Technical Economic Aspects Research Articles

Design for Manufacturing and Assembly Optimization of Home-Scale Biodigester-Composter Using VDI 2222 and Finite Element Analysis Methods

This research focused on the Design for Manufacturing and Assembly (DFMA) optimization of home-scale biodigester-composter machines. The aims to determine feasibility from technical-economic aspects. The technique was to design the machine's mechanical process, physical, and constituent components. There are two methods conducted on this research, VDI 2222 to optimize and Finite Element Analysis (FEA) to assess the optimal quality results of the machine design based on simulation analysis. This research ended with making a physical prototype of a home-scale biodigester-composter machine using the optimal design, then validating it with a working test of the machine. The results of the VDI 2222 method show an optimal design concept through the structure of the working mechanism. All its constituent components match with the ten target specifications and the machine manufacturing cost of IDR 2,393,000, as well as the assembly chart design for each constituent component. These results are also evaluated using the FEA method. The resistance value of the frame system to maximum Von Mises Stress is obtained at 128.75 MPa with a minimum value of 6.93e-04 MPa. It is concluded to be acceptable at withstanding normal and shear stresses effectively with a relatively small displacement value of 0 to 0.47 mm. The equivalent strain value results are 3.89e-09 ul to 5.83e-04 ul and safety factor value results are 1.93 to 15 ul. It can be concluded that the frame system design concept is safe.

Design of an electrical drive for motorized bicycles

The aim of this work is the design of an electrical drive for a motorized bicycle, characterised by new solutions for the control method and the regenerative braking system. A dynamic model of the vehicle has been realised, and the characteristics of the drive have been individuated. An effective closed-loop control strategy has been studied, adjusting the motor torque and the current in order to increase the availability range. Finally, a feasibility study of a regenerative braking system based on the supercapacitor technology has been carried out. All the components of the drive have been selected among the models available on the market. In the paper the results of the simulations are presented and other technical-economical aspects such as energy consumption and costs are also briefly discussed.

ВНЕДРЕНИЕ ИННОВАЦИОННЫХ ТЕХНОЛОГИЙ РАСПРЕДЕЛЕННОЙ ГЕНЕРАЦИИ В ТРУДНОДОСТУПНЫХ И ИЗОЛИРОВАННЫХ РАЙОНАХ

The article presents an analysis of the opportunities for implementing innovative distributed generation technologies in hard-to-reach and isolated regions, with a focus on the territories of Yakutia. Special attention is paid to the assessment of economic efficiency and technical-economic aspects of using various types of energy facilities, including small nuclear power stations and renewable energy sources. The research is supported by a multi-criteria analysis, where the key indicator is the levelized cost of electricity (LCOE). The primary task of the study is to identify the most effective and economically justified technologies for use under conditions of limited resource availability and high transportation costs. Modern trends and projects related to small nuclear power plants have been analyzed, as well as the possibilities and prospects of using hybrid systems that combine various energy sources. It was found that small nuclear stations are of significant interest due to their ability to generate a large amount of energy at relatively low operational costs compared to other alternatives. The potential for using wind and solar energy, particularly relevant for regions with limited traditional energy resources, was also considered. The article conducts a comparative analysis of the LCOE for different types of power-generating installations, highlighting the most promising options for specific conditions. The importance of considering all aspects of the lifecycle of facilities, including construction, maintenance, operation, and decommissioning, is emphasized, allowing for a more accurate assessment of the real costs of energy production.The conclusions of the study underline the significance of developing and implementing technology solutions tailored to each specific region, taking into account technical, economic, social, and environmental aspects. This approach will not only ensure reliable energy supply to inaccessible areas, but also contribute to their sustainable development.

Entering the Green Stone Age – introduction

Abstract The present special publication addresses opportunities and challenges in meeting the demand for essential and critical metals and minerals needed to supply the green and sustainable societies of the future. The notion of criticality in different countries is discussed and examples of ongoing national and cross-country research and mapping programmes are presented. In addition to the resource/reserve and technical–economic aspects, the social and environmental dimensions are also elaborated in some of the contributions, as holistic approaches to the exploration and exploitation of critical minerals and materials are needed to fulfill the green transition and goals for the Green Stone Age.

A Method to Quantify Technical-Economic Aspects of HTS Electric Power Cables

In prevision of an expansion in the installed power and the progressive increase in electrification toward energy transition, high-efficiency electric grids are required. In this process, superconducting power cables could play an important role as they can be installed either to realize new lines or to replace existing infrastructures, potentially reducing the costs and the environmental impact compared to conventional solutions. The technical-economic convenience of the superconducting choice depends on the design parameters of the line, such as the voltage and power levels and the line length. For each condition, the configuration of the cable and its cooling system must be optimized while complying with a number of electrical and geometrical constraints. Identifying a priori the optimal cable configuration is not trivial, as the numerous variables involved are mutually dependent. This article describes a novel tool developed to quantify technical-economic aspects of superconducting cables, allowing the user to freely select the operating conditions for a generic electric line. The tool adopts a genetic algorithm to solve a constrained minimization problem for a multivariable function, returning the cable configuration characterized by the lowest costs. For this study, ac concentric cables realized with high temperature superconductors are selected, but the approach described can easily be adapted to other types of cable. By means of suitable simplifying hypotheses, the equations used to size the cable components and their corresponding costs, estimate the thermal inputs and describe the cryogen flows are introduced as parametric equations. Finally, the results of a detailed study on the impact of the relevant parameters on the cable design and costs is provided.

CHANGES OF THE CONCEPT OF NEUTRAL POINT EARTHING OF MID-VOLTAGE GRIDS

Neutral point earthing of mid-voltage grids is implemented variously around the world, depending on the practice of individual countries with the emphasis on the technical regulations in force. Croatia is in the process of transition from star-point earthing through resistors to resonant earthing. Questions on the choice of arc suppression coil technology and the consequences for the operation of relay protection in transformer stations arise in relation to that. It is necessary to view all technical-economic aspects in order to reach an appropriate solution, while at the same time acknowledging the reliable operations of star-point earthing devices, and ensuring a satisfactory quality of electric energy supply.

Technical-economic Aspects of Construction of sSmall Hydro Power Plants in the Energy Market Environment

As a result global trends in the energy market environment and of the political and regulatory decisions of the European Union, which put great emphasis on renewable energy sources and decentralized energy production, there is division of the traditional energy value chain into a increasing number of market segments. In these newly established market segments opportunities are created for new specialized players, which leads to competition in all phases of the value chain. Small hydropower plant also represent an essential renewable energy source. This article elaborate technical economics aspects of construction and operation of small hydropower plants in energy market environment. In this context, a concrete example is given of the mission and vision of the construction and operation of a small hydro power plants in energy market environment.

Overview of microgrid systems

<span>This research paper discusses the different types of microgrids, their structural arrangements and the technology adopted for different power management projects. It also deals with various control strategies and security plans used for optimal performance. A detailed overview of the direct current (DC) microgrid system is discussed, outlining its configurations and technical-economic aspects. Performance evaluation of microgrid carried out through various reliability codes is also provided.</span>

The Main Technical-Economic Aspects of the Fruit Market at Research and Development Station for Fruit Growing Iași

The Romanian fruit market has a high growth potential but, to a great degree, after 1989 it has registered a reverse phenomenon. The fruit estate, consisting of orchards and nurseries, totaled in the 80s around 290.000 ha, representing 2% of the agricultural area of the country. Nowadays, the fruit heritage is a lot diminished. In 2010, Romania had 196,000 hectares of orchards, these surfaces decreasing by 2016 when they totaled 138,000 hectares, representing 1% of the agricultural area of the country. For the recovery of this sector, it is necessary to renew the fruit plantations. Also, the range of fruit products needs to be diversified so that Romania can enter the European markets. In addition, Romanian producers should be encouraged by introducing tax exemptions and by granting new types of subsidies. In this way, Romania will be able to become competitive on the European and global market. The studies carried out on Research and Development Station for Fruit Growing (RDSFG) Iasi show how using high performance hybrids, as well as widening the range of products and maintaining a distribution process with no intermediaries have helped the company preserving a significant market share and increasing its turnover in the last years.

Technical-Economic Aspects of the Units Creation and Exploitation for Ladle Treatment of Cast Iron and Steels

Technical-Economic Aspects of the Units Creation and Exploitation for Ladle Treatment of Cast Iron and Steels

Avaliação de custo direto e benefícios do sistema construtivo de painéis sanduíche, com núcleo de garrafas pet, moldados no local

Os métodos construtivos tradicionais possuem baixa produtividade, baixa padronização e altos índices de desperdícios e retrabalhos. Em virtude dos problemas destacados e levando em conta aspectos ambientais, novos sistemas construtivos, que empregam materiais reutilizáveis ou recicláveis de outras indústrias, têm sido desenvolvidos. O presente trabalho teve como objetivo avaliar o custo e o benefício do sistema construtivo painéis sanduíche, moldados no local, reutilizando garrafas de politereftalato de etileno (PET) para compor o núcleo das paredes e lajes. No aspecto econômico, fez-se um comparativo entre o sistema construtivo em alvenaria estrutural e o sistema estudado. Foi analisado o custo direto e observaram-se os benefícios relacionados aos atributos de valor para opções pré-fabricadas de construção, utilizando-se como referencial teórico a lista de significativos atributos de valor que podem ser vinculados ao emprego de pré-fabricados na construção proposta por Cook. Investigaram-se etapas, atividades, produtividade e recursos necessários para executar um projeto no sistema construtivo em alvenaria estrutural e no sistema construtivo analisado. Foi delineado o mapeamento dos processos, no qual se podem identificar os possíveis benefícios do sistema construtivo. O estudo do custo e benefício demonstrou a relevância técnico-econômica do sistema construtivo investigado, nem tanto em função do custo direto, mas em função dos benefícios de gestão do sistema construtivo.

Technical-economical aspects of the Alcarreña sheep farms in Spain and characterization of their meat products

SummaryAlcarreña is an endangered Spanish sheep breed (8 009 breeding animals) characterized by its adaptation to a particularly harsh environment and by having a sustainable pasture-based, small-scale, production model. The first objective of this study was to identify the technical-economic aspects of the Alcarreña farms, based on information obtained from surveys. The second objective was to quantify the influence of slaughter weight (12, 19 and 23 kg) on the sensory characteristics of the lamb meat. The mean age of the Alcarreña sheep farmers was lower than the average age of Spanish sheep farmers; however, generational renewal is not assured because most of the farmers’ children were still in school. Mean flock size was higher than the average Spanish sheep flock. Alcarreña sheep were reared under an extensive management system, grazed year-round and had a reproductive schedule of three lambings within 2 years. The carcass and meat qualities of the 12 and 19 kg lambs did not differ significantly, although the lightest lambs had the softest meat and the clearest subcutaneous fat. The most important differences between the lighter lambs and the 23-kg lambs were in meat and fat colour and lipid composition. Among the sensorial characteristics, the 19-kg lambs had the lowest meat fibrosity, and meat colour and slaughter weight were negatively correlated.

Electronic Cash Registers as a Part of the Fight against Tax Evasion

The usage of electronic cash registers in the conditions of the Slovak Republic does not have a long, but definitely interesting history, which is very often related to changes and amendments in its legislative and technical-economic aspects. Small and medium enterprises need to pay a close attention to the area of electronic cash registers, as often changes and amendments of legislation and technical aspects cause them problems and additional costs. The usage of electronic cash registers is one of the measures of the Slovak government to prevent tax avoidance and tax evasion.

Electron-beam processed corn starch: evaluation of physicochemical and structural properties and technical-economic aspects of the processing

The properties of starch can be modified by a variety of methods in order to meet desirable technological needs. Electron beam irradiation is able to induce changes in starch properties. The paper deals with investigation of physicochemical and structural modifications of corn starch processed by electron beam up to 50 kGy and evaluation of the technical-economic aspects of starch processing. Paste viscosity, pasting and peak temperatures decreased in a dose-dependent manner, indicating degradation of the macromolecule. Small circular perforations on the granule surface were observed for 50-kGy irradiated sample. Spectral characteristics suffered minor changes, suggesting that the inter- and intramolecular hydrogen bond stability was affected by the electron beam. These modified starches could find applications in foodstuffs requiring low-viscosity starch. A cost estimate of the electron beam processing of corn starch with an average absorbed dose of 30 kGy showed an increase of corn starch price by 16%.

Sizing optimization, dynamic modeling and energy management strategies of a stand-alone PV/hydrogen/battery-based hybrid system

This paper presents a sizing method and different control strategies for the suitable energy management of a stand-alone hybrid system based on photovoltaic (PV) solar panels, hydrogen subsystem and battery. The battery and hydrogen subsystem, which is composed of fuel cell (FC), electrolyzer and hydrogen storage tank, act as energy storage and support system. In order to efficiently utilize the energy sources integrated in the hybrid system, an appropriate sizing is necessary. In this paper, a new sizing method based on Simulink Design Optimization (SDO) of MATLAB was used to perform a technical optimization of the hybrid system components. An analysis cost has been also performed, in that the configuration under study has been compared with those integrating only batteries and only hydrogen system. The dynamic model of the designed hybrid system is detailed in this paper. The models, implemented in MATLAB-Simulink environment, have been designed from commercially available components. Three control strategies based on operating modes and combining technical-economic aspects are considered for the energy management of the hybrid system. They have been designed, primarily, to satisfy the load power demand and, secondarily, to maintain a certain level at the hydrogen tank (hydrogen energy reserve), and at the state of charge (SOC) of the battery bank to extend its life, taking into account also technical-economic analysis. Dynamic simulations were performed to evaluate the configuration, sizing and control strategies for the energy management of the hybrid system under study in this work. Simulation results show that the proposed hybrid system with the presented controls is able to provide the energy demanded by the loads, while maintaining a certain energy reserve in the storage sources.

Implementing membrane technology in the process industry: problems and opportunities

Although membrane filtration is an accepted technology in water treatment and in the dairy, food and beverage industries, membrane-based separations are relatively new for the chemical industry. Therefore, for a major part of these techniques, there is still a long way to go to make them truly attractive as an alternative to distillation, absorption and adsorption or extraction. However, the improvement potential in large-scale processes is enormous. In this paper, we present four different successful implementations of membrane-based separations in our chemical company, ranging from upgrading of a process gas stream in a bulk chemical process to recovery of enzymes in a fine-chemical process. The technical-economical aspects of these projects are discussed. The approach for implementation strongly differs depending on the existing situation in the plant. Replacement of existing separation units by more efficient membrane units quite often appears economically unattractive, whereas in new installations or debottlenecking situations, membrane separations have a better chance of success. Reliability and durability are key criteria in the process industry. Therefore, it should be strongly recommended that a large-scale data base be created, e.g. by proper demonstration projects. Some general conclusions are presented concerning recommended directions in the future development of membrane technology.

Anaerobic biotechnology and developing countries—I. Technical status

A survey of biogas programmes in different countries (based on available data) reveals that biogas digesters have become quite popular during the past 15 yr. The present study analyses their development in industrialized countries (IC) and examines possibilities for transferring the most appropriate ones to the majority of developing countries (DC). It is possible to conclude from the present study that collaboration with IC to evaluate the technical-economic aspects of various plant designs and to optimize their process parameters can play an important role in the establishment and successful implementation of biogas technology programmes in the long run.

Technical-economic aspects of small geothermal power plants

This paper describes the criteria followed in designing small geothermal steam turbines with particular reference to 3–5 MW portable units. Attention is drawn in particular to certain features of the machinery directed at a more rational exploitation of the geothermal resource.

Technical-economic aspects of the utilization of geothermal waters

A brief description is given of the physico-chemical parameters characterizing a hot water geothermal reservoir and of its exploitation by means of single or coupled (doublet) wells. The technical aspects of geothermal heat to the users is then discussed, beginning with corrosion of materials caused by seven main agents: oxygen, hydrogen sulphide, carbon dioxide, ammonia, hydrogen, sulphates and chlorides. A brief mention is made of scaling due to calcium carbonate, silica and calcium sulphates. The basic components of a geothermal plant for non electric uses are then discussed: production pumps, surface pipelines, heat exchangers, heat pumps and reinjection pumps. The advantages and disadvantages of the different equipment and materials used in the geothermal sector are also presented. A list is also given of the criteria used in the energy and economic balance of a geothermal operation.

Natural gas and other alternative fuels for transportation purposes

Natural gas has been used as fuel for transportation for decades and, currently, about half a million vehicles of different types are running either on compressed natural gas (CNG) or on liquefied natural gas (LNG) in a number of countries, including Italy, New Zealand, the U.S.A., Australia, Iran and France. The country with the most developed program on utilization of natural gas as a transportation fuel is Italy, where almost 300,000 vehicles are running on CNG. Several other countries such as Brazil, Egypt, Canada, Bangladesh and the Soviet Union are implementing programs to use natural gas for domestic transportation needs. Natural gas is composed essentially of methane, which can be obtained also through anaerobic fermentation of different organic products yielding biogas (60% methane). The role of methane as a fuel has shown increasing importance due to the growth in digester construction all over the world, and especially in developing countries. Natural gas can also be used as raw material for the production of liquid fuels suitable for transportation purpose such as methanol, ammonia, gasoline, diesel oils, methyl esters of vegetable oils, and MTBE, a high-octane component of gasoline. In addition, natural gas liquids (propane/butane) can also be used as automotive fuels. This paper covers the technical-economic aspects of natural gas and methanol as fuels for transportation and presents a summary of worldwide experience with emphasis on the existing experience in a developing country such as Brazil, including its commercial large-scale experience with ethanol fuels.