Causes and Countermeasures of Frozen Cracking of Water-cooled Surface Coolers in Air Conditioners in Winter Operation 2

3.3. If the air-conditioning system is small and the fresh air volume of the system is only a few hundred, a new air outlet can be installed on the fresh air pipeline, located on the pipe section of the air-conditioning room (if conditions permit, the air in the air-conditioning room is not polluted). ), and at the same time, a closed-type split multi-leaf regulating valve is installed in both of the new air outlets. In this way, when the air-conditioning system is operating in summer, one fresh air valve can be closed and another air valve can be opened; while in winter, the outdoor fresh air valve can be closed and the fresh air valve on the fresh air pipe section in the air conditioner room can be opened. For an air-conditioning room with heating, since the air in the room must be higher than the outdoor air temperature and higher than 0°C, the air in the air-conditioning room is used as fresh air to enter the air conditioner to avoid freezing of the water-cooled surface cooler in the air conditioner. bad phenomenon. When the outdoor air temperature is higher than 0°C, the fresh air vent on the fresh air duct section in the air conditioner room can be closed and the outdoor fresh air vent can be opened for operation.

3.4. At present, the fresh air and return air of some air conditioners enter in parallel, which is not conducive to the mixing of fresh and return air, especially in winter, it is easy to produce air stratification. Once the cold air at the bottom below 0°C passes through the surface cooler, the phenomenon of freezing of the water-cooled surface cooler may occur. Therefore, the fresh air and return air of the air conditioner are best to enter each other vertically.

At the same time, install the split multi-leaf regulating valve at the inlet of the new and return air. After the fresh air and return air pass through the fresh and return air mixing section and the primary filter section of the air, the mixing is relatively sufficient. At the same time, due to the small proportion of fresh air used by the air conditioning system during operation in winter, the temperature of the air after mixing is generally higher than 0 °C. For example, the winter temperature in an air-conditioned room is tN=18℃, the relative humidity is 50%, the outdoor fresh air temperature is tW=-10℃, the relative humidity is 25%, and the ratio of fresh and return air is 1:3. The dry bulb temperature of the air state point is much higher than 0°C, so that the phenomenon of freezing damage of the water-cooled surface cooler in the air conditioner can be avoided.

3.5. For an air-conditioning system that operates on a one-shift basis, during winter operation, when the system is shut down after get off work in the afternoon, the new, return air valve and air supply valve of the system must be closed to avoid the low temperature air entering the air conditioner due to the chimney effect. Water-cooled surface coolers freeze out. If necessary, open the inspection door on the fresh air section of the air conditioner, so that the air above 0°C in the air conditioner room with heating can enter the air conditioner. Or, after the air-conditioning system is stopped, the heat medium flow control valve installed at the inlet of the air heater is left with a certain degree of opening, so that a small amount of heat medium can still enter the air heater, so that it can dissipate heat into the air conditioner, so that the Keeping the temperature in the air conditioner always higher than 0°C can prevent the freezing damage of the water-cooled surface cooler.

Suzhou Pharma Machinery Co.,Ltd.

2022/09/29

Birkey