Manufacturing network flows: a generalized network flow model for manufacturing process modelling

Abstract It is essential for every company to know their business processes well, because these companies must allocate their resources in an efficient way in order to keep or strengthen their market position. During the research we aimed at optimizing the material flow at a wooden box producer company with the use of the generalized network flow model as this model is widely used for modelling production processes. In the first part of our work we calculated the optimal material flows focusing on two objectives, and in the second part we determined a compromise solution. Finally, we compared and evaluated the results of the three models.

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A Multiperiod Generalized Network Flow Model of the U.S. Integrated Energy System: Part I—Model Description

IEEE Transactions on Power Systems ◽

10.1109/tpwrs.2007.894844 ◽

2007 ◽

Vol 22 (2) ◽

pp. 829-836 ◽

Cited By ~ 136

Author(s):

Ana Quelhas ◽

Esteban Gil ◽

James D. McCalley ◽

Sarah M. Ryan

Keyword(s):

Network Flow ◽

Flow Model ◽

Energy System ◽

Model Description ◽

Network Flow Model ◽

Integrated Energy System ◽

System Part ◽

The U.S ◽

Generalized Network Flow

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Operation of a CCHP System Using an Optimal Energy Dispatch Algorithm

ASME 2008 2nd International Conference on Energy Sustainability, Volume 1 ◽

10.1115/es2008-54096 ◽

2008 ◽

Cited By ~ 4

Author(s):

Heejin Cho ◽

Sandra D. Eksioglu ◽

Rogelio Luck ◽

Louay M. Chamra

Keyword(s):

Energy Efficiency ◽

Energy Cost ◽

Network Flow ◽

Flow Model ◽

Energy Requirement ◽

Optimal Operation ◽

Operational Conditions ◽

Optimal Energy ◽

Network Flow Model ◽

The Cost

The Combined Cooling, Heating, and Power (CCHP) systems have been widely recognized as a key alternative for thermal and electric energy generation because of the outstanding energy efficiency, reduced environmental emissions, and relative independence from centralized power grids. Nevertheless, the total energy cost of CCHP systems can be highly dependent on the operation of individual components and load balancing. The latter refers to the process of fulfilling the thermal and electrical demand by partitioning or “balancing” the energy requirement between the available sources of energy supply. The energy cost can be optimized through an energy dispatch algorithm which provides operational/control signals for the optimal operation of the equipment. The algorithm provides optimal solutions on decisions regarding generating power locally or buying power from the grid. This paper presents an initial study on developing an optimal energy dispatch algorithm that minimizes the cost of energy (i.e., cost of electricity from the grid and cost of natural gas into the engine and boiler) based on energy efficiency constrains for each component. A deterministic network flow model of a typical CCHP system is developed as part of the algorithm. The advantage of using a network flow model is that the power flows and efficiency constraints throughout the CCHP components can be readily visualized to facilitate the interpretation of the results. A linear programming formulation of the network flow model is presented. In the algorithm, the inputs include the cost of the electricity and fuel and the constraints include the cooling, heating, and electric load demands and the efficiencies of the CCHP components. This algorithm has been used in simulations of several case studies on the operation of an existing micro-CHP system. Several scenarios with different operational conditions are presented in the paper to demonstrate the economical advantages resulting from optimal operation.

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