Solar Power Output Under the Influence of ShadeSolar Power Output Under the Influence of ShadeLily Hsu, Brie Ilarde, Nick Kabel, James Marsh, Cosmo Peng Lily Hsu, Brie Ilarde, Nick Kabel, James Marsh, Cosmo Peng

Abstract

At this point in time, if any one cell on a solar panel is in the shade, that cell and the cells before it in the circuit have a slower energy output. If certain cells are in the shade, the power output of the panel drops dramatically. Our plan was to rectify this problem by changing the circuitry of the panel to separate the cells into smaller sets, isolating the shaded areas. In order to build this, we researched the structure of solar panels and how solar electrical systems work. Then we built panels in series, parallel, and our new wiring system and compared their efficiency in various conditions. This design could be implemented anywhere in the world, though especially useful in places with varying amounts of shade. What makes this topic interesting is it is a well-known topic, just with a fresh approach to it.

Results

  The results of our experiment show that the custom panel we designed consistently produced higher wattage than the series panel and only produced higher wattage than the parallel panel under certain shade conditions. The graph compares the average wattage produced by each panel in different shade conditions. The average wattage is the product of the mean of all trials of voltage and the mean of all trials of amperage. Under every shade condition, the series panel produced the least amount of watts while the other two panels competed with each other. On average, the series panel produced 12.25% less energy than the custom panel and the parallel panel produced, on average, 1.14% less energy than the custom panel.

Methods and Materials

Our goal was to find out if and how changing the wiring of a solar panel would affect the output of the panels when shaded. Currently, if any cells on a panel are shaded, the energy output is reduced for the whole panel. We built three different panels in wooden frames with 16 cells in each in a four by four square. One panel was wired in series, one parallel, and one with our custom wiring design. The panels were then be placed side by side. We recorded the voltage and amperage of each panel, then used cardboard to cover the same part of each panel to simulate shade. We then repeated the process and recorded the voltage and amperage of each shaded panel, using that to calculate wattage, and displayed all the results on a graph to compare the different wirings to see which is most efficient.

Discussion

From our results, we came to the conclusion that although our custom wiring design for solar panels isn’t always the most efficient, it still is consistently efficient. It always did better than the series panel, by as much as 24%. While we were hoping that our idea would turn out to be an improvement to the current problems with shade and wiring, it didn’t do too badly. In two shading types, it actually produced higher voltage than the parallel panel, which did the best in the other three shading types. Our experiment did have a few weaknesses. For example, of the seven times we took readings of the panels’ voltage and amperage, we only had time to take readings with corner 2 shaded four times and corner 4 six times. This could be the reason why the averages for corner 2 were greater than even the unshaded averages, except for the parallel panel, which made only slightly less. This makes it seem as if a panel shaded in that corner produces more energy than a panel without shade, which does not make sense. Another possible flaw is that we only started measuring amperage after the second reading. If we were to conduct this experiment again, we would address these problems. Readings of both voltage and amperage would consistently be taken at the same time with multiple panels. Also, the panels would be larger than four cells by four cells. This would result in greater data values and therefore clearer patterns would emerge. After this further testing, we could present our design to solar panel manufacturers and find out if they agree with us that this model is as feasible as series and parallel, the wirings currently in use. If they like our idea, it could be mass-produced and may even come into common usage. We could also continue to experiment with wirings that could greatly reduce the shade problem. If we found a design that works, this could also be proposed to manufacturers. In conclusion, our new panel wiring style functions and produces power just as well as, if not better than, the current series and parallel wirings. It could even lead to finding a wiring for solar panels that works around existing shading problems.

Camas High School Magnet Program

Left- Soldering the wires of a panelRight- The frames of the panels

Acknowledgments

Special thanks to Dino Ilarde, Sharp Electronics, WSU Vancouver, Laura Friedenberg, Jennifer Dean

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Figure 2. Wirings for each panel.

Figure 1. Effect of Different Wirings and Shading on Wattage