The solar water heating system will dissipate heat faster in winter, especially in cold areas. I am worried that the low temperature will damage the solar water heating system. In fact, in order to prevent serious heat loss in the solar water heating system in winter, the solar collectors and system pipelines will be insulated. Thermal insulation measures can significantly reduce the heat loss of the solar water heating system, and at the same time can also delay the freezing of the system. The following introduces the anti-freezing design of the solar water heating system itself and the relevant measures that can be taken.
The antifreeze of solar water heating system includes antifreeze of solar collector and antifreeze of pipeline. In some areas where the temperature is lower than 0℃ in winter, the installation of solar water heating system must consider the issue of antifreeze. If the temperature of the system collector and pipeline is lower than 0°C, it will cause the volume of water to expand after freezing. If the allowable deformation of the pipe is less than the expansion of water freezing, the pipeline will be damaged by expansion.
In order to avoid such things as much as possible, two commonly used active antifreeze solutions are mainly introduced.
1. The system adopts a closed pressure-bearing system, with antifreeze as the circulating working fluid of the primary loop of the collector;
Antifreeze is also an active antifreeze solution, which is more reliable and safe. It is mainly suitable for heat pipe vacuum tube collectors. The antifreeze is added to the closed system of the circulating heating pipeline from the collector to the water tank. Check the antifreeze in the pipeline regularly. Therefore, antifreeze antifreeze is generally used in split heat pipe solar water heating systems.
2. Use the method of emptying, when it reaches a certain temperature, actively empty the water collector and pipeline;
Emptying antifreezing is an active antifreezing scheme in the antifreezing measures of solar water heating systems. The antifreezing performance is relatively reliable, especially the reflux and emptying antifreezing. Therefore, it is generally used for winter antifreeze of flat plate collector system.
As for the all-glass evacuated tube collector system, it is generally not recommended to use the emptying and antifreeze solution, because after the emptying is completed, the water needs to be refilled, which may cause the all-glass evacuated tube to burst. If you use the drain antifreeze, it is recommended to increase the slope of the system pipeline and the collector to facilitate the smooth flow of water.
When choosing a collector, flat plate collectors, heat pipe vacuum tube collectors and all-glass vacuum tube collectors will be used.
In severe cold areas, heat pipe vacuum tubes are suitable for antifreeze measures; emptying antifreeze is suitable for flat plate collector systems. Generally speaking, flat-plate collectors and all-glass evacuated tube collectors are not recommended in cold winter areas.
Facing cold areas, it is recommended to choose heat pipe vacuum tube collectors. The hot start temperature is low, and the low temperature resistance is good. In low temperature and high cold areas, the performance advantage is obvious. There is no water in the tube, no scale formation, long-term efficient heat exchange. Mainly do good pipe insulation.