In winter, we not only need to protect ourselves from the cold and keep warm, but as refrigeration workers, we also have to “love and maintain” our refrigeration equipment, especially in the cold north. We must pay attention to the central air-conditioning and take precautions against the cold, especially in shopping malls, manufacturing enterprises, and hotels. Commercial central air conditioners such as large-scale venues need more antifreeze, so how to prevent freezing, and what measures are there for antifreezing?
1. Host antifreeze
Close the inlet and outlet valves of the host condenser or evaporator, open the drain valve and vent valve, and then use compressed air to blow off the remaining water.
2. Water pump antifreeze
Close the inlet and outlet valves of the refrigerant water pump, open the drain valve and vent valve of the water pump, and drain the water. Open the valve at the lowest point of the cooling water system, drain the cooling water, and open the drain valve of the water pump. After the system water is drained, in order to prevent rainwater from entering the cooling tower, close the main water outlet valve of the cooling tower, and open the drain valve of the cooling tower water collecting pan , so that the rainwater is drained from the drain valve in time.
3. Antifreeze of cooling tower water supply pipe
In general, the water supply pipe of the cooling tower is exposed to the outside, and most designers use heat preservation to prevent freezing. However, in actual use, even with heat preservation, frost damage often occurs.
In order to solve this problem, when the water supply pipe of the cooling tower is connected from the room, a valve is added, and a water discharge valve is added at the lowest point of the water supply pipe. When winter comes, the indoor valve is closed, and the lowest point water release valve is opened to exhaust the water in the outdoor pipe, so that the pipe does not need to be kept warm and will not be cracked by freezing.
4. Antifreeze of the expansion tank
The expansion tank is generally installed on the roof or in the equipment room on the top floor. Although the expansion tank is insulated on the outside and has a circulation pipe, in actual use, the circulation pipe is rarely able to circulate, that is, there is a problem in the expansion tank in winter. If the water is in a low temperature environment for a long time, it will be frozen even though it is kept warm, and the expansion tank will not expand if it is frozen, and the temperature in the system will increase, and the pressure will increase.
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. (This article comes from the WeChat official account of Baijia Refrigeration) 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 tank, which can keep the expansion tank intact for a long time after the pump is stopped. freeze.
5. Fresh air system antifreeze
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 surface cooler of the fresh air unit is directly in contact with the cold outside air. In order to prevent the surface cooler from being damaged by freezing when the heating is stopped , An electric multi-leaf regulating valve should be added at the fresh air inlet, and it should be 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, which 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. surface cooler.
6. Add antifreeze
In winter, when it is inconvenient for the unit to discharge water and drain the water and the power may be cut off, antifreeze must be added for heating of the equipment, and the minimum local temperature must be used as an important parameter for selecting antifreeze.
The main component of the antifreeze is ethylene glycol. The antifreeze is poured in from the replenishing water tank. After the frozen water in the water system is discharged, the antifreeze stock solution is injected first, and the frozen water is injected if it is not enough, and then the water pump is turned on to make the antifreeze and water fully Fusion, by the way, all the air in the water system should be discharged. The water system should not have air. The presence of air will cause the air conditioner to report to the water flow switch for protection, and it is easy to form cavitation.
7. All refrigeration pipes are insulated
The main purpose of chilled water pipe insulation is to prevent condensation on the outside of the pipe, and another function is to prevent the water in the pipe from freezing. The thickness of the insulation layer is generally more than 20mm.
In addition, an electric heating cable should be wound on the outside of the water pipe. As long as the heating cable is powered, it can continue to heat the pipe. The temperature of the water in the pipeline is above 10°C. Freezing leads to water shortage protection of the hot water machine. The heating cable should be selected with a temperature limiter, just keep a certain temperature.
Post time: Jan-09-2023
