Solar farm panel orientation? - Page 1
Forum section: electronics / general

author: PwrElectronics
author_rank: Regular Contributor
timestamp: May 22, 2021, 05:45:38 pm
content: Last week, I was at the family farm in rural Minnesota. A solar farm was put in the area last year and appears to now be in operation.I thought it strange they arranged the panels in a North-South orientation instead of the expected East-West. When I passed by on the way TO, it was late afternoon-evening and the panels were tilted to face west. When I passed by on the way FROM it was around noon and panels were tilted to being essentially flat.This location is on about the 45th parallel North. In the dead of winter, the sun is very low in the southern sky at noon so I would have thought they set these panels up to tilt into that. As it is, they are not going to get any optimal angle in the winter.Why would they do it like this?

author: fordem
author_rank: Regular Contributor
timestamp: May 22, 2021, 10:08:02 pm
content: The way I was taught to do it is to orient the panels north~south with a tilt that was dictated by the latitude of the location, since Minnesota is in the north hemisphere, the panels would essentially be south facing.Designing the system to track the sun as it changed position during the day was an option, at the time (back in the late 80's) considered to be worthwhile, but with the reduction in cost/watt, this school of thought may no longer be applicable, the geographical area required to prevent the panels from shading each other as they tilted can now be occupied by additional panels to compensate for the losses resulting from not tracking the sun, at costs comparable to the older systems, especially when the tracking mechanisms and their maintenance can be eliminated.Given that this system has been designed to track the movement of the sun during the day, what are the odds that provision has been made to change the angle of the panel during the different times of the year? It might be easier to achieve, even if it's done manually as it is not something that will need to be adjusted on a daily or even weekly basis.

author: penfold
author_rank: Frequent Contributor
timestamp: May 23, 2021, 12:16:34 am
content: In comparison with roof-top solar, the tilt angles of solar-farm style arrays can look a bit counter-intuitive. The whole mess would be optimized based on cost per annual energy yield for the given fixed amount of land they have available. Increasing the pitch would also necessitate increasing the separation to avoid each panel shading the one behind it. So it's unlikely they would do this if it meant they could only fit half the panels and sacrifice the total summer yield.The east-west "roll" rotation would increase the yield regardless of the season and there's an interesting tradeoff between the range of movement and total installable surface area/panel cost. There are also some weather and prevailing wind conditions to take into consideration from a "safety" perspective which can also bias the designer's tendency to tilt or not, which may not be immediately apparent.

author: fordem
author_rank: Regular Contributor
timestamp: May 24, 2021, 02:39:46 pm
content: Quote from: penfold on May 23, 2021, 12:16:34 amI don't know what happens elsewhere, but, in this corner of the world, roof-top solar panel orientation is dictated primarily by the roof top, which is typically there long before the solar panels get installed.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 24, 2021, 03:14:09 pm
content: There is a similar installation near me, and the explanations make sense to me. What I found most interesting about the local installation is that construction was complete and then it was nearly a year before the tracking feature was operational. Another indication that a fixed system might make make beat overall economic sense.

author: penfold
author_rank: Frequent Contributor
timestamp: May 24, 2021, 03:52:15 pm
content: Quote from: fordem on May 24, 2021, 02:39:46 pmPretty much the same here within a few degrees offset.I kinda meant that since roof-top installations are more numerous and likelihood of being noticed they can easily cause a perception of normality. Especially when combined with the typical viewing angles from ground level they can look a bit more extreme in angle... Both factors can make ground level installations look a bit weird when they optimised for factors other just optimal direction towards the sun. And on top of that, on ground level there may also be a distribution of heights accorss the field which can visually distort viewers further.