
Understanding and Measuring Vitamix Horsepower - nkurz
http://joyofblending.com/vitamix-horsepower/
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nkurz
To me, the most interesting statistic in the article is that the overall
efficiency of heating water with a Vitamix blender is 68-69%. That is, more
than 2/3 of the input wattage coming from the wall goes to heating the mixture
being blended. The overall efficiency of heating a cup of water in a microwave
oven, by contrast, is usually less than 50%.[1]

I find that to be a remarkably high efficiency. It's obviously less efficient
than an immersion resistance heater (100% efficiency since all the "waste"
heat is absorbed), but I wouldn't have guessed that the high speed motor would
be that efficient in converting electricity into rotational motion.

[1] Tom Murphy measures 43% for a microwave oven here (as well as figures for
other approaches): [http://physics.ucsd.edu/do-the-math/2012/05/burning-
desire-f...](http://physics.ucsd.edu/do-the-math/2012/05/burning-desire-for-
efficiency/)

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randomstring
OK, now I want to try boiling water with my Vitamix.

As an added bonus, after 11.5 minutes of listening to a Vitamix on high, you
won't need that cup of coffee to wake up.

~~~
zaqwsxwsxzaq
I know! Holy shit, I did not know that you could boil water purely by means of
subjecting it to the motion induced by a blender.

 _Update:_ from the sound of things, it's the action of the blades and the
friction induced by their interaction with the water[1], rather than the
swirling motion of the water itself, which sounded kind of ridiculous.

[1]
[http://frozendrink.com/vitamix/household.html](http://frozendrink.com/vitamix/household.html)

~~~
arcticsilo
There's blade-water friction as well as water-water friction. The link you
provided does not quantify their relative contributions. [edit: Actually, I'm
not even sure how much blade-water friction there is, due to the boundary
layer effect.]

There is also heating from cavitation bubbles collapsing in the water. If you
look up cavitation heaters you will find a wacky rabbit hole with
unsubstantiated claims about achieving heating efficiencies over unity.
However, apparently there are some industrial processes that benefit from
cavitation heating by getting even liquid heating and avoiding heating
elements that can develop scaling. More info:
[http://hydrodynamics.com/cavitation-technology/scale-free-
he...](http://hydrodynamics.com/cavitation-technology/scale-free-heating/)

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stcredzero
_Indeed, in the early days, horsepower was used to describe how many draft
horses a steam engine could replace._

Is this an example of engineering marketing? Probably:
[https://en.wikipedia.org/wiki/Horsepower#History_of_the_unit](https://en.wikipedia.org/wiki/Horsepower#History_of_the_unit)

