Sign up for the Design News Daily newsletter.
How to Optimize Your Solar Panel Array
Solar panels are becoming more affordable, but land is not. Here's how to set up a solar panel array that absorbs maximum energy while taking up minimum space.
July 11, 2018
8 Min Read
Solar panels are becoming more affordable, but unfortunately the land and roof space needed for them is not. In order to maximize efficiency and keep costs low, it's important to understand how to optimize solar panel placement in an array. In experiments, the concept presented here can more than triple output for a given area. Data shows an increase in output of 670%. That means if you have 100 square feet of space for solar panels, you can go from 1kW to 6.7kW of output power. And it only scales up from there.
To understand this, we have to begin by treating light as a wave, and not as particles. If light were particles and we wanted to optimize for efficiency, we would try to maximize area on the plane perpendicular to the source in order to collect as many of these particles as we can. But light is a wave, a vibration with an energetic potential difference between points of positive and negative amplitude. So, rather than collecting photons in a bucket, we're going to harvest the energy from a wave of light in a way similar to other known waves.
As a sound engineer for many years, I have witnessed for myself how efficiently sound waves can be captured. Sound waves, for a given area, are best absorbed not by a flat wall, but by an array of ridges known as studio foam. In a recording studio environment, it is advantageous to reflectively direct sound waves into wedge-like cavities to absorb that energy instead of allowing the sound to bounce off the wall while maintaining a large portion of its energy. In a solar array, as we are about to find, it is similarly advantageous to do the same.
Knowing that light is a wave, we can take advantage of that same property. And given that light is of a higher frequency than sound (0.003-7.5 x 10^14Hz at 299,000,000 m/s compared to 20Hz-20kHz at 343.2 m/s), we will have more reflections for a given distance and therefore more opportunities to capture that energy. Light is a wave that reflects. Each time it reflects, some energy is lost and some energy remains. Based on this, we can decide to orient the solar configuration so that it reflects again and again, allowing for energy to be captured repeatedly from a single ray of light.
We will keep in mind that, when capturing the energy of a wave, energy will decrease at every successive interval because amplitude is lost at each reflection point. This will result in exponentially decreasing energy with respect to the number of reflections. But these reflections, if graphed based on our theoretical geometry, show a fractal pattern of data that is additive at every point of reflection. At the scale of this experiment, we will be capturing the energy from up to 100,000 reflections or more, as opposed to one single reflection captured with a typical flat solar array orientation.
Instead of letting light hit our solar panels and bounce off as wasted energy, we will set up a configuration that reflects each light wave multiple times, extracting more and more energy each time. This reflection will cause the inside of the solar panel configuration to appear darker than a standard flat configuration, which we can observe by measuring reflected light traveling in the inverse direction as the source. Most importantly, though, we will observe that by taking advantage of the known wave properties of light, we can extract significantly more energy for a given area.
Solar Cells, uniform (ex. 2×4″, 6v,1w)
2-22 gauge Insulated Wire
Digital Voltmeters, low draw (may require resistors/dummy load)
8×10″ Plexiglass sheets
8 – 12
5/16″ Washers, End Caps
You can source individual parts from Digi-Key.
Drew Paul has made a kit of all the components available as well.
Click here to download a diagram that includes a data sheet to be filled out during testing.
Soldering Iron, Solder
Drill, Bits, and Cut Disk
Hot Glue Gun, Glue
Luxmeter (light meter)
What we will be doing is geometrically orienting the solar cells to capture more solar energy by minimizing losses due to reflection and to fit more photovoltaic material in a given space.
The first step is to wire our cells. Normally, we can fit two traditionally oriented, 2×4″ cells in an area of 4×4″. With the new orientation design presented here, we can fit six 2×4″ cells in a space of only 1.5×4″.
Our first pair will be our control configuration. We’ll wire them up in series and signify the leads by attaching appropriately colored wire.
The next array will be the experimental setup: six cells in series that will keep current constant for this experiment, allowing us to measure variable voltage. Allowing an extra few millimeters in the length of the wire used for the series connections and pre-bending them will avoid binding in the next step. You may also add your output leads to the opposing positive and negative terminals and your wiring will be complete.
Take this opportunity to test for functionality and continuity.
2.) Orientating the Array
First, we will orient our control set side by side just like every solar array you’ve ever seen.
Next, we will create the experimental array. This can be built according to the specifications here or adjusted at your discretion. With our set of six wired cells, we will attach them one at a time with glue. We will pair our cells in “V” shapes with a measured angle of 22.5 degrees, which results in a gap at the open end of 0.5 inches for each pair. This can easily be recalculated for cells of a different dimension. Each “V” should have the solar cells facing inward.
We will now attach the three pairs with glue, which should result in an overall width of only about 1.5 inches, as shown.
These two arrays can then be tested again, adjusted if necessary, and put to the side.
It is important to have a level, stable, and consistent platform to keep all variables constant for experimental purposes. We will be measuring distances from artificial light sources to a high degree of accuracy and placing the platform in natural light, which must remain exactingly consistent for accurate results, which can be dependably scaled up.
3.) Building the Platform
To build this platform, attach the components to a sheet of plexiglass or other suitable material. First, plan, measure, and trace the component placement on the sheet based on the diagram shown. Then, drill holes for wiring, and in the corners for mounting, and cut holes for your meters. After the wiring and meter holes have been made in the first sheet, you will want to drill corner holes in both sheets simultaneously for parallelism.
You may then mount your two solar array configurations side by side and upright, on the same tangent with reference to a light source above.
Next, mount your voltmeters and wire them accordingly. The meters serve for demonstration purposes, but I also incorporated additional leads to attach a multimeter for more accurate experimental readings and better display in bright sunlight.
Once complete, add a nut to your bolts and drop on the sheet with holes in the corners and ensure it is level. This sheet will serve as a bottom cover. Add another nut to secure the bottom sheet and for spacing. Then add your top sheet with components mounted and secure it in place.
The experimental platform is now ready to test.
This array can be tested in a lab in the presence of a consistent-lumen light source, such as a standard lamp. With a single artificial light source in close proximity, test each array independently in order to keep input constant. First, place a light meter on the flat control array, apply constant light, and note the lux reading. Then, carefully remove the meter and note the voltage. With low intensity artificial light, your meters may be insufficient and a more accurate powered multimeter may be required to obtain a reading.
Repeat the process with the experimental array. It is very important to ensure both tests are performed at exactly the same light level. Because the experimental array sits higher, you will need to adjust your light source in order to test at the same lux reading as your control. Once you have reached a lux reading precisely equal to your control test, carefully remove the meter and note the voltage.
You will find that even your experimental array produces significantly more power even though it requires only a fraction of the area!
Repeat the process outside in natural high intensity sunlight and the results will be compounded even more!
To calculate the efficiency increase with respect to area, adjust voltage for input variance if necessary, calculate voltage per square inch, and simplify to get a qualitative result that we’ll call our efficacy coefficient.
My tests show an improvement of 670%, over six times the energy from the same space!
Try the experiment for yourself, record your data, and then scale it up to power your home, electric car, or anything else. Try combining this configuration with a solar tracker, and you will be able to harness more solar energy from a square meter than you ever thought possible.
[All images courtesy Drew Paul / Drew Paul Designs]
You May Also Like
3 Commonly Overlooked Techniques for Developing Reliable FirmwareMar 5, 2024|6 Min Read
007 Science: Inventing the World of James BondMar 4, 2024|12 Slides
Action on the Floor of IME WestMar 4, 2024|1 Min Read
How Repairable Is Apple's AR/VR Headset?Mar 4, 2024