How to prevent freezing of central air conditioning in winter

How to prevent freezing of central air conditioning in winter

In winter, the temperature is getting lower and lower, even exaggeratedly saying that there is a feeling of freezing, so you should not hesitate to prepare for the cold. But there is another problem that cannot be ignored. In the sub-zero temperature, please don't forget to prevent freezing of the hard-working central air conditioner, especially the central air conditioner used in shopping malls, manufacturing enterprises, hotels and other large places. So how do central air conditioners prevent freezing in winter?

　　The antifreeze of the main engine and water pump

　　 When the temperature in the main engine room is lower than 0℃ in winter, anti-freezing measures shall be taken for the main engine, refrigerant water pump and cooling water pump.

　　1. Anti-freezing of the main engine: close the inlet and outlet valves of the condenser and evaporator of the main engine, open the drain valve and the vent valve, and then use compressed air to blow off the remaining water.

　　2. Antifreeze of the water pump: close the inlet and outlet valve of the refrigerant water pump, open the drain valve and vent valve of the water pump, and drain the clean water. Open the lowest point valve of the cooling water system, drain the cooling water, and open the water pump drain valve. After the system water is drained, in order to prevent rainwater from entering through the cooling tower, close the cooling tower water main valve and open the cooling tower water tray drain valve , So that rainwater can be drained from the drain valve in time.

　　 Antifreeze of cooling tower water supply pipe

　　 In general, the cooling tower water supply pipe is exposed to the outdoors, and most designers use heat preservation to prevent freezing. However, in actual use, even if heat preservation, frost often occurs. In order to solve this problem, add a valve when the cooling tower water supply pipe is connected from the room, and add a drain valve at the low point of the water supply pipe z*. When winter comes, close the indoor valve and open the z* low-point drain valve to drain the water in the outdoor pipe, so that the pipe does not need to be insulated and will not be cracked by freezing.

　　 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 cold outdoor air, that is, the surface cooler of the fresh air unit directly contacts the outside cold air, in order to prevent the surface cooler from being frozen when the heating is stopped. , An electric multi-blade control 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 new fan is closed, the air valve is closed. This can prevent the fresh air unit and the refrigerant water pump from stopping. The outdoor cold air directly cools the water in the surface cooler, which freezes the water and damages the surface cooler.

　　 Before turning on the fresh air unit in winter, it is necessary to check whether the water in the system is flowing and 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.

　　 Antifreeze of expansion tank

Expansion water tanks are generally located in the equipment room on the roof or the top floor. Although the outer surface of the expansion water tank is insulated and is equipped with a circulating pipe, in actual use, the circulating pipe can really circulate very few, that is, there are expansion water tanks in winter The water is kept in a low temperature environment for a long time, although it keeps warm, it will still be frozen. If the expansion tank is frozen, it will not expand. When the temperature in the system rises, the pressure increases. In order to solve this problem, a DN20 interface can be installed in the air-conditioning water supply main pipe during construction, and a valve can be installed to open properly to ensure that the water in the water tank is circulated. If the air conditioner is not used at night, the valve can be fully opened before the water pump is stopped to increase the temperature of the water in the expansion tank, which can keep the expansion tank from freezing for a long time after stopping the pump.

　　 Antifreeze during long holidays

During the Spring Festival or weekends, the temperature is low, and some parts of the bromine chiller water system may be below 0°C for a long time, which may be frozen out. Therefore, the management personnel are required to turn on the water pump and increase the temperature of the water in the system according to the actual situation. Ensure that the water system is not damaged by freezing.

Conclusion: In northern China, the temperature is low in winter, and the water system is prone to be frosted. Firstly, the designer should consider this problem and add anti-freezing facilities to the system; secondly, the staff who manage the bromine chiller must be A comprehensive understanding of the central air-conditioning system of bromine refrigerators, find out the easy-to-freeze parts, take precautions in advance, and again operators should continuously improve their professional skills and strictly follow the operating procedures.