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Flat solar collectors is suffering a very different with other countries, the situation in the rapid development of the China market, flat solar water heater solar water heater market share incredibly don't rise but lower, in small home solar water heater market, about the same also was kicked out, even its own existence, but also hard to sustain the hot water engineering in the south with a certain degree of application.
Investigate its actually, flat solar water heater in south China market PianAn corner reason the author thought as follows: 1. Can't in northern region, hard anti-freeze application; 2. The highest water temperature is lower, so are considered "efficiency is low"; 3. The price is more expensive, is costly. We summarize what its evils, can use six words to express: afraid of frozen, inefficient and expensive.
The first reason is because most flat solar collectors are using cold water directly through collection hot plate method for water pipe heat, this method doesn't circulating water pump, according to the principle of after water is heated up water heating, this method get cycle are really very simple and cheap, but not a good method: it is caused by thermal efficiency is low and integrating the form quickly, and dirt by board of the flow inside the canal is ordinary water, in the slightly sustained some under different temperature conditions, extremely easy to cause the freezing of water and expand, make collection hot plate tube, such technology thoroughly scrap form, make solar energy water heater with flat, and only in the south because use scaling and other reasons, the battery life is also quite short - although and vacuum tube use of solar water heater energy life, but not inferior compared with in the western world penchant for 40 years of service life than too little.
Water natural circulation of solar water heater originally should not appear: just because you can save a circulating water pump and some load cold agent, flat collector will lose the efficiency, life and freeze resistance, so that price is too heavy, it is too dearly purchased, it is worth to be considered.
Water circulation in the difficult circumstances, because the insulation properties than vacuum-tube solar hot water, so it's flat collector temperature is likely higher than flat collector of a lot of, but we don't forget, temperature and heat are two concepts: lighter than the flame temperature of the water temperature high vacuum tubes, can achieve 800 ℃ above, but relative to the environment temperature, its quantity of heat is not big: a lighter to all the heat out, even in the cases, 100% efficiency and also only can make 10 kilograms of water rise 3 ℃ just, as long as collectors can timely will heat transfer out, flat solar water heater set a much higher heat efficiency, so we can say, flat collector efficiency below the vacuum tube collectors, is a completely wrong and absurd conclusions.
Flat solar third question, may be even more important, because a lot of using some non-ferrous metal, flat solar panel would cost more than the vacuum tube collectors, in such a case, each flat solar manufacturers have embarked on a lower the cost of road, even walked some partial. They try every means to bring down the dosage of the copper coin collectors, more thin, cause its thickness has not called the COINS, but should called copper foil; Copper tube wall thickness is in constant decreases, can only bear a few kilograms of pressure tube leaked liquid not maintain; And do everything possible to use aluminum instead of copper; These efforts to reduce costs, make flat solar this in the world, all-powerful reigns in our country the energy-saving products, but has come to the point of almost unnoticed.
China's flat PV module, almost all to this a vicious cycle path, that is lower costs - the thinning COINS - slow performance - price lower... Many manufacturers of COINS, already thin to less than 0.15 mm, largely lost collection hot plate heat capacity to brass conveying, this is also causes the flat solar collection hot performance "incredibly" as the main reason for the solar collectors vacuum tubes.