Project Soon - A Vertical Solar solution
Introduction
One of the main solutions for alternative energy has been solar energy. An increasing amount of people have utilized solar panels on buildings, telescopes, satellites, and other structures for producing a source of clean energy. For solar to continue to rise it needs to become more efficient per amount of space it takes up. One can think of a number of situations where the amount of space available is a constraint in the horizontal plane but there is ample space available vertically. The top of a high rise building, deck of a container ship and the top of a mountain are some examples. One way to make solar more efficient is to be able to find a way to make it take up more space upwards rather than on the ground. This would allow it to be more usable per the amount of feet it takes up on the ground.
Most of the solar installation that you see are flat solar i.e., panels are installed horizontally in a single layer either on land or floating in the water. Why is there not an abundance of vertical solar installations? One reason could be that most of the solar panels are heavy. However in the recent years thin film solar panels are available from various vendors like power film which are very light almost like a sheet of plastic. Another reason could be that vertical stacking of panels can cause the top panel to drop a shadow on the bottom panel significantly reducing its efficiency. In this project we looked at this problem of stacking solar panels vertically and came up with some approaches to avoid shadows if the location of the panels is not in the equator. We did our experiments in the San Francisco Bay area which is in the norther hemisphere and at a latitude of 37.5 degrees North. We used the solar elevation at our location (San Francisco Bay Area) and some geometry to develop a solution to this problem. Solar Elevation is the angle which the sun's rays hit the surface of the earth at a particular location at solar noon. Solar Elevation angle can vary based on the time of the year. There are three types of scenarios where it varies.
Case 1 : Vernal and Autumnal equinox
During this time center of the earth lies in the plane of the sun and the rays of the sun shine most directly at the equator.
Case 2 :Winter solstice
The sun shines down most directly on the Tropic of Capricorn in the southern hemisphere on the occasion of the winter solstice. The sun's declination angle is delta = -23.5 degrees on the winter solstice.
Case 3: Summer Solstice
The sun shines down most directly on the Tropic of Cancer in the northern hemisphere. On the occasion of the summer solstice, making a declination angle delta = + 23.5 degrees with the equatorial plane.
What we found from these calculations is that the Sun is never vertically overhead at our location. The solar elevation angle at our location (San Francisco Bay Area) is the lowest during the winter solstice and is 29 degrees. The solar elevation at our location is the largest during the summer solstice and is 76 degrees.
Since the sun is never vertically overhead at our location and the worst case solar elevation angle was only 76 degrees, we tried to use some geometry to calculate if we could separate the panels vertically to such a distance that the top panel would not leave a shade on the bottom panel.
Once you have found the Solar elevation you can use it to find the minimum distance that must go between the panels. To do that you use our panel distance formula.
What we were able to derive using geometry was that in the worst case i.e during the summer solstice if we our panels had a side of length S, then if we separate the panels vertically by a height Hmin >= 4.01 * S then the top panel will not leave a shadow on the bottom panel. This discovery opens up a lot of possibilities on saying goodbye to flat solar and building innovative solutions using vertical solar.
Another way to make solar more efficient is to make it portable. In order to do this we made small designs capable to fit on the back of a truck. This allows people to gain energy wherever they are even if they are on a boat on the back of a train or anything. This would allow people to be able to gain solar power even while they are away from home to use on appliances. Our project's goal was to find a more efficient way to maximize solar energy per the amount of space. Also our goal was to make solar energy more portable.
We build two prototypes to test our ideas. We used 3 thin film solar panels made by power film for our experiments. Each of these panels was rated at 6.5 Volts and 50 milli amperes. For the first prototype we build a physical tower using marshmallow skewers to vertically stack our solar panels.
For our second prototype we used strings to separate the panels and then used balloons to hoist them up vertically.
Both the prototypes proved that with the correct vertical separation between panels, no shadows are cast on the bottom panels by the top panels.
Our first design was a tower attached to a cardboard base it generated 190 milliamperes of current at its peak and 6.6 volts of energy per panel. The main problem with this design was that it was to flimsy and the wind would knock it over.Its design was efficient per amount to inches it took up and was able to power a tiny fan. This brought us to our second design in which instead of a tower design we used balloons to hoist each panel into the air like a tower. This design was more durable but it compromised the idea that no panel would shadow each other because of the design being susceptible to the wind blowing tilting the design. In total we conclude that when solar panels are properly spaced in the air it maximizes efficiency per square foot of area. Our research would help build more efficient solar in cities because you can build any thing unlimited feet into the sky.
Procedure for Solar Tower
1.)Solder 1 red wire to the positive terminal and one black wire to the negative terminal of each power film solar panel
2.)Start building the solar tower by first cutting each marshmallow stake into 20 inches
3.)Next pierce holes into the corner of the plates with the marshmallow stakes
4.)Start by placing the first plate on the ground
5.)Then put each a marshmallow stake through each corner of the plate
6.)Next place a straw over each marshmallow stake
7.)Next place a plate on top of the straws
8.)Put 4 marshmellow stakes through the corners of the plate
9.)Put straws on top of the marshmallow stakes
10.)Put another plate on top
11.)Add tape to the bottom of the solar panels
12.) Connect the wires in parallel i.e., all the red wires together and all the black wires together.
13.) Take your solar tower outside in the Sun.
14.) Test with a multi-meter or optionally a motor with propellers.
Procedure for Suncatcher
1.)Solder 1 red wire to the positive terminal and one black wire to the negative terminal of each powerfilm solar pane. Read the manufacturer’s instructions or view their instructional video.
2.) Tape a solar panel onto each plate (a styrofoam dessert plate from the grocery store).
3.) Insert two bamboo skewers through the desert plate. We will tie the string on these skewers.
4.)Next cut the rope into 12 20 inch strings
5.) Use access rope to tie the skewers on the first dessert plate down to a cardboard box for support
6.) Tie the first four strings through each corner of the plate on the bamboo skewers and through the holes in the corners of the next plate. Repeat the process.
7.)For the topmost plate, create a handle to tie the balloons by knotting the strings together into one point
8,) Connect the wires from the three panels in parallel i.e., connect all the red wires together and all the black wires together.
8.)Tie the 6 helium balloons (you can get these from your grocery store or party supply store) to the handle at the top of the last plate. The balloons should rise and pull the strings tight and keeping the solar panels separated vertically.
9.) Test with a multi- meter or optionally with a motor with propellers
Materials
6 Solar Panels
6 Wires
8 Marshmallow Stakes
Rope
4 Styrofoam Bowls (dessert bowls from the grocery store).
6 balloons
3 Plates
6 Red Wires
6 Black Wires
6 Straws
2 Cardboard Boxes ( you can get these from COSTCO )
Tape (double sided mounting tape).
Research Data
Conclusion
Most of the solar installations are flat solar i.e in a single layer horizontally. However there are many instances where we may be constrained in the amount of space we have horizontally but may have unlimited space available vertically. We investigated the reasons for this flat solar trend and developed two new prototype designs to showcase vertical solar. We used solar elevation angle and geometry to derive a formula to calculate the spacing for vertical solar to prevent the top solar panel from casting a shadow on the bottom solar panel. We build two prototypes and tested them for one full day in summer to demonstrate the feasibility of vertical solar. Vertical solar opens the possibilities for new design to solve our energy problems and reduce our carbon footprint. Using solar hot air balloons and thin film solar technologies we hope that one day container ships will use vertical solar technologies to power their propellers as they transport good across the globe. We hope that such technologies will significantly reduce our carbon footprint and mitigate the adverse effects of climate change.
Videos
References
http://mypages.iit.edu/~maslanka/SolarGeo.pdf
https://www.youtube.com/watch?v=aqUhs9wQYsI
https://x.company/loon/
https://www.nasa.gov/scientificballoons
