Research and development of flat panel solar water heater
Solar water heater market in China, the current vacuum tube water heater has an absolute advantage is an indisputable fact, but also extremely strong development momentum, the outlook is even more charming. But we can not ignore the fact that in recent years, flat panel heater, becoming the highlight of the show, the new darling of the domestic users, the mainstream international market, and was even some experts and scholars believe that the future direction of development of solar water heaters. If we are complacent in the size and level of vacuum tube water heater, rather than to study carefully the advantages of flat panel solar water heater and development, we can not look at long-term, and grasp the future, to master the initiative to enter the international high-end market.
First, the basic structure of flat panel solar water heater
Flat-plate solar water heater is mainly flat-plate collector, storage tanks, pipes, brackets and fittings and other components. Flat-plate collector is a key component of flat-panel water heater, the heater thermal performance is a measure of the level of an important indicator of good or bad. It includes coated with selective absorbing coating of the absorber plate, transparent material cover, insulation and shell four major sections. When the sun shines through the glass cover plate absorber on the board, most of the absorption of solar radiation absorbed by the body, into heat energy, and transmitted to the fluid channel of the working fluid. By natural circulation or forced circulation, and the water storage tank water heating. Absorber plate material abroad are basically copper and stainless steel, the country has a lot of use of copper, aluminum, steel, galvanized sheet, poor water quality in coastal areas, you can use plastic or glass instead. Because the metal surface of high reflectivity, low absorption, in order to enhance the absorption, the metal surfaces must be prepared by coating the heat-absorbing plate. According to different preparation process, the coating can be divided into the plating coating, electrochemical conversion coating, vacuum coating and the coating of the coating are four main forms. Because the collector is surrounded by air, so when the collector absorber plate of solar radiation in the transformation of heat energy to water, also the heat loss to the surrounding environment, which makes solar radiation energy is converted into water can not be all the heat. In order to reduce this energy loss, in the light absorbing material installed on top of the lid to cover and not through the far infrared through visible light, thus reducing energy loss, to more effectively improve the heat-absorbing plate and the water temperature. High-quality translucent material cover on the water heater\\ s efficiency and life have a significant impact. Cover material used at home and abroad mainly ordinary plate glass, tempered glass and glass steel, which is still the most widely used glass. In the heat-absorbing plate and bottom placed around the insulation material, used to reduce the collector heat loss to the surrounding environment, to improve the collector efficiency. Commonly used insulation materials, rock wool, mineral wool, polystyrene and polyurethane, etc. Polystyrene will shrink at higher temperatures, so use it as insulation materials, often in the heat-absorbing plate with a thin layer between the first rock wool or mineral wool put. In order to heat-absorbing plate, light cover and insulation to form a whole, and to maintain a certain degree of stiffness and strength is easy to install, need to have a more solid appearance of the shell, usually with aluminum, steel, plastic, glass, etc. made . In addition, there are flat panel solar water heater tank, frame, pipe fittings and other structural elements most.
Second, the development of flat panel solar water heater
Flat plate solar water heaters in China has experienced a \"U\"-shaped process, a new starting point now gradually gaining ground, experts, scholars and entrepreneurs attracted attention. According to the data show that in 1997 the annual production of solar water heaters of 350 million square meters, of which about 45% of flat panel solar water heater, vacuum tube water heater accounts for about 30%. By 2001 the proportion of China\\ s flat panel solar water heater on the decline to 26.3%, while the vacuum tube water heater up to 63.2%. Up to now, after nearly 10 years of continuous decline, China\\ s share of flat panel solar water heater will yield only about 90% of the. However, in the international market, flat panel solar water heater, but always the dominant product, foreign (such as Japan, USA, etc.) more than 90% of solar hot water systems use flat-plate solar collectors, even in very cold winter in Denmark, Sweden other Nordic countries without cases. China\\ s relevant departments of the global development of solar water heaters for the statistical analysis. By statistics in Europe, America, Oceania and Asia, 21 countries in 433 solar energy companies, with flat panel solar water heater 401, the total number of enterprises accounted for 92.61%; a 12, accounting for 2.77% of total number of enterprises; Simple solar water heater 20, accounting for 4.62% of total enterprises. Clearly, the application of solar water heaters in foreign countries, the flat plate solar water heater production and trading business is far greater than the number of other product types. With the promotion and popularization of new energy, and technological progress and development, China\\ s flat panel solar water heater technology and product performance, quality is improving, and in the integration of multiple aspects of the development of a unique performance advantages. Project of the Beijing 2008 Olympic Games, \"Olympic Village\" in the large-scale tender to select the German production of flat plate solar collectors, so that our vacuum tube have to reflect on your breath. March 6, at the sixth Chinese solar brand product exposition, Haier successful Australian ten thousand square meters of solar flat-plate collector to become the largest single news arouses envy. Haier Group, the introduction of advanced flat-plate collector from Germany technology, developed for the Chinese market, high-temperature flat plate solar collectors, the successful resolution flat-panel solar thermal insulation, sealing and other industry problems. Sun, rain, Aucma and other domestic brands have also invested plate solar water heater project. After a solar water heater industry and construction industry joint efforts, China\\ s flat panel solar water heater is from the bottom into a new stage of development.
Third, the characteristics of the advantages of flat panel solar water heater
Flat panel solar water heater after decades of development, technology has become more mature and complete, and have the other types do not have the advantages of solar features.
1 particularly suitable for integration with the architectural requirements. Flat plate solar water heater because of its structural characteristics, in the building integration of solar energy applications, flexible free form structure, form or size of the design constraints are not easy to achieve with a combination of building components. Along with its collector plate of metal, wire knot can be easily used, welding connections for installation, maintenance and use facilitated. 8 | 3i5? 9r1h; S
2 has a high thermal efficiency. Because the vacuum tube solar collector is composed by a number of vacuum tubes, there is a gap between the tube, was too much sunlight, some solar collectors are not accepted. Flat plate solar collectors is a continuous plane, the entire collector surface can receive sunlight. Therefore, in the same area and sunlight intensity lighting, flat panel solar water heater is generally higher than the daily average efficiency vacuum tube solar water heater efficiency of 6% on average.
3 has a good performance under pressure. As the flat panel solar collector absorber plate is made of metal materials, the collector and the storage tank is also used to connect metal parts, therefore, from the water and can withstand the pressure of the circulating pump. Currently, water is generally a centralized water supply systems, water pressure is high, which requires out of hot water from solar water heaters have a certain pressure, thus, reducing the water heater outlet and the pressure difference between outlet for user convenience and comfort.
4 composed of a large system performance and stability. For some large places such as hotels, swimming pool, factories and other places, the use of solar water heaters, they often need a lot of blocks composed of large-scale solar collector water supply system. If the use of flat plate solar collectors, the collector and the metal connection between the systems, and vacuum tube solar water heater, rather than as connected with the rubber parts, we can ensure the stability of the entire system.
Therefore, the establishment of large-scale solar water heating systems, they often use flat solar collectors. In addition, the structure of flat-panel solar water heater is simple, convenient and easy processing of large-scale production, but also makes it a low manufacturing costs, installation costs and long service life Province. Of course, the existence of flat plate solar collector heat loss and high antifreeze and other issues, also need to be resolved through further technological innovation. In order to actively participate in international competition, to develop the domestic high-end market, we must attach importance to research and development of flat panel solar water heater, a more open mind, improve our level of solar thermal technology and international level.