sunshine_eggo
Happy Breffast!
It's been discussed several times that splitting an array into different directions can improve morning and evening harvest at the expense of mid day, which makes intuitive sense, but I haven't seen many analyses to that effect.
In my case I have the following:
34°N latitude
2970W of Talesun panels tilted at 29.6° and facing 165°.
A boatload of label-intact 285W SanTan panels unused inside the shipping container.
Both brands of panels have near identical Vmp/Voc ratings.
Given that my array orientation favors morning production, my after-4pm PV performance is pretty pitiful, so I thought I'd run a little "What-if" analysis with PVWatts.
I wondered what a 3S array of the santan panels facing due West (270°) would buy me. I considered 30, 45 and 60° tilts. I ran each scenario in PVWatts and downloaded the hourly data. I looked at the annual total and the amount produced after 4pm annually.
The following table summarizing the results:
The first 3 rows show annual, >4pm, the % power produced after 4pm and the loss vs. optimal placement. Example:
855W of panels tilted at 30° facing 270° will produce 1258kWh annually, 220kWh after 4pm (17.49% of the total) and will produce 21.16% less than an optimal South facing array.
Optimal is the same 855W placed in an optimal South orientation and tilt.
Current is my 2970W array.
Of note is the 60°@270° array. Placing 3S 285W (855W) in that orientation essentially double my after 4pm output. That's significant. I think I'd be willing to sacrifice 34% of those panels' annual output to double my post-4pm intake.
Why did I bother with this? It was pretty hot up North over the holiday weekend, and we ran the A/C 7-8 hours/day to maintain comfort. We started the weekend with low battery SoC due to a poorly timed discharge test. We definitely needed to run 1.5-2.5 hours after 4pm, and that dipped into our battery capacity pretty significantly - particularly when you're only getting up to ~45% during the day.
In my case I have the following:
34°N latitude
2970W of Talesun panels tilted at 29.6° and facing 165°.
A boatload of label-intact 285W SanTan panels unused inside the shipping container.
Both brands of panels have near identical Vmp/Voc ratings.
Given that my array orientation favors morning production, my after-4pm PV performance is pretty pitiful, so I thought I'd run a little "What-if" analysis with PVWatts.
I wondered what a 3S array of the santan panels facing due West (270°) would buy me. I considered 30, 45 and 60° tilts. I ran each scenario in PVWatts and downloaded the hourly data. I looked at the annual total and the amount produced after 4pm annually.
The following table summarizing the results:
The first 3 rows show annual, >4pm, the % power produced after 4pm and the loss vs. optimal placement. Example:
855W of panels tilted at 30° facing 270° will produce 1258kWh annually, 220kWh after 4pm (17.49% of the total) and will produce 21.16% less than an optimal South facing array.
Optimal is the same 855W placed in an optimal South orientation and tilt.
Current is my 2970W array.
Of note is the 60°@270° array. Placing 3S 285W (855W) in that orientation essentially double my after 4pm output. That's significant. I think I'd be willing to sacrifice 34% of those panels' annual output to double my post-4pm intake.
Why did I bother with this? It was pretty hot up North over the holiday weekend, and we ran the A/C 7-8 hours/day to maintain comfort. We started the weekend with low battery SoC due to a poorly timed discharge test. We definitely needed to run 1.5-2.5 hours after 4pm, and that dipped into our battery capacity pretty significantly - particularly when you're only getting up to ~45% during the day.
