I live in Manitoba. Keeping my system arrays clear of snow is of interest to me. Attached is an image of my equipment shed which I built last summer. It has 15 panels mounted on it. The 15 panels are actually two arrays. All 15 panels are identical and were purchased and delivered at the same time. The 6 panels on the right side of the image are one array, providing power to a mini-split heat pump, with the panels wired as one string in series (1S). The 9 panels on the left side of the image are another array, providing power to the main power system, with the panels wired in a 3S 3P configuration. You can observe that the right hand array has no snow on it while the left hand array does. It started snowing today after it got light although we have not had any direct sun - just diffuse light through the clouds.
All I can think is that the higher panel voltage in the minisplit array somehow creates more heat loss from the panels in order to give this effect. If that is the case then good design for snowy locations would be higher voltage arrays. Any thoughts on this theory?
Will
If both arrays were producing the same amount of watts maybe that would be a better way to compare if the heating is more with higher voltage.
Larry
Hi Larry,
The right hand mini split array produces about 2/3 or less than the left hand array. The mini split takes about 1.5 Kw at maximum output however the array for it is 2.4 Kw. The minisplit can take a lot of overpanelling however it's high voltage limitation is 310 Vdc Vmp so that is what I designed it for at -40C. The left hand array feeds the house power system and is rated at 3.6 Kw. The house will take whatever it can make and using the diversion system put this power into the batteries and/or the HWT and/or the car.
Will
Well that would almost make you think the one on the right is less efficient at making power if they heat up more the the ones on the left. But good for melting the snow !
It would be interesting to look at them with thermal imaging camera at different temps and conditions and see how much warmer they look. I suppose you could do that with a regular infrared temp gun too to see temperature of them.
Larry
It's my understanding that the more watts a panel is providing, the cooler it runs.
A unloaded panel will be hotter than a loaded panel -
because a loaded panel is sending energy away somewhere and will be cooler