digitalabacus
New Member
- Joined
- May 3, 2022
- Messages
- 6
Hello everyone,
The question is simple but I am getting conflicting data from SAM. In short, how much space do I *actually* need on my roof for solar panels for an 8 - 10kW system (still haggling with myself on the exact system details)?
To figure this (and many other things) out, I downloaded and installed SAM. When I punch in my my system details I get the following:
Now, when I drag my sorry carcass on the roof, I measure 18.9m x 6.5m = 122.85 m^2. Bummer.
But wait! Something doesn't add up here. I can buy (as an example) these 415W Canadian Solar CS3N-415MS panels. Checking the module specs, they are listed as 76.4" x 41.3" = ~2m^2. This would mean that I would need 8kW / 415W = 19.27 panels, round that up to 20 which is in the same ballpark (~18 - ~24) as other houses in my area (No, I totally don't go around surreptitiously counting other peoples solar panels ?). Finally, multiply 2m^2 per panel by 20 panels and we get a final result of ~40m^2, which much more closely matches what "common sense" dictates.
I considered that SAM is including my geographic area but I am in the desert with a southern facing roof (Zone 10); I should be pretty ideally situated for maximum generation. Also, my understanding is that unobstructed solar flux is something like ~1kW / m^2 which seems to fit much more in line with the "common sense" math above once panel efficiency is considered.
So, what gives?
The question is simple but I am getting conflicting data from SAM. In short, how much space do I *actually* need on my roof for solar panels for an 8 - 10kW system (still haggling with myself on the exact system details)?
To figure this (and many other things) out, I downloaded and installed SAM. When I punch in my my system details I get the following:
Now, when I drag my sorry carcass on the roof, I measure 18.9m x 6.5m = 122.85 m^2. Bummer.
But wait! Something doesn't add up here. I can buy (as an example) these 415W Canadian Solar CS3N-415MS panels. Checking the module specs, they are listed as 76.4" x 41.3" = ~2m^2. This would mean that I would need 8kW / 415W = 19.27 panels, round that up to 20 which is in the same ballpark (~18 - ~24) as other houses in my area (No, I totally don't go around surreptitiously counting other peoples solar panels ?). Finally, multiply 2m^2 per panel by 20 panels and we get a final result of ~40m^2, which much more closely matches what "common sense" dictates.
I considered that SAM is including my geographic area but I am in the desert with a southern facing roof (Zone 10); I should be pretty ideally situated for maximum generation. Also, my understanding is that unobstructed solar flux is something like ~1kW / m^2 which seems to fit much more in line with the "common sense" math above once panel efficiency is considered.
So, what gives?
