Copper Rod for Cooling

[VictorValencia]

Hi Everyone,

I have an interesting problem that I hope you can
help with. I am building an insulated wine storage
cabinet with a volume of about 13.5 cu ft. The outside
is solid wood and the inside is lined with 1" rigid
foam.

I heard that you can "cool" a cabinet by driving
large copper rods into the ground and have them
stick into the cabinet.

The question is how can I calculate the size and
number of rods that I would need?

Here are some other parameters:

1) We should be able to determine the performance
of the insulation.

2) We should be able to determine the performance of
the dual-pane cabinet glass door.

3) The temperature of the ground at 6' is steady at
62 deg F year round (Santa Clara, California)

4) The temp inside the cabinet does not have to change fast.

5) The ambient temp of the room averages 74 deg F

6) The cabinet is made of 3/4 cherry with a 1" quartzite
counter top covering it.

7) 1"-2" (10 feet long) copper rod is very expensive

The next material down the list of thermal conductivity
is significantly worse and the only thing better is
diamond

Is there some way to determine what would work?

Thanks,

Victor

 

[MintJulep]

You want to store your wine at about 55F or so, right?

You have the ground as a source of 62F.

You can't get there from here.

 

[VictorValencia]

Agreed. It will never get below the ground temp of 62 deg F.
62 is better than 74 though.

 

[blacksmith37]

There are better conductors, silver for one, being CA I guess money is no object. But as noted, you can't get there with conduction. But a Thompson (and or Peltier) heat pump could do it; especially by burying the second end as you propose. There are small inexpensive, portable cooler/heaters available (by reversing the applied voltage you can put heat in or take it out of your box.) It would require customizing, not practical , but very interesting.

 

[EdStainless]

Actually this is done with heat pipes. The are tubes with a wick inside and a low boiling point fluid. The fluid boils on the hot end and condensers on the cold end.
The can't be driven, but holes would need to be bored and then back filled around them. They are passive.

How cool is the ground 12' down? My hunch is that you should be able to get within 5deg of that temp.

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Plymouth Tube

 

[Compositepro]

Heat pipes are usually much more efficient at transferring heat upward or horizontally than downward. Capillary action can only raise fluid to a limited height.

Wine cellars are called cellars for a reason. If there were an easier way, it would already be done that way. The alternatives are non-passive cooling.

 

[IRstuff]

My take is that you'd be better off plumbing a closed loop water line into a buried heat exchanger. Alternately, you could directly plumb your cold water supply through the cooler.

TTFN

FAQ731-376