Geothermal Cooling idea/questions

[tangir1]

There are a lot of thing that you can try on this issue, but if you are not engineering type, it is best to leave this to the professionals.

To start, I suggest you broswe thru the followings:
http://www.geothermal.org/
http://geothermal.marin.org/

In addition, you should also look into the following regarding solar cell:
http://www.globalpvspecialists.com/
http://www.n-v-t.com/
(NVT still have some leftover solar panels from the Discovery Museum in Anaheim, but compare their rate with others)

With that said, one of the way to do this is not direct heat exchange, but with a heat pump with titanium heat exchanger. One loop goes with the buried pipe (freshwater), while the other loop is on the tank water.

 

[smaug]

Actually i had a brain strom today. Instead of using tubing in a heat exchanger why not make a tank or tub with a partion made of titanium. a sheet of titanium is remarkably cheaper than tubing and you would not need a pump to move your salt water at all just run the pump on the underground loop when the water in the tank gets to warm, and you could do the same with a solar water heating panel.

Smaug

 

[smaug]

Here is a quick pic the yellow would be a titanium plate 3/16 inch or so maybe 10x10 inch square it would be sandwiched between plexi peices so you dont have to wory about your fresh water and salt water mixing.

 

[AnnArborBuck]

The only issue with your design using a sheet is that you have a very small surface area. The amount of heat that you can trasfer from the hot side is directly related to the surface error for exhange, the heat transfer coefficient of the transfer barier (titanium in your case) and the temp difference between the hot and cold side. I really doubt 100 square inches is really going to work for you.

 

[tangir1]

Ditto. FWIW, solar heater use lots of surface area, and if you can't get enough surface area, you may try to increase the flow to help the heat exchange a little.

 

[smaug]

So maybe a larger sheet of stainless steel with a epoxy coating to protect it form salt? Drop in chillers dont have a lot of surface area but they more than likley get a lot colder.

Smaug

 

[Anonymous]

So maybe a larger sheet of stainless steel with a epoxy coating to protect it form salt? Drop in chillers dont have a lot of surface area but they more than likley get a lot colder.

Smaug

I a not trying to rain on your parade, but heat exchanges utilize tubing to maxamize surface area. Also, flow helps transfer heat and your flat panel may or may not do it as well.

One solution I saw was to use long, straight titanium tubes. They are much cheaper than the coils. Insert them into a 3 or 4" PVC pipe with caps on both ends. It can be as long as you want with as many titanium tubes as you can get in it. Epoxy the tubes where they come out of the end caps. Flow your water through the PVC via a port at each end and you have a very efficient heat exchanger, but it is larger than most, due to the straight tubes, but its a lot cheaper.

 

[tangir1]

Regarding stainless steel, you don't need epoxy coating if you use the right kind. SS316, for example, is saltwater-"safe" for a long time, and can be useful in this case.

As for the titanium, there are many grades too. For aquarium application, stick with CP grade. It is easier to work with (but still very difficult to bend), and safer than regular titanium alloy for structural purpose (say, bicycle frame.