These are some of the notes when we were learning about photovoltaic(PV) panels and the capture of energy. The energy that is captured is called a photon. The formula for the energy is E=hf. The amount of energy captured is effected by where the sun is. The weird looking 8 at the top of the picture is a diagram of where the sunlight is. Just like in the movie cast away, every day of the year the sun's shadow will move. This is important because, if the PV panel is not facing the direct sunlight, there is not as many photons captured. At about 9 am the panels may produce about 800 kw/h (killawatt/hour) and at noon it will be about 1500 kw/h. Since earth is at a 23.5˚ tilt, in Hawaii on december 21st, at exactly noon the sun will be directly overhead.
We were talking about PV panels because we are going to be testing solar hot water heaters. Dr. Bill explained how the cold water comes in, the panels heat the water, then gets stored in a tank. After the water has been sitting in the tank for a while, it starts to cool down so thats why the insulation is there. In the middle of the picture, there is a diagram of the pump, hot water tank, and the shower. I found the importance of this information because the people who install these things usually do them wrong and end up costing people sometimes double the money.
Some things I thought of to improve the system would be to naturally insulate the tank by putting the tanks underground. This would get rid of the very unattractive look and also insulate the tank very well. A couple flaws with this would be that it would have to get dug up and pulled out by a crane. Also, if the tank starts to leak, it would be leaking into the soil and you might not notice it. Right before the water goes into the shower, if it is not hot enough then they used propane to heat the water. I thought of changing the use or propane into just the use of excess electrical power. Since most people don't use their hot water heater during the day, instead of keeping the water hot all day, just keep it warm. Most of the electricity can be stored in a battery which can be used later. From Newtons law of cooling, the water in the tank that is warm would stay warm for a long period which would only need to heat up for a little. If you keep the tank at a high temperature the entire day, it cools quicker so that causes your pump to be running all day to keep the water hot.