交大开元太阳能

 Thermal energy storage

1, heat storage. Significant material use of thermal energy storage is the simplest method of energy storage. In practice, water, sand, gravel and soil can be as energy storage materials, including water, the greatest heat capacity, more applications. Qibashinian generation has been the use of water and soil as well as trans-seasonal storage of solar energy coverage. But the material significantly less heat, energy storage subject to certain restrictions.
2, latent heat storage. The use of phase-change material in the time of inhalation and released latent heat energy storage, the stored energy, and temperature change in the decentralization heat conditions. In the low-temperature storage of solar energy used in the crystallization of water containing salts of the energy storage, such as sodium sulfate 10 water / water calcium chloride, sodium phosphate 12 water and so on. However, in use to solve the cooling problems and stratified to ensure that the operating temperature and life. Solar temperature in the storage temperature above 100 ℃ in general, 500 ℃ below, usually about 300 ℃. At the appropriate temperature in the storage of materials: high-pressure hot water, organic fluid, such as eutectic salt. Solar heat storage temperature above 500 ℃ in general, is currently testing materials are: sodium metal, molten salt, and so on. 1000 ℃ for more than a very high temperature storage, use aluminum oxide and germanium fire-resistant ball.
3, chemical heat storage. The use of chemical storage reaction heat, heat storage, small size, light weight, the product of chemical reactions detachable storage, exothermic reaction occurred when the need arises, storage for a long time. Really hot for the storage of chemical reactions must meet the following conditions: reversible reaction, no reaction; quickly; reaction products and can easily separated from the storage stability; reactants and the products non-toxic, non-corrosive, non-flammable ; Reaction heat, low price of reactants, has been selected a number of endothermic chemical reaction can basically meet the above requirements, such as Ca (OH) 2 thermal decomposition, use of the above-mentioned endothermic reaction thermal energy storage, on the other hand, when the heat Exothermic heat release. However, Ca (OH) 2 in the atmospheric pressure dehydration reaction temperature is higher than 500 ℃, the use of solar energy in the dehydration temperature is very difficult to achieve, by adding a catalyst to reduce the reaction temperature, it is still very high. Therefore, the chemical reaction needed to store energy in-depth study and can not be practical. Other storage can be used to heat the chemical reaction of metal hydride there are thermal decomposition reaction of hydrogen sulfate ammonium cycle of reaction and so on.
4, crystal plastic storage heat. In 1984, the United States in the market introduction of a plastic material for heating crystallization family. Xue Jing Plastic called neopentyl glycol (NPG), and it is similar to the LCD, the three-dimensional periodic crystals, but the mechanical properties such as plastic. It can in a constant temperature thermal storage and heat, but not to rely on a solid-liquid phase change thermal storage, but through the plastic crystal molecular configuration occurred solid - solid phase change thermal storage. Plastic crystal in the temperature 44 ℃, during the day to absorb and store solar energy at night to release the stored heat during the day. The United States NPG thermal storage performance and application of a wide range of research, will be melted to the plastic crystal glass and organic fibers in the wall panels can be used for thermal storage, the ratio will be adjusted after the accession to the plastic crystal and glass fiber wall panels made of , To cool refrigerant. China's grain plastic also carried out a number of experimental studies, but has not yet practical application.
5, solar thermal storage tank. Solar pool is a certain concentration gradient of salt water can be used to capture and store solar energy. Because of its simple, low cost and suitable for large-scale use of people's attention. 60 era, many countries in the sun on the pool of research carried out, Israel has also built three solar power pool. 70s, the sun on our pool is also carried out research, some of the initial application.

Electrical energy storage
Storage of electrical energy than the energy storage difficulties, is commonly used in batteries, is the research and development of superconductor is the energy storage. The world's lead-acid batteries have been invented 100 years of history, which uses chemical energy and power of the reversible conversion, the realization of charge and discharge. Lead-acid battery prices lower, but short life, weight, requiring constant maintenance. Recently the successful development of the less maintenance, maintenance-free lead-acid batteries to improve the performance of some. At present, the photovoltaic power generation systems and storage devices, for most of the lead-acid batteries. 1908 invention of nickel - copper, nickel - iron alkaline batteries, to facilitate the maintenance of its long life, light weight, but the more expensive price, generally in small storage energy use. The existing low-density energy storage battery, it is difficult to meet the high-capacity, long storage of electrical energy. The newly developed silver zinc batteries have a battery, battery potassium, sodium sulfur batteries, and so on. Some of the metal or alloy in very low temperature superconductors become, in theory, power in a superconducting coil within the resistance-free unlimited storage for a long time. Superconducting energy storage that is not subject to any other energy conversion directly to electrical energy storage, high efficiency, rapid start-up, can be installed in any location, especially near the center of the consumer does not have any pollution, but the superconducting energy storage technology is not yet in Mature, the need to continue research and development.
Hydrogen storage
Hydrogen can be substantial, long storage. It to gas, liquid, solid-state (HG) or compounds (such as ammonia, methanol, etc.) in the form of storage. Gas storage: hydrogen storage volume, the pressure can be used wet gas cabinets, high-pressure containers for the storage; a large number of storage can be stored in underground storage warehouses, Bulou Shui soil by covering the aquifer, salt and artificial cave inside the cave. Liquid storage: hydrogen has a high hydrogen storage capacity per unit volume, but the large evaporation losses. Hydrogen will be translated into the need for liquid hydrogen and compressed hydrogen purification, is hydrogen - into hydrogen Chung, the last of liquefied conducted. Liquid hydrogen production process is complicated and costly, currently used as the main rocket engine fuel. Solid-state hydrogen storage: the use of metal hydride solid-state hydrogen storage, high-density hydrogen storage, security, good. At present, to meet the basic requirements of the solid-state hydrogen storage material is rare earth alloy and titanium alloys. Metal hydride hydrogen storage technology research has been more than 30-year-old has made a lot of results, but there are still many issues to be solving. China's metal hydride hydrogen storage technology for many years, with some success, the current work is an in-depth research and development.
Mechanical energy storage
Solar energy is converted to electrical energy, and promote electric pump to pump water to low high, in the form of potential energy to be able to store solar energy; converted to solar energy, promote the hot air machine, can store solar energy. But the mechanical energy stored in the most concern is the flywheel energy storage. In the early 50's it was suggested that the use of high-speed rotation of the flywheel energy storage idea, but has not been a breakthrough. In recent years, due to the high-strength carbon fiber and glass fiber, manufactured by the greatly increased speed flywheel, an increase of the quality of the energy storage unit; electromagnetic suspension, the superconducting maglev technology, combined with vacuum technology, greatly reducing friction Wind resistance and wear and tear; new power electronics, so that the motor and flywheel energy exchange system more flexible. Therefore, the recent flywheel technology has become a hot research on the United States more than 20 units engaged in the research, has developed into a flywheel energy storage 20kWh, 5MWh ~ 100MWh is developing superconducting flywheel. China has for the development of energy storage flywheel 0.3kwh small experiments. In the solar photovoltaic system can replace the flywheel battery for storage.