How thermo-electric effect reduces fan noise without compromising cooling

In a conventional air cooling unit (Figure 2), the CPU is in direct contact with the heat sink. If fan speed is reduced, the heat sink, and therefore the CPU, will become hotter.

In contrast, in a thermo-electric cooling unit (Figure 1), the CPU is isolated from the heat sink by the thermo-electric unit (a solid-state heat pump). If fan speed is reduced, the heat sink will become hotter. But the thermo-electric unit is a heat pump and can maintain a large temperature difference between the CPU and the heatsink. Even if the heatsink is hot, the thermo-electric unit can be kept cold, allowing the fan to work at minimum speed. Noise can be reduced while maintaining the same level of cooling of the CPU. This is not possible with conventional air cooling.
Figure 1
Figure 2

In a conventional cooling system, when the fan voltage and, therefore, noise is reduced (Graph 2), the heat sink temperature immediately increases (Graph 4). At the same time, the temperature of the CPU will increase accordingly (Graph 6).

In a thermo-electric cooling system, when the fan voltage and, therefore, noise is reduced (Graph 1), the heat sink temperature increases (Graph 3), but the CPU temperature is not necessarily affected. By pumping more heat from the cold plate to the heat sink, the thermo-electric unit keeps the temperature of the cold plate and CPU low (Graph 5). Using Active Cool thermo-electric technology, computer noise can be reduced without compromising cooling.

Active (thermo-electric cooling)
Conventional (air) cooling

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