- Issue Time
- Jan 7,2017
Solar water heaters as a solar thermal technology, a major success to green environmental protection, energy saving and other advantages into the tens of thousands of households. As the guardian of the sun's loyal "guards", the light and heat donated to people, to provide people with convenient life.
First, the principle of solar water heaters - collector (graphic)
We know that solar water heaters from the vacuum collector, water tank and bracket three parts, and accessories are control device, electric heating, solenoid valves, sensors, special pipe and fittings, ball valves and so on. (Pictured below)
Second, the principle of heat and circulation
System of the collector element. Its function is equivalent to the electric water heater in the electric tube. And other water heater is different from the solar collectors is the use of solar radiation heat heating of cold water, so the heating time only in the sunlight during the day.
As shown in the figure, the vacuum heat pipe is like a slender warm bottle, and the inner and outer layers are vacuum. Common sizes are 1800mm × 58mm, 1500mm × 47mm and so on. The outer surface of the inner tube of the vacuum tube is coated with a special material which can effectively absorb the solar radiation energy. When the photon hit the film when the light energy into heat, and conduction to the tube of water, the water temperature will gradually increase.
As the ratio of major cold water, hot water, a small proportion of the principle, the vacuum tube and the insulation tank will form a cold water down, hot water up the natural cycle, the hottest water cycle to the insulation tank. (As shown below)
Third, the insulation tank
And other insulation tank, is the storage of hot water containers. Because solar water heaters can only work during the day, and people generally use hot water at night, in order to make the daytime hot water production in the evening or the next day to maintain a certain temperature when used, it must be through the hot water storage tank.
1, the tank tank water tank is an important part of the storage of hot water, the material strength and corrosion resistance is essential, high-quality selection should be imported SUS2B304 sheet, the thickness of 0.4mm - 0.8mm between the stainless steel plate , Argon protection, high-frequency automatic welding, to improve the steel in a variety of water or corrosion resistance of various environments.
2, the performance characteristics of water tank insulation materials and technical parameters: the quality of insulation materials is directly related to the thermal efficiency and the use of the early morning, especially in the cold northeast. At present, better insulation is imported polyurethane insulation, if the ingredients, process, environment, temperature discomfort, can also cause uneven foam or foam is too large, refrigerant slowly loss of insulation effect of the gradual decline, which requires Manufacturers have a special foaming machinery, standardized mold and a higher level of technology. In addition, we not only understand the product timber technology, but also the manufacturers of machinery and equipment, molds and other organic cost level, quality monitoring standards. Product quality is directly related to the interests of consumers. Polyurethane insulation thickness: 50mm Closed-hole rate: 65.69% Thermal conductivity: 19.83mw / m.k, and after high-temperature aging treatment.
Insulation tank is how to keep hot water for a long time, not with the night and winter and other external temperature changes? As shown, the insulation tank has three parts: outer bladder, polyurethane foam layer and stainless steel liner, which is responsible for the polyurethane foam layer of solar water heater insulation. Polyurethane insulation performance, is the lowest thermal conductivity of all building materials (≤ 0.024), the highest thermal resistance of the insulation material. Solar water heater foam layer thickness is generally between 50mm-70mm, the actual insulation performance depends on the manufacturer's foam machinery, standardized mold and process technology.
Fourth, the working principle of solar water heaters
Will be transported to the cold water into the water tank into the collector, and then from the holding tank of hot water to the channel to the use of hot water. Called the connecting pipe, in order to make the entire system to form a closed loop, must be designed to connect properly, the cycle of the solar system on the pipeline is to achieve the best working condition is essential. Hot water pipes must be heat treated. Pipes must be of high quality and have a service life of at least 15 years. Installation requirements horizontal and vertical.
To the solar water heater to fetch water up, rely on the water pressure, no tap water or can not be 24 hours for tap water users, you have to rely on pumps or booster tank to the solar water heater to fetch water.
Water, as long as any indoor open a faucet, water heaters inside the water tank will rely on the principle of natural fall out.
Energy saving and environmental protection
Per square meter of flat solar collectors or five vacuum tubes (∮ 58 mm × 1800 mm) in a normal sunshine days, can produce the equivalent of 2.5 kWh of electricity, according to this standard, annual savings of about 200 kg of standard coal can Reduce more than 700 kilograms of carbon dioxide emissions. The extensive use of solar water heaters, in saving money, to facilitate our while also greatly improving the earth's environmental pollution.
Fifth, flat-panel solar water heater works
As a domestic solar water heaters, flat-panel solar water heaters and vacuum tube solar water heater work was almost, here we are not the same as a place for them to make a brief introduction:
First, endothermic process
Solar radiation through the glass cover, is absorbed by the collector plate along the wall and the wall to the heat transfer tube of water. The heat in the tube absorbs heat and the temperature rises, and the specific gravity decreases and rises, forming an upward momentum to form a thermosyphon system. As the hot water continues to move up and stored in the upper part of the storage tank, while the next cycle by constantly replenishing the lower temperature of water, so the cycle, the final FCL water are elevated to a certain temperature. The conventional flat plate type heat collector basically adopts a combination of good multi-tube combination method, such as rolling or calendering method, wherein the thermal resistance between the water pipe and the heat absorbing plate is almost negligible. The main factors that affect the performance of flat plate collector core structure, one structural design, the second is the surface absorption coating. The well-designed collector plate core fin efficiency should be above 93%. The core fin efficiency of the collector is related to the core structure, the surface treatment and the whole structure of the collector. The influence of the overall structure of the collector can be described by the total heat transfer coefficient, its impact degree and its own geometry (fin thickness, material) is the same. In other words, in the case of the same efficiency, the collector core heat loss can be thinner. Selective absorption of surface can improve the efficiency of heat collection, but the market for these products in order to improve economic efficiency, often rib thinner. For water heater occasions, the actual collector effect of such products and selectivity worse (even not selective), but the thickness of the fins of the collector will not have much difference.
Second, the circulation pipeline
Domestic solar water heaters usually work by natural circulation, there is no external power, well-designed system as long as 5 ~ 6 ℃ above the temperature difference can be a good cycle. The rationality of water pipe diameter and pipe distribution directly affects the heat exchange efficiency of the collector. In most cases, the natural circulation of domestic water heater system in the pipeline flow can be regarded as laminar flow. The resistance of the piping system in the collector mainly comes from the resistance along the way. The influence of the local resistance is much smaller, and the resistance of the branch pipe is much greater than that of the supervisor. When the water temperature rises, due to reduced kinematic viscosity, along the process resistance becomes smaller, the greater the impact of local resistance. In a certain range, when the diameter of the main pipe is not changed, the branch pipe diameter will be enlarged, not only the resistance along the road will be reduced rapidly, but also the local resistance will be reduced. In general, the hydraulic radius of the branch pipe should be 10 mm or more. When the main pipe diameter reaches a certain value, increase the diameter of the main pipe to reduce the system resistance is of little significance.
Third, the use of top-water process
Domestic solar water heaters are divided into water-way and top-water type. Water use is not affected by the tap water supply, the drawback is the use of the process of water temperature after the first low-high, easy to master, then easily lead to water shortages embarrassment. The top water method is the water temperature is high and low, easy to grasp, the user easy to adapt, but requires water to maintain water supply capacity. In the case of guaranteed tap water, it is recommended to use the top water method. Domestic solar water heater design into the top water way, the internal structure of the tank must be a reasonable design to ensure that the water evenly, to avoid the formation of water "short circuit" or dead ends. The use of piping is best designed to be converted into a water-down connection, in the tap water shortage or emergency water supply.
This is about "home vacuum tube, solar water heater works -, flat-panel solar water heater principle," all the introduction, hoping to give you a comprehensive understanding of solar water heaters and flat-panel solar water heater works helpful.
(The above article by the solar water heater manufacturers - Haining Xianke New Materials Technology Co., Ltd. Xiao Bian to provide you with, if you want to know the vacuum tube solar energy or flat-panel knowledge, please visit the official website xiankesolar.com)