Solar power generation principle:
Solar cells are devices that use the photoelectric effect of semiconductor materials to convert energy solar into electrical energy. The basic process of photovoltaic effect: Assuming that light shines on the solar cell and is accepted at the interface layer, photons with sufficient energy can excite electrons of covalent bonds in P-type silicon and N-type silicon, resulting in the photovoltaic effect. electron generation - Pair of holes.
The electrons and holes adjacent to the interface layer will be separated from each other by the action of the electric field of the space charge before recombination. The electrons move towards the positively charged N region and the holes move towards the negatively charged P region. The separation of charges across the layer of interface will form an outward testable voltage between the P region and the N region.
At this point, electrodes can be added to both sides of the silicon wafer and a voltmeter can be connected. For crystalline silicon solar cells, the typical value of open circuit voltage is 0.5 to 0.6 V. The more electron-hole pairs generated by light illuminating the interface layer, the lower the current is high. The more light energy the interface layer receives, the larger the surface area of the interface layer, i.e. the cell, and the greater the current formed in the solar cell.
What is the principle of solar water heater?
The working principle diagram of solar water heater 1. Cold water enters the heater solar water through the pipe and passes through the heat collecting plate, which can collect solar energy, convert solar energy into thermal energy, and thenheat cold water. Since the density of cold water is higher than that of hot water, the hot water will automatically increase and then form circulating power. The water will gradually heat up on the heat collecting plate. After reaching a certain temperature, it can enter. the hot water tank. Those who need hot water will be able to get hot water at any time. Heating Figure 2. In fact, the principle of solar water heaters mainly includes the following two principles: (1) The principle of water circulation, that is, the water flows automatically. This is based on the fact that cold water is denser than hot water. Cold water flows and hot water rises, forming natural convection that gradually heats the water in the water tank until it reaches the set water temperature. When the intensity of the sun is not sufficient to meet the needscirculation, a water pump can be added to the closed water circulation circuit to obtain forced circulation. (2) Collector heat absorption principle: There is a special coating on the collector surface of the solar water heater. This coating has a high absorption rate in the visible range of solar energy. After absorbing it in the form of heat, heat. the radiation from the collector will have the wavelength in the longwave range and the coating has low longwave emissivity, thus effectively retaining solar heat. This heat is then used to gradually heat the cold water into hot water. Solar collector tube Let's talk in detail about the collector tube on this collector. The collector tube is actually like an elongated hot water kettle liner. It is made of two glass tubes, one large and one small. the inner layer is covered with a spectrum-selective absorption coatingif and a straight void is drawn between the inner and outer tubes. It forms the core of the solar water heater and is used to maximize the absorption of thermal energy after solar radiation. The vacuum glass tube is round, with the characteristics of naturally following the broad source of the sun, coupled with the reflection principle of the reflector, the glass tube can receive light from all sides, the heat collection effect lasts longer, the water temperature is higher. , and it can work normally all year round even in alpine areas.
Many families have installed electric water heaters and solar water heaters because solar water heaters are very environmentally friendly and energy-saving equipment. So, what is the principle behind solar water heaters?
1. Principle of operation of the solar water heater
According to its literal meaning, this type of water heater uses energysolar energy and then converts it into thermal energy thanks to the action of light energy. , it can turn cold water into water. It turns into hot water and the water temperature is relatively high, which can meet the needs of people's living and production. One of the most commonly used on the market is an evacuated tube solar water heater with a collector tube, which mainly relies on this collector tube to convert solar energy into thermal energy. During the whole use process, cold water will flow, then hot water will float, so that a cycle can be achieved, and finally hot water can be obtained.
2. Can solar water heaters be used only on sunny days?
1. Many people have found that if it is cloudy, the solar water heater cannot work and cannot produce hot water. Mainly because solar water heatersires use the sun to function after all.
2. In response to this situation, some manufacturers have developed a space energy water heater. Although it is only one step away from the solar water heater, it is different. This type of water heater can also be used in cloudy weather, and according to its literal meaning, you can also understand that it combines solar energy and air energy, and the principle is relatively simple.
3. For example, if a Hot Rod device is added, solar energy can be used for heating on sunny days, but air energy can be used for heating on cloudy days. loss of water heater, hot water supply can be guaranteed almost 24 hours a day.
4. Whether it is summer or winter, whether it is sunny or cloudy, it can provide hot water, so it is more convenient. In addition, this type of solar water heater has a relatively long lifespan, and. maybeused for 15 years.
Editor's Summary: The working principle of a solar water heater is relatively simple, which is to use solar energy to convert cold water into hot water. In comparison, this type of water heater can only get hot water when. used on sunny days.