Peltier or Ground source heat pump (thermosyphon or heat pump)?

Question

I am trying to devise am energy efficient way to cool a small outdoor pond (approx 3 m long by .3 m wide). I keep Axolotls in it and their optimum temperature is 60-64 F (16-18 C). The pond is mostly under plant shade so it is more about the ambient air temperature being too high in summer (Western Australia - gets up to 45C). I am, thinking either Peltier modules with solar panels to provide power, or thermosyphon / heat pipe.

This is not a solar pond so the temperature differential between layers of water would not be so great. I am wanting to draw heat from the water into the warmer air above the pond.

Any thoughts on the above or any other method you can think of would be appreciated. Not too keen on running a refrigerated setup as power consumption would be high.

cheers

Evan

DAB · Answer

Hi Evan,

The most efficient way to cool the pond would be for you to bury a hose several feet below the ground and circulate the pond water through it and let the earth pull the heat out of the water.

Trying to use the hot air to cool the water is very inefficient, but the earth makes a great heat sink.

DAB

dougw · Answer

If you have extra water, using the latent heat of evaporation can extract a lot of heat. Simply blowing air across the water will increase evaporation and provide extra cooling. I think every liter of water that evaporates extracts something like 541 kilocalories of heat. Every calorie decreases the temperature of 1 ml of water by 1 degree C.

14rhb · Answer

And building on dougw knowledgable comments: if you built something that looked like a fined heatsink, but where the fins were some sort of rigid matting, that would wick the water upwards and increase surface area....blow the fan through the end of that ? The downside could be it turns out to be a good base for mosses and slime to start growing.

Rod

Peltier or Ground source heat pump (thermosyphon or heat pump)?

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