52
3 Energy
The general understanding of the energetic correlations in manufacturing companies is necessary to be able to model, simulate, and optimize the energy
consumption of a production system. The focus of this thesis is centered on the
optimization of the use of electric energy in the main production processes. Peripheral processes, which are not directly linked to the production, e.g., heating,
lighting, ventilation, and climate control of offices, are not considered in this
book 7 .
Besides the general overview of energetic correlations in production, the consideration of the energy consumption behavior of production machines is required.
The consumption behavior of machines in industry is usually not constant but
highly dynamical depending on the current operating state of the machine.
Machine processes are built of several energy consuming process steps causing a
specific electrical load profile when the machine is in an operating state. By classifying different operational machine states, the definition of load profiles becomes
possible. Generally, the following operating states can be found in literature
[We2010, p. 62; Be+2011, p. 1063; Th2012, p. 21]:
• OFF—no energy consumption, the main switch is off
• WARMUP—energy use for start-up process after machine has been switched
off or remained in standby, often causes a peak demand
• IDLE—relatively constant energy use after completed start-up
• SETUP—positioning and loading before actual processing
• PROCESSING/PRODUCING—actual production process is running
• STANDBY—machine has a reduced consumption rate
• FAILURE—the failure state generally also consumes energy
Operational machine states can be divided into time-constant and time-variable
machine states. While the machine undergoes a technically necessary and timed
start-up plan at time-constant conditions, such as a machine startup after off-mode,
the retention time and the energy requirement of a machine in a time-variable
machine state, such as the producing state, are dependent on the production task
[We2010, p. 61]. While the time-constant states are usually technically necessary,
the time-varying states can be differentiated into value-adding and non-valueadding machine states (Figure 3.9).
7 The reason for this lies in the height of the actual share of total energy consumption, which is
usually only between two and 20 percent depending on the production machine. The majority
is thus attributable to the production machine itself [Mü+2009, p. 26].
3 Energy
The general understanding of the energetic correlations in manufacturing companies is necessary to be able to model, simulate, and optimize the energy
consumption of a production system. The focus of this thesis is centered on the
optimization of the use of electric energy in the main production processes. Peripheral processes, which are not directly linked to the production, e.g., heating,
lighting, ventilation, and climate control of offices, are not considered in this
book 7 .
Besides the general overview of energetic correlations in production, the consideration of the energy consumption behavior of production machines is required.
The consumption behavior of machines in industry is usually not constant but
highly dynamical depending on the current operating state of the machine.
Machine processes are built of several energy consuming process steps causing a
specific electrical load profile when the machine is in an operating state. By classifying different operational machine states, the definition of load profiles becomes
possible. Generally, the following operating states can be found in literature
[We2010, p. 62; Be+2011, p. 1063; Th2012, p. 21]:
• OFF—no energy consumption, the main switch is off
• WARMUP—energy use for start-up process after machine has been switched
off or remained in standby, often causes a peak demand
• IDLE—relatively constant energy use after completed start-up
• SETUP—positioning and loading before actual processing
• PROCESSING/PRODUCING—actual production process is running
• STANDBY—machine has a reduced consumption rate
• FAILURE—the failure state generally also consumes energy
Operational machine states can be divided into time-constant and time-variable
machine states. While the machine undergoes a technically necessary and timed
start-up plan at time-constant conditions, such as a machine startup after off-mode,
the retention time and the energy requirement of a machine in a time-variable
machine state, such as the producing state, are dependent on the production task
[We2010, p. 61]. While the time-constant states are usually technically necessary,
the time-varying states can be differentiated into value-adding and non-valueadding machine states (Figure 3.9).
7 The reason for this lies in the height of the actual share of total energy consumption, which is
usually only between two and 20 percent depending on the production machine. The majority
is thus attributable to the production machine itself [Mü+2009, p. 26].