See the effect of concentrating heat. The ability of concentrating light and collecting heat is an important symbol to measure the performance of water heaters, and it is also an important factor affecting the heat gain of water heaters. Vacuum tube is the "heart" of solar energy, which converts light energy into heat energy and heats the water in the water tank, so the heat obtained by vacuum tube directly affects the water temperature under the same external conditions. At present, there are two kinds of vacuum tubes on the market, one is made by traditional gradient membrane technology, and the other is made by internationally leading patented interference membrane technology, which has the characteristics of "high temperature resistance, cold resistance and high efficiency". The latter is a substitute product of the former, which increases the heat gain of the water heater by 30%, and completely solves the problems that the traditional vacuum tube is not hot in rainy days and the solar energy is not easy to use when the temperature is too low in winter.
Second, look at the thermal insulation performance. The water storage tank is the "hot water warehouse" of the water heater, and its performance is mainly reflected in the heat preservation effect. A good insulated water tank depends not only on the thickness of the insulation layer, but also on the insulation material and technology. The thickness and material of the insulation layer of water tank are important parameters that affect the insulation capacity of water tank. Especially in the area north of the Great Wall, it is recommended to buy brand solar water heaters with insulation layer thickness above 60 mm ..
Third, look at the strength of tolerance. Solar stents are like human "skeletons". Of course they can't be weak. At present, the streamlined tower support is widely used, and the ultra-high base is reinforced, which overcomes the shortcomings of traditional thin rod support that it is not wind-resistant, and has stronger wind-proof, rain-proof, snow-proof, hail-proof and corrosion-proof capabilities.
Fourth, look at brands and services. The main engine of solar water heater is outdoors, which is subjected to wind and rain all the year round and needs professional maintenance. At present, there are thousands of solar water heater manufacturers in China. Because there is no uniform testing standard for solar water heaters in China, the quality of some products is not up to standard and the installation service is not in place, which brings troubles to users. Experts believe that buying solar energy is not only a product, but also a service. Therefore, we should choose the products of famous professional manufacturers with strength. Generally, the installation service personnel of such manufacturers have received professional technical training and provided thoughtful services, so that consumers can have no worries and get the best protection.
Guide to purchasing solar water heaters.
Compared with electric water heaters and gas water heaters, solar water heaters have many advantages:
Solar energy hot water engineering 1, solar energy is inexhaustible. As long as there is sunshine, solar water heaters can be converted into light and heat, which can be operated all year round. 2. Green and environmental protection. As a clean and renewable energy source, solar energy has no environmental pollution and potential safety hazards. 3, long service life, the service life of main components can reach more than fifteen years; 4. It can be used together with other energy sources to realize all-weather operation; 5. Significant economic benefits. One-time investment and long-term benefit are the remarkable characteristics of solar water heaters. The payback period of solar water heater is related to the price of conventional energy. Generally speaking, the investment can be fully recovered within 1 ~ 4 years.
However, there are hundreds of brands of solar water heaters on the market at present, which is dazzling and consumers have no choice. In order to enable consumers to choose solar water heaters with excellent quality and good after-sales service, experts from China Solar Energy Association and AQSIQ advise consumers to choose according to the following steps:
The first step: to determine the water consumption, we must first make clear the number of permanent residents and the per capita hot water consumption, and then calculate the total amount of hot water in one day. Then according to the total amount of hot water and hot water production capacity f(75-90kg/ day? M2), design the solar collector area S(m2) and the heat preservation water tank capacity V(m3). According to our many years' experience, the following parameters can be referenced for the hot water consumption of 55℃ per user:1; Domestic users: shower water consumption is 80- 100kg/ person? Days, or per person 1m2 solar collector area; 2, factory employees, school shower spray water: 40-60kg/ person? Day; 3. Hotel shower water: 80- 120kg/ person? Day; 4. Bath water: 300-500 kg/person? Jesus Christ. Determine the total consumption of hot water P(kg) per day, and make P(kg)÷F(kg)/m2 to obtain the area S(m2) of the solar collector. According to the ratio of 0. 1m3 thermal insulation water tank capacity per square meter of solar collector, the thermal insulation water tank capacity can be calculated: v = s (m2) * 0.65438+. The cost of solar water heater is directly related to the area of solar collector and the volume of heat preservation water tank, which is close to direct ratio. Considering the long-term and comprehensive interests of users, it is beneficial for users to choose a larger area of solar collectors, because more solar hot water is invested for the first time, and the operating cost in the next 15 year is also more economical.
Step 2: Choose solar collectors and other accessories. After the area of solar water heater is determined, it is necessary to choose the type of solar collector. At present, there are four types of solar collectors used in the domestic market: flat plate type, vacuum tube type, heat pipe type and U-tube type. Each of the four types has its advantages and disadvantages, and none of them is perfect and has absolute advantages. Users should choose the type of solar collector according to the climate characteristics of the installation site, the required hot water temperature and the purpose. For users in southern regions such as Guangdong, Fujian, Hainan, Guangxi and Yunnan. It is very suitable to choose a flat-plate solar collector, because the problem of anti-freezing is not considered in winter. The disadvantage of the flat-plate solar collector is that it is not anti-freezing, so it will not show this disadvantage when used in southern China, but the advantages of the flat-plate solar collector are very prominent: high thermal efficiency, metal tube plate structure, maintenance-free, 15. Users in the Yangtze River and Yellow River basins will freeze in winter, and the temperature in winter is higher than -20℃, so it is more appropriate to choose vacuum tube solar collectors, which can resist freezing and have higher cost performance than heat pipes and U-tubes. Users in the three northeastern provinces, Inner Mongolia, Xinjiang and Tibet must choose the heat pipe solar collector, because the heat pipe can resist the low temperature of -40℃, and the flat plate and vacuum tube can't resist such a low temperature, but the heat pipe has high cost and the lowest thermal efficiency. To sum up, different types of solar collectors are not absolutely good or bad. It is important to choose the type with the best cost performance according to the climate characteristics and uses of the use area, and don't be misled by some manufacturers and spend more money. Water pipes, heat preservation water tanks, control systems and other accessories are also used in solar hot water system, and the performance of accessories directly affects the superiority of the whole system. Copper pipe, stainless steel pipe and PPR pipe can be selected instead of galvanized pipe, among which PPR pipe has the highest cost performance; Do not choose a water tank with thermal insulation cotton, because thermal insulation cotton will absorb water; The bottom of the heat collecting plate can be insulated with insulation cotton instead of polystyrene; It is best to choose imported brands for the control system.
Step 3: Evaluate the design scheme When evaluating the system design scheme of solar water heater, we should focus on the following five points, which can basically reflect the advantages and disadvantages of the design scheme: 1. Is the designed heating water enough? Are the collector area and water tank capacity large enough? 2. Is the auxiliary heater powerful enough? In principle, starting electric auxiliary heating in rainy days should fully meet the water demand within 3-5 hours, and starting heat pump auxiliary heating should fully meet the water demand within 8- 16 hours; 3. If the user's water consumption and time change, can the system still meet the user's requirements? (Because in actual use, users' water consumption and water consumption time often change); 4. Under various weather conditions, under various water consumption time and water consumption changes, does the system maximize the use of solar energy and minimize the consumption of conventional energy, that is, does it maximize energy saving? 5. Is it the most cost-effective? If through the comparison of various schemes, it is found that the answers to the above questions are all positive, it is an excellent design scheme. Otherwise, as long as the answer to one question is negative, the design scheme is imperfect or even failed. Buyers can make up their minds by using their own intelligence and knowledge to evaluate the above five aspects.
Step 4: Try to choose a brand. Choose big brands instead of small brands. Brand is a kind of credit guarantee for manufacturers to consumers, and big brand means more and more reliable guarantee. Some small and medium-sized enterprises hold the mentality of grabbing and leaving, and product quality and after-sales service are difficult to guarantee. The after-sales service of solar water heaters is very important, because solar water heaters are durable consumer goods and are generally installed on the roof. Once something goes wrong, it is difficult for users to solve it themselves, so after-sales service must be guaranteed. Generally speaking, agents or small shops without their own brands only have short-term service capabilities, and it is difficult to have long-term service capabilities, because their existence is short-term; The after-sales service of companies or their branches with independent brand awareness is guaranteed for a long time. Really good brands rarely need on-site after-sales service, and their on-site after-sales service costs are also low, and manufacturers are more confident to set the free warranty period longer, 1 year, 2 years. From this point of view, to some extent, we can also speculate on the advantages and disadvantages of products. Another important criterion for evaluating a brand is the length of the company's history. It is best to choose an enterprise with a history of more than 8 years. A long history means that the company has stable development, strong viability, strong strength, leading technology, excellent product quality and guaranteed after-sales service. According to statistics, the probability that a newly established company will close down within two years is 80%. Therefore, a short-established company has just started, its products and services are not mature, and its viability has not stood the test of time, and it is likely to disappear in the market competition within two to three years. Of course, this does not mean that a new company is not credible at all. If you don't know this technology, you can ask someone who does. In some cases, a new company often has its own unique advanced technology if it wants to gain a foothold in numerous competitions!
According to the above four steps, you can choose the most suitable solar water heater products and services.
Top ten brands
There are various ranking methods in the "Top Ten Solar Energy Rankings" on the Internet, most of which are made by manufacturers themselves, which are not objective and fair and lack certain evaluation basis.
1. First of all, at this stage, no one or any unit has the right to casually evaluate where others rank. If an industry really wants to rank, the first thing to do is to create a selection unit. This is that the unit must be open and fair. So far, there is no such unit in the whole solar energy industry. Have you found out who makes the so-called industry rankings? Why are they all mysterious people? Why don't they say who they are and where they work? If there is such an organization in the industry, will it still hide? Don't! It will expose its identity and let everyone know. Will give the general public and consumers a satisfactory answer.
2. The second thing for industry ranking is to make rules. This rule must be made public, and most people in the industry should participate in the opinions. The established rules need to be recognized by the industry. It is also important who makes the rules. Whoever makes the rules will have more say and certain advantages. It is impossible for all manufacturers to participate, and it is impossible for a few manufacturers to formulate behind closed doors. It's hard to get recognition from the industry.
3. The selection will definitely be held and announced on a regular basis, instead of not knowing when to start and when to end, as seen on the Internet now.
4. Is it necessary to rank? The answer is yes! There's no need! If you really want to do industry rankings, it is difficult to be fair and notarized. This is not only impossible at home, but also in developed countries abroad. Like the global top 500 or something. In fact, it is the total market value of the company, not strength, profit, efficiency and so on. Why do you want to do industry rankings? I really can't think of the necessity of it. It will not promote fair competition in the industry and will not really help the development of the industry. A meaningless thing is always fired, because there are always people who believe these untrue things.
5. Top ten brands of solar water heaters: Our answer is that there is no ranking!