3.2 The Concept of Energy
47
Figure 3.6 Energy balance. Adapted from [Pe2010b, p. 22]
• dissipation due to missing energy recovery
• operation mode of machines by workers
• efficiency losses/ conversion losses
• losses due to wrong energy acquisition type.
One of the most important forms of energy used in industrial production is electrical energy. It is a high-quality exergy that can be converted into almost all other
forms of energy. The working capacity of electrical energy is based on moving
electric charges and their electric and magnetic fields. While negatively charged electrons and anions repeal each other due to the same charge, they attract
positively charged protons and cations. Electric charges generate electric fields,
moving electric charges additionally generate magnetic fields [Mü+2009, p. 83].
The electrical work W is determined, calculating the integral over the current
power P. Thus, the current value of the power is always time-dependent [Bö2013,
p. 769]:
W =
t 2
t 1
P dt
(3.10)
The current power in the direct current circuit is defined as the product of
voltage U and current I [Bö2013, p. 310]: