Externet Posted January 19 Posted January 19 Hi. This could be in other subforums, but here it goes. Placing a row of fixed solar panels on flat soil, the better perpendicular insolation elevation angles -at say latitude 380N- is about 40 degrees for winter and 60 degrees for summer. But that is for noon time. For say 08H to 10H and by 14H to 16H, the sun elevation is lower. And azimuth makes it even a poorer incidence angle. What ± elevation angle is considered a convenient compromise to collect most solar energy? Is that from some integral calculation ? My books do not suggest much on it.
swansont Posted January 19 Posted January 19 Noon is when the Intensity is the highest, so it makes sense to maximize the geometric efficiency for a fixed panel for the part of the day when you get the most sun. You’re only tilting based on angle above horizon at noon, not on the orthogonal direction, and the sun passes through more atmosphere near sunrise and sunset, which scatter blue light more efficiently (i.e.the light actually used by the panels) Do you want to optimize for when you’re getting 50 W/m^2 or when you’re getting 250 W/m^2?
Externet Posted January 19 Author Posted January 19 Thanks. 250W/m2 Would be great! Efficiency I have is barely over 20 ! The intention is a better cumulative daylight integration of power collected. If deviating 5 lower elevation degrees from the optimal celestial noon yields a larger morning and afternoon watts collected increasing the daylight total, well, is to consider sacrificing a few extra watts around noon for a better yield mornings + afternoons... -if am explaining it well-
swansont Posted January 19 Posted January 19 52 minutes ago, Externet said: Thanks. 250W/m2 Would be great! Efficiency I have is barely over 20 ! The intention is a better cumulative daylight integration of power collected. If deviating 5 lower elevation degrees from the optimal celestial noon yields a larger morning and afternoon watts collected increasing the daylight total, well, is to consider sacrificing a few extra watts around noon for a better yield mornings + afternoons... -if am explaining it well- It might be more instructive to think of power you’d be throwing away. If a sub-optimal angle reduced your power by, say, 10%, do you want to lose 10% of a small number, or a big number?
gerbizor Posted February 5 Posted February 5 If you install a lens above the panels, thereby increasing the number of rays coming to the panel, what energy will be released, and is it possible?
exchemist Posted February 5 Posted February 5 On 1/19/2025 at 5:31 PM, Externet said: Hi. This could be in other subforums, but here it goes. Placing a row of fixed solar panels on flat soil, the better perpendicular insolation elevation angles -at say latitude 380N- is about 40 degrees for winter and 60 degrees for summer. But that is for noon time. For say 08H to 10H and by 14H to 16H, the sun elevation is lower. And azimuth makes it even a poorer incidence angle. What ± elevation angle is considered a convenient compromise to collect most solar energy? Is that from some integral calculation ? My books do not suggest much on it. This source: http://www.solarelectricityhandbook.com/solar-angle-calculator.html. suggests that the optimum angle is to be perpendicular to the incident rays when the sun is at its zenith. Obviously this varies across the seasons. However, given that the user's demand for electricity will also be seasonal (as will also be the price of electricity paid by the grid), there is a preliminary question to answer, which is whether the user simply wants the max annual kWh, irrespective of when in the year it is produced, or whether it is better to optimise for the season of maximum demand (and highest electricity price). 30 minutes ago, gerbizor said: If you install a lens above the panels, thereby increasing the number of rays coming to the panel, what energy will be released, and is it possible? That only works if the area of the lens is greater than the area of the panels, i.e. the lens intercepts more radiation and directs it onto the panels, concentrating it. A lens does not magically increase the amount of energy in the radiation (conservation of energy). In practice, a lens that size would be very heavy, expensive to make and unwieldy. I feel sure it is more practical to simply install more panels, to intercept radiation across a bigger area.
studiot Posted February 5 Posted February 5 47 minutes ago, gerbizor said: If you install a lens above the panels, thereby increasing the number of rays coming to the panel, what energy will be released, and is it possible? That would not work well due to the Law of conservation of Energy, assuming the panels were optimally laid out in the first place.
swansont Posted February 5 Posted February 5 6 hours ago, gerbizor said: If you install a lens above the panels, thereby increasing the number of rays coming to the panel, what energy will be released, and is it possible? Concentrating the rays can work if the lens or mirror array has a larger area than the collector. Mirrors are used in thermal solar, but lensing has the problem of what happens with off-axis rays - unless the system tracks the sun, you might miss the collector.
Externet Posted February 5 Author Posted February 5 Augmenting insolation to solar panels is not done with lenses but mirrors.
studiot Posted February 5 Posted February 5 (edited) Just now, Externet said: Augmenting insolation to solar panels is not done with lenses but mirrors. That still has to obey energy conservation. Edited February 5 by studiot
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now