Do solar panels collect energy from the whole light spectrum or just focus on the red?
Typical commercially available crystalline silicon PV cells are 20-25% in conversion efficiency as supplied, but have a theoretical efficiency of 34% mainly using the visible light spectrum.Multi-junction solar cells include additional materials that are sensitive to the other radiation spectra outside of the visible light spectrum try to convert their energies to free electrons. Usually, you need to concentrate the inbound light for this to work. Some of these cells have over 500 sun intensity using Fresnel lenses.The current record holder is 46%. By the way, the theoretical limit for an infinite number of junctions is 86.8% under concentrated sunlight.There are commercially available 2-layer, cells that are at 30% under one-sun illumination, and can go up to around 40% under concentrated sunlight; however, they are usually used for special applications (e.g. space vehicles) due to their much higher cost.
Radiant energy, solar collector, active solar heating system in one sentence and show how they are related?
Radiant Energy, Solar Collector and Active Solar Heating System relate to each other in such a way that they are all used for solar energy. The difference between the three is that Radiant Energy used particularly when radiation is emitted by a source into the surrounding environment or solar energy and it is an energy of electromagnetic waves; Solar Collector a device for converting the energy in solar radiation into a more usable or tolerable form. The energy in sunlight is in the form of electromagnetic radiation from the infrared (long) to the ultraviolet (short) wavelengths. The solar energy striking the Earth's surface depends on weather conditions and is particularly related on collecting energy while Active Solar Heating System is Active solar heating systems is a kind of system that use solar energy to heat a fluid -- either liquid or air -- and then transfer the solar heat directly to the interior space or to a storage system for later use.
Can you charge a solar cell by using a light bulb or LED?
A solar cell can charge a battery from natural sunlight or from artificial lighting like an incandescent light bulb. A solar cell responds in much the same way to either kind of light; you can use incandescent light with a solar cell to charge a watch or calculator battery, provided the light is bright enough. The cell converts a range of light wavelengths into electrical energy; both sunlight and incandescent light contain these wavelengths, so the solar cell charges the battery from both sources.I get a lot of my information from here: http://solar-energy.downloadIncandescent lights, the Sun and all other light sources produce what scientists call a spectrum a spread of light wavelengths including long infrared waves, visible light, short ultraviolet waves and X-rays. Every source has a distinctive spectral pattern; for example, the Sun generates copious amounts of ultraviolet whereas an incandescent bulb produces very little. A solar cell responds to light wavelengths in different ways, converting some wavelengths to electricity while ignoring others. The cell roughly matches the Suns spectrum; it processes visible light colors but cannot use the longest infrared waves. Because the spectrum of an incandescent light is close to the Suns, a solar cell has no problem running on its light.In addition to its spectral qualities, solar energy on a sunny day amounts to about 1,000 watts per square meter on the Earths surface. However, a typical solar cell receives only a tiny fraction of this because its size is only a few square centimeters. A standard incandescent light bulb produces between 40 and 100 watts total and has most of the energy in the longest infrared wavelengths. If you hold a solar cell a few inches from a light bulb, it will receive a similar amount of light as it does from the Sun; although the Sun is more powerful by far, the close distance of the incandescent lamp makes up for its smaller output.The energy received by a solar cell from an incandescent light diminishes rapidly with distance. The less light that falls on the solar cell, the weaker its output, so it takes longer to charge a battery. If the cells voltage is lower than a minimum threshold value, it becomes impossible to charge the battery; for example, a 12-volt battery needs 12.9 volts to charge it. As long as light shines strongly on a solar cell, voltage should not pose an issue.
How is energy conserved in a flame test?
Pretty vague, but one way is that the energy from the flame is being absorbed by electrons which enables them to jump to a higher energy level. Upon returning to the lower energy level, the electrons give off that excess energy in the form of light energy in distinct wavelengths. In summary, the energy is absorbed as heat, but given off as light. Energy is conserved (neither created nor destroyed).
What artificial lights are needed to make solar panels work indoors?
Solar panels produce electricity with any light source, not only sunlight. However, there are two key limitations:With artificial indoor lighting, you will only get a small fraction of the energy output with sunlight.Artificial lighting uses electricity to produce light, and solar panels convert light back to electricity. You end up with the same form of energy you started with, and lose most of it in the two energy conversion steps (electricity to light, light back to electricity).If you want to use solar power at night, the most viable approach is to oversize your installation to produce surplus energy, and then store that energy in a battery array.
Why don't solar panels put off their rated wattage, even if faced at an optimal angle at an optimal temperature?
Because the standard lab “test” conditions cannot be achieved in reality. There are a dozen of factors. Irradiation, Panel temperature, Air Mass, angle of incidence, transmission and conversion losses, are just a few.Now consider this scenario, the sunlight is comprised of multiple wavelengths generally broken down into Visible Spectrum VIBGYOR (which stands for Violet, Indigo, Blue, Green, Yellow, Orange, Red), Infrared, the wavelength of light lower than red in the VIBGYOR and UltraViolet, wavelengths higher than Violet.Infrared spectrum has a property that it heats objects falling in line of its travel. That's the reason sunlight heats. Now, consider the solar panels which are constantly in sun. They get heated, a lot, which negatively impacts their efficiency. Indicated by a term called Coefficient of Temperature, generally pegged at -0.5% / +1℃ above the STC temperature of 25°, output of solar panels fall by 0.5% with every increase of 1℃ above 25℃ (temperature at STC). So at 50℃ (panel surface temperature), and every other parameter being standard, a 100 watt solar panel will output 87.5 watts of energy. (50–25)*0.5% = 12.5watts. Just be informed that the temperature we are talking here about, in terms of solar panels is the panel surface temperature and not the ambient temperature we generally talk about in terms of weather. Panel surface temperature is notches above the ambient air temperature and hampers the panel's efficiency a lot.Irradiation @ 1000W/SqM is the STC radiation. This is not true for the entire planet. Areas nearer to the equator get much more than that. Locations away from the equator, and towards the poles receive way less, owing to a higher angle of incidence, and so are panels in these areas perform low in comparison to their counterparts in tropical and equatorial regions.
Why are rough surfaces better absorbers and radiators of energy than smooth surfaces?
This is a generallization so it is not always true. It depends on the detials. If you make some simplifying assumptions such as: 2 samples of the same material at the standard temperature and in the same thermal environment and the "energy" you are interested in is thermal energy and the only difference is the surface roughness of the two samples where one sample is very smooth and the other sample is as rough as 60 grit abrasive, then, yes, the rougher surface will be a better radiator and better absorber. A given material has a given emissivity (the opposite of absorbtivity) for a given type of electromagnetic radiation. The emissivity of that material changes with temperature. So... if the only difference is a smooth surface vs a rough surface, it is all about the amount of surface area and the rough surface has more surface area. (depending on the specifics of that rough surface but it may have a LOT more surface area, maybe a couple orders of magnitude higher surface area).