The system integrated solar water heater was developed by an expert system organized by China at the beginning of the 21st century, and has a new type of solar water heater with independent intellectual property rights. The exact name of this system should be: “Natural circulation system integrated solar collector-water heater”; in order to distinguish it from the traditional natural circulation flat (or vacuum tube) collector, we call it abbreviated as “solar collector-water heater” “. The so-called “solar collector-water heater” is a new type of solar heat collection and circulating heating system that has integrated the entire natural circulation heat exchange mechanism and is highly integrated within the scope of a single flat plate (or single evacuated tube) collector. As a part (device). By combining the basic components of the “collector-heat (water or air)” with the standardized structure of this single flat plate (or single vacuum tube), and combining them in series, the natural circulation series can be formed with different heat production scales. Adjust the temperature, adjust the installation angle, realize the coordinated installation of building integration, efficient operation of household or shared (hot water or hot air) type collection and storage separation system, can also be successfully transplanted for industrial and agricultural production applications, large-scale solar energy The utilization engineering system of hot water or hot air drying.
The purpose of developing the new system integration product that year was to develop a system that can realize the separation of collection and storage by further optimizing the structure of the plate (or vacuum tube) natural circulation water heater system under the premise of ensuring an efficient natural circulation heat exchange mechanism. After that, there is no need to set a high-position insulation circulating water tank. It not only simplifies the system circulation pipeline structure, but also realizes a new type of solar heat collection component with simple and stepless adjustment of the installation angle. Based on the natural circulation heat exchange mechanism, this component has some excellent qualities of direct flow or forced circulation, becoming a standardized, modular, systematic and intensive installation that can meet the high standards of building integration, simple and coordinated anchoring installation. , Generalized new technology products, and as a more mature, more widely adaptable, higher heat collection efficiency and cost-effective flat (or vacuum tube) updated standard modular product.
As we all know, a typical flat tube-sheet natural circulation solar hot water system must not only have a high-position insulation circulating water tank, but also a circulating heat exchange circuit composed of ten pipes, in order to actually operate normally: cold water pipes, heat Underwater water pipes, upper circulating pipes, lower circulating pipes, upper header, lower header, heat collection pipe, sewage pipe, vent pipe, overflow pipe, all lack one. Due to the irreplaceability of the above-mentioned functional components, the technical transformation of the natural circulation system affects the whole body and loses the necessary flexibility and diversity. This is after Yunnan took the lead in launching the compact household solar water heater represented by the “TGB-150A” “round horizontal water tank and flat panel” at the “First National Solar Energy Utilization Technology Exhibition” in the early 1980s. The water heater followed closely, but it had to be imitated as a “standard model”. For more than 30 years, the basic reason for the imitation of gourd paintings is still the root cause.
In the 21st century, China finally made a major breakthrough in the new technology of “flat-panel natural circulation system integrated flat box solar collector-water heater”. On a 0.4mm thick stainless steel sheet, we used a 1200T hydraulic press to form a large area at one time, and then through a new process of hot seam welding, we successfully developed a 2.18㎡ flat box system integrated water heater core, and then developed it. A series of patented products such as plastic-steel frame profiles for multi-functional flat-plate collectors, air venting and water-stop valves, and constant-temperature water-discharging valves are produced. Finally, they are organically combined into a flat-plate “solar collector-water heater” with a thickness of only 68mm, a geometric plane of 1030 x 2246mm, and a complete natural circulation heat exchange function. As shown in Figure 1.
On the “collection-water heater” integrated in this type of flat-box natural circulation system, only two pipe connections for externally connecting cold water inlet and one hot water outlet are retained. In addition, the functions of other circulation piping systems that are indispensable to the entire natural circulation system have all been integrated into the flat box plate core. Using the theory of fluid mechanics to test the fluid temperature difference circulation mechanism of the flat box core by computer simulation, based on qualitative and quantitative analysis research and physical testing, the flat box core circulation channel is finally optimized and manufactured by mold opening. Ground realizes the temperature difference convection cycle heat exchange process in a plane range.
The flat-type flat box solar collector-water heater manufactured by using the new technology of system integration is actually a flat-type natural circulation system that realizes an ultra-thin and ultra-light structure. The pipe network of the original traditional natural circulation system has been fully integrated into the geometric plane structure of the plate core. The temperature difference convection circulation channel optimized by the application of fluid mechanics technology has clear functions and smooth operation, which greatly reduces the system circulation pipe network. The length of the pipe, internal water resistance and heat dissipation area, and the entire temperature difference circulation system is more tightly sealed in a flat-plate hot box that is tightly sealed and insulated from the side and rear with a new technology of monolithic toughened glass and polyurethane foam. Therefore, the light-to-heat conversion efficiency and available heat output of the system have been greatly improved, while the average heat loss factor has been significantly reduced. With the system composed of this new type “collection-water heater”, there is no need to install a high-position insulation circulating hot water storage tank to participate in the temperature difference cycle heat exchange process of the system. The water heater and the hot water storage tank after complete collection and storage separation are realized. Both of them can be installed in accordance with the requirements of architectural integration in the strict sense. The roof is directly anchored and installed on the tile-face sloped roof of the traditional civil-wood structure (Figure 2). The hot water storage tank of the solar collector-water heater has entered the house and has been hoisted above the ceiling of the indoor toilet below the flat-plate collector-water heater, or placed in other concealed locations designated by the load-bearing structure of the building design. Since the system’s thermal insulation hot water storage tank only contains hot water, the mixing of cold and hot water will no longer occur. Almost all of the hot water produced on that day can be effectively extracted and utilized, and the net amount of hot water available daily is more than double that of traditional products.
The successful research and development of the above-mentioned flat-type flat box natural circulation system integrated solar collector-water heater is a major technological advancement we have made in system integration theory and practice. It has greatly stimulated our in-depth development of the system integrated solar collector-water heater. Morale has laid the theoretical foundation and practical experience to further realize the innovative research and development of other structural forms of solar hot water system integration technology.
After the flat-plate flat-box solar collectors are produced in small batches and delivered to various regions for actual trials and demonstrations, the actual measurement records show that the thermal efficiency is significantly higher than any existing flat-plate collectors, and the hot water output reaches 100L/㎡~ 120L/㎡, the temperature of the produced water is adjustable between 45℃ and 55℃ as required. The collector-water heater can be easily and reliably installed on the Chinese-style tile-faced sloping roof of the civil structure, and the heat preservation hot water storage tank can be hoisted in the indoor wooden house. On the rack, the problem of the separation of collection and storage that the natural circulation system has not been able to solve, and the low installation of the water tank into the house is realized. The water tank only contains hot water, and no mixing of hot and cold water occurs. The valve opens and hot water comes, saving water resources. All the hot water produced on the day can be extracted and used, and the available hot water output is 2 to 3 times higher than that of the traditional system. For household systems installed on flat roofs, the installation angle of the collector is simple and steplessly adjustable between 10° and 50°, which effectively improves the utilization rate and suitable range of solar radiant energy. The water tank is placed on a tripod under the collector, and the total height of the system is lower than the height of the parapet of the flat roof, which does not damage the architectural landscape. The remaining water in the water tank that is not used up the day before can be passively automatically selected by the water heater for secondary circulation heating the next day. System control adopts self-contained photovoltaic power generation control system; a self-guarantee monitoring system with intelligent control has been established. The system has the basic functions of separation of water and electricity, low-pressure operation, no scaling, no siltation, anti-frost, self-cleaning, no harm to people and health, and no pollution to the environment. However, in some areas where the pressure of tap water is unstable, the inherent problems of the flat box system’s poor pressure resistance are also exposed.
In order to further solve the pressure problem of the flat box plate core, in 2006, China successfully developed a flat plate tube-plate natural circulation system integrated solar collector-water heater.
With the mass production of natural circulation system integrated tube-sheet solar collector-water heaters, domestic water heaters not only break the traditional pattern of horizontal water tanks and collectors that have been made for decades, but also integrate performance and function with buildings. In terms of installation methods, all-round technological innovations have been realized. The new products have won users’ welcome and praise with their brand-new appearance, and have also withstood the practical test of the stable operation of the trial system for many years.
In terms of the innovation of new technologies for the integration of natural circulation systems, China has successively developed a series of tube-sheet solar collectors-water heaters with various uses and functions, and it has made progress in every possible way. In 2010, it took the lead in realizing a major technological breakthrough in the integration of the all-glass vacuum tube natural circulation system. So far, China has independently and continuously completed the integration of natural circulation systems in the field of solar thermal utilization: flat box type, tube plate type and evacuated tube solar collector-a three-step leap in the development of innovative technology for water heaters.
Starting from 2003 when the project was initiated to impact the integration of natural circulation systems, after ten years of hard work, China has developed a new type of multi-functional plastic steel frame. Three new types of natural circulation system integrated board cores with different materials and system structures, a batch of dedicated tripod systems with different functions and related pipe valve accessories. By 2010, the new flat (or vacuum tube) collector and its hot water system intelligence that can meet the high standards of building integration flat roof, tiled roof, balcony guardrail, window sill up and down, or left and right installation methods have been obtained. A series of innovative technological achievements such as controllers. Only the project involves as many as 20 invention and utility model patents authorized by the state.
The introduction of the innovative concept of natural circulation system integration not only makes the design, manufacture and installation of China’s building-integrated domestic solar water heaters fully standardized, standardized, and modular, but also a new basic component of its large-scale industrial production: temperature difference circulation flat plate Core and vacuum tube set-the technology development and industry of a series of patent assembly standard components such as the core components of the water heater, the fully sealed plastic steel frame, the venting and water stop valve, various types of special tripods, active or passive information intelligent control systems, etc. Chemical production not only promotes the upgrading of domestic hot water systems in China, but also can be widely transplanted to other large-scale industrial and agricultural production solar (low temperature) heat utilization engineering systems. The new generation of integrated solar water heater patented products of building integration system, after the realization of large-scale industrial production, will surely promote China’s solar thermal utilization technology to a new level. At the same time, it also laid a solid technical foundation for China’s new generation of information intelligent control high-efficiency flat panel, vacuum tube solar collector-water heaters to the world.
The realization of system integration of natural circulation solar water heaters, separation of collection and storage, flexible installation of building integration and intelligent control of information is the general trend of global new energy application development, the inevitable progress of science and technology, and the new trend of the development of solar thermal utilization. Innovation goals and visions pursued by human society.