Views:31 Author:Site Editor Publish Time: 2014-03-05 Origin:Site
Vacuum tube solar water heater tank is not under pressure, through the exhaust port in connected with the external environment in order to maintain pressure. In the northern winter ice jam problems often happened, causing cracking or suck up water tanks deflated affect use. This article is recommended to readers of a low-cost, no power, no electricity solar water heater tank antifreeze blocking new technologies.
A freeze plugging problems and prevention methods
Winter night temperatures in most parts of northern China are generally below -10 ℃, arctic regions and even achieve the following -30 ℃, and with larger wind. At night, the vacuum tube solar water heater tank to retain a certain amount of water to ensure the tube will not be cracking, frozen. Vapors inside the tank, condensate or wet air flowing through the vents in the cold condensation may appear frozen ice blocking phenomenon, frozen blocking the severity of the problem with the exhaust port opening toward is related.
1.Up exhaust port 2.Side exhaust port 3.Bottom exhaust port
As shown, the vacuum tube solar water heater tank has 1.Up exhaust port 2.Side exhaust port 3.Bottom exhaust port three ways; differ in terms of thermal performance and cold blocking issues:
The exhaust gas (1) and an exhaust side
Since the vapor density of the air is less than 2/ 3, when the exhaust port in the upper part of the tank, either upward or to the side of the opening, regardless of whether the pressure balance inside and outside the tank, the steam released into the atmosphere is always accessible to the environment, while constantly cold flowing into the tank vapor space occupied by built- replace. This situation is like the thermos flask with cork open, the steam to escape away with a lot of heat, resulting in lower water tank insulation effect, water temperature dropped too quickly, thereby reducing the overall thermal efficiency of solar energy. The advantage is a continuous flow of steam, continuous supply of heat, even if the outside temperature is low, the exhaust port is not easy to freeze, frozen block accident only under extreme conditions.
(2) Bottom exhausts port
Exhaust vent down tank may well avoid heat loss, as shown in Figure 2. Bottom exhaust port and up exhaust port is very different from the appearance point of view, it is clear that the exhaust heat outside run for up exhaust port, while for bottom exhaust port without any apparent phenomenon. For bottom exhaust port, as long as the external pressure tank consistent , the tank would not have steam or moist air to escape, in fact, the pressure inside the tank is gradually declining , inhale a small amount of cold air. In the cold and wet exhaust air heat generated portion of the condensed water, condensed water in the tank will have to enter the exhaust pipe , the condensed water accumulates in the lower end of the exhaust port of the tap , at an ambient temperature below -8 ℃ , easily blocked vent will cause freezing cold block .
Tank vent tube solar water heater is frozen block in a cold winter course a very common problem. Currently solar water tank exhaust frozen block are solved by heating, or hot water from the tap in the tank leads to a heating, but both will cause additional power consumption.
2 superhydrophobic freezing water shutoff nozzle
Recently, Shandong Academy of Sciences Key Laboratory of solar surface- coating method, developed a superhydrophobic inner wall of the nozzle, to solve the problem of freezing cold regions blocking solar water heater tank vent.
The technology is based on low surface energy organic resin as functional materials, Nano-wear-resistant aggregate, step by aging at different temperatures, the formation of nanostructured surfaces covered with low surface energy coating with superhydrophobic properties of lotus leaf bionics coating to achieve the degree of super-hydrophobic (contact angle greater than 150 °), so that water droplets not adhered to the exhaust pipe, so impossible droplets accumulate ice phenomenon.
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