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Introduction— The use of renewable sources for energy generation has grown in importance due to the adverse effects that fossil fuels generate on the environment. From the available sources, generation of energy through biomass has great advantages because of its high energy potential and low cost. Objective— To evaluate the performance of a heat absorption refrigeration system using photovoltaic solar energy conversion and biogas as renewable energy sources. Methodology— The energy characterization of the implemented sources was carried out collecting data on solar radiation and biogas calorific value to calculate the Coefficient of Performance (COP). All the experimental tests were made by placing 1 liter of water inside of the system. Results— It was found that the operation of the equipment takes approximately 8 hours, the biogas chemical composition was 58% methane and 42% carbon dioxide, and a calorific value of 23.05 MJ/kg was attained. The Coefficient of Performance obtained were 0.58; 0.08; 0.27 and 0.07 for electrical energy, LPG, solar energy and biogas respectively. Conclusions— There is an important energy potential in the usage of solar energy and biogas for cold generation processes and it was proved that it is possible to implement renewable energies in absorption cooling systems ; Introducción— El uso de fuentes renovables para la generación de energía ha crecido en importancia debido a los efectos adversos que los combustibles fósiles generan en el medio ambiente. De entre las fuentes disponibles, la generación de energía a través de la biomasa presenta grandes ventajas por su alto potencial energético y su bajo coste. Objetivo— Evaluar el rendimiento de un sistema de refrigeración por absorción de calor utilizando la conversión de energía solar fotovoltaica y el biogás como fuentes de energía renovable. Metodología— La caracterización energética de las fuentes implementadas se realizó recogiendo datos de radiación solar y poder calorífico del biogás para calcular el Coeficiente de Rendimiento ...

To reduce the effects of climate change due to massive CO 2 emissions, renewable energy sources have been implemented; among them biomass through gasification. An important aspect of studying are the environmental impacts of this process. Therefore, a search was made in the database of the science website using keywords gasification environmental impact in the period from 2001 to 2017. When analyzing the 238 articles, an increasing tendency was observed in the publication of studies related to the ecological effects of the biomass gasification process. The United States, the United Kingdom, Italy, Spain and the People’s Republic of China are the countries that have the most studies on the subject. The indicator total local citation score is used in order to identify the items that are the most cited, which indicates the degree of development they have in the study of the impacts of gasification. ; Salinas, Luis F. Caicedo-ecc65c4f-ba9a-4695-9285-2ca5033258fd-600 ; Ochoa, Guillermo Valencia-014dd768-7476-4cb6-b6e4-23fe57a10ac1-600 ; Cardenas, Yulineth Escorcia-355a0135-3ef7-44e9-8e5d-dcc703f3f714-600

Improving the conversion efficiency of solar panels has become a challenging area of study for researchers. Solar trackers are an alternative to reach this goal, as has been shown in many cases, by tracking the position of the sun changes, the productivity of the panel increases. This paper presents a new design of a dual-axis solar tracker system based on a real-time measurement of solar radiation in order to improve the conversion efficiency. As a first design stage, the dynamic models for solar radiation, solar panel and electromechanic system, were obtained using Matlab-Simulink. Then a control unit for capturing the signals from radiation sensors and an inertial measurement unit, was implemented in a High-Performance 16-Bit Digital Signal Controller DSPIC33FJ202MC. The acquired data are compared with a mathematical algorithm to calculate sun's position and set the control action to orient the panel. An embedded system with real-time sampling was developed. It does not rely on external databases and takes into account the relative position between the radiation sensor and solar panel to improve the efficiency of the system. ; Mejorar la eficiencia de conversión de los paneles solares se ha convertido en un área de estudio desafiante para los investigadores. Los seguidores solares son una alternativa para alcanzar este objetivo, como se ha demostrado en muchos casos, al rastrear la posición de los cambios del sol, aumenta la productividad del panel. Este documento presenta un nuevo diseño de un sistema de seguimiento solar de doble eje basado en una medición en tiempo real de la radiación solar para mejorar la eficiencia de conversión. Como primera etapa de diseño, los modelos dinámicos para radiación solar, panel solar y sistema electromecánico, se obtuvieron utilizando Matlab-Simulink. Luego se implementó una unidad de control para capturar las señales de los sensores de radiación y una unidad de medición inercial en un controlador de señal digital de alto rendimiento de 16 bits DSPIC33FJ202MC. Los datos ...

This study was proposed for evaluating the CO2 fixation by Spirulina platensis in different media, in order to understand the growth dynamics of the photosynthetic microalgae, a useful resource for the mitigation of climate change. The percentage of CO2 fixation by the strain S. platensis UTEX LB 2340 was determined during 11 days of sampling, using four (4) culture media. According to the statistical models, spirulina medium represented the best option in terms of cell growth between the tested ones. In this model, the variable day had presented a significant difference, this could be related to the exponential phase of the microorganism used. ; Suarez Marenco, Marianella María ; MORGADO GAMERO, WENDY BEATRIZ-will be generated-orcid-0000-0003-2394-2589-600 ; Sarmiento-Rubiano, Luz Adriana-will be generated-orcid-0000-0002-8680-5816-600 ; Parody Muñoz, Alexander Elias-will be generated-orcid-0000-0003-0155-266X-600 ; Silva, Jesus

To reach the Sustainable Development Goals and delivering on the Paris Agreement on climate change mitigation, a Biomass on grid power system is proposed to supply 33,640 kWh/day, which is the average annual energy consumption from a group of office buildings. This study shows the behavior of the gas emission of a Biomass on Grid Energy System Using HOMER Pro Software, composed by two 500 kW biogas-powered electric generator, using different types of biomass resource from the Colombian Caribbean Region like manure obtained from the livestock sector and solid urban organic waste. The simulation results showed some emission decrease when operating on the grid the Biogas generator such as the carbon dioxide, the sulfur dioxide and the nitrogen oxides on 11.6% while the carbon monoxide increased on 8.7% concerning the power supply system through electrical grid coming from thermoelectric power plants and hydroelectric power plants ; Para alcanzar los Objetivos de Desarrollo Sostenible y cumplir con el Acuerdo de París sobre la mitigación del cambio climático, se propone un sistema de biomasa en la red eléctrica para suministrar 33,640 kWh / día, que es el consumo promedio anual de energía de un grupo de edificios de oficinas. Este estudio muestra el comportamiento de la emisión de gases de un sistema de energía de biomasa en la red que utiliza el software HOMER Pro, compuesto por dos generadores eléctricos de biogás de 500 kW, que utilizan diferentes tipos de recursos de biomasa de la región del Caribe colombiano como el estiércol obtenido del sector ganadero Y sólidos residuos orgánicos urbanos. Los resultados de la simulación mostraron cierta disminución de las emisiones al operar en la red el generador de biogás, como el dióxido de carbono, el dióxido de azufre y los óxidos de nitrógeno en un 11,6%, mientras que el monóxido de carbono aumentó en un 8,7% en relación con el sistema de suministro de energía a través de la red eléctrica proveniente de la termoeléctrica. En las centrales eléctricas y en las centrales ...

The fact is the stock market has an asymmetric effect on macroeconomic variables. In this study, we examine the nonlinear stock market reaction to the environment. This is the first study that considers the possibility of asymmetric effects of stock market on environmental pollution in Asia. This study considers the experiences of Asia economies by using the panel NARDL methodology over the data period from 1995 to 2019. The long-run panel NARDL results showed that the positive change in stock market increases carbon emissions. In adverse, the negative change in stock market significantly mitigates the carbon emissions in Asia. The short-run stock market asymmetric effects continued into the long-run asymmetric effects on the environment in Asia. Thus, policymakers and authorities should initiate to promote green financial activities in Asian stock markets. ; Ramos Meza, Carlos Samuel-will be generated-orcid-0000-0002-8103-6704-600 ; Kashif, Maryam-will be generated-orcid-0000-0002-8197-7459-600 ; Jain, Vipin ; Grimaldo Guerrero, John William-will be generated-orcid-0000-0002-1632-5374-600 ; Roopchund, Randhir ; Niedbala, Gniewko ; Phan, The Cong

The synthesis and use of materials as hydrotalcites have a high impact on development of new materials and technological advances, applied in areas such as catalysis and environmental chemistry. An aspect of vital importance is the temperature of collapse of the HTLc structure, because from this fact depend the properties of solids obtained. In this work was studied the thermal behavior of nickel-aluminum hydrotalcite, and determined the Ea associated with the collapse and formation of NiO. It was observed that the greater interaction among carbonate ions and OH groups occurs at 250 °C, temperature at which the collapse of the HTLc structure occurs. The solid N0,75A0,25 requires less energy to collapse, which is due to the greater distances between the positive sheets. The solid N0,66A0,33 need more energy for the formation of NiO, which is due to higher content of Al3+, disfavoring the growth of the initial particles of NiO. ; Las hidrotalcitas tienen un alto impacto en el desarrollo de nuevos materiales y en avances tecnológicos en áreas como catálisis y química ambiental. Un aspecto de vital importancia es la temperatura del colapso de la estructura HTLc, ya que de esta dependen las propiedades de los sólidos obtenidos. En este trabajo se estudió el comportamiento térmico de hidrotalcitas de níquel-aluminio y se determinó la Ea asociada al colapso y formación de NiO. Se observó que la mayor interacción entre iones carbonato y grupos OH ocurre a 250 °C, temperatura en la cual desaparece la estructura HTLc. El sólido N0,75A0,25 requirió menos energía para que ocurriese el colapso, debido a la mayor distancia entre las láminas. El material N0,66A0,33 necesito más energía para que ocurriese la formación del óxido de níquel, lo que se debe a que el mayor contenido de Al3+, desfavorece el crecimiento de las partículas iniciales de NiO. ; Ríos León, Ilich-b379bd1e-590d-432f-8871-c306b70f305f-0 ; Solano Polo, Cesar-d0458b0a-efec-4d52-aff0-1484db57e509-0 ; Rodríguez Ruiz, Johana-161f3ccc-96dc-4bad-9474-ab194a74536e-0 ...

Studies have been carried out on the phenomenon of auto-ignition in liquid fuels and natural gas, but research on the application of gaseous fuels obtained from biomass is limited. Existing investigations about autoignition mainly focused on the combustion kinetics to determine the delay time, but not on the prediction of the set of parameters that encourage the presence of the phenomenon. In the present research, a thermodynamic model is developed for the prediction of the auto-ignition in Spark Ignition Internal Combustion Engine operated with gaseous fuels, which are obtained from the process of gasification of biomass. The formulated model can handle variable compositions of gaseous fuels and to optimize the main operational parameters of the engine, to verify its influence on the phenomenon under study. Results show the application of this type of alternative fuels in commercial engines that operated with natural gas, varying engine operational parameters while maximizing the power output of the engine ; Se han llevado a cabo estudios sobre el fenómeno de la autoignición en combustibles líquidos y gas natural, pero la investigación sobre la aplicación de combustibles gaseosos obtenidos de la biomasa es limitada. Las investigaciones existentes sobre la autoignición se centraron principalmente en la cinética de la combustión para determinar el tiempo de retardo, pero no en la predicción del conjunto de parámetros que fomentan la presencia del fenómeno. En la presente investigación, se desarrolló un modelo termodinámico para la predicción del autoignición en el motor de combustión interna con encendido por chispa que funciona con combustibles gaseosos, que se obtienen del proceso de gasificación de la biomasa. El modelo formulado puede manejar composiciones variables de combustibles gaseosos y optimizar los principales parámetros operativos del motor, para verificar su influencia en el fenómeno en estudio. Los resultados muestran la aplicación de este tipo de combustibles alternativos en motores comerciales ...

El trabajo presenta la modelación del comportamiento energético y la determinación de los parámetros del circuito equivalente de un panel fotovoltaico con el empleo de técnicas de inteligencia artificial. Para tal efecto, se desarrolló en Matlab un algoritmo genético que permite obtener los parámetros físicos no brindados por los fabricantes para la implementación de funciones matemáticas que se homologuen al comportamiento dinámico de un panel solar. El algoritmo desarrollado en Matlab permite determinar, además, la eficiencia del algoritmo seguidor del punto de máxima potencia del inversor, el cual es un parámetro de no simple obtención o no determinado en condiciones de campo. Finalmente, el algoritmo se probó satisfactoriamente en un panel solar monocristalino de 50W obteniendo adecuados resultados en comparación con el modelo experimental para diferentes niveles de irradiación solar. Los resultados demuestran que el proceso desarrollado constituye una herramienta que puede ser aplicada a paneles fotovoltaicos en condiciones de campo. The paper presents the modeling of the energy behavior and determination of equivalent circuit parameters for a photovoltaic panel using artificial intelligence techniques. For this purpose, it was performed a genetic algorithm in Matlab, which calculates the physical parameters not provided by manufacturers to implement mathematical functions that approve the dynamic behavior of a solar panel. In addition, the algorithm can determine the efficiency of the maximum power point tracking algorithm of the inverter, which is a parameter of not simple obtaining or not determined under field conditions. Finally, the algorithm was successfully tested in a monocrystalline solar 50W panel with excellent results, compared to the experimental model for different levels of solar irradiation. The results demonstrate that the developed process is a tool that can be applied to photovoltaic panels under field conditions.

Thermoeconomic evaluation aims at diagnosing the malfunction of energy systems and at optimizing their structure and performance. One of the main limitations of this approach is the adequate treatment of dissipative components, i.e., components where exergy is destroyed without gaining thermodynamically useful output (condensers, throttling valves, etc.). Such components are constituents of some energy systems and influence their overall thermal efficiency. This research introduces the use of a different criterion of exergy efficiency to assess dissipative components. In this case, it is possible to define the efficiency of dissipative components without the introduction of negentropy flows. As case study, a Rankine cycle discussed in literature is selected. The different approaches to evaluate dissipative components are applied and compared with the proposed one. Results show that with the proposed approach it is possible to evaluate dissipative components in isolation avoiding the inconsistencies resulting from the use of negentropy flows in the assessment. The introduction of negentropy flows also increases the complexity of the assessment.