Yeah, the antifreeze system was a bit spendy. We used an electric hot water heater tank due the fact it has a tube that goes to the bottom. Used a CO2 tank from a soda machine.
I had some photos of insulated and non insulated side by side. It was fairly dramatic when full sun came out on fresh snow. Snow was all off the insulated panels by 10 am and the non insulate still had some snow in them when the sun went down. I am of the opinion that you have to ensure there is no air gap between the insulation and the backs of the panels. Spray foam can be purchased in “froth pak” kits. It is not messy. Very easy to apply. Two tanks that look like freon tanks. They feed into a disposable gun. They give you a few disposable nozzles because once you start spraying, the nozzle is good until you stop. The chemicals mix in the nozzle and it plugs up in seconds after stopping spraying. From: Steve D Sent: Sunday, September 20, 2015 1:55 PM To: af Subject: Re: [AFMUG] The dreaded annual "how to keep snow and ice off my solarpanels" thread Anyone got any pics of insulated panels side by side with uninsulated panels? We tried taping a piece of styrofoam to the back of one once, but it never seemed to make enough of a difference (especially for the hoar frost that plagues our mountain tops). Bosses aren't convinced the mess of sprayfoam would be worthwhile. I enjoyed reading your testing with the different sprayers Chuck. The antifreeze was fairly expensive though if I recall? -Steve D On Sun, Sep 20, 2015 at 11:36 AM, Chuck McCown <[email protected]> wrote: I did lots of experiments about 15 years ago adding heat to panels with various methods. Heat tape, hot air blowers, exhaust, all kinds of ideas were worked on. I came up with two things that work. First, lots of insulation on the backs. Spray foam worked extra good. It helps to speed up snow/ice sliding/melting off when the sun comes out. Second thing that works is the application of antifreeze. Propylene glycol is environmentally safe for the wildlife. Sprayer at the top works pretty good. We rigged up one tank that was pressurized with air and had solenoid valve that was turned on via telemetry. Takes almost no energy to pump. Did CO2 pressurization too but that will carbonate the antifreeze and it doesn’t spray as well. You can vent the tank and have it drain back if you want. I also tried a deicing product made from beet juice. It didn’t work too well. Plugged up the spray nozzle. From: Steve D Sent: Sunday, September 20, 2015 12:05 AM To: af Subject: [AFMUG] The dreaded annual "how to keep snow and ice off my solarpanels" thread Maybe it's Saturday night exhaustion talking, but piping the exhaust from a standby generator toward the back of solar panels a bad idea? I'd expect it to not put heat on the panels in the summer except it's weekly exercise cycle but that shouldn't be too bad? LP too so shouldn't be any soot. Or would this just create one little hole of open panel and a pile of ice? Bad in general for the panels? If I did this again, I'd put the damn thing directly under the panels... these Onan's get stinking hot. My little "cool running", comparatively speaking, portable yamaha's will melt a two foot radius of snow around them if they run for a good length of time, all this heat going to waste! The Onan would probably clear the whole rack if it was sitting right below it. Grumble grumble... snow... something, something, curse words... Cheers, Steve D
