Fearless of the Cold—How to Choose Antifreeze for Environmental Test Equipment Winter Maintenance?

According to the Central Meteorological Observatory, a new wave of cold air is about to arrive around New Year’s Day 2024, so everyone should not be careless. After all, it’s a cold winter, especially in northern regions, where temperatures drop to -10°C in the morning and evening, and can even reach around -30°C~-40°C. Using environmental test equipment (test chambers) under these conditions is a huge challenge. Therefore, pay attention to daily maintenance during this period. One important task is to select the correct antifreeze for the chiller. So how should you choose antifreeze?

The only indicator is the freezing point of the antifreeze, which should be 5°C lower than the local winter low. Please see the chart below. Based on recent winter low temperature statistics from various provinces, cities, and autonomous regions, recommended antifreeze solutions for each region have been developed for your reference. Some provinces, cities (autonomous regions) have vast areas, with large temperature differences between mountainous and plain areas. When choosing antifreeze, please consider the city’s minimum winter temperature.

1. In areas where the winter minimum temperature is above 0°C, antifreeze is not recommended; purified water or distilled water can be used. For example, in Hainan and Guangdong, but in the mountainous areas of northern Guangdong’s Qingyuan and Shaoguan cities, temperatures occasionally drop below 0°C.
2. For winter lows below -10°C, such as in the Yellow River basin regions such as Shaanxi, Shanxi, Shandong, and Gansu, it is recommended to add antifreeze with a freezing point below -30°C.
3. In winter, when the minimum temperature is below -30°C, such as in the three northeastern provinces, Inner Mongolia, Xinjiang, and Tibet, it is recommended to use antifreeze with a freezing point of -40°C.

Other notes:

1. Since the cooling gas temperature is relatively high during product operation and the coolant storage container is not a completely sealed container, it is recommended to replace the coolant every 3-5 years and purified water every 2 years.
2. Antifreeze is a very mature industrial product; there’s no need to blindly trust big brands; genuine antifreeze purchased locally is sufficient.
3. If you cannot afford to buy ready-made antifreeze, you can also purchase pure ethylene glycol with over 95% purity, mix with water to make homemade antifreeze. However, you must strictly follow the proportion; too much ethylene glycol can actually lower the freezing point (see table below).

4. Although the freezing point of antifreeze products on the market is similar to those of self-formulated antifreeze, they have corrosion resistance and anti-scaling properties, so antifreeze products on the market are preferred.

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