#6: What does Sand have to do with Solar Energy? (Reflection)
Welcome back!
Today, we’re going to be doing something slightly different, and instead of exploring a new concept in sustainable energy, this article will purely be documenting an experimental exploration I did into the impact of sand deposition on photovoltaics. It was my first experience researching solar cell technologies from a more practical basis, so I wanted to share some reflections I wrote along the way.
They’re short and sweet, but also interesting. Sorry for the shorter article, I’m just really busy this month, so don’t have time to crank out a proper version. Hope you enjoy!
REFLECTION 1 [August 25, 2017]
For this paper, I was just deciding which topic (and area) I wanted to focus my research on. I had already completed a research paper on international relations related to sustainable energy (see the paper here and the commentary here), so I wanted to go for something more technical.
Having just started working on my research paper, things have already started to come together. I have decided on a preliminary research question, in the field of physics, more specifically related to solar panels and cells. While I have not yet decided on a specific topic, I have a number of ideas regarding what I may choose to investigate.
At the moment, I am considering studying the effect of a particular factor on solar cells, as this would provide a number of applications in the real world, giving significance to my topic. Specifically, I am considering looking at the effects of temperature, or perhaps a study on the spectral response of solar cells. Both ideas relate to the efficiency of a solar cell, which can be studied from the perspective of voltage, current or power.
In terms of preliminary research, I have done a good amount of background reading, through both educational texts and past research papers. The readings are primarily content-based and attempting to see how different solar cells work. I have been reading on this topic beyond my school syllabus, in order to produce a paper that eventually extends my critical thinking beyond the scope of the class.
Additionally, this is currently helping me determine the independent and dependent variables. By analyzing the different parts of solar cells, I am able to study and understand how different factors affect their current and voltage, as these would probably be measured in my eventual experiment.
To date, I believe I will primarily focus on polycrystalline solar cells, as these are very well represented in the market, particularly in Morocco. However, before deciding on this, I plan to continue reading about how solar cells work, as we have not studied this in physics class at this point.
However, I am confident that there is a significant amount of space to explore, which will hopefully lead me to a strong topic. Below is a diagram I found to be quite interesting regarding how solar cells work.
REFLECTION 2 [SEPTEMBER 12, 2017]
Here, I had started to carry out some significant research into photovoltaics and decided on exploring sand deposition on solar cells. This is quite a serious issue, which relates to the implementation of solar cells in different environments.
As I continued my research on the topic of solar cells, I wanted to choose a topic that was unique, and that would touch upon multiple areas of physics. In my first post, I mentioned that I wanted to investigate relationships between solar panels and temperature or wavelength, but I felt that there was an overabundance of information on this, and some well-documented relationships already.
Having done an internship at MASEN, the Moroccan Agency for Sustainable Energy, which has a large solar plant in the southern desert, I already knew that one of the main issues faced by these plants was the presence of sand on the panels, as this prevented sunlight from getting through to the panel to produce electricity.
This sparked my imagination, and I thought I would be greatly interested in investigating, and even quantifying this effect, as it would be relatively unique for an EE. It would also allow me to attain my goal of combining multiple topics of physics into one EE, as this would actually lead to a discussion of both optics (the interaction between particles such as sand, and light), and of course solar energy (which is topic 8 in the Physics syllabus). As a result of this, I have found a research question: To what extent is the efficiency of a solar panel decreased by the deposition of dust?
While I have only recently decided on this research question and topic, I already have done some research, and hence have determined several techniques in order to answer it. Primarily, I plan to place a polycrystalline solar panel in the sun, deposit it with dust, and see how this dust affect its power (voltage and current are measured). Of course, I still need to develop this idea, as at the moment the investigation is probably too simple. However, I am sure that the more I work on the planning of my essay, the more I will be able to build up and strengthen my ideas. Below, is an image of dust on solar cells that represents what I mean.
Additionally, I met with my supervisor last week regarding the EE and presented my topic to him. He raised several points I had not considered regarding the deposition of dust on the panels, which are issues I will need to address while carrying out my experimental setup. Particularly, he raised the idea that I may not be able to evenly distribute the dust onto the panel, which may skew the results. I am still thinking of ways to resolve this issue, but I think some more research in the experimental procedure will allow me to do so.
REFLECTION 3 [SEPTEMBER 27, 2017]
This last reflection is quite scientific, as I’m working towards figuring out what experimental method I’ll be using for my experiment.
Following the determination of my initial topic, I carried out some research to determine my method. Particularly, since my topic had to do with dust and solar cells, I decided that it would be important to understand what I would be varying. In summary, I chose to expand my investigation by testing three different types of solar cells as well as 4 different dust types. The following shows how I arrived at my method:
- Independent Variable: This was initially going to simply be the presence of dust on solar cells. However, because I wanted to be thorough, and better link my empirical approach to theory, I chose to look at different particulate types (soot, talc, sand, dust). I also thought it would be important for me to vary the amount of dust placed on the panel, in order to see how the cells responded to an increased density of these particulates on the surface of the panel. This would allow me to quantify the relationship in a more efficient manner. Also, I chose to investigate three different panels
- Dependent Variable: I chose to measure voltage and current in a circuit with a small resistor, in order to find the power. I realized that in order to find Pmax of the cells, I would need to use multiple resistors and make an I-V graph. I did that, to ensure that all solar cells were operating at maximum power for effective comparison.
As I stated in my last entry, the initial idea was to put the solar panels in the sun. However, further thinking and a discussion with my supervisor made me realize that because the particles were so volatile, they would be blown around by the wind. Additionally, I would need to find a place with very few clouds. Moreover, because I anticipated that data collection would take several hours, the sun would likely move a great amount and would have varied in intensity, which greatly skews the results. As a result, I decided to collect my data in the following manner:
- Place the solar panel indoors in a dark room
- Hold a light of known intensity (or wattage) at a certain height above the solar panel
- Lay different particulates and repeat the experiment in this manner
Unfortunately, this meant that my experiment would need to be held only within the visible light spectrum (the sun also emits IR and UV; mono- and poly- cells also respond to IR radiation), but once again because the spectral response is not directly relevant to the experiment.
However, I have decided to proceed with the experiment, and see the extent to which the investigation lines up with theory. I think it proves to be interesting, and I will continue posting any modifications onto this blog, in order to document my progress.
I have an additional two reflections, which revolved around the completion of my experiment. However, given that these were submitted to the testing board, I have not published them here, in fear of plagiarism. If you are interested in seeing them, please comment below, and I will reach out to find out if I can publish them anyway (if not, afterward).
Hope you enjoyed! This was slightly different from what I normally do on this blog, but I think it does have some real value. I think it’s quite cool to get an outside perspective on a project that literally ended up taking months of my time. Let me know if you want to see more! Until then, see you!
UPDATE [12/12/18]: Hello! I wanted to let you know that during my gap year, I have managed to take this research a step further. More specifically, I was able to circumvent several of the assumptions I had made and used more sophisticated tools (instead of the crude equipment here) to test this and develop a generalized relationship.
