to dig the hole. It shouldn't take more than 30mins to dig if your ground isn't all packed with rocks and the guy is skilled. Might cost you about $50-100bucks. Go to a machine shop with a couple of heavy duty garbage bags. Tell them you want to buy a couple garbage bags full of aluminum turnings/chips from a waste tub. They will either just give it to you or charge $5-10. Next pickup about 8-10 sacks of cement (cement, not concrete) and some hot water heater pipe insulation and insulation tape. Foam wrap and tape off the upper 2-3 feet of the titanium pipes, and install whatever hose ends you find best suited for your plumbing (likely some sort of slip over and lock type fitting).
Stick the U-bend in the hole, and pour in the trash bags filled with alumium turnings. They might fill the hole all the way up, but they are going to get crushed down when you start adding the cement powder in. Get a hose running down in the hole and start pouring in the cement bags onto the aluminum shavings. Keep the hose knocking the cement dust to the bottom while you are adding more cement bags. Do this until the hole is filled up to the point where the insulation on the tubes starts. You have no need to try to form a heatsink here, as the ground in the first couple feet of very hot areas in very hot days could be above desired water temperature, which would be conter-productive to the cooling of the water. The ground 4-9ft down however will be cool. Likely always staying below 65deg.
Now you have an enviromentally friendly high power chiller that costs only the power of the small pump to circulate water through to operate. You could have it plugged into your reef controller just like your chiller would be. However, you need some tiny little 1-2 gallons per hour of flow circulating through the loop at all times to prevent the water from going bad from lack of oxygen. It doesn't take much, perhaps just a little dedicated MJ400 throttled back to a dribble but always running.
Now you can easily have a very powerful chiller without the 500-1000w drain on power, or adding heat into the room the chiller is located in.
You might think I'm crazy for thinking the ground is 65deg(or less) on a +100deg day. I work in the datacenter industry, and these ground cooling loops are being used in an Arizona data center with the aluminum shaving cement as a heat sink. On 110deg days, with the surface dirt in direct sunlight reading 135deg, the temperature at 10ft deep was still 60-65deg. It's a very cheap eco friendly motorized chiller alternative that can save huge amounts of money when done on large scales. This perticular datacenter is using a ground loop system to absorb over 4 million watts of energy continously. Ground loops save many hundreds of thousands of dollars in power every year. If they are installed correctly, they are essentially a no maintence no fussing system with a working life of 20+years.
