Sustainability

This week Josh showed me a competition for robotics. The competition requires that I design a robot that presents at least one principle of sustainability. Josh came up with the idea of building a robot that is equipped with a solar panel. The robot will follow the sun light to optimize the efficiency of the solar panel. I decided to go along with his idea because I could not come up with anything of my own. For this week’s assignment, I decided to look up how basic solar cells work. I found an interactive activity and article on PBS. This is what I learned:

Solar panels capture sunlight using photovoltaic cells. These cells are made of two layers of silicon. Silicon is a poor conductor. To take care of this, one layer has boron added to it and the other layer has phosphorus added to it. The boron layer, with fewer electrons, is placed on the bottom and vice versa for the phosphorus layer. The extra electrons in the phosphorus layer will sink down to the boron layer. This creates an electric field where the two layers meet. As sunlight hits the cell, the photons from the sun knock electrons in the silicon layers loose. The cell is coated with an anti-reflective coat so that the photons are absorbed instead of reflected away. When the electrons that are knocked loose reach the electric field, they are pushed upward to the top of the cell. On the top of the cell lie metal conductor strips. The electrons flow through these strips towards a wire and then to an inverter. The inverter converts the direct current into an alternating current for appliances and other electronic devices to use. Electricity flows back into the cell through a metal backing and the whole process starts again. 

Unfortunately, many of the electrons that are knocked loose hardly ever make it to the electric field. This makes the solar cell inefficient. This along with the lack of power at night and high cost of production make solar panels unpopular. So, for my next article, I decided to look up ways to make the cell more efficient. I found a good number of methods. You could make the cell less reflective, use different materials, and change the structure of the cell so that electrons found their way to the electric field more easily. I found an article on CPV panels.

In all honesty I found methods besides CPV that were much more interesting. I, however, couldn’t find enough information to write enough and share with you all. Concentrated photovoltaics (CPV) panels use lenses and mirrors to intensify the light before it hits the cells. Because of this, the efficiency of a cell increases greatly. Because of the cells efficiency, fewer are needed in a panel. This brings the cost of production down. With this, two of the cons of solar panels are at least identified and made less of a problem. 

I have not decided how to design my robot yet. I was introduced to Auto CAD, a design and modeling software that I found to be similar to Photoshop. I’m decently skilled in Photoshop so I should be moving along pretty soon. Below are my citations and links to read the articles if you are interested.

Chaddha, Rima and Stephanie Chasteen. “Howdo Solar Panel’s Work?” NOVA. PBS, 24 Apr. 2007. Web. 30 Nov. 2012.

Halper, Mark. “Magnifying SolarElectricity’s Future.” SmartPlanet. CBS, 20 May 2011. Web. 30 Nov. 2012.