What is a solar panel?
A solar panel is the main component of a solar photovoltaic assembly. It is actually made out of a shallow cardboard box holding an array of solar cells. Solar cells work upon the principle of photoelectric effect i.e. generation of electricity by electron excitation with the help of radiation. A solar panel provides a renewable and pollution free mechanism for producing electricity. Besides, photo-electricity is produced on site. Solar panels act as Renewable Energy sources (RES) which offer clean ways of producing energy to meet our growing demands or to counter energy deficit in the globe. In addition to that, it enables us to develop energy without any emission which is detrimental to our delicate environment. Hence, these act as providers of green or sustainable energy.
Majority of the photovoltaic systems in the world use crystalline silicon panels. Silicon is a tetravalent metal i.e. it has 4 electrons in its outer shell. In order to gain stability, it needs to have 8 electrons and therefore 2 silicon atoms share their electrons in the outer shell, forming a crystal. With greater alignment of the solar molecules, the photoelectric conversion efficiency will be higher.
When rays of light fall on the cell it creates an electric field across the layers.
The stronger the intensity of sunlight, more is the electricity produced. Organic solar cells are mounted together forming solar panels or modules that can be installed on rooftop to produce energy sufficient to meet the electricity demands of the residents.
What are the types of solar panels?
Monocrystalline panels: Such panels are made out of a single crystal of semi-conducting material like silicon crystal. Monocrystalline solar cells are constructed out of cylindrical silicon ingots, arranged to form solar wafers. Made out of the highest grades of silicon, it has a very high efficiency. The electrical energy generated per unit area is quite high in case of a monocrystalline panel. In addition, these acquire minimum space and perform well, even in conditions of low light.
Polycrystalline panels: In order to make polycrystalline panels, raw silicon is heated to high temperatures causing melting. Molten Silicon is then poured over upon a square mold. Cooling is done and silicon sheets so formed are cut into square wafers. Polycrystalline solar panels have less heat tolerance and should be used with caution. Their material use efficiency is higher.
Flexible organic thin film solar panels: These are formed by depositing multiples of thin layers of photovoltaic material over each other. These offer the advantages of raised mechanical strength. The flexibility characteristics definitely make them unbreakable and durable in the long run.
The heat tolerance limit of thin film solar cell panels is quite high and few versions can even stand high temperatures of upto 350 ⁰C.
What are the advantages of solar panels?
- Solar panels provide a feasible mechanism to utilize solar radiation.
- Solar panels help in generating photoelectricity using the mechanism of photoelectric effect in a pollution free and environment friendly manner.
- Solar panels help to produce electricity onsite i.e. at the point of consumption. There are no transmission losses unlike conventional thermal electricity where there are high power losses owing to long transmission lines.
- Solar panels help to provide electricity in remote areas with no access to electrical grids.
What are the limitations of solar panels?
- Since a lot of solar cells are required to provide meaningful power, making it a fragile and not very reliable way of energy generation.
- Present technologies help to generate limited electricity which might not suffice for large scale consumptions or heavy duty operations
- The starting costs required for fabrication and installation of solar panels is quite high. This might make it as a not so profitable alternative.
Construction of solar panel
- Purchase of solar cells: Solar cells can be purchased from online offices like eBay or hardware stores. A uniform dimension must be selected. For eg. 3×6 mono-crystalline solar cells. The number of solar cells is pre-fixed according to desired power output. For instance, an assembly of 36 solar cells, helps in generating electrical power equivalent to 18V.
- Cleaning of cells: Since the cells are shipped in wax, these need to be cleaned by dipping in hot water but not boiling water.
- Preparing a surface for attaching cells: A thin board is cut out of a non-conducting material, to be used as a template for attaching polycrystalline solar cells. The sides of the cardboard box should not shade the solar cells which are to be kept inside, when solar radiation falls. Then the pieces of solar cells are screwed and glued forming subpanels, which may be assembled later on. The thin crevices in the bottom rail of the assembly are coated by fiberglass insulation.
What are the practical applications of solar panels
Creating energy plus homes: Larvick, Norway is one city where solar energy capture installations have resulted in a situation wherein electricity generated has exceeded consumption requirements. So, consumers don’t have to pay any bills. These houses which produce more energy than needed also called E plus homes or zero emission building(zeb) houses. A solar power system with a total capacity of 400 kilowatts supplies enough electricity to meet the total energy consumption of the residential estate in the annual balance and to feed excess electricity into the electricity grid.
New technology innovations: In Germany, houses equipped with solar panels with mobility of 180⁰ are called heliotropes. These move as per the direction of incident solar ray. Because of the distinct ability of the panel to rotate to capture maximum solar light, they can produce 5 times more energy than usual.
Urban planning: In Massachusetts, an architectural firm with the name Interface has developed an entire energy plus or e plus townhouse. The outstanding feature of this townhouse is that a total of 39 solar panels installed upon townhouse are able to generate as much as 10,000 kW. Some of the home owners are even able to sell surplus energy to the ‘city grid’. Solar energy utilization has thus become an inseparable part of urban planning.
Creating wonderful architectural specimens: Architects, energy designers and planning specialists at Bayer AG worked in unison during the conceptual development stage of a planned children’s day care centre in Monheim, Germany.
With this ambitious solar energy project, the building is the first in the nation to have achieved a positive energy balance and has thus more than achieved its stated target of climate neutrality.
- Prior to selecting a solar energy cell type, one must know its features and limitations like energy conversion efficiency and heat tolerance limit.
- The number of solar cells chosen for a solar panel must take into account the area available for installation.