David Baillie wrote:If you read the details of the article it does not say that each individual panel it would produce " up to 20 times more power" which is technically impossible but that a stack of panels at various angles would produce that much sitting on the same spot... Each individual panel would be actually much less efficient since it would spend most of its day out of the direct angle of the sun.Never mind the panel cost, racking cost, engineering challenge, heat buildup, etc... So its technically true as long as you squint and look at it a certain way but not very practical. Once upon a time we used trackers when panels were expensive they used to accomplish what the paper states was the researches main goal. We stopped using them because the answer ended up being cheaper panel on fixed arrays sometimes angled for morning and night.
Cheers, David
That is exactly right, they don't claim that any panel produces 20 times more power, they claim that the tower itself produces 2 to 20 times more power than a flat panel of the same size. I've only seen model sized examples of this. The one I saw used panels that were maybe 5" by 5" on a tower that was built from scrap lumber, mostly 1"x2" approx. If the results can be believed, the panel cost would be the same. I would think (and this is a guess) that the heat buildup may be less, since the panels are surrounded by air, rather than lying against a roof. This wouldn't apply to panels on a rack obviously. If you are talking about a rack system, materials shouldn't cost appreciably more, although I'm not certain what a full sized solar panel weighs. Regardless, I thought it was an interesting concept. I may build a model sized one just as an experiment.
Here is the abstract from an article in Energy and Environmental Science. I didn't purchase the entire article.
Solar energy generation in three dimensions†
Marco Bernardi,a Nicola Ferralis,a Jin H. Wan,b Rachelle Villalonc and Jeffrey C. Grossman
Abstract
We formulate, solve computationally and study experimentally the problem of collecting solar energy in three dimensions. We demonstrate that absorbers and reflectors can be combined in the absence of sun tracking to build three-dimensional photovoltaic (3DPV) structures that can generate measured energy densities (energy per base area, kWh/m2) higher by a factor of 2–20 than stationary flat PV panels for the structures considered here, compared to an increase by a factor of 1.3–1.8 for a flat panel with dual-axis sun tracking. The increased energy density is countered by a larger solar cell area per generated energy for 3DPV compared to flat panels (by a factor of 1.5–4 in our conditions), but accompanied by a vast range of improvements. 3DPV structures can mitigate some of the variability inherent to solar PV as they provide a more even source of solar energy generation at all latitudes: they can double the number of peak power generation hours and dramatically reduce the seasonal, latitude and weather variations of solar energy generation compared to a flat panel design. Self-supporting 3D shapes can create new schemes for PV installation and the increased energy density can facilitate the use of cheaper thin film materials in area-limited applications. Our findings suggest that harnessing solar energy in three dimensions can open new avenues towards Terawatt-scale generation.