In -20 - 1 ° C ice-expansion coefficient as 1.125 x 10-4 / K than steel (3.6 x 10-5 / K) and copper (5.1 x 10-5 / K) are great. Collector plate and piped water containers, and other damage, mainly in the 0 ° C phase change occurred because of the water caused, once completed phase transition process, even to cool containers will not be damaged. Solidification of ice water and a process is needed, not twinkling completed, if we adopt certain measures to control water collector pipes in the freeze order, it will first freeze of space occupied by the ice that part of the smooth water discharge, and this the volume phase transition can be avoided by expanding the damage caused, once completed phase change, even if the temperature continues to drop, the collector will not be This is the order freezing the basic tenets of antifreeze.
How to achieve order freezing? In order to answer this question, we, first a small experiment. Take two of the same length and diameter steel tube, with one end sealed steel welding, pipe full of water, of which a outdoor low temperature environment, and the other opening-roots upward, insert heaped with the in water. Two pipe test the temperature changes found: first root canal ends of the intermediate temperature lower than the temperature, indicating that the two ends of the tube will first freeze and then gradually transition to middle freeze, which is a natural freeze order, but also many storage containers at low temperature was the reasons for the second root canal from end to the other end of the temperature gradually decreased, indicating that the tubes freeze order will be for low-end to direction, as the heat) the existence of heat flow in the direction of the reversal, which changed the original freeze order. This experiment shows that heat can be adjusted in the water pipe to freeze order.
The water in the tubes and ribbed tubes in the film freeze order, the order arrived by the wall began center. Completion of time and frozen and finned tubes the diameter, ribbed films freeze at a faster pace. So can use the heat source location, the size and diameter increased fin, and other means to achieve collector in the order freezing water. We designed antifreeze water heater, and its upper and lower sets of the cycle are used rubber materials, and are used Pipe bands efficient copper-aluminum composite, as rubber-tube diameter from top to bottom, water capacity, and low heat dissipation properties far in a fin, good heat transfer properties of the row so that the upper and lower sets of terms relative to Pai played a role in heat, thus achieving a row by the central tube to the ends of the freeze order. Pai in the expansion of the water discharged into the collection tube as a result of the cycle of the upper and lower storage tanks linked with the top, so water tanks on the heat cycle of plays a role. The lower part of the freezing process from the beginning, gradually upward to freeze expansion of the water discharged into the water tank, upper and lower sets of finalizing the freeze, a small portion of the remaining water to freeze expansion, as rubber flexible, will not be.
Antifreeze solar water heater using the principles of design freeze order made, to freeze without bad antifreeze purpose of its thermal performance is very good. Antifreeze solar water heater is a basic requirement in the winter can also produce hot water to use for the purpose. Because of the capacity of its water collector small, frozen winter night in the water near sun rises the next day soon will be all melted (General Beijing winter morning 8:30 collector of water would be all melted), and the beginning of the loop heating. 。 The collector plate used efficient copper-aluminum composite core bands, coupled with selective coating aluminum anodizing, greatly improving the collection efficiency, the general winter day can be 6 ° C cold water to 40 ° C.
Beijing Solar Energy Research Institute of antifreeze SWH has won state invention patents, the technology is a world first, the international leader, with the exception has been produced in batches, but also caused a number of foreign companies keen interest, have begun to sell products abroad.