Solar Panels (Research Paper Sample)

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Solar panels
Introduction
A solar panel is an electronic system made of solar cells that converts sun energy which is in form of photons into an electric current in form of electrons. A solar panel is made up of electrically connected solar cells that are mounted into solar arrays. They still work not only in full sunlight day but also during cloudy days. However, during a sunny day, more electricity is likely to be produced than during a cloudy day. Solar cells are made of semiconductors that are excited by photons to produce free electrons that flow as electrical current. Sunlight on the cells creates electric fields across the cell layers which in turn produces electric current (Morris, Pg. 102). A solar cell is a semiconductor device in solid state that is stimulated by photons to produce electric power in form of direct current. Semi conductors such silicon and gallium arsenide are used in making solar cells (Hantula, 79).
Efficiency of solar panel
This is defined as the measure of a photovoltaic solar cell to convert sunlight into beneficial energy necessary for human use. A higher efficient solar panel is best fit for small roofed houses for optimal utilization of the constrained space. This efficiency is found in the specification sheet accompanying the panel on purchase. The formula used for calculating maximum efficiency of a panel is given as;
n=PE*A
n = maximum efficiency
P = maximum power output
E = incident radiation flux
A = collector area
Incident radiation flux is a sunlight amount reaching the earth surface. From the equation therefore for a roof with large area, a less efficient solar panel can be used which means a low cost panel but still optimal power shall be availed. A small roofed house on the other hard shall need a high efficient panel for optimal power output (Boxwell, Pg. 87).
Types of solar panels
Types of solar panels are based on the material used to make the, arrangement of the material or how the produce electrical energy. They are; thin film solar panels and generally silicon solar panels. Convectional and non-convectional are the main classifications of solar panels (Hantula, 105).
Conventional solar panels
Monocrystalline silicon or single silicon
This is a very effective solar panel that has been lately developed to capture optimum sunlight falling in it and converting almost the whole energy into electricity since there levels of silicon are high. The panels are more costly than any other type of solar panel. These solar systems are mostly used in roof for production of electrical energy (Morris, Pg. 112).
Polycrystalline silicon or multi silicon
Polycrystalline silicon panels are less expensive to produce because they use less silicon in their cells. However, they are designed in such a way that they are still efficient and effective in their energy production hence some they can be found in roof tops though they are meant for large farms energy production due to large space required in their installation (Hantula, 130).
Thin film solar panels
These are less effective solar panels that are produce inexpensively by spreading a thin film of silicon in a large surface of ceramic plate. Successful thin films used includes; amorphous silicon, copper gallium and cadmium telluride. They have efficiency ranging from 10% to 19% (Boxwell, Pg. 102).
Non conventional solar panels
Building integrated photovoltaics
They are normally integrated in roof system of a building which makes them look like roof tiles. The roof normally appears very attractive with BIPV though they are less efficient compared with other types of solar panels. They also require a bigger space for their installation and don not last long as the conventional solar panels (Morris, Pg. 124).
Solar thermal panels
These are solar panel that are not designed to produce electricity bur to heat water in water tanks and proved air conditioning when necessary as while as heating of the house when require (Hantula, 137).
Design of solar panels
Normally for any design, optimal output is core driving factor within the best effective cost parameter of production. For a solar panel for example maximum power generation is the major facilitating factor while cost being as effective as possible. Therefore for the design of a photovoltaic system, it is important to figure out how various components of the system works together and how the system as whole fits within the building. In consideration of the photovoltaic system sizing of each component to fit best in the system is a key parameter in design of a solar panel (Morris, Pg. 131). Normally the most of the photovoltaic systems are pre- engineered to ensure components works together as a unit for optimal output ensuring compatibility and specifications of all components is addressed.
The solar panel and the building is also considered and a system. Aesthetic of the system should be addressed placing solar panels appropriately for this reason. For optimal output solar panels should not be shaded in any way within the roof. Therefore solar panels should be place close to the ridge of the roof far from shades as a result of gables, overhangs of the building and surrounding trees. Optimal utilization of this concepts results to cost effective output while producing maximum power. However, given the site description, distributors can design a solar panel by sizing and selecting major component of photovoltaic cells. This is because distributors have all the resources necessary for design development. Wiring then can be done by the installer (Boxwell, Pg. 129). Other than system considerations in the design of the cell cost consideration is also another major factor. Major factors affecting the cost are size, type, battery back-up and mounting of the system. The factors results from cost of components, trade off cost and labor cost (Hantula, 137).
Manufacturing process
Purifying the silicon
In the natural state silicon is not pure and needs to be purified before its use for manufacturing of solar cell. Silicon is purified by adding carbon in electric arc furnace. The two elements react and oxygen is released from silicon to form a product of carbon dioxide and molten silicon. Silicon product is further purified by a technique known as floating zone technique which involves passing silicon through a zone of intense heat a number of times in the same direction. Pure silicon is left in one side and impure silicon in the other side of the floating zone (Boxwell, Pg. 155).
Making a single crystal silicon
Silicon boules are then made by dipping a seed crystal of silicon into melted polycrystalline silicon. The resulting boule purified more because more impurities are captured by the liquid. Silicon boules are used for production of solar cells (Morris, Pg. 136).
Making silicon wafers
Silicon boules are then sliced each a time by a circular saw to produce silicon wafers of 0.5 millimeters thick. About one half of silicon is lost in the process of making a silicon wafer from a silicon boule that is normally circular. It is important then to make wafers into hexagonal or rectangular shapes that are used in making solar cells. Polishing of the wafers is the next step in manufacturing process though from recent investigation it has been found rough cells are better in observing sunlight than polished ones. This step therefore can be skipped for this reason (Hantula, 144).
Doping
Doping is a process of treating the resulting pure silicon with phosphorous or boron to make it a better semiconductor. This process is done in a controlled temperature environment to ensure an appropriate depth of uniform junction is formed. Generally doping is a traditional method of adding impurities
Placing electrical contacts
This is the step of connecting all the cells together as well2 as electrical receiver. Electrical contacts are used for this purpose. During this solar cells are covered completely by use of let say wax for protection purposes. Also a very thin layer of contact is made to ensure solar cells are not blocked from sunlight. After the entire contact placement is complete, thin strips are then placed between the cells (Morris, Pg. 141). These strips are normally made of tin coated copper.
The anti reflective coating
Silicon being a shiny element, reflect sunlight up to about 35% hence a great loss is experienced (Hantula, 151). To ensure sunlight is not reflected an ant reflective coating has to be made on the silicon wafer. Some of the commonly used ant reflective coating includes; titanium dioxide and silicon oxide.
Encapsulating the cell
Solar cells are then sealed into a rubber made up of silicon. The sealed solar cells are finally placed into aluminum plate. (Boxwell, Pg. 168).
Installation
Solar panels are installed on points with no shades such as roof tops, structural building tops or stand alone facilities. This is done to ensure solar panels are exposed to direct sunlight to ensure solar panel is maximally effective all year long. Modern technology incorporates a design for tracking sun in the sky. For optimal capacity solar panels should be place direct to sun light. Photovoltaic array is positioned under the noon time sun (Morris, Pg. 154). All branches of trees and other un necessary items that may in any way block direct sunlight are trimmed and removed from the scene. Photovoltaic solar panels are installed by use of solar panel mounts.
Operation
A solar cell is made up of p-n junction. Using a photovoltaic effect the junction converts light energy into electricity which is a direct current. The p-n junction is made of silicon a material with a high ability of absorbing solar energy known as photon. Electrons are then raised to a higher energy state hence flowing to an external circuit. The...