A look at temperature controlled fans – Joe
SUMMARY: Temperature controlled fans with reasonable temperature range, low noise.
The good guys at Antec sent along two temperature controlled fans (SmartFan), 80 and 92mm models; a 120mm model is also available.
The advantage of temperature controlled fans is that they couple air flow to cooling requirements. The hotter the source, the faster the fans spin, increasing air flow. When you’re pushing things and heat is increasing, these fans spin up. At idle with lower heat output, they spin down. A tight coupling of air flow to heat production reduces overall noise (e.g., if you leave the PC on 24/7, it’s essential).
They use a small thermistor
mounted on the exhaust side of the fan. One thing I like about these fans is that the legs on the thermistor are long enough that you could clip it off, add extension wires and monitor temps closer to the source being cooled.
The temp range of these fans is quite nice:
I have some other 80 mm fans temp controlled fans and it takes something like 70C to get them moving – the Antec’s temp ranges are closer to what you might experience with case cooling or even CPU cooling. Temperature controlled fans such as these are nice upgrades to power supply fans – I have done this with good results.
With the Antec fans, you could move the thermistor to the PS heatsink for a more direct coupling of fan to heat source.
To test these out, I used a hair dryer to increase air temps. I placed a thermocouple next to the fan’s thermistor and, with the hair dryer running, monitored rpms using a motherboard’s fan header. Here’s where I ran into trouble:
At their lowest speed, these fans give spurious rpm readings – I had to divide by two or three to get a reading close to spec. There was no way the fans were spinning at the rpms indicated (would have been much noisier) For example, at 21C, the 92mm read 5273 rpm and the 80 mm 6136 rpm. As I increased temps, rpm readings bounced around but were much closer to spec.
Antec’s SmartFans can be nice additions to cooling solutions where noise is a concern.
Thanks again to Antec for sending this our way.
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