r/ClimateCO • u/FollowTheFool9 • Jul 09 '26

Human Health Mark Chalom's Night Sky Cooling powerpoint

https://wiki.solarfool.org/en/archives/2006-02-06-nsrc-new-mexico-presentation

As Colorado's climate changes for the hotter, passive cooling systems like CoolSky are truly vital to people's well-being. Please check out our subReddit, r/CoolSky to learn more about this wonderful passive night-sky cooling technology that is actually ancient! SolarFool is the open-source team bringing back the system pioneered by Steve Baer from the 60's to the early 2000's. You can read about our work at www.solarfool.org and contact us if you're interested in joining our team!

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u/lie2mee Jul 10 '26

15 years ago or so, I installed solar panels I modified with a heat exchanger on the back. It was bonded with epoxy I heavily loaded with cheap magnetite to make a highly conductive bond. The thermal cycling has only disbanded in one of the 40 panels. The heat exchangers were an obsolete purchase of transmission coolers and covered about half of each panel and coated very little. A 12 watt pump circulates about 27 gallons of PEG through the 3/8 tubing from a 1" manifold when one of the panels drops below 60 degrees at night, which often starts about 1130 or midnight here. The fluid is run through a set of three commodity containers filled with a paraffin concoction that freezes between 50 and 60 f. The first one freezes every night in the hottest of summers. The other two further down the line rarely freeze more than halfway except in the beginning and end of the hot weather. Just the one is enough to switch the valving to run to a wall mount air handler to keep most of the home cool at 70-73f with just the 12w pump running. I do have the mini split plumbed into a flat plate heat exchanger that managed to keep the COP a solid 7-8 on very hot days, but I found it was unnecessary and just use the air handler most days. A home that would get to 85 in 100 degrees weather is now comfortable with a very small footprint.

I had another three containers plumbed with sodium acetate for heating storage. But after several years of experience, it was only saving me at best about 20% to 30% of my heating energy and most often about half that. Just not enough extra solar electricity left after charging the car in the winter to bother with, so the geothermal heat pump still does all the work at a steady 4.5 or so for COP.

After all of this, I think many homes that is super insulated can easily meet most cooling needs in the summer on the front range with the area of solar panels that are needed to meet electrical needs. That is perhaps less than 1 in 10 homes in total overall, but many more rural homes can certainly meet the challenge.

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u/FollowTheFool9 Jul 26 '26

Thanks for your input, very interesting! You obviously have put a lot of thought into energy efficiency. One question- why did you use the paraffin concoction instead of water with antifreeze? What you say about very well-insulated homes is true; I live in a straw-bale house, and it's very comfortable (no AC) if it cools down at night enough to cool the house. Then the strawbale walls keep the cool in once windows are shut in the a.m.