In order to increase the efficiency of the solar collector, the only effective way is to minimize the convection and radiant heat loss while maintaining maximum solar energy collection. The use of high quality selective absorbing coating materials and high transmittance cover materials is an important way to meet the above requirements.
With the development of solar thermal utilization technology, China has been studying the selective absorption materials for 20 years. The development of solar collectors is also the development of coating technology. During the period from non-selective ordinary black lacquer to selective lead sulfide, metal oxide coatings, from black nickel, black chrome to aluminum anodized coatings and other generations of replacement process. With the continuous advancement of coating technology, the coating performance has been greatly improved. At present, the absorption surface of flat plate collectors in China mainly adopts anodized coloring on aluminum strips and black chromium selective coating on copper strips.
The coating production technology of intermittent magnetron sputtering aluminum-nitrogen-aluminum material selective absorption coating is developed with the generation of vacuum tube collector, which basically represents the current production level of medium and low temperature selective absorption materials in China. . Due to the poor weather resistance of the coating, it is not suitable for use in flat panel collectors.
At present, the production of selective absorbing coatings in developed countries, especially in Europe, has two main characteristics: one is vacuum coating technology, and the other is winding continuous coating. Even the wet coating uses a continuous coating process. For example, BATEC in Denmark produces black chrome absorbing coatings and uses continuous plating on copper strips. With an annual production capacity of more than 100,000 square meters, the optical properties and weather resistance of the products are ideal. In addition, several companies in Germany that produce selective coatings, such as INTERPANE, TINOX, and ALANOD, use vacuum methods and continuous production methods for absorbing coatings.
The vacuum coating technology production process does not have pollution problems, the coating optical performance is excellent, but the continuous production line investment is large, the coating production cost is high, and the vacuum coating performance of some vacuum coating coatings is not ideal. Wet coating technology is produced by electrochemical method, improper process design or production control, and it is easy to cause a certain degree of pollution, but the coating (such as black chrome coating) continuous production line investment is small, the coating has excellent optical properties and also It has excellent heat and humidity resistance and is a cost-effective solar selective coating.
Beijing Solar Energy Research Institute Co., Ltd. started the research of black chrome selective coating production process in 2003. In 2004, it built the first black chrome solar selective coating continuous production line in China. The product was tested [8]: absorption of coating The rate α≥0.93, the infrared emissivity ε≤0.10, the performance reaches the advanced level of foreign flat panel solar collector coating.
Beijing Solar Energy Research Institute Co., Ltd. also carried out research on the production technology of weather-resistant coating vacuum coating. A cermet selective absorbing coating of stainless steel nitride and stainless steel carbide was developed. In order to realize the production of the film, a three-target magnetron sputtering vacuum coating machine was developed and successfully tested. Qualified products are prepared for use in flat panel collectors by small batch trial production.
At present, a number of domestic research structures and manufacturers are conducting research on high-performance solar selective coating production processes and equipment for flat panel collectors. Therefore, the technological gap with solar selective coatings in foreign countries will be smaller and smaller, which lays a foundation for the improvement of domestic flat panel collector technology.
Wall Pack,Led Wall Pack Lights,Outdoor Led Wall Pack Lights,Alleyways Wall Pack Light
Fuonce-Lighting , https://www.szfuoncelighting.com