How Do You Measure Energy Conversion Efficiency?

[cedricuk]

TL;DR

What are the main challenges in measuring energy conversion efficiency in real-world systems?

Energy conversion looks straightforward in theory, but measuring efficiency in real systems can be challenging.

How do you account for energy converted into heat or other forms that are difficult to measure? Which instruments or experimental methods give the most reliable results?

I'd be interested in hearing practical examples from different areas of physics.

 

[mfb]

Usually you measure the input and the output. That way you don't have to measure every loss mechanism separately. But it really depends on the specific setup you are interested in.

 

[Baluncore]

That sounds like school or homework to me.

How do you account for energy converted into heat or other forms that are difficult to measure?

You do not.
You look at the total energy output in the form you require, and divide it by the total energy input.

 

[berkeman]

How do you account for energy converted into heat or other forms that are difficult to measure? Which instruments or experimental methods give the most reliable results?

Is this question in relation to your optical diffuser question from a day or two ago?

TL;DR: How does a frosted diffuser affect the amount and distribution of light passing through it?

I’m interested in the physics of light scattering in frosted plastic. Does a diffuser mainly redirect light, or does it also reduce the total light transmitted? How would its transmission be measured experimentally?

If it's a general energy conversion efficiency question, I can move this thread to our Thermodynamics Forum, which would be a better fit for the general question.