72
4 State of the Art
consideration of certain limitations (sub-section 3.1) and thus 86 papers for the
full-text review have been selected. Based on the selection process using the aforementioned search terms and key word combinations, the abstracts of the search
results have been read and refined by means of the following factors:
• The approach focuses on the increase of energy efficiency of production
processes by implementing process improvements rather than technological
innovations
• The approach considers energy consumption in an appropriate level of detail
• The approach considers simulation and/or optimization techniques
• The definition of system boundaries for the investigated scenarios is at least
on the level of a multi-step production machine
Research approaches that did not match these criteria based on their abstract have
not been considered for further investigation. Papers lacking information in the
abstract, have been taken into account for the full-text review and have been sorted out afterwards. The full-text-review again concluded that several publications
were not relevant for further investigations. This selection process resulted in the
consideration of 25 publications in total. All publications included in the literature
review have been analyzed regarding the key aspects of the study, grouped corresponding to the previously defined intersections from Figure 4.1 and evaluated
according to the group specific variables subsequently described.
4.1.2 Studies on the Optimization of the Energy Demand
in Production Systems
Optimization covers a wide range of problems, aiming at finding the optimal solution for a certain problem, whereas the complexity of the approach depends on
the objective function and constraints as well as on the design variables [Ya2018,
p. 5]. Several studies on optimization approaches in the context of improving
energy consumption of production processes can be found. Fulfilling the mentioned limitations for the paper selection process, seven research papers could
be identified as relevant for intersection I. The optimization approaches will be
shortly summarized in chronological order according to the year of publication.
Devoldere et al. analyze the energy consumption of production systems in
their different operating states in the fields of bending presses, milling, and laser
cutting machines. Besides the productive operating states, non-productive phases such as stand-by, set-up, and shut down times are considered. Aiming at the
4 State of the Art
consideration of certain limitations (sub-section 3.1) and thus 86 papers for the
full-text review have been selected. Based on the selection process using the aforementioned search terms and key word combinations, the abstracts of the search
results have been read and refined by means of the following factors:
• The approach focuses on the increase of energy efficiency of production
processes by implementing process improvements rather than technological
innovations
• The approach considers energy consumption in an appropriate level of detail
• The approach considers simulation and/or optimization techniques
• The definition of system boundaries for the investigated scenarios is at least
on the level of a multi-step production machine
Research approaches that did not match these criteria based on their abstract have
not been considered for further investigation. Papers lacking information in the
abstract, have been taken into account for the full-text review and have been sorted out afterwards. The full-text-review again concluded that several publications
were not relevant for further investigations. This selection process resulted in the
consideration of 25 publications in total. All publications included in the literature
review have been analyzed regarding the key aspects of the study, grouped corresponding to the previously defined intersections from Figure 4.1 and evaluated
according to the group specific variables subsequently described.
4.1.2 Studies on the Optimization of the Energy Demand
in Production Systems
Optimization covers a wide range of problems, aiming at finding the optimal solution for a certain problem, whereas the complexity of the approach depends on
the objective function and constraints as well as on the design variables [Ya2018,
p. 5]. Several studies on optimization approaches in the context of improving
energy consumption of production processes can be found. Fulfilling the mentioned limitations for the paper selection process, seven research papers could
be identified as relevant for intersection I. The optimization approaches will be
shortly summarized in chronological order according to the year of publication.
Devoldere et al. analyze the energy consumption of production systems in
their different operating states in the fields of bending presses, milling, and laser
cutting machines. Besides the productive operating states, non-productive phases such as stand-by, set-up, and shut down times are considered. Aiming at the