Question

I need to find the energy efficiency of an elevator. I have found 2 energy efficiency equations on the internet but don't know which one to use. Could someone tell me which one to use?

Answer 1

I am not sure this is going to help but...

Explanation:

I am also not sure the kind of data you have but I would use:
`"efficiency"=P_("out")/P_("in")xx100%`
Where:
`P` is the power in Watts or `"joule"/"seconds"` that measures the transformation (or use) of energy (in Joules) at each second.
You basically consider the rate at which energy is "lost" during your transformation as a pecentage.
Let say that you get

`0.4xx100%=40%`: this tells us that your machine is delivering only `40%` of the energy per second it absorbs or if you give `100J` each second to the machine `60J` are "lost" each second.