Why is there a limit to the operating temperature of cooling fans? Part 2

3. Viscosity change of lubricating oil

The viscosity of lubricating oil in fan bearings changes at different temperatures. At low temperatures, the lubricating oil may become too viscous, leading to increased bearing friction and reduced fan speed. At high temperatures, the lubricating oil may become too thin, losing its lubricating effect and accelerating bearing wear. Typically, at -20°C, the viscosity of the lubricating oil is twice that at 20°C.

4. Air density and flow efficiency

Fans dissipate heat by moving air. As the temperature decreases, the density of air decreases, which reduces the airflow and heat dissipation efficiency of the fan. In low-temperature environments, fans may not provide sufficient cooling effect. At high temperatures, the heat capacity of air increases, and the fan requires more energy to move the same volume of hot air. For example, the density of air at 0°C is about 8% lower than at 40°C.

5. Tolerance of circuits and electronic components

Cooling fans contain circuits and electronic components, which have specific temperature tolerance ranges. Low temperatures may slow down the response speed of circuit components, while high temperatures may cause component performance to decline or even damage. For example, the response time of some semiconductor components at -40°C is 30% slower than at 25°C.