[Liveanimalcams]

I've been working on solar powered Peltier AC for my home. This past summer it was able to keep my living room (250sqft) at a comfortable 72F - 75F even when the outside temp was over 95F. It is crazy power hungry, using 12v 5A, but with solar its fine. The hard part as people have said is the heat dissipation and dealing with high ambient temperatures.

My newest design incorporates a few new upgrades. 1) geothermal cooling to dissipate the heat. As the ground temperature stays consistent at ~65F. Allowing me to not worry about the ambient temperature anymore 2) I moved to a 24V 6amp peltier which has a larger delta from the hot to cold side. 3) I now use a 24v ~7.6amp solar panel to power it. 4) I added a 15 Amp high-power motor driver so I can switch between producing cold and hot air. So now it will be viable in all weather conditions.

A core idea is to keep costs cheap which is why I have not added a battery to the mix. Although it would be nice as some nights are quite hot. I got the 24v panel used at $50 and the peltiers are super cheap (3 for ~15). The motor-controller/h-bridge was ~$40, but I didn't want to cheap out on that though and start a fire.

Its quiet unless I turn the fans up and doesn't cost anything to run after initial setup costs, due to the solar. My future plans for making it even better are to use multi-stage peltiers and try to leverage the hot side to produce more power. Also to add raspberry pi so I can control it remotely.

[skyde]

How do you use geothermal? Do you have a diagram or picture of your setup? I would love to build something like this

[Liveanimalcams]

I use geothermal as a way to absorb/dissipate the heat. I got the idea from here: https://forums.overclockers.com.au/threads/concrete-slab-wat... Instead though I dug a trench outside that was 4ft deep 20ft long and then buried some pex pipe. As the water flows into the aluminum block attached to the peltier it absorbs the heat and then as it enters the ground it dissipates so when it comes out of the ground of its back at 55F. The water is moved with a 12v pump. The longer the run the better as the ground is not efficient in energy transfer. If its to short it wont cool down all the way.

I thought of trying to use copper pipe with round engine heat sinks attached to it, to increase the energy transfer rate. However it didn't seem like the copper would last long before potentially reacting with the ground.

Simple diagram: https://www.ernstheating.com/wp-content/uploads/2018/01/Erns...

[skyde]

Thanks a lot. I agree copper will probably not last long but maybe some HDPE flexible pipe would work.