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Drastically increasing the efficiency of Ceiling Fans [50%] | Tech Ingredients (www.youtube.com)

submitted 3 weeks ago* (last edited 3 weeks ago) by ProdigalFrog@slrpnk.net to c/technology@slrpnk.net

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From a commenter under the video:

Summarized the measurements, with rough timestamps:

Stock blades (6:43): 1 m/s, 64.3 W,

simple airfoil (7:55): 0.8 m/s, 66 W

modern airfoil (9:12): 1.2 m/s, 64.5 W

stock motor no blades (13:49): 53.8 W

BLDC motor no blades (16:24): 8 W

BLDC stock blades (18:27): 1.8 m/s, 59 W

BLDC stock blades at reduced speed (19:35): 1.0 m/s, 27.3 W

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[–] The_Che_Banana@beehaw.org 7 points 3 weeks ago

Thanks for the summary, wish he would have had that during the vid

[–] m0darn@lemmy.ca 5 points 3 weeks ago

Interesting video, thanks for tabulating the data

I'm surprised he is measuring with the fan so close to the ground, with the electronics obstructing the fan downwash, with the anemometer so close to the fan, with the anemometer so close to the edge of the fan, and with the anemometer so irrepeatably placed...

I don't think he has accurately measured the efficiency of the induction motor (no load -> stock blades @ 1 m/s is a power change of 10.5 induction and 19.3 for bldc). He is pretty casual in his dismissal of the cost premium of bldc motors too.

[–] slippyferret@lemmy.blahaj.zone 4 points 3 weeks ago

I love the intro explaining that sweet spot between something you are interested in and something everyone is talking about. Great video!

[–] anothercatgirl@lemmy.blahaj.zone 3 points 3 weeks ago

the video fails to consider the effects of angle of attack on efficiency. Ideally, they would isolate the motor from the fan and measure the power in the shaft, using a torque sensor and some angular velocity data. That way, they can find an efficient fan blade and its optimal speeds separately from motor efficiency.

[–] keepthepace@slrpnk.net 3 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

BLDC motors, also called brushless, is the silent geeky revolution that brought us lighter, cheaper and more efficient robotics. It also allowed to make battery-powered electric version of many gardening equipment. More precisely, it is the design of cheap lighter controllers that made all of this possible (a good controller will require a fast-ish microcontroller on board)

Kind of a niche subject but happy to see it here!

[–] MysteriousSophon21@lemmy.world 1 points 1 day ago (1 children)

The energy efficiency difference is insane - 8W vs 53.8W at no load means BLDC motors use about 85% less power just to spin, which is why my electic bike can go so far on a single charge.

[–] keepthepace@slrpnk.net 1 points 17 hours ago

DC motors will tend to be optimal only at a set speed/torque whereas BLDC motors do need a microcontroller to be driven, but are able to optimize the flow in a much wider range. Coils in a DC motor are basically ON or OFF whereas they can ramp up in a BLDC depending on the speed.