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Records with Subject: Process Operations
Showing records 1 to 25 of 139. [First] Page: 1 2 3 4 5 Last
Dry Mesophilic Anaerobic Digestion of Separately Collected Organic Fraction of Municipal Solid Waste: Two-Year Experience in an Industrial-Scale Plant
Adolfo Le Pera, Miriam Sellaro, Massimo Migliori, Micaela Bianco, Giuseppe Zanardi
October 12, 2022 (v1)
Keywords: biogas, biomethane, dry anaerobic digestion, industrial scale plant, organic waste, separately collected organic fraction of municipal solid waste
In this paper, performance analysis over two years’ operation of an industrial anaerobic digestion (AD) plant of a separately collected organic fraction of municipal solid waste is presented. The continuous plug-flow AD plant is still regularly operating and it has been fully operational since September 2018. Since then, it has been supplied with 40,000 t/y of pretreated separately collected organic fraction of municipal solid waste from municipalities of the Calabria region in Southern Italy. The AD process is carried out in a mesophilic regime at 40 ± 0.5 °C, using a constant hydraulic retention time (HRT) of 22 days and a substrate with average total solids and average total volatile solids of 30.0% and 22.2%, respectively. In the last two years, the plant produced an average of 191 m3 and 860 m3 of biogas per tonne (t) of organic input material and of total volatile solids, respectively, with an average methane specific production of 508 m3/t (total volatile solids). The average CH... [more]
GHG Emissions Reduction – Optimal Design and Operation of the Integrated Distributed Energy Systems Cross Different Energy Sectors
Ruonan Li, Vladimir Mahalec
October 6, 2022 (v1)
Keywords: Cross-sector integration, GHG emissions reduction, Optimal design and operation
This research seeks the opportunity to further reduce the minimum GHG emissions achieved by individu-ally operating energy systems in the civic, industrial, and transportation sectors through their integration. Each entity – buildings or industrial plants, is equipped with a set of combined cooling, heating, and pow-er (CCHP) system. At the same time, there is heat and electricity transfer among entities. The integration intends to solve the mismatch between the energy demand and energy provided by the CCHP system, which further increases the operation of the CCHP system and reduces GHG emissions of the entire sys-tem. This research introduces an optimization approach for identifying the optimal design and operation of the integrated system, which provides the maximum GHG emission reduction benefits (represented as GHG emissions reduction percentage (GHGD%)). Compared to existing studies on the integrated system, this research (1) differentiates the temperature of industrial heating de... [more]
Investigation of Electrochemical Processes in Solid Oxide Fuel Cells by Modified Levenberg−Marquardt Algorithm: A New Automatic Update Limit Strategy
Mark Žic, Iztok Fajfar, Vanja Subotić, Sergei Pereverzyev, Matevž Kunaver
January 24, 2022 (v1)
Keywords: automatic limit strategy, CNLS, LMA, off-limits, processes
Identification of ongoing processes in solid oxide fuel cells (SOFC) enables both optimizing the operating environment and prolonging the lifetime of SOFC. The Levenberg−Marquardt algorithm (LMA) is commonly used in the characterization of unknown electrochemical processes within SOFC by extracting equivalent electrical circuit (EEC) parameter values from electrochemical impedance spectroscopy (EIS) data. LMA is an iteration optimization algorithm regularly applied to solve complex nonlinear least square (CNLS) problems. The LMA convergence can be boosted by the application of an ordinary limit strategy, which avoids the occurrence of off-limit values during the fit. However, to additionally improve LMA descent properties and to discard the problem of a poor initial parameters choice, it is necessary to modify the ordinary limit strategy. In this work, we designed a new automatic update (i.e., adaptive) limit strategy whose purpose is to reduce the impact of a poor initial parameter ch... [more]
Dynamic Lifecycle Assessment of Solid Oxide Fuel Cell System Considering Long-Term Degradation Effects
Mina Naeini, James S. Cotton, Thomas A. Adams II
December 15, 2021 (v1)
Keywords: Environmental impacts, Life Cycle Analysis, Performance degradation, SOFC
The submission includes SimaPro project for LCA of SOFCs with 10-year replacement plan, a text file explaining how to run the SimaPro file, and SOFC inventory tables provided in an Excel file.
Constant Power Generation by Scheduling Installation of SOFC Modules Operating in Varying Power Mode
Mina Naeini, Thomas A Adams, James S Cotton
October 21, 2021 (v1)
Keywords: constant power output, optimal operating conditions, optimal operating mode, performance degradation, Solid Oxide Fuel Cells
In this paper, producing constant power load of 550 MW from systems of Solid Oxide Fuel Cells (SOFCs) operating in varying power output mode was investigated. This is useful because previous research has shown that individual cells can have significant lifetime extensions when operated according to certain dynamic trajectories in which power production decreases over time. In this study, we determined that a constant net power output of a system comprised of many individual SOFC modules can be achieved by scheduling the installation and operation of each SOFC module in a particular manner. All the modules were operated under the optimal operating conditions obtained in our previous optimization study where power output of each module declined over time. The dynamic degradation of SOFCs was taken into ac-count by using a detailed mathematical model of long-term performance degradation as a function of operating conditions. The result is a system in which every 5 days, one new SOFC modul... [more]
Optimization of an Inter-Plant Hydrogen Network: A Simultaneous Approach to Solving Multi-Period Optimization Problems
Rusong Han, Lixia Kang, Yinghua Jiang, Jing Wang, Yongzhong Liu
June 21, 2021 (v1)
Keywords: inter-plant, multi-period hydrogen network, simultaneous optimization approach, superstructure
Inter-plant hydrogen integration can reduce the consumption of hydrogen utility in petrochemical parks. However, the fluctuation of operating conditions will lead to complex multi-period problems of hydrogen network integration. This work develops a simultaneous optimization approach to solving multi-period optimization problems for the inter-plant hydrogen network. To do this, we consider the inter-plant hydrogen integration and the fluctuation of operating conditions in each plant at the same time, and aim to minimize the total annualized cost of the entire hydrogen system of all plants involved. An industrial case study of a three-plant hydrogen network with seven subperiods was adopted to verify the effectiveness of the proposed method. Results show that the optimal structure and the corresponding scheduling scheme can be obtained when the lowest cost of the system is targeted. Compared with the stepwise methods, the proposed approach features taking the characteristics of all subp... [more]
Comparing Reinforcement Learning Methods for Real-Time Optimization of a Chemical Process
Titus Quah, Derek Machalek, Kody M. Powell
June 2, 2021 (v1)
Keywords: artificial neural networks, Particle Swarm Optimization, process optimization, Proximal Policy Optimization, real-time optimization, reinforcement learning
One popular method for optimizing systems, referred to as ANN-PSO, uses an artificial neural network (ANN) to approximate the system and an optimization method like particle swarm optimization (PSO) to select inputs. However, with reinforcement learning developments, it is important to compare ANN-PSO to newer algorithms, like Proximal Policy Optimization (PPO). To investigate ANN-PSO’s and PPO’s performance and applicability, we compare their methodologies, apply them on steady-state economic optimization of a chemical process, and compare their results to a conventional first principles modeling with nonlinear programming (FP-NLP). Our results show that ANN-PSO and PPO achieve profits nearly as high as FP-NLP, but PPO achieves slightly higher profits compared to ANN-PSO. We also find PPO has the fastest computational times, 10 and 10,000 times faster than FP-NLP and ANN-PSO, respectively. However, PPO requires more training data than ANN-PSO to converge to an optimal policy. This cas... [more]
Rapid Multi-Objective Optimization of Periodically Operated Processes Based on the Computer-Aided Nonlinear Frequency Response Method
Luka A. Živković, Viktor Milić, Tanja Vidaković-Koch, Menka Petkovska
May 17, 2021 (v1)
Keywords: computer-aided nonlinear frequency response, cost–benefit indicator analysis, dynamic multi-objective optimization, forced periodic regime, Process Intensification
The dynamic optimization of promising forced periodic processes has always been limited by time-consuming and expensive numerical calculations. The Nonlinear Frequency Response (NFR) method removes these limitations by providing excellent estimates of any process performance criteria of interest. Recently, the NFR method evolved to the computer-aided NFR method (cNFR) through a user-friendly software application for the automatic derivation of the functions necessary to estimate process improvement. By combining the cNFR method with standard multi-objective optimization (MOO) techniques, we developed a unique cNFR−MOO methodology for the optimization of periodic operations in the frequency domain. Since the objective functions are defined with entirely algebraic expressions, the dynamic optimization of forced periodic operations is extraordinarily fast. All optimization parameters, i.e., the steady-state point and the forcing parameters (frequency, amplitudes, and phase difference), ar... [more]
Digital Twin for Lyophilization by Process Modeling in Manufacturing of Biologics
Leon S. Klepzig, Alex Juckers, Petra Knerr, Frank Harms, Jochen Strube
April 30, 2021 (v1)
Keywords: biologics, digital twin, lyophilization, manufacturing, model validation, Process Intensification, quality-by-design
Lyophilization stabilizes formulated biologics for storage, transport and application to patients. In process design and operation it is the link between downstream processing and with final formulation to fill and finish. Recent activities in Quality by Design (QbD) have resulted in approaches by regulatory authorities and the need to include Process Analytical Technology (PAT) tools. An approach is outlined to validate a predictive physical-chemical (rigorous) lyophilization process model to act quantitatively as a digital twin in order to allow accelerated process design by modeling and to further-on develop autonomous process optimization and control towards real time release testing. Antibody manufacturing is chosen as a typical example for actual biologics needs. Literature is reviewed and the presented procedure is exemplified to quantitatively and consistently validate the physical-chemical process model with aid of an experimental statistical DOE (design of experiments) in pil... [more]
Study on the Transient Characteristics of the Centrifugal Pump during the Startup Period with Assisted Valve
Qiao Li, Xiang Ma, Peng Wu, Shuai Yang, Bin Huang, Dazhuan Wu
April 27, 2021 (v1)
Keywords: centrifugal pump, numerical simulation, startup period, transient characteristics
The startup period, one of several transient operations in a centrifugal pump, takes note of some problems with these devices. Sometimes a transient high pressure and high flow rate over a very short period of time are required at the startup process. The pump’s dynamic response is delayed because of the rotational inertia of the pump and motor. Our research focuses on how to get a large flow in a short time when the pump cannot meet the requirements alone without a large power driver. To achieve a strong response in the startup process, a ball valve is installed downstream of the pump. The pump’s transient behavior during such transient operations is important and requires investigation. In this study, the external transient hydrodynamic performance and the internal flow of the pump during the transient startup period are studied by experiments and simulations. In order to find an appropriate matching method, different experiments were designed. The content and results of this paper a... [more]
Improvement of Energy Efficiency and Productivity in an Electric Arc Furnace through the Modification of Side-Wall Injector Systems
Yonmo Sung, Sangyoun Lee, Kyungmoon Han, Jaduck Koo, Seongjae Lee, Doyoung Jang, Changyong Oh, Byunghwa Jang
April 16, 2021 (v1)
Keywords: electric arc furnace, energy savings, Natural Gas, oxy-fuel burner, oxygen lancing, steelmaking
The energy cost of producing steel in an electric arc furnace (EAF) has a sizable influence on the prices of natural gas and electricity. Therefore, it is important to use these energies efficiently via a tailored oxy-fuel combustion burner and oxygen lance. In this study, an important modification of the side-wall injector system in the EAF at Hyundai Steel Incheon works was implemented to reduce electrical energy consumption and improve productivity. A protruding water-cooled copper jacket, including a newly designed burner, was developed to reduce the distance between the jet nozzle and the molten steel. In addition, the jet angles for the burner and lance were separately set for each scrap melting and refining mode. The modifications led to a reduction in electrical energy consumption of 5 kWh/t and an increase in productivity of approximately 3.1 t/h. Consequently, total energy cost savings of 0.3 USD/t and a corresponding annual cost savings of approximately 224,000 USD/year were... [more]
Potential Dynamics of CO2 Stream Composition and Mass Flow Rates in CCS Clusters
Sven-Lasse Kahlke, Martin Pumpa, Stefan Schütz, Alfons Kather, Heike Rütters
April 16, 2021 (v1)
Keywords: CCS, CO2 quality, energy mix, impurities, pipeline transport
Temporal variations in CO2 stream composition and mass flow rates may occur in a CO2 transport network, as well as further downstream when CO2 streams of different compositions and temporally variable mass flow rates are fed in. To assess the potential impacts of such variations on CO2 transport, injection, and storage, their characteristics must be known. We investigated variation characteristics in a scenario of a regional CO2 emitter cluster of seven fossil-fired power plants and four industrial plants that feed captured CO2 streams into a pipeline network. Variations of CO2 stream composition and mass flow rates in the pipelines were simulated using a network analysis tool. In addition, the potential effects of changes in the energy mix on resulting mass flow rates and CO2 stream compositions were investigated for two energy mix scenarios that consider higher shares of renewable energy sources or a replacement of lignite by hard coal and natural gas. While resulting maximum mass fl... [more]
Optimization Algorithm and Joint Simulation to Micro Thermal Deformation Using Temperature Measurement in the Orifice of Hydraulic Valve
Qianpeng Chen, Hong Ji, Hongke Zhao, Jing Zhao
March 14, 2021 (v1)
Keywords: hydraulic valve orifice, joint simulation, micro thermal deformation, optimization algorithm, temperature measurement
When exposed to viscous heating, hydraulic valve orifices experience thermal deformation, which causes spool clamping and actuator disorder. Quantitative research on thermal deformation can help reveal the micro-mechanism of spool clamping. In this study, miniature thermocouples are embedded into a valve orifice with an opening size of 1 mm to measure temperature distribution. An optimization algorithm based on measurement data (M-OA) for the thermal deformation of the valve orifice is proposed. The temperature and thermal deformation of the valve orifice are calculated through Fluent and Workbench joint simulation, with the measurement data serving as boundary conditions. Results show that, for a valve orifice with a valve wall length of 18 mm, when the temperature of the sharp edge is at 60 °C, thermal deformation measures 7.7 μm via observation and 7.62803 μm via M-OA, indicating that the M-OA method is reliable. The results of the joint simulation can be accepted because measuremen... [more]
Digital Twins in Pharmaceutical and Biopharmaceutical Manufacturing: A Literature Review
Yingjie Chen, Ou Yang, Chaitanya Sampat, Pooja Bhalode, Rohit Ramachandran, Marianthi Ierapetritou
February 22, 2021 (v1)
Keywords: biopharmaceutical manufacturing, digital twin, Industry 4.0, pharmaceutical manufacturing, process modeling
The development and application of emerging technologies of Industry 4.0 enable the realization of digital twins (DT), which facilitates the transformation of the manufacturing sector to a more agile and intelligent one. DTs are virtual constructs of physical systems that mirror the behavior and dynamics of such physical systems. A fully developed DT consists of physical components, virtual components, and information communications between the two. Integrated DTs are being applied in various processes and product industries. Although the pharmaceutical industry has evolved recently to adopt Quality-by-Design (QbD) initiatives and is undergoing a paradigm shift of digitalization to embrace Industry 4.0, there has not been a full DT application in pharmaceutical manufacturing. Therefore, there is a critical need to examine the progress of the pharmaceutical industry towards implementing DT solutions. The aim of this narrative literature review is to give an overview of the current statu... [more]
Optimization of CCUS Supply Chains for Some European Countries under the Uncertainty
Grazia Leonzio, Pier Ugo Foscolo, Edwin Zondervan
December 17, 2020 (v1)
Keywords: CCUS supply chain, mathematical model, Optimization, stochastic model
This paper develops a two-stage stochastic mixed integer linear programming model to optimize Carbon Capture, Utilization and Storage (CCUS) supply chains in Italy, Germany and the UK. Few works are present in the literature about this topic, thus this paper overcomes this limitation considering carbon supply chains producing different products. The objective of the numerical models is to minimize expected total costs, under the uncertainties of the production costs of carbon-dioxide-based compounds. Once carbon dioxide emissions that should be avoided are fixed, according to environmental protection requirements for each country, the optimal design of these supply chains is obtained finding the distribution of carbon dioxide captured between utilization and storage sections, the amount of different carbon-based products and the best connection between each element inside the system. The expected total costs for the CCUS supply chain of Italy, Germany and the UK are, respectively, 77.3... [more]
Single- and Multi-Objective Optimization of a Dual-Chamber Microbial Fuel Cell Operating in Continuous-Flow Mode at Steady State
Ibrahim M. Abu-Reesh
November 9, 2020 (v1)
Keywords: fmincon, fminimax, Matlab function, maximum current density, maximum power density, maximum substrate removal efficiency, multi-objective optimization, optimization of microbial fuel cells
Microbial fuel cells (MFCs) are a promising technology for bioenergy generation and wastewater treatment. Various parameters affect the performance of dual-chamber MFCs, such as substrate flow rate and concentration. Performance can be assessed by power density ( PD ), current density ( CD ) production, or substrate removal efficiency ( SRE ). In this study, a mathematical model-based optimization was used to optimize the performance of an MFC using single- and multi-objective optimization (MOO) methods. Matlab’s fmincon and fminimax functions were used to solve the nonlinear constrained equations for the single- and multi-objective optimization, respectively. The fminimax method minimizes the worst-case of the two conflicting objective functions. The single-objective optimization revealed that the maximum PD ,   CD , and SRE were 2.04 W/m2, 11.08 A/m2, and 73.6%, respectively. The substrate concentration and flow rate significantly impact... [more]
Prediction of Particle-Collection Efficiency for Vacuum-Blowing Cleaning System Based on Operational Conditions
Yuan Xi, Yan Dai, Xi–long Zhang, Xing Zhang
October 26, 2020 (v1)
Keywords: Computational Fluid Dynamics, operational condition, separation efficiency, uniform design, vacuum-blowing cleaning system
The dust-collection system, as the core of a sweeper vehicle, directly inhales dust particles on the pavement. The influence of variable operational conditions on particle-separation performance was investigated using computational fluid dynamics (CFD) Euler−Lagrange multiphase model. The particle-separation performance efficiency and retention time were used to evaluate the dust-collection efficiency. The uniform design (UD) and multiple regression analysis (MRA) methods were employed to predict and optimize the effects of reverse-blowing flow rate, pressure drop, and traveling speed on separation efficiency. The results indicated that the dust-collection performance initially increased and then decreased with increasing reverse-blowing flow rate. As the pressure drop increased, there was an increase in total dust-collection efficiency. However, the efficiency decreased with increasing traveling speed. The regression model showed that the proposed approach was able to predict the part... [more]
Mode-Based Analysis and Optimal Operation of MSF Desalination System
Hanhan Gao, Aipeng Jiang, Qiuyun Huang, Yudong Xia, Farong Gao, Jian Wang
October 26, 2020 (v1)
Keywords: first principle modeling, MSF, optimal operation, seawater desalination, Simulation
Multi-stage flash (MSF) desalination plays an important role in achieving large-scale fresh water driven by thermal energy. In this paper, based on first-principle modeling of a typical multi-stage flash desalination system, the effects of different operational parameters on system performance and operational optimization for cost saving were extensively studied. Firstly, the modelled desalination system was divided into flash chamber modules, brine heater modules, mixed modules and split modules, and based on energy and mass conservation laws the equations were formulated and put together to describe the whole process model. Then, with physical parameter calculation the whole process was simulated and analyzed on the platform of MATLAB, and the water production performance effected by operational parameters such as the feed temperature of seawater, the recycle brine from the discharge section, steam temperature and flowrate of recycled brine were discussed and analyzed. Then, the opti... [more]
Is Recycling Always the Best Option? Environmental Assessment of Recycling of Seashell as Aggregates in Noise Barriers
Begoña Peceño, Carlos Leiva, Bernabé Alonso-Fariñas, Alejandro Gallego-Schmid
October 26, 2020 (v1)
Keywords: circular economy, construction, environmental sustainability, life cycle assessment, mollusk shell, porous concrete
Waste recycling is an essential part of waste management. The concrete industry allows the use of large quantities of waste as a substitute for a conventional raw material without sacrificing the technical properties of the product. From a circular economy point of view, this is an excellent opportunity for waste recycling. Nevertheless, in some cases, the recycling process can be undesirable because it does not involve a net saving in resource consumption or other environmental impacts when compared to the conventional production process. In this study, the environmental performance of conventional absorption porous barriers, composed of 86 wt % of natural aggregates and 14 wt % cement, was compared with barriers composed of 80 wt % seashell waste and 20 wt % cement through an attributional cradle-to-grave life cycle assessment. The results show that, for the 11 environmental impact categories considered, the substitution of the natural aggregates with seashell waste involves higher e... [more]
Model-Based Process Optimization for the Production of Macrolactin D by Paenibacillus polymyxa
Dominik Krämer, Terrance Wilms, Rudibert King
October 6, 2020 (v1)
Keywords: Fermentation, multi-model approach, NIR spectroscopy, nonlinear state estimation, online optimization
In this study, we show the successful application of different model-based approaches for the maximizing of macrolactin D production by Paenibacillus polymyxa. After four initial cultivations, a family of nonlinear dynamic biological models was determined automatically and ranked by their respective Akaike Information Criterion (AIC). The best models were then used in a multi-model setup for robust product maximization. The experimental validation shows the highest product yield attained compared with the identification runs so far. In subsequent fermentations, the online measurements of CO2 concentration, base consumption, and near-infrared spectroscopy (NIR) were used for model improvement. After model extension using expert knowledge, a single superior model could be identified. Model-based state estimation with a sigma-point Kalman filter (SPKF) was based on online measurement data, and this improved model enabled nonlinear real-time product maximization. The optimization increased... [more]
Optimization and Selection of Maintenance Policies in an Electrical Gas Turbine Generator Based on the Hybrid Reliability-Centered Maintenance (RCM) Model
Moath Alrifaey, Tang Sai Hong, Azizan As’arry, Eris Elianddy Supeni, Chun Kit Ang
August 29, 2020 (v1)
Keywords: analytic network process (ANP), co-evolutionary multi-objective particle swarm optimization (CMPSO), developed maintenance decision tree (DMDT), failure modes (FMs), hybrid linguistic failure mode and effect analysis (HL-FMEA), oil and gas plant, Optimization, policy selection, reliability-centered maintenance (RCM)
The electrical generation industry is looking for techniques to precisely determine the proper maintenance policy and schedule of their assets. Reliability-centered maintenance (RCM) is a methodology for choosing what maintenance activities have to be performed to keep the asset working within its designed function. Current developments in RCM models are struggling to solve the drawbacks of traditional RCM with regards to optimization and strategy selection; for instance, traditional RCM handles each failure mode individually with a simple yes or no safety question in which question has the possibility of major error and missing the effect of a combinational failure mode. Hence, in the present study, a hybrid RCM model was proposed to fill these gaps and find the optimal maintenance policies and scheduling by a combination of hybrid linguistic-failure mode and effect analysis (HL-FMEA), the co-evolutionary multi-objective particle swarm optimization (CMPSO) algorithm, an analytic netwo... [more]
Real-Time Optimization of Pulp Mill Operations with Wood Moisture Content Variation
Wipawadee Nuengwang, Thongchai R. Srinophakun, Matthew J. Realff
August 5, 2020 (v1)
Keywords: moisture content of wood variation, pulp mill modeling, real-time optimization, rolling horizon approach
In tropical countries, such as Thailand, the variation of tree moisture content can be significant based on seasonal variations in rainfall. Pulp mill operation optimization accounting for wood moisture variation was used to determine optimal operation conditions and minimize production cost. The optimization models were built using empirical modeling techniques with simulated data from the IDEAS software package. Three case studies were performed. First, a base case of nominal annual operation at a fixed production rate was used to calculate production cost that varies with wood moisture content. The second case is annual optimization where production was allowed to vary monthly over an annual cycle to minimize production cost. For the third case, real-time optimization (RTO) was used to determine optimal production rate with the wood moisture content varying every 3 days. The rolling horizon approach was used to schedule production to keep inventory levels within bounds and with a pe... [more]
Industrial Processes Management for a Sustainable Society: Global Research Analysis
Emilio Abad-Segura, Manuel E. Morales, Francisco Joaquín Cortés-García, Luis Jesús Belmonte-Ureña
July 17, 2020 (v1)
Keywords: effective management, green technology, industry, scientific research, sustainable process, sustainable society
Few decades ago, the development of the industrial sector was disconnected from society’s protection. Negative effects awareness emerges from the current industrial processes through the Sustainable Development Goals (SDGs), considering the causal implications to build up a more sustainable society. The aim of this study is to analyze the state of the art in industrial processes management to obtain positive and sustainable effects on society. Thus, a bibliometric analysis of 1911 articles was set up during the 1988−2019 period, bringing up the authors’ productivity indicators in the scientific field, that is, journals, authors, research institutions, and countries. We have identified environmental management; the impact assessments of industrial processes on the environment and its relation with a more sustainable society; as well as the study of the sustainable management of water resources as the related axes in the study of environmental protection with political, economic, and edu... [more]
Performance Evaluation of Elimination of Stagnation of Solar Thermal Systems
Miroslav Rimar, Marcel Fedak, Jakub Vahovsky, Andrii Kulikov, Peter Oravec, Olha Kulikova, Michal Smajda, Miroslav Kana
July 17, 2020 (v1)
Keywords: energy performance, stagnation, thermal collector
The study deals with the possibility of elimination of stagnation of thermal systems. The state of stagnation of thermal systems leads to overheating and evaporation of the heat transfer medium, which increases pressure and can lead to damage to the solar thermal system. Stagnation can occur due to a fault and stopping of the circulation pump, which causes the circulation of the heat transfer medium to stop. Another possibility is to achieve thermal saturation in the system, which can be affected by low heat consumption from the system. Elimination of stagnation is possible by various construction designs of collectors or by using other technical means. This study describes an experiment verifying the usability of a thermal collector’s tilting system to eliminate thermal stagnation of the system. The system is fully automatic, and when recording the limit values, ensures that the panel is rotated out of the ideal position, thus reducing the amount of received energy. In this way, the t... [more]
Measuring the Implications of Sustainable Manufacturing in the Context of Industry 4.0
Larisa Ivascu
July 17, 2020 (v1)
Keywords: efficiency, implementation framework, Renewable and Sustainable Energy, scale development, sustainability strategy, sustainable process, sustainable supply chain management
Sustainability is increasingly being addressed globally. The manufacturing industry faces various constraints and opportunities related to sustainable development. Currently, there are few methodological frameworks for evaluating sustainable organizational development. Assessing and improving organizational capacity is important for producers and researchers in the field and local, national, and international authorities. This research proposes a hierarchical framework for sustainability assessment of manufacturing industry in Romania. The proposed framework integrates performance elements and measures to improve all the processes and activities from the triple perspective of sustainability. Sustainability assessment captures the entire supply chain of the organization, including stakeholder interests and end-of-life directions for products. To establish the elements to be integrated in the development of the proposed framework, market research (online questionnaire-for the characteriz... [more]
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