Calculation of the efficiency simply explained

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When it comes to calculating the efficiency, what is meant is the ratio of the energy used to the energy used. That sounds more complicated than it is, the calculation is quite simple.

Efficiency demonstration
Efficiency demonstration

That is the efficiency

For the calculation of the efficiency, it is advantageous if you know some relationships and understand certain physical terms correctly:

  1. Energy is a fundamental quantity that is used in many areas such as physics, biology, Technology, chemistry and business plays a central role. If you look at the interrelationships, the degree of efficiency is easier to understand.
  2. Energy can exist in different forms and can be converted from one form to another. Take a rubber ball and drop it from a height of 1 m. Keep in mind the energy the ball originally had and how the forms of energy change.
  3. As long as you hold the ball at a height of 1 m, it has the potential energy of position E.pot = m g h, the unit is m [kg] g [m / s2] h [m] = m g h [kg m2/ s2 = Nm]. The kinetic energy of the ball is 0 because it does not move.
  4. When you let go of the ball, the energy of the posture decreases because the ball falls down, but it gets faster and faster. If he's dropped that one meter, he'll only have kinetic energy - E.kin = 0.5 m f2.
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  5. As soon as the ball touches the ground, it is deformed, it dents in and out again. The kinetic energy is converted into deformation energy when the ball is dented and the deformation energy is converted back into kinetic energy when the ball is dented again.
  6. Now the ball bounces up again, whereby the kinetic energy is converted back into potential energy.
  7. The ball would have to arrive again at a height of 1 m. I am sure you know that this is not the case. This is due to the fact that part of the energy is withdrawn as thermal energy from this system cycle, or that deformations can no longer be completely reversed. This apparent loss of energy is the basis for the fact that you can never draw the same amount of power as you put into it.
  8. The ratio between the energy resp. Achievement You get referred to in relation to what you have to use.

Calculation of power losses

  • To stay with the example of the ball: in order to keep the ball at a height of 1 m, you need a power of Pin = E / t apply = m [kg] g [m / s2] 1 [m] = 1 m g [kg m2/ s2], if the ball only arrives at a height of 80 cm after the process, then you now have the power of Pthe end= m [kg] g [m / s2] 0.8 [m] = 0.8 m g [kg m2/ s2]. If you now Pthe end by Pin share, you get the efficiency. P.the end/ Pin = 0,8/1 = 0,8.
  • For the calculation of the efficiency, it does not matter which state changes take place or which energies are converted into which. For example, you can use electrical energy to pump water upwards (convert electrical energy into potential) or set something in motion (convert into kinetic energy). You always have to put the power used in relation to the power output if you want to calculate the efficiency.

You have to note that every service can always be traced back to the basic units of mass, length and time. For electrical energy For example, 1 Ws = 1 J = 1 Nm = 1 kg m2/ s2.

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