There will be a large area of rain, snow and temperature drop in the near future, which is very likely to cause freezing damage to outdoor central air conditioning water system facilities. In order to ensure that the central air conditioning water facilities can safely survive the winter and not affect normal work and operation, it is imperative to make preparations for winter antifreeze. In particular, central air conditioners used in large places such as shopping malls, manufacturing companies, and hotels need to be antifreeze. So how to prevent central air conditioners from freezing in winter?
1. Antifreeze of main engine and water pump
When the temperature in the main engine room is below 0℃ in winter, anti-freeze measures should be taken for the main engine, refrigerant water pump and cooling water pump.
1. Antifreeze of the host: Close the inlet and outlet valves of the host condenser and evaporator, open the drain valve and vent valve, and then use compressed air to blow away the remaining water.
2. Antifreeze of water pump: Close the inlet and outlet valves of the refrigerant water pump, open the water pump drain valve and vent valve, and drain the water. Open the valve at the lowest point of the cooling water system, drain the cooling water, and open the water pump drain valve. After the system water is drained, close the cooling tower outlet valve to prevent rainwater from entering through the cooling tower, open the cooling tower water collection tray drain valve, and drain the rainwater from the drain valve in time.
2. Antifreeze of cooling tower water supply pipe
Generally, the cooling tower water supply pipe is exposed to the outdoors, and most designers use insulation to prevent freezing. However, in actual use, even with insulation, it often freezes. In order to solve this problem, when the cooling tower water supply pipe is connected from the room, a valve is added, and a drain valve is added at the lowest point of the water supply pipe. When winter comes, close the indoor valve and open the drain valve at the lowest point to drain the water in the outdoor pipe. In this way, the pipe does not need insulation and will not be frozen and cracked.
3. Antifreeze of fresh air unit
The function of the fresh air unit is to process the outdoor fresh air and send it to each room. In winter, the fresh air unit heats the outdoor cold air, that is, the fresh air unit surface cooler is in direct contact with the outside cold air. In order to prevent the surface cooler from being frozen when the heating is stopped, an electric multi-leaf regulating valve should be added at the fresh air inlet and linked with the fresh air unit. When the fresh air unit is running, the air valve is opened, and when the fresh air unit is turned off, the air valve is closed. This can prevent the outdoor cold air from directly cooling the water in the surface cooler after the fresh air unit and the refrigerant water pump stop running, causing the water to freeze and freeze the surface cooler. Before turning on the fresh air unit in winter, you must check whether the water in the system is flowing and whether the temperature is appropriate. If the water pump is not running, the fresh air unit cannot be turned on. If the water pump is running but the water temperature is low, the fresh air unit cannot be turned on.
4. Antifreeze of expansion tank
The expansion water tank is usually installed in the equipment room on the roof or top floor. Although the expansion water tank is insulated and equipped with a circulation pipe, in actual use, the circulation pipe can rarely play a real circulation role. That is, in winter, the water in the expansion water tank is in a low temperature environment for a long time. Although it is insulated, it will still freeze. If the expansion water tank is frozen, it will not play an expansion role. The temperature in the system rises, and the pressure increases. In order to solve this problem, during construction, a DN20 interface can be set on the main water supply pipe of the air conditioner, and a valve can be installed to open it appropriately to ensure that the water in the water tank is circulated. If the air conditioner is not used at night, before the water pump stops, the valve can be fully opened to increase the water temperature in the expansion water tank, which can ensure that the expansion water tank will not freeze for a long time after the pump stops.
5. Antifreeze during long vacations
During the Spring Festival or weekends, the temperature is low and some parts of the chiller water system may be below 0℃ for a long time, which may cause them to be frozen. Therefore, management personnel are required to turn on the water pump and heat the water in the system according to the actual situation to ensure that the water system is not frozen.
Conclusion: In northern my country, the temperature is low in winter and the water system is prone to freezing. First, designers should take this problem into consideration and add anti-freeze facilities to the system. Secondly, the staff who manage the chiller unit must have a comprehensive understanding of the entire chiller central air-conditioning system, identify the parts that are prone to freezing, and take preventive measures in advance. Thirdly, operators should continuously improve their professional and technical level and strictly follow the operating procedures.
更多内容（请点击查看）
基础篇：
运营篇：
