Solar Energy Principle

Solar energy refers to the radiant energy of sunlight. There are two ways to utilize solar energy: passive utilization (photothermal conversion) and photoelectric conversion. Solar power generation is an emerging renewable energy utilization method. In a broad sense, solar energy is the source of many energies on the earth, such as wind energy, chemical energy, water potential energy, etc.

　　The main methods of utilizing solar energy are:

　　* Using solar cells to convert the energy contained in sunlight into electrical energy through photoelectric conversion

　　* Use solar water heaters to heat water using the heat from the sun

　　* Use the heat from the sun to heat water and generate electricity from the hot water

　　* Using solar energy to desalinate seawater

　　The principle of solar energy is very complicated, and semiconductors can generally be used to achieve photoelectric conversion. And the conversion efficiency is getting higher and higher.

　　At present, the use of solar energy is not very popular, and the use of solar energy for power generation still has problems such as high cost and low conversion efficiency. However, solar cells have been used to provide energy for artificial satellites.

　　Currently, the world's largest rooftop solar panel system is located in Buerstadt in southern Germany, covering an area of ​​40,000 square meters and generating 4.5 million kilowatts of electricity per year.

　　The system that uses solar energy to generate electricity consists of a solar cell group, a solar controller, and a battery (group). If the output power is AC 220V or 110V, an inverter is also required. The functions of each part are:

　　1. Solar panels: Solar panels are the core part of the solar power generation system and also the most valuable part of the solar power generation system. Their function is to convert the sun's radiation into electrical energy, or send it to the battery for storage, or drive the load to work. The quality and cost of solar panels will directly determine the quality and cost of the entire system;

　　(ii) Solar controller: The function of the solar controller is to control the working state of the entire system and protect the battery from overcharge and over discharge. In places with large temperature differences, a qualified controller should also have the function of temperature compensation. Other additional functions such as light-controlled switches and time-controlled switches should be optional for the controller;

　　(III) Storage battery: generally lead-acid battery, nickel-metal hydride battery, nickel-cadmium battery or lithium battery can also be used in small and micro systems. Its function is to store the electrical energy generated by the solar panel when there is light, and release it when needed.

　　(IV) Inverter: In many cases, 220VAC or 110VAC AC power is required. Since the direct output of solar energy is generally 12VDC, 24VDC, or 48VDC. In order to provide power to 220VAC appliances, the DC power generated by the solar power generation system needs to be converted into AC power, so a DC-AC inverter is required. In some cases, when multiple voltage loads are required, a DC-DC inverter is also required, such as converting 24VDC power into 5VDC power (note, not a simple voltage reduction).

　　Solar energy principles can be divided into 2 categories:

　　1. Solar Photovoltaics

　　A photovoltaic panel assembly is a power generation device that generates direct current when exposed to sunlight. It consists of thin solid photovoltaic cells made almost entirely of semiconductor materials (such as silicon). Since there are no moving parts, it can operate for a long time without causing any loss. Simple photovoltaic cells can provide energy for watches and computers, and more complex photovoltaic systems can illuminate houses and supply power to the grid. Photovoltaic panel assemblies can be made into different shapes, and assemblies can be connected to generate more electricity. In recent years, photovoltaic panel assemblies have been used on rooftops and building surfaces, and even as part of windows, skylights or shading devices. These photovoltaic facilities are usually called building-attached photovoltaic systems.

　　2. Solar thermal energy

　　Modern solar thermal technology concentrates sunlight and uses its energy to produce hot water, steam and electricity. In addition to using appropriate technology to collect solar energy, buildings can also use the sun's light and heat energy by incorporating appropriate features into their design, such as large south-facing windows or using building materials that absorb and slowly release the sun's heat.