Here you can find Solar Panels and technological accessories related to Solar Energy: Click Here If you want to learn about Solar...
Here you can find Solar Panels and technological accessories related to Solar Energy: Click Here
If you want to learn about Solar Panels, to advise you before buying or to build your own Solar Panel: Click Here
Bifacial solar panels are one of the most revolutionary recent advances in solar technology and today I have some new comparison results to share and it's not what I expected but that's why I like data I can get real answers instead of just opinions I receive tons of questions about putting bifacial panels on the roof and now I have good data to answer that question if you watch my video where I installed a three kilowatt array on my shed you know I did the top half with standard panels and the bottom half with bi-facial panels to "shed" some light on this question welcome back to Projects with Everyday Dave let's look at some real world data on these bifacial panels let me briefly go over the setup I used to get these numbers so you can understand them in context I'll break down the results and finally compare them to the data I gathered from my ground array analysis and draw some final conclusions no tasks can perfectly represent every condition so let me first identify the characteristics that I think will negatively and positively affect our results the results are the combined data for two months of production August and September this roof is pure white a best case scenario if you have a dark colored asphalt shingle roof that would dramatically reduce the performance from the numbers I'm going to show today the panels slightly overhang the edge of the roof I'm not sure if that's a positive or negative less reflection but maybe more ambient light probably not a huge impact there are slight differences in the panel's rated output and age I used correction factors to make the comparison as close to Apples to Apples as possible for instance the jingle panels are 385 Watt and the Canadian bifacial panels are 390 watt so I multiply the jinko panels output by 1.013 to get an equivalent result I also made a slight adjustment for the mission solar panels to compensate for their age if anything my adjustments give a slight advantage to the standard panels there is some slight shading in the day from a nearby tree this would give a slight advantage to the standard panels as well but it's so late in the day I don't think it's a significant factor the walking space I made at the edge of the roof faces South and directs light under the first panel later you'll see in the data that this makes a significant difference for the edge panel to collect the data I used NEP micro inverters each inverter can support two matching panels a standard setup would put two matching panels on each inverter as shown in this diagram however to get the data I wanted I paired the top left Mission solar panels together and the bottom left bi-facial panels together the top right jinko and bottom right bifacial panels each had one dedicated inverter to eliminate any clipping for those data points that left me with an odd number in the middle so I paired those mismatch panels to one inverter that turned out to be a bad idea they both under produced all the other panels by about seven percent the manufacturer says not to have mismatch panels on one inverter but I kind of wanted to see what what would happen the result was not what I expected I'll have to look into it a little bit more later but that's not today's topic so we'll remove those two panels from today's analysis with the setup out of the way it's time to look at the numbers over the two-month period the top left pair of standard Mission solar panels produced 83.6 kilowatt hours on average don't get hung up on how one of the pair produced 80 and the other produced 87.3 the inverter software does not perfectly allocate the power produced by each panel so averaging them gives the most precise result the bottom left pair of Canadian bifacial panels produced an average of 93.18 kilowatt hours this is an 11.4 percent increase in power quite a bit more than I expected if we jump over to the panels on the edge with the dedicated inverters there's an even bigger difference the standard panel produced 90.3 kilowatt hours and the bifacial panel produced 104.9 kilowatt hours that's a 16.2 percent increase in power two things to note here one eliminating clipping increased the overall output over the left group during during the two months by an average of about 10.3 percent but don't get too excited the increase was exactly zero percent in the Cloudy month of November people seem to think clipping is bad but when applied appropriately it makes economic sense but this video isn't about clipping strategy the second reason for the increase I believe is a result of the additional Reflection from the one foot walkway it appears to account for an additional about 4.6 percent jump in performance from the light hitting the roof and reflecting back under the panel let's put all this together and see how it Stacks up to make the comparison simple let's assume we have a standard panel producing 100 kilowatt hours over the two-month period Then the bifacial panels in the middle of a white roof would achieve 111 kilowatt hours or an 11 boost in power however if you were able to provide sufficient space between the panels to allow some additional light to come underneath you could see as high as 116 kilowatt hours or a 16 boost taking data from my previous more in-depth analysis of bifacial panel performance we know that on a ground array without special reflection efforts the lower panel which would achieve 113 kilowatt hours or 13 boost and the upper panel would achieve 119 kilowatt hours or a 19 Improvement finally the theoretical Max I came up with based on my previous analysis assuming full sun exposure on both sides of the panels would be 150 kilowatt hours or a 50 percent of course we don't have a great way to get full sun exposure on both sides of the panels that's why it's theoretical I have received numerous suggestions on reflection materials and strategies to achieve higher production some of which I plan to try out and show in my future videos including some snow reflection results I've already started to analyze I'm in the process of expanding my ground array to allow me to fit more panels test more inverter Solutions and get closer to achieving full off-grid production for my home let's digest the Practical applications of this new information does it make sense to put bifacial panels on your roof well it depends first this was a best case scenario with a bright white roof while I did get a bigger boost than I expected it still wasn't dramatic also keep in mind bifacial panels are bigger than standard panels for the same rating I believe that is a result of the packaging for the cells in such a way to prevent shading on the back side real estate on the roof can be a significant factor and power per square foot may be more important for you than cost per watt if we consider an 11 boost in performance which you won't get if you have a dark colored roof our bifacial panels produced 169 watts per meter squared which is one watt per meter squared less than the 170 watts per meter squared that the standard panels produced how about payback if we assume all eight panels were standard 390 watt panels they would have produced 668 kilowatt hours at 20 cents per kilowatt hour that would be 100 134 dollars for the two months if we assume all eight panels were 390 watt bi-facial panels that would be a hundred and forty nine dollars for that two months that's an additional fifteen dollars in the two months or seven dollars and fifty cents a month so should you pay extra for bi-facial panels if you're putting them on the roof if you do it can't be much extra if they are the same price per watt and you have space for them and don't mind handling the extra weight during install I'd say go for it if you're going to put panels on the roof here are some ways to maximize their performance first keep the largest passable gap between the panels and the roof the lighter the roof color the better tilt them at an angle relative to the roof if you can and finally put space between the panels if you have the real estate to do that if you want to see a more detailed analysis of bi-facial panels in various conditions watch this video right here if you want to see how I built the shed array watch this video every situation is different so my goal in these videos is to provide you with as much data as possible so you can make informed choices that apply to your specific situation thanks for watching and I'll see you next time ...
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