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Increase in energy efficiency and reduction in greenhouse gas (GHG) emissions in industry are important steps towards a more sustainable economy. Due to the growing share of high value-added industries, multi-period operation becomes more common in process industry. Therefore, retrofit of existing multi-period production plants is a key aspect towards more sustainable production processes. Hence, in this work, an existing two-level evolutionary algorithm using a genetic algorithm and a differential evolution for multi-period heat exchanger network retrofit is extended to consider GHG emissions as a second objective to the total annual cost (TAC). The multi-objective problem is addressed by incorporating a non-dominated sorting genetic algorithm (NSGA-II) and hypervolume indicators into the algorithm. By analyzing an industrial case study of a potato chips production, the results of the multi-objective optimization shows that GHG emissions can be reduced by 50%. However, compared to the single-objective optimization, TAC is increased by 27%. By selecting capital costs and operating costs as objectives instead, similar results to the single-objective optimization are achieved showing that the results are highly dependent on the selection of the objectives. Further, changes in utility costs and caused emissions have a high impact on the results., + ID der Publikation: hslu_103958 + Art des Beitrages: Wissenschaftliche Medien + Sprache: Englisch + Letzte Aktualisierung: 2024-04-17 15:58:39

Process heat electrification, energy efficiency improvement, and renewable technology integration are the most effective ways of achieving industrial decarbonization. However, precise knowledge of thermal energy demands and excess heat sources along with the corresponding temperature levels is imperative for the most optimum integration of aforementioned process. The current study presents a novel methodology for constructing sector-wide composite curves to accurately characterize the thermal energy demands and the available excess heat sources for the Swiss industry subsectors. The sector-wide energy demand profiles derived from this methodology offer valuable insights into the quantity of heat demand and the quality of the available excess heat. Thus, enabling the implementation of energy efficiency and decarbonization technologies such as heat pumps, and renewable heating and cooling technologies. The sector-wide energy demand profiles are built using Pinch Analyses and top-down statistical approach, thus ensuring complete sectoral coverage. The application of this novel approach is demonstrated using Swiss meat and chocolate industry subsectors as case studies. Based on the sector-wide energy demand profiles developed for meat and chocolate production, heat pump integration and solar thermal integration can potentially reduce about 80% of process heat demand, for both sectors., + ID der Publikation: hslu_103959 + Art des Beitrages: Wissenschaftliche Medien + Sprache: Englisch + Letzte Aktualisierung: 2024-04-23 13:39:33

This annex was originally suggested in 2008. Annex XV Task 1 was finalized in the spring 2015. From September 2016 to August 2018 Task 2 was successfully completed. Nevertheless, a number of further questions were identified which are to be tackled within the framework of this Annex - Task 3 (01.11.2019 to 31.10.2021). The Annex takes on a multi-disciplinary approach to the concept of excess heat recovery integrated in industrial complexes, aiming at the optimization of energy efficiency in global terms. The approach is based on industry needs and application, combining the knowledge of industrial technologies with energy efficiency and cost-effectiveness. The findings from Task 2 lead to a number of areas which resulted in this Task 3. Thus, the present Annex XV, Task 3 enabled to broaden the scope and included some new aspects, which may not be considered separately for changed framework conditions within an industrial environment. The included Subtasks were o Subtask 1: Combination of methods for excess heat identification and quantification o Subtask 2: Consequences for excess heat levels of future changes in industrial energy systems o Subtask 3: Operational aspects in industrial energy systems o Subtask 4: Opportunity and risk assessment for excess heat projects o Subtask 5: Compilation of innovative excess heat projects The achievements and results summarized in o a synthesis report on findings in the projects included in the Task as well as reported in literature, divided into the five subtasks, o a recommendation for further work internationally, o one report from each participant project (one or more per country), o Dissemination activities of each participating country. There have been in total 6 meetings in the task, including 5-day deep dive sessions for the individual Subtasks.

The challenge of heat exchanger network retrofit is often addressed using deterministic algorithms. However, the complexity of the retrofit problems, combined with multi-period operation, makes it very difficult to find any feasible solution. In contrast, stochastic algorithms are more likely to find feasible solutions in complex solution spaces. This work presents a customized evolutionary based optimization algorithm to address this challenge. The algorithm has two levels, whereby, a genetic algorithm optimizes the topology of the heat exchanger network on the top level. Based on the resulting topology, a differential evolution algorithm optimizes the heat loads of the heat exchangers in each operating period. The following bullet points highlight the customization of the algorithm: •The advantage of using both algorithms: the genetic algorithm is used for the topology optimization (discrete variables) and the differential evolution for the heat load optimization (continuous variables). •Penalizing and preserving strategies are used for constraint handling •The evaluation of the genetic algorithm is parallelized, meaning the differential evolution algorithm is performed on each chromosome parallel on multiple cores., + ID der Publikation: hslu_93764 + Art des Beitrages: Wissenschaftliche Medien + Jahrgang: 2022 + Sprache: Englisch + Letzte Aktualisierung: 2023-01-24 12:28:10

In Swiss process industry, process integration is often applied to retrofit existing plants with multi-period operation. Such periods may experience a high degree of variation in temperature or mass flow. Some process streams may not exist in every period or are soft streams. The resulting retrofitted network needs to be able to ensure feasible heat transfer in each period by the integration of mixer configurations to control the temperature. These attributes increase the complexity of the solution space. Hence, this work proposes an evolutionary two-level algorithm for heat exchanger network retrofit. Genetic algorithm is used for topology optimization and a differential evolution algorithm handles the heat loads. The algorithm is extended with practical constraints such as a maximum number of heat exchangers. Explicit mixer temperature calculations are implemented using the Lambert W-function. The algorithm was successfully applied to an industrial case study, reducing its total annual cost by approximately 66%., + ID der Publikation: hslu_93469 + Art des Beitrages: Wissenschaftliche Medien + Jahrgang: 2022 + Sprache: Englisch + Letzte Aktualisierung: 2022-10-26 17:30:39

Consulta en la Biblioteca ETSI Industriales (7985), [EN] The purpose of this study is to gain insight into the process of cooling of buildings with a standard installation. The relation between work and changes in entropy generation arise from the simultaneous treatment of the first and second laws referred as exergy (or available energy) analysis. In this study , it is discuss a thermodynamic analysis of the whole facility. A parametric study of each sub-system, in which the whole system is divided to, is carried out to determine the variation of the second law efficiency as a function of mass flow rate, relative humidity and temperature. An energetic analysis is also studied in addition to the irreversible losses, which are calculated by a further application of the second law, and it is double checked , by applying an exergy balance on each sub-system. The great importance of this exergy analysis is that it allows a direct comparison between different energy types (e.g. heat, electricity, fuel) on a common basis, and the concept of exergy consumption is useful for expressing how and where energy is dispersed in the course of the energy conversion and heat transfer steps. And this is one of the main goals of this study, to calculate the exergy flows of the system, and finally be able to draw the energy and exergy flow diagrams. The results show that most of the exergy losses take place in the refrigerant cycle and in the heat transfer through the heat exchangers. In addition the energetic parameters, the COP and the energetic efficiency is not as high as it could be. The common solution suggested to improve these two last parameters and decrease the exergy losses is to reduce the inner temperature lift in the refrigerant cycle.