Performance and Lifetime of Solar Panels
Solar panels, as we have seen, even though they are very useful devices, they have the drawbacks of high (one-time) cost. Also the efficiency that is depicted by the most carefully fabricated solar panel devices are very poor compared to the devices that generate electricity (through non-renewable sources of energy) in the present market. Hence it becomes very tricky for the manufacturers of the solar panels to market their products. Performance and lifetime of solar panels are given very crucial importance and these parameters are nurtured seamlessly by the solar panel industry. Let us have a look into these parameters.
Performance of the solar panel is related to its throughput, efficiency and sunlight conversion rate. Sometimes, the marketability of a solar panel product is improved when the range of frequencies are mentioned in the product specifications. After all, better the performance of the product, market opportunity creeps in.
Certain testing is done by the solar panel manufacturers before deploying their products in the market. To accomplish testing of their products a (predefined) test environment is created with standard test conditions. Following setup is generally used:
- 1000 Watt/m2 of controlled power subjected to solar panels per unit area
- Standardized solar spectrum of AM 1.5
- Temperature of 25 degree Celsius
Following parameters are measured to define how the solar panel will perform when put to use:
Nominal Voltage (Volts): It defines the voltage of the battery that can be typically charged by the solar panel under test. This parameter is the key to determine if a solar panel can be used to supply power to any existing electrical system.
Open Circuit Voltage (Volts): This refers to the maximum voltage output of a solar panel module when connected under no load. The circuit should not be completed while testing this. Connect a voltmeter directly in order to measure this.
Short circuit current (Ampere rating): Refers to the current output produced under the standard test conditions when the output terminals of a module are connected with zero resistance (short circuit). This offers the least resistive path for the current to flow, hence maximum current output.
Range of frequencies: It all depends upon how the solar panel is designed and constructed when it comes to the frequency response to the broad range of solar spectrum that it can offer. A single solar panel module can be responsive to only a limited spectrum of sun's energy. Generally, there is lesser conversion rate offered for the frequencies that belong to ultraviolet range and infrared range. In addition to this, there is also a problem in low or diffused light subjected on to solar panels. Hence different modules that are responsive to different frequency spectrums are stacked on to one another to offer high frequency response of the overall solar panel system.
Peak power (Watts): This is the maximum power output that can be generated by the solar panels under STC.
Solar panels must be designed to be all-weather proof. Weather extremities tend to deter the solar panels' lifetimes, if not solar panel output. Solar panels must be designed in order to withstand different weather conditions, be it heat, rain, cold, hailstorms etc. Here we are talking about warranty issues. Standard warranties offered in the market offer 90% rated power output for 10 years and an 80% rated power output for 25 years.
Genie Lens Technologies developed a new transparent covering for increasing solar panel output. It is made up of a polymer called FUSION. It is available in the form of a sticker to be pasted on to the solar and it is claimed that the solar power output increases by as large as 10% when these are put to use. The technology behind the production of FUSION is cheap, making it possible to lower down the production cost of solar panel systems.
Thus we have seen in this article various key performance indicators related to solar panels and their importance.