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The organic Rankine cycle (ORC) is an efficient technology for electricity generation from low- and medium-temperature heat sources. In this type of power cycle, the radial inflow turbine is the option usually selected for electricity generation. As a critical ORC component, turbine performance markedly affects the efficiency of the system. Therefore, the challenge is to model the behavior of the radial inflow turbine operating with organic fluids for heat recovery applications. In this context, various groups of fluids are highlighted in the scientific literature, including R-123, R-245fa, and R-141b, which are the fluids used in this research. Since little research has focused on the turbine efficiency effect on the power cycle design and analysis, this study presents an analysis of a radial inflow turbine based on a mathematical model of a one-dimensional design of the turbine. From this analysis, geometric, thermal, and operating parameters were determined, as well as volute, stator, and rotor losses. For this purpose, an algorithm was implemented in MATLAB to calculate the one-dimensional parameters of the turbine. Using these parameters, a 3D model of the turbine was designed in ANSYS-CFX, with performance curves of each projected turbine under design and off-design conditions. The numerical results suggest that the isentropic efficiency of all the proposed turbines under design conditions can surpass 75%. Additionally, the findings indicate that different design conditions, such as specific speed, pressure ratio, and turbine size, can affect the efficiency of radial inflow turbines in ORC systems.

Given the increase in population and energy demand worldwide, alternative methods have been adopted for the production of hydrogen as a clean energy source. This energy offers an alternative energy source due to its high energy content, and without emissions to the environment. In this bibliometric analysis of energy production using electrolysis and taking into account the different forms of energy production. In this analysis, it was possible to evaluate the research trends based on the literature in the Scopus database during the years 2011–2021. The results showed a growing interest in hydrogen production from electrolysis and other mechanisms, with China being the country with the highest number of publications and the United States TOP in citations. The trend shows that during the first four years of this study (2011–2014), the average number of publications was 74 articles per year, from 2015 to 2021 where the growth is an average of 209 articles, the journal that published the most on this topic is Applied Energy, followed by Energy, contributing with almost 33% in the research area. Lastly, the keyword analysis identified six important research points for future discussions, which we have termed clusters. The study concludes that new perspectives on clean hydrogen energy generation, environmental impacts, and social acceptance could contribute to the positive evolution of the hydrogen energy industry.

This study examined an Organic Rankine Cycle powered by a parabolic trough collector and a two-tank thermal storage system based on the development of a mathematical model, for the conditions of the city of Itajubá in Brazil. First, geometrical optics and heat transfer models of the collector–receiver set were used to determine the thermal equilibrium of the solar thermal collector system and parameters such as the efficiency of the solar field, heat and optical losses, and thermal energy of the outlet fluid. Next, the thermal equilibrium of the Organic Rankine Cycle was found in order to establish its operational parameters. Finally, the behavior of the thermal storage system was analyzed through its modeling. Once the characterization of the storage system was completed, the integrated operation of the proposed system was evaluated. Given Itajubá’s weather conditions, the results indicate that an electricity generation system can be implemented with the Solel UVAC Cermet selective coating for the absorber tube, water as the heat transfer fluid, and R-245fa as the working fluid. Based on the solar irradiation profile (1 March 2019), the parabolic trough collectors provided 63.3% of the energy required by the Organic Rankine Cycle to generate 7.4 kW, while the thermal storage system provided 36.4% of the energy demanded by the power generation block. Additionally, the results demonstrate the main conclusions that the turbine’s efficiency was influenced by parameters such as rotational speed, which is affected by the turbine inlet temperature, which, in turn, depends on the behavior of the solar irradiation profile onsite.

This article presents the use of an interactive computer tool developed in MATLAB® called RISK-ASSESSMENT v1.0, to perform market risk analysis of commercial products, through the development of cash flow, sensitivity analysis, and SpiderPlot graphics, which allow the identification of the economic-financial equilibrium point of a company. The tool facilitates the reduction of the uncertainty produced in the return on investment due to changes in the economic environment of the sector in which the company operates, through statistical techniques and tools that involve parameters such as the annual effective rate in the Colombian national currency, net present value, internal rate of return, period of recovery of capital, through a sensitivity analysis. To validate the effectiveness of using software in the development of risk analysis, a case study was conducted for an alcohol beverage sales business, where, based on the portfolio containing the product quantity, unit variable cost, sales price, percentage of sales growth and annual sales volume, in addition to detailed information on the initial investment, the cash flow with a 5-year horizon, the net present value, the internal rate of return, the period of capital recovery and the average accounting profitability are calculated. The tool also performs sensitivity analysis and SpiderPlot for each of the products. Finally, the program presented allows to calculate the annual cash flows in a fast and didactic way, which normally requires time and specialized training in a traditional exercise.

Electrical power systems and their elements such as power transformers, transmission lines, capacitors, reactors and other elements, during normal operation generates electromagnetic fields that changes according with design, equipment distribution, current and voltage operation levels. This paper describes the monitoring electromagnetic fields and safe operation levels in electrical power transmission and distribution lines during the last five years in power lines located in warm climate with high salinity, corrosion and pollution level. A literature review was considered during the study. This paper characterizes power lines in order to guarantee safe operation to occupational exposure and general public since planning process. Results will be used in order to characterize power lines and will be used as a tool for utilities with the aim to reduce legal penalties and promote social responsibility. Results also were contrasted with International Commission on Non-Ionizing Radiation Protection (ICNIRP) recommendations with the reference levels for occupational exposure to time-varying electric and magnetic fields. Results provide recommendations for electrical grid utilities also the study compare real values with simulated values in order to guarantee an acceptable approach according with ICNIRP and international standards recommendations.

Nowadays, the companies with national leadership have decided to provide services that allow the industries to give solutions for manufacturing, repair, reconstruction, maintenance and supply to the necessary tools necessary for the operation of the machinery required in the development of projects. The objective of this work is based on the identification of the relationship and points of convergence between the ISO 9001:2015, ISO 14001:2015, ISO 50001:2011, and OHSAS 18001:2007 standards, for the implementation of the IMS-HSE (Integrated Management System and Health, Safety and the Environment respectively), in companies in the metal-mechanical sector that develop their economic activity in Colombia. An analysis of the regulatory structure was conducted, identifying common and non-common aspects to find a compliance baseline that provides business leaders with a decision-making tool for implementing Geographical Information System (GIS) and HSE aimed at continuous improvement. The result of this research offers a characterization regarding scope, planning, performance evaluation and development in legal terms, applied to the systems integrated into the service company in the metal-mechanical sector. So that, the results can be used as an operational and organizational tool that provides them with a characteristic of viability, competitiveness, and profitability compared to companies in the same dynamic scenario, guaranteeing compliance with the legal commitments of the Colombian regulatory framework.

Demand estimation models are used for energy planning activities. Their primary function is focused on securing energy supply to final users using available resources in generation, transport and interconnection. Long-term planning models typically use non-linear optimization techniques considering an error not exceeding 5%. The reference model used by UPME in Colombia is limited to an average error of 1.6% considering non-linear modeling estimation techniques. However, they are limited in their ability to anticipate uncharacteristic variations in curves or externalities, which increases the probability of an erroneous prediction. Therefore, this research proposes a model to forecast electricity demand using neural networks in order to anticipate non-characteristic variations. The study first documents current methodologies for the prediction of maximum power demand, as well as the current deficiencies in the used forecasts, A new model is then formulated with the application of neural networks using the algorithm Cascade-Forward Back propagation using MATLAB R2017a. During the model comparison process, it was identified that the data obtained reflects the characteristics of demand behavior with an acceptable margin error equal to 0.5%.

Mini solar flat plate collectors have gained traction due to their cost-effectiveness, high efficiency in converting solar radiation to heat energy, and versatility in residential and commercial applications, offering long lifespans with minimal maintenance. Optimizing the thermal performance of solar flat plate collectors using numerical simulations helps enhance their efficiency, making them even more appealing for small-scale heating and hot water applications. This study investigates the flow behavior and temperature distribution of air within a small-sized solar collector (286 × 800 × 70 mm) and optimizes its design for achieving the highest outlet air temperature. The optimization process included varying geometric parameters, such as the wavy structure hole diameter, and considering a range of operating conditions, including ambient conditions and solar intensities. This analysis aimed to understand the flow behavior and temperature distributions within the solar collector. The numerical studies provided valuable insights into the thermal and flow characteristics of the collector. The velocity distribution of the fluid within the collector aided in understanding the flow behavior, optimizing the flow path to minimize pressure drop, and maximizing heat transfer. Additionally, calculations were performed to determine total useful heat, outlet temperatures, and efficiencies. The study also discusses the optimal design and operating conditions for the collector.

In the refining and petrochemical industrial sector, large amounts of energy are used, so using the concept of exergy allows a rational use of this resource. In the different exergy and exergoeconomics studies applied in petrochemical plants, parameters of interest have been determined to evaluate the thermal efficiency, the potential for process improvement, the irreversibilities produced by the interaction between the components of the system and the operation of each one, and the energy costs associated with each of these irreversibilities. This paper presents an advanced exergy analysis and an exergy-economic analysis applied to a nitric acid production plant with an installed capacity of 350 metric tons per day, whose operating principle is based on the Ostwald method, and both the behavior of endogenous exergy destruction and the behavior of exogenous, avoidable and unavoidable exergy destruction are studied, exogenous, avoidable and unavoidable exergy destruction and the associated exergy costs in each of the heat transfer equipment and reactive equipment that make up the plant, about the cooling temperature in the intermediate stages of the compression train are studied using a mathematical model. The chemical reactions involved in the production process are the points of interest in the research of this work. Some of the results show that 54 % of the total exergy destruction can be recovered by intervening in the components. On the other hand, in the Catalytic Converter (CONV), it is convenient to consider the investment costs to reduce the exergy destruction costs. Similarly, in the Tail Gas Heater (TGH), it is beneficial to reduce the total investment to improve the process economics. On the other hand, the cost of exergy destruction of the plant resulted in 770.77 USD/h. In addition, it could be determined that the interactions between the components significantly affect the investment costs.

A bibliometric analysis of proton exchange membrane fuel cells (PEMFCs) content from a total of 15.020 research publications was conducted between 2008 and 2018, the papers being detailed in the online version of SCI-Expanded, Thomson Reuters Web of Science. Data processing tools such as Hitscite, CiteSpace, ArcGIS and Ucinet 6 were used to process the information. The parameters analyzed in the analysis were: type of document; the language of publication; volume and characteristics of publication output; publication by journals; performance of countries and research institutions; research trends and visibility. The study showed that ''Fuel'', ''Cell'', ''Membrane “and ''Proton'' were found in most of the titles of the documents, while ''Performance'', ''Pemfc”, ''Pem Fuel Cell'' and ''Fuel Cell'' were the keywords most commonly used in documents. The analysis found that PEMFC studies have tended to be growing and that leading peer-reviewed journals have produced numerous publications on the subject. The investigation revealed that the country with the most significant production in the field is USA with a contribution of 3009; 20% of the total publications. Followed by China 2480; 16.5%, South Korea 1273; 8.5% and Germany 1121; 7.5%, showing to the main world powers as the most significant contributors to the research.