Continuing with our theme of answering questions from forums, let's now answer the second part of the question:
"I will also be installing a 28,000 BTU 3-Zone 21 SEER DuctlessAire mini split air conditioner with variable-speed DC inverter compressor so yes I will need a lot of power to run it. I live in west ky if this helps what region I'll be in. "
In the last blog we determined that from a 35X15 ft roof, we could fit on average 30 panels, and depending on the power output we could produce between 7.5kw and 24kw, approximately, depending on which panels we used and how many of them there are, which will also depend on their individual size.
If we do a google search for a "28,000 BTU 3-Zone 21 SEER DuctlessAire mini split air conditioner with variable-speed DC inverter compressor" then we get something like this at home depot. While the listing of specifications at Home Depot doesn't tell us how many watts it typically uses, it does tell us that it consumes about 6.95A at 230V. But since the voltage (in volts) by the current (in amps), using the formula: Watts = Amps x Volts, so we know 6.95A*230V = 1600W (approximately)
and
How much power does a 28000 BTU air conditioner use?
A 28,000 BTU air conditioner units are typically in the 9-10 EER range, and the wattage of most of these units ranges from 2,800 watts to 3,100 watts.
So there we have the range from on the low end 1600W and at the high end 3,100w.
Since we know that our array as previously computed could produce between 7.5kw and 24kw, it should be easily able to power between 1.6kw and 3.1kw.
Of course, the solar output will vary during the day, but a safty margin of 2X (7.5/3.1) to 7X (24kw/3.1kw) should generally be enough, but solar doesn't run in the dark and gets less efficient when not in direct sunlight. So in the next blog, we'll have to figure out how much battery storage we will need.