Special Issue "Technical Aspects of Renewable Energy Sources (RES)"

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Energy Systems".

Deadline for manuscript submissions: 31 July 2021.

Special Issue Editors

Dr. Artur Wójcik
E-Mail Website
Guest Editor
Department of Mechanical Engineering and Agrophysics, University of Agriculture in Krakow, 30-149, Krakow, Poland
Interests: friction; mechanical properties of plant granular material; surface metrology
Dr. Marek Wróbel
E-Mail Website
Guest Editor
Department of Mechanical Engineering and Agrophysics, University of Agriculture in Krakow, 30-149, Krakow, Poland
Interests: biomass; biofuels; torrefaction; quality of biofuels; pressure agglomeration
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The 7th edition of the Renewable Energy Sources International Conference (ICORES2019) will be one of the most recognizable scientific meetings connected to RES in Poland. It will be held form 9 to 11 June, 2021. From the very beginning, this conference has been a unique occasion for gathering Polish and international researchers’ perspectives on renewable energy sources and balancing them against governmental policy considerations. Accordingly, the conference has also offered panels to discuss best practices and solutions with local entrepreneurs and federal government bodies. The meeting attracts not only scientists but also industry representatives, as well as local and federal government personnel. We are open to new and fresh ideas concerning renewable energy, which is why so many scientists from Central and Eastern Europe visit Krynica to discuss the “Green Future” of this region.

In 2021, the conference is organized by the University of Agriculture in Krakow, in cooperation with the AGH University of Science and Technology (Krakow), State Agrarian and Engineering University in Podilya, University of Žilina, International Commission of Agricultural and Biosystems Engineering (CIGR), and Polish Society of Agricultural Engineering.

Dr. Artur Wójcik
Dr. Marek Wróbel
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Solar energy
  • Geothermal energy
  • Biomass and biomass fuels
  • Combustion, co-combustion, and CHP in RES systems
  • Heat pumps
  • Wind energy
  • Fuel cell
  • Waste and heat
  • Modelling, simulation, and optimization of renewable energy systems
  • Advanced energy storage technologies
  • Politics and economics of renewable energy sources

Published Papers (4 papers)

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Research

Article
Optimisation of Energy Use in Bioethanol Production Using a Control Algorithm
Processes 2021, 9(2), 282; https://doi.org/10.3390/pr9020282 - 02 Feb 2021
Viewed by 415
Abstract
In this work, the possibility of limiting energy consumption in the manufacturing process of bioethanol to obtain biofuel was analysed. For this purpose, a control algorithm has been optimised while retaining the good quality of the control signals. New in this study is [...] Read more.
In this work, the possibility of limiting energy consumption in the manufacturing process of bioethanol to obtain biofuel was analysed. For this purpose, a control algorithm has been optimised while retaining the good quality of the control signals. New in this study is the correlation of the control algorithm not only with the signal’s quality, but also with the energy consumption in such an energy-intensive process as rectification. The rectification process in a periodic production system has been researched. The process was modelled on a test station with the distillation mixture capacity of 25 dm3. For the optimization, the following control algorithms have been applied: relay, PID and PID after modification to I-PD. The simulation was carried out on a transfer function model of the plant that has been verified on a real object, a rectification column. The simulations of energy consumption and control signal’s quality have been carried out in the Matlab®-Simulink environment after implementing the model of the research subject and control algorithms. In the simulation process, an interference signal with an amplitude of 3% and frequency of 2 mHz was used. The executed analyses of the control signal quality and the influence of the control algorithm on the energy consumption has shown some essential mutual relationships. The lowest energy consumption in the rectification process can be achieved using the I-PD controller—however, the signal quality deteriorates. The energy savings are slightly lower while using the PID controller, but the control signal quality improves significantly. From a practical point of view, in the considered problem the best control solution is the classic PID controller—the obtained energy effect was only slightly lower while retaining the good quality of the control signals. Full article
(This article belongs to the Special Issue Technical Aspects of Renewable Energy Sources (RES))
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Article
The Impact of Moisture and Number of Contact Points on the Process of Friction in Plant Granular Materials
Processes 2021, 9(2), 215; https://doi.org/10.3390/pr9020215 - 25 Jan 2021
Viewed by 346
Abstract
Friction occurs in the processes of transport and storage of granular plant materials used in the energy (RES—Renewable Energy Sources) and food sectors. This paper presents the results of a study on the impact of the moisture content of the material and the [...] Read more.
Friction occurs in the processes of transport and storage of granular plant materials used in the energy (RES—Renewable Energy Sources) and food sectors. This paper presents the results of a study on the impact of the moisture content of the material and the number of its contact points with a smooth surface (a steel sheet) on the process of friction in grains of wheat and buckwheat. The friction process was studied for four different levels of moisture (9.5%, 13.5%, 17.5% and 21.5%) and three different average numbers of contact points. To measure the force of friction, an universal testing machine with appropriate instrumentation was used. To determine the number of contact points, computer imaging analysis was conducted. An increase in static and kinetic friction was observed along with the increase in moisture level and the increase in the number of contact points. Correlation and regression analysis was performed for the data obtained. Full article
(This article belongs to the Special Issue Technical Aspects of Renewable Energy Sources (RES))
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Article
Optimisation of the Geometric Parameters of Longitudinally Finned Air Cooler Tubes Operating in Mixed Convection Conditions
Processes 2021, 9(1), 111; https://doi.org/10.3390/pr9010111 - 07 Jan 2021
Viewed by 307
Abstract
The results of optimisation calculations presented in the article are related to longitudinally finned tubes of a heat pump evaporator operating under natural wind-induced flow of outdoor air conditions. The finned surface is characterised by an unusual, wavy fin shape. The article presents [...] Read more.
The results of optimisation calculations presented in the article are related to longitudinally finned tubes of a heat pump evaporator operating under natural wind-induced flow of outdoor air conditions. The finned surface is characterised by an unusual, wavy fin shape. The article presents the methodology applied to seeking optimal geometric parameters of the finned tube in which thermal calculations were performed by modelling a mixed convection process on the finned surface using the finite volume method. In the case of maximising the heat flow with the minimum mass of the fins, the optimal solution was dominated by the minimum mass of the fins and thus geometric parameters correspond to the number of fins n = 6, fin height h = 0.065 and fin thickness s = 0.0015 m. Optimisation calculations made for maximum efficiency of the exchanger at constant mass indicated that the tube with ten fins (n = 10) with a height of h = 0.11 m and a thickness of s = 0.0018 m allowed maximum heat flow at the assumed mass of the fins in the exchanger tube model. The article proposes a simplified method of determining the optimal geometric parameters of the profile for any mass and maximum thermal efficiency. Full article
(This article belongs to the Special Issue Technical Aspects of Renewable Energy Sources (RES))
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Article
A Model of Transport of Particulate Biomass in a Stream of Fluid
Processes 2021, 9(1), 5; https://doi.org/10.3390/pr9010005 - 22 Dec 2020
Viewed by 415
Abstract
The motion of a solid particle introduced into a stream of fluid is a crucial problem in the contexts of pneumatic transport and the purification and separation of non-uniform mixtures. However, the complexity of the underlying equations of motion enforces the creation of [...] Read more.
The motion of a solid particle introduced into a stream of fluid is a crucial problem in the contexts of pneumatic transport and the purification and separation of non-uniform mixtures. However, the complexity of the underlying equations of motion enforces the creation of semi-empirical models. Therefore, analysis of particle motion in a pneumatic channel was performed. To reduce the number of independent variables, several simplifying assumptions were made in regard to both the particle and the stream. The resulting model provides trajectory equations for a particle introduced into the stream at given values of the initial angle and initial velocity, which are then solved using numerical integration methods. A hodograph function was formulated on the basis of the Runge–Kutta and NDFs methods to test the correctness of the solutions under various initial parameters and to provide a universal method of solving the equations of motion. To verify the model, terminal velocities were measured and particle trajectories recorded using an original experimental stand. The predictions of the model were subsequently compared to these empirical trajectories and were found to fall within the range of uncertainty. Full article
(This article belongs to the Special Issue Technical Aspects of Renewable Energy Sources (RES))
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