PV Photovoltaic Cell Report Questions Question to answer in the Report 1‐ What are the current sources of Energy? Name as much as you can. 2‐ What is Renewable Energy? Why some of them are call renewable and other no? For example, the energy of Hydraulic Turbines comes from the nature, the energy is abundant and there is no contamination by combustion to generate electricity. Why this type of energy is not call Renewable? 3‐ Why there is a new trend investing in Renewable Energy? a. What are the disadvantages of the actual way to generate energy? 4‐ What are the different ways to get energy from the sun? 5‐ What is a Photovoltaic cell (PV cell)? 6‐ How it is composed? 7‐ How PV cells work? 8‐ What is a PV Panel? 9‐ What are the drawbacks of a PV panel? 10‐ Why it is require a PV system to extract energy from a PV Panel? 11‐ How a PV system works? a. What is a converter DC‐DC, DC‐AC, AC‐DC. 12‐ What is Maximum Power Point Tracking (MPPT)? 13‐ What are the types of MPPT? 14‐ How is the characteristic curve (i‐v) of a PV panel? 15‐ How is the irradiation patter during a perfect sunny and not cloudy day? Sketch it. Also, plot a cloudy day. 16‐ How is the electrical model of PV panel? Does it match with the i‐v curve? a. Remember the power convention of load and generator 17‐ What are the parameters that affect the MPP in a PV panel? 18‐ How is the simplest model of a PV cell and a shaded cell? 19‐ What happened to the model when we have clouds? Answers 1. What are the current sources of Energy? Name as much as you can. The biggest companies for generation of produce energy by term of Heat Engines. This machines need FUEL to rise high temperatures like steam‐cycle power plants.  Fossil fuel  Coal, there are different kind of coal, bituminous, ….  Natural Gas  Oil  Water falls  Sun  Wind  Ocean Waves  Nuclear  Biomass: derived from living, or recently living organisms. It most often refers to plants or plant‐based materials which are specifically called lignocellulosic biomass.  Geothermal: is thermal energy generated and stored in the Earth.  Ocean Thermal: uses the temperature difference between cooler deep and warmer shallow or surface ocean waters to run a heat engine and produce useful work, usually in the form of electricity 2. What is Renewable Energy? Why some of them are call renewable and other no? For example, the energy of Hydraulic Turbines comes from the nature, the energy is abundant and there is no contamination by combustion to generate electricity. Why this type of energy is not call Renewable? Is the energy that comes from resources which are naturally replaced on a human time‐scale. In other words, are infinite and can be renewed. Hydraulic Turbines are not renewable because the effect over the environment to build a Dam. 3. Why there is a new trend investing in Renewable Energy? a. What are the disadvantages of the actual way to generate energy? This trend is due to the level of pollution that the current generation systems are producing. In fact, It is also one of the most polluting of all industries, responsible for :  3/4 three‐fourths of U.S. sulfur oxides (SOX) emissions  1/3 one‐third of our carbon dioxide (CO2) and nitrogen oxides (NOX) emissions  1/4 one‐fourth of particulate matter and toxic heavy metals emissions. Just in USA. 4. What are the different ways to get energy from the sun? Solar Passive Housing: Classic examples of basic passive solar structures are greenhouses, sunrooms and solariums ‐‐ as the sun's rays pass through the glass windows, the interior absorbs and retains the heat. Modeling this concept in your home can cut heating costs by half compared to heating the same home by traditional means without the use of passive solar. In terms of design, success of the passive solar system depends on orientation and the thermal mass of the structure's exterior walls, which means their ability to store and redistribute heat. A passive solar system does not involve mechanical devices or the use of conventional energy sources beyond that needed to regulate dampers and other controls. A passive solar system typically relies on south‐facing windows as collectors to capture solar energy, although some systems may also use supplemental PV panels. In any case, the goal is to redistribute the energy collected according to a fundamental law of thermodynamics, which states that heat moves from warm to cool areas and surfaces. The simplest method of transferring the heat from passive solar collectors is through convection. To illustrate, think of a sunroom with windows on a southern wall. As the sun's rays travel through the glass, the heat is directed into the room. It then rises to areas where the air is cooler, including other rooms beyond and above. Solar Active Housing: Active solar systems use external sources of energy to power blowers, pumps and other types of equipment to collect, store and convert solar energy. Once energy from the sun is absorbed, it is stored for later use. Small systems are used to furnish electricity for heating and cooling systems in homes and other buildings, while large systems can furnish power for entire communities. Solar collectors are more complex than passive collectors in both design and mechanism. They consist of flat‐plate PV panels that are usually mounted and remain stationary, although some are designed to track the sun throughout the course of the day. In some designs, multiple panels are connected together to form modules. Active solar collectors contain either air or a liquid as a conductor. Those that use air are referred to as "air collectors," while liquid‐based types are called "hydronic collectors". The advanced design of these collectors makes an active solar heating system the most cost‐effective in terms of reducing reliance on traditional energy sources 5. What is a PV cell? PV cell is a device that transforms solar energy to electric energy. 6. How it is composed? It is composed of a thin wafer that consists in two layers of doped silicon N type and P type. Just imagine that an N‐Type silicone is a material that when is doped then it gets a lot of “free” negative charger (electrons). In the other hand a P‐type silicon is a material when is doped, it get positive charge (hole). But this charges are not completely free, they need energy to be free and move. Also, you have to know that between the two layers there is a barrier formed for an electric field. The e− and h− need to gain energy to pass the barrier to create a current. 7. How PV cells works? Sunlight consists in particle of solar energy called PHOTONS. The PV is exposing to this particle. (To the sun) Note: The cover for these solar panels has to be transparent. Then; photons can be reflected If enough quantity of photons are absorbed then the e‐ gain enough energy to jump the barrier to pass, and create a current (of course if you have a load to close the loop). The barrier is an electric field with 0.7V approximately. When the e‐ pass the barrier then the 0.7V appear in the terminals of the cell. It has to be working at 0.7V. If you want a PV of 70V you have to put 100 cells in service. If you want a lot of current you have to make connection in parallel 8. What is a PV Panel? SOLAR PANEL is an array of solar cells. Array in series for adding voltage and in parallel to generate more current. 9. What are the drawbacks of a PV panel? The PV panel depends on the solar irradiance which is not constant. Then the power produce or generated will be no constant also. That means that the voltage and current are not constant, we need to control this variables. 10. Why it is require a PV system to extract energy from a PV Panel? Due to the drawback, it is necessary to control v and I from the PV. For this reason we need a PV system. The voltage delivered by the PV is variable. You cannot connect the load directly to PV. You need a PV system. 11. How a PV system works? When the sun is too high the PV feed the load and charge the battery through the converters. In the night, the battery bank feed the load and discharges itself. See more in class and in the lab report. 12. What is Maximum Power Point Tracking (MPPT)? Is a search algorithm that seek the maximum power matching the impedance of the DC‐DC converter to the impedance of the PV panel. 13. What are the types of MPPT?  Incremental conductance  Perturb and Observe  Constant Voltage MPPT Algorithm  Intelligent Techniques, Fuzzy, GA, PSO, 14. How is the characteristic curve (i‐v) of a PV panel? See report lab. 15. How is the irradiation patter during a perfect sunny and not cloudy day? Sketch it. Also, plot a cloudy day. See white board in class. 16. D How is the electrical model of PV panel? Does it match with the i‐v curve? a. Remember the power convention of load and generator See report lab and class 17. What are the parameters that affect the MPP in a PV panel? ‐The temperature ‐the irradiance 18. How do these parameters affect the PV? While temperature increase the MPP decrease but with small amount. While the irradiance increase the MPP increase of course!!! More photons!!! More W/m2 !!! 19. How is the simplest model of a PV cell and a shaded cell? Just a DC source and a resistance 20. What happened to the model when we have clouds? It is just a resistance.