Since the solar water heater is installed outdoors, it is recommended to use aluminum-plastic pipes.
1. The low temperature resistance of aluminum-plastic pipes is higher than that of PPR pipes. PR is fragile when cold (the fragility point is -20°C), special care is therefore required during construction in winter (below 5°C). Aluminum-plastic pipes have no cold brittleness (the brittle point is -70°C) and can be easily installed below -20°C.
2. The expansion coefficient of the PPR pipeline is high. Since PPR pipe is a rigid straight pipe, it cannot absorb deformation, so it is easy to cause bending, deformation and even leakage of the pipeline system. Aluminum-plastic pipe is composite with aluminum. As a whole, its linear expansion coefficient is equivalent to that of aluminum, approximately0.025 mm/m·℃, which is 1/6 of PPR pipes. Therefore, when subjected to temperature changes, the pipe is made of aluminum and plastic. the amount of deformation is small and the aluminum-plastic pipe is a flexible coil, and the pipe itself can absorb a certain amount of deformation and will not cause thermal expansion and deformation of the piping system.
3. PPR pipe has poor aging resistance. The PPR molecular chain structure - (-CH2—CH-)n- contains a large number of unstable tertiary carbon atoms, which are more sensitive to CH3 light and oxygen. , and impurities (such as copper, iron ions) and aging. Therefore, the PPR product manual generally stipulates that the open air stacking time should not exceed six months. PE plastic used in aluminum-plastic composite pipes has a molecular chain structure - (-CH2-CH2-)n-, which is the most stable structure among plastics and because the aluminum layer in the middle of the aluminum-plastic pipe separates. To the inner and outer layers, the outer plastic can add enough stabilizer which resists aging by light and oxygen without affecting the hygiene of the inner layer in contact with water.
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Advantages of aluminum-plastic pipes
The advantages of aluminum-plastic pipes can be summarized in the following three aspects:
p>1. Outstanding hygienic performance: The inner and outer layers of the aluminum-plastic pipe are made of special polyethylene materials, which are clean and non-toxic. The most important thing is that the middle layer of the aluminum-plastic pipe is made of aluminum, which not only blocks light but also blocks oxygen. As we all know, the approximatelyenvironment conducive to the growth of microorganisms must contain light and oxygen. The aluminum core layer of the aluminum-plastic pipe prevents the growth of microorganisms and algae, which is beyond the reach of all-plastic pipes. Not only do all-plastic pipes themselves add a large amount of antioxidants to prevent material degradation, but the antioxidants are extracted into the water retained in the pipes, which can easily cause water pollution, because they do not block light or oxygen. -By blocking materials in all-plastic pipes, it is very easy for microorganisms to breed and cause secondary pollution of water quality.
2. Excellent high and low temperature resistance: long-term use temperature is 95 degrees (50 years, IMPa), maximum use temperature is 110 degrees and lThe thermal expansion coefficient of the aluminum-plastic pipe is small. Its thermal expansion coefficient is equivalent to that of aluminum and only one-sixth that of all-plastic pipes. When subjected to temperature changes, the amount of deformation is small and the aluminum-plastic pipe is a flexible coil. The pipe itself can absorb a certain amount of deformation and will not cause thermal expansion or deformation of the piping system. The high and low temperature resistance of all-plastic pipes is relatively poor. The long-term use temperature of PPR is only 70 degrees (50 years, IMPa), and the maximum use temperature is 95 degrees. At the same time, the expansion coefficient of PPR pipelines is large. When the external water temperature (hot and cold water) changes, a large amount of deformation occursSince PPR pipelines are rigid straight pipelines, it cannot digest the extent of deformation, which can easily cause the system to bend, deform or even leak.
3. Long service life: The molecular chain structure (-CH2-CH2-) of PE plastic used in aluminum-plastic composite pipes is relatively stable among plastics, and because the aluminum layer in the middle of the aluminum pipe -plastic separates the inner and outer layers Insulation, the outer plastic layer allows the addition of sufficient stabilizers to resist aging by light and oxygen without affecting the hygiene of the inner layer in contact with water, improving thus its anti-aging performance.
PPR pipe
Main advantages
1. Lightweight
The density at 20℃ is 0.90g/cm3 and the weight is only that of steel pipes. One ninth of the copper pipe, one tenthcopper pipe, lightweight, greatly reducing construction intensity.
2. Good heat resistance
The instant use temperature is 95°C, and during long-term use, the temperature can reach 75°C. This is currently the most ideal indoor temperature. hot and cold water pipe.
3. Corrosion Resistance
Non-polar materials have no chemical effect on any ions in water and building chemicals, and will not rust or corrode.
4. Low thermal conductivity
It has good thermal insulation performance when used in hot water systems, there is generally no need for additional thermal insulation materials.
5. Small resistance of the pipeline
The smooth inner wall of the pipeline makes the resistance along the way smaller than that of pipemetal lines and energy consumption is lower.
6. The pipe fitting is firm
It has good hot fusion performance connects pipes and fittings of the same material into a perfect whole, eliminating the risk. water leak.
7. Hygienic and non-toxic
It does not pollute the environment during production, construction and use, and is an environmentally friendly building material.
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Common vacuum tubes on the market have two diameters, 47mm and 58mm. Almost all major brands of solar collectorsThey have a diameter of fifty-eight millimeters. . Attention should be paid to the length of the vacuum tube. For example, if you use a vacuum tube with a length of 1.6 meters, you can insert a vacuum tube with a length of 1.8 meters. the tube inserted into the water tank is too long, the circulation of water inside the water tank will be restricted, causing the water temperature to be too low, etc. Therefore, when replacing the vacuum tube, the diameter and length should be the same as the original tube size.
How to judge whether the solar water heater pipe is broken
I personally recommend using a solar water heater with a 1.8 meter pipe. There are two reasons:
First, regardless of the size of the pipe, the water temperature of the solar water heater tank is generally designed according to the requirements, which stipulate that the daily temperature water should not exceed 60°C. degres in sunny conditions. In the product design of all domestic solar water heaters, the hot water will not exceed the specified temperature, mainly to avoid scalding and vacuum tube scaling.
Second, this type of vacuum tube is a common model on the market. If broken, any brand of solar vacuum tube can be replaced. But if you use a long tube, I'm sorry, how much does anyone else want? Money is someone else's business. Except for vacuum tubes from this manufacturer, you cannot find vacuum tubes this long. No other home has pipes this size.
Third, it is actually very simple to increase the water temperature. For water tanks with the same water capacity, the manufacturer may install more vacuum tubes. It is not difficult for the manufacturer. to the dealer to personalize it.
When thesolar water heater pipe breaks down, you can judge it through some visual signs. First of all, the water level inside cannot rise normally, which may be caused by water supply problems caused by broken pipes. Second, if you can go to the roof for inspection and find that the vacuum tube is not leaking but has an abnormal color, this may also indicate damage to the tube. At this time, it must be replaced in time.
The replacement process is relatively simple. First, mix dish soap and water and apply it near the silicone ring at the bottom end of the water heater tank. Then put on gloves, hold the lower part of the tube. , and remove the old tube by twisting it and pushing it upwards. Remove the silicone ring and check, if there is no problem, install a new tube. Once the new pipe has equalIf it has been treated with dish soap, it can be reinstalled in its original position.
The vacuum tube of a solar water heater is its main component, and its quality and design directly affect the performance of the equipment. The structure of the vacuum tube is similar to that of an elongated thermos bottle. The interior is vacuum sealed and the outer layer is covered with a coating that absorbs solar radiation. When the sun shines, the vacuum tube converts solar energy into thermal energy, causing the water temperature to increase. At present, domestic enterprises that produce vacuum tubes, such as Linuo, Yuansheng, Yaohui, etc., have various production methods, including tube types with and without water leakage, to adapt to different market needs.
Generally speaking, as the core of solar water heaters, the performance and design of vacuum tubes dshould be adjusted according to the region, user needs and building characteristics to achieve the best solar energy utilization effect.