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Comment by Faaak | Hacker News Reader

A simple example I used recently in order to guesstimate how much energy is needed to heat 300liters of water by 5K:

  You have: 5K * 300kg * water_specificheat
  You want: kWh
  * 1.7433333

really easy to use.

How much power could you obtain with a small water turbine if you had 10m of head and 1l/s ? Easy !

  You have: 10m * 1kg/s * gravity
  You want: W
  * 98.0665

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Thanks, I did not know that units is able to work with constants. I always used Insect[0] for this.

0: https://github.com/sharkdp/insect

I do these kind of calculations all of the time and never realize units had this level of functionality. Wow, thanks Faaak!

I kept reading this as “water specific cheat” and was really confused.

~ units

586 units, 56 prefixes

You have: 50m * 1kg/s * gravity

unknown unit 'gravity'

how did you get gravity?

  $ units
  Currency exchange rates from FloatRates (USD base) on 2020-12-21
  3677 units, 109 prefixes, 114 nonlinear units
  
  You have: 10m * 1kg/s * gravity
  You want: W
          * 98.0665
          / 0.010197162
  You have:

You lack some units and prefixes.

How do you get the other units/prefixes?

EDIT: Figured it out, just had to brew install gnu-units

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