Imagine putting an unlit black frying pan in the Mojave Desert during the daytime. The pan slowly heats to the touch until it is at or above 90 degrees Celsius (195degF). It is then possible to pour an egg into the pan, and the egg is cooked in a matter of minutes. It could be more apparent. However, this simple test illustrates solar power harvesting.
The harvesting of solar energy is typically associated with photovoltaic panels you see on rooftops of homes. But the commercialized use of harvesting solar power covers many applications that supply astonishing quantities of energy to the world. We will look at five different solar energy harvesting technology.
1.) Photovoltaic solar panels
Photosolar (PV) solar panels utilize the sun’s power to generate electricity. It is the most commonly used method for harvesting solar energy. The meetings, which vary in dimensions from a few square centimeters to several sq meters, are made with several PV cells in a complex grid. It is intuitive that the greater the area of surface accessible to sunlight through the cells of the solar panel, the more significant amount of sunlight energy is captured.
Every PV solar cell usually comprises a compound semiconductor wafer and can be a polycrystalline or monocrystalline structure. The two semiconductor wafers – one P-type and one N-type separated. The two wafers are stacked over each other, and the natural reaction between the two types of semiconductors creates a depletion region that reaches equilibrium and does not generate any electricity. Thanks to the PV cell’s structure, when light photons travel through it and interact with the semiconductor wafers, their interactions release enough energy to cause an equilibrium disturbance within the depletion area. The result is an instantaneous flow of electricity. But, due to light sources, the exchange continues to occur and generates enormous electricity.
The power generated through a single photon is reflected across the entire surface of the solar cell. It is then incorporated into a complete array of solar cells before forming a massive collection of PV panels. This small interaction within the depletion zone could become repeated and then multiplied, which results in a large amount of energy. PV solar arrays, however, generate DC energy. To integrate them with modern power transmission technologies like the electrical outlets you have in your home, this DC energy is converted into AC power using an inverter. There are many exclusive variations of this essential technology, which aims to improve the effectiveness of each PV cell at a molecular level as well as the assembly that makes up the solar panel and the board’s ability to be integrated into an array of solar panels.
2.) Energy harvesting from thermal sources The energy of electromagnetic radiation
The sun generates a broad spectrum of radiation with different wavelengths, which includes infrared. This spectrum effectively transfers heat to the bodies that absorb it. The elements that can absorb this energy are known as “black bodies,” since they absorb all radiation frequencies apparent to our eyes. The ideal black body can effectively absorb and emit every wavelength of the electromagnetic spectrum.
Electromagnetic radiation is utilized to heat many passive thermal systems, like the egg cooker in Roman bathhouses and Ancient Egyptian homes, and modern technologies like the thermal solar panel and thermosiphons. The thermal harvesting strategies for solar energy rely heavily on the physics of black bodies and their capability to absorb and transmit electromagnetic radiation. At the home level, the power gathered from thermal sources is mainly used for water heaters. However, there are more suitable options to generate energy on a large scale.
3.) The solar water heater
One of the best examples of Thermal solar power harvesting systems, commonly used in sunny regions worldwide, is the solar-powered water heater. The simplest form of the solar water heater utilizes a pump to circulate cold water over a dark body panel. It looks like the PV solar panel, which is a black panel that absorbs heat and is then refrigerated by the circulated water, which heats the water. The water circulates continuously through the loop, generating warm water during solar activity. Specific systems can bypass pumping by using the buoyancy produced by heated water. The warmer water “floats” while the more extraordinary water sinks, causing small amounts of flow through the system, which creates the thermosiphon. The storage tank is above that solar absorber source, as shown in this.
4.) Vacuum Tube Solar Water Heater
Advanced and effective Solar water heating units use vapor tubes and self-contained heat pipes to transfer heat to a second tank. The vacuum tube guarantees that radiant energy can enter the system. However, the energy converted into thermal energy remains within the box. The heat pipe sucks up this energy and transfers it to the massive water tank. They are much more efficient in heating water in cold weather since only small amounts of heat energy escape from the vacuum tube, which transforms the majority of radiating energy into thermal energy.
5.) Molten salt solar power
Recent advances in the molten salt system have pushed the limits of power generation with solar energy. Like the power-generated water heating system powered by solar, these power plants use electromagnetic energy to melt salt. This molten salt is transported to a heat exchanger, which converts steam into heat that is then circulated by a steam turbine to produce electricity—power plants made of molten salt, like the Ivanpah Solar Plant. Ivanpah Solar Plant relies on a vast heliostat mirror system that directs sunlight to a specific area, commonly called the central tower or power tower. The tower absorbs energy from all heliostats around it sufficient to melt salt to temperatures around 1500 degrees. The molten salt is stored in tanks with insulation, which allows that energy to be utilized even if the sun has stopped shining.
The future of solar energy
Solar energy harvesting technology is being used to replace the electricity produced by fossil fuels. While a myriad of solar energy harvesting techniques are in use, all of them rely on the sun’s energy to accomplish work in a particular manner, something we typically depend on electricity to perform. Improvements in efficiency and process efficiency will continue to increase solar harvesting efficiency in the future and could reduce the necessity for fossil fuels altogether.