Search

Investments in the development of the district heating system require a thorough analysis of the technical, economic, and legal aspects. Regarding the technical and economic context, a mathematical model of the district heating system has been proposed. It optimizes both the technical and economic aspects of the function and development of a district heating system. To deal with non-linearities, the developed linear programming model is divided into three phases: flow, thermal, and pressure. Therein, non-linear dependencies are calculated between the linear optimization phases. This paper presents the main assumptions and equations that were used to calculate the parameters of the heating system, along with the optimal level of heat production, the flow rate of the heating medium in the heat nodes and edges of the network graph, the heat, power, and temperature losses at each edge, and the purchase costs of heat and its transmission. The operation of the model was tested on a real-world district heating system. The case study results confirm that the model is effective and can be used in decision support. The economic results of the model, before the calibration process, were 3.6% different from historical values. After the calibration process, they were very similar to the real data—all percentage deviations were within 1%. [ABSTRACT FROM AUTHOR]

In recent years, a growing number of enterprises have taken different steps to reduce the energy consumption and carbon emissions of information and communication technology (ICT) assets. Because of the expansion of digitalization and the need for rapid access to information, enterprises have been compelled to optimize the location and utilization of their ICT hardware. In this context, this paper presents a novel method based on a mixed-integer linear programming approach for optimizing the physical location and task allocation of printing devices in office floor plans considering the power usage of the ICT assets, the costs related to the purchase and service of the individual devices, operating costs, and distance between employees and printing devices. The applicability of the proposed model is illustrated using the case study of a company with 100 functional departments located in several office buildings across Poland. The results reveal that the model guarantees the execution of all printing tasks and satisfies the functionality requirements expressed by the users of the workstations. Moreover, the selection of more energy-efficient printing devices leads to a considerable reduction in electricity consumption, related not only to the direct operation of these devices but also to their modes of operation (work, idle, or sleep). Such results also bring tangible effects in reducing carbon dioxide emissions, which is particularly important for businesses operating in countries where fossil fuels still dominate the energy mix. [ABSTRACT FROM AUTHOR]

The delivery of natural gas to consumers requires significant infrastructure that consists of numerous technical units and other gas transmission assets. The failure of a single component in a gas transmission and distribution network might compromise the reliability of the gas supply system. Thus, the proper location of facilities for employees and contractors performing inspections and maintenance activities is of critical importance for the uninterrupted operation of a natural gas network. In this context, this study addresses the problem of identifying the optimal location of gas network maintenance centres (GNMCs) in a natural gas transmission company which is actively seeking to improve its maintenance and service response times while minimising costs. In an effort to determine the optimal number of GNMCs required to maintain assets in areas covered by the company, a decision-support tool based on a mixed-integer linear programming approach (MILP) is proposed. The tool is applied to the case study of a natural gas transmission company operating in central Poland. The case study is extended to explore four alternative scenarios which illustrate the additional functionalities of the proposed model. The model results indicate that the total system cost of the gas network maintenance infrastructure can be reduced by up to 13% with the operation of only two out of five existing GNMCs and one candidate facility. The results also demonstrate the versatility of the optimisation model since it enables decision-makers to evaluate the effects of changing maintenance strategies. • A model for the optimal location of gas network maintenance centres is proposed. • The case study of a natural gas transmission company operating in Poland is presented. • A scenario analysis of different organisational structures is performed. • Efficient assignment of GNMCs to gas transmission assets or stations. [ABSTRACT FROM AUTHOR]