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This paper discusses the development of a coating made of solid waste and residual biomass and its application as ecological solar absorber coating. This absorbent solar coating is made with a binder that consists of essential grapefruit rind oil and expanded polystyrene, both obtained from waste materials, as well as forest biomass soot (FBS) processed by mechanical grinding and used as a functional photothermal material. This mixture produces a paint that can be applied to metallic substrates to form a solar energy-absorbing surface. The characterization and evaluation is shown in three steps: (a) Characterization of the materials using XRD, SEM, TEM, XPS, Raman spectroscopy and IR; (b) coating evaluation using AFM, optical characterization to measure solar absorption, TG to determine the operating temperature and laser flash analysis to determine thermal conductivity; and (c) a testing with thermosolar technology to determine the thermal parameters of solar cookers. It has been identified that the pseudo-amorphous carbon in FBS has solar energy absorption capacity due to the sp2-sp3 bonds present in this kind of carbon, associated with the material’s graphitic domain. Also, results show that the coating can be used with thermosolar technologies operating above 250 °C with a solar absorption index above 96%, and it has thermally-efficient properties. In addition, the coating, it shows better results with solar cookers than other coatings used with this technology, increasing cooking power, so it can potentially be employed with various thermosolar technologies due to the replicability of its materials, its low environmental impact and low economic cost. more...

Today, energy use is an important and urgent issue for economic development worldwide. It is expected that raw material in the form of biomass and lignocellulosic residues will become increasingly significant sources of sustainable energy in the future because they contain components such as cellulose, hemicellulose, lignin, and extractables with high energy-producing potential. It is then essential to determine the behavior of these materials during thermal degradation processes, such as pyrolysis (total or partial absence of air/oxygen). Pyrolyzed biomass and its residual fractions can be processed to produce important chemical products, such as hydrogen gas (H2). Thermogravimetric (TGA) analysis and its derivative, DTG, are analytical techniques used to determine weight loss as a function of temperature or time and associate changes with certain degradation and mass conversion processes in order to evaluate kinetic properties. Applying kinetic methods (mathematical models) to degradation processes permits obtaining several useful parameters for predicting the behavior of biomass during pyrolysis. Current differential (Friedman) and integral (Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, Starink, Popescu) models vary in their range of heating speeds (β) and degree of advance (α), but some (e.g., Kissinger’s) do not consider the behavior of α. This article analyzes the results of numerous kinetic studies using pyrolysis and based on thermogravimetric processes involving over 20 distinct biomasses. The main goal of those studies was to generate products with high added value, such as bio-char, methane, hydrogen, and biodiesel. This broad review identifies models and determines the potential of lignocellulosic materials for generating bioenergy cleanly and sustainably. more...

The COVID-19 pandemic has generated multiple impacts. In particular, in the educational sector, the virtual class modality generated changes in the patterns of energy consumption at the institutional level; the identification of this consumption will allow us to reflect on new energy saving and efficient use strategies. In this research, we present a case study of the effects of the COVID-19 pandemic on electricity consumption in 13 state universities in Michoacán, Mexico. Electric energy consumption has been evaluated before and during the presence of the COVID-19 between 2019 and 2020. The comparative analysis estimated the reduction in energy consumption and its economic and environmental impact. The results show a considerable decrease in electricity consumption, generating an average saving of 76.24 MWh/month, which translates into an annual emission reduction from 2019 to 2020 of approximately 497 TnCO2e, and in economic terms of $8,882.25 USD each month. In general, it was identified that consumption patterns in the use of machinery and computer equipment for administrative activities were drastically reduced. If education continues in virtual or hybrid modes, energy consumption schemes will continue to decline and institutions could move towards resilient, affordable, and sustainable models of energy production and consumption. more...

This study presents a prospective study for the potential exploitation of pelagic Sargassum spp. as a solid biofuel energy source. It was carried out in three stages. First we conducted a morphological, physical-chemical, and structural characterization using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (DRX), respectively. Second we evaluated the material&rsquo, s functional properties as a solid biofuel based on its calorific value and the quantification of polymeric components like hemicellulose, cellulose, and lignin, as well as thermogravimetric and differential analysis to study the kinetics of its pyrolysis and determine parameters like activation energy (Ea), reaction order (n), and the pre-exponential factor (Z). Third we analyzed the energetic potential considering the estimated volume of pelagic Sargassum spp. that was removed from beaches along the Mexican Caribbean coast in recent years. Results of the kinetic study indicate that Sargassum spp. has an enormous potential for use as a complement to other bioenergy sources. Other results show the high potential for exploiting these algae as an energy source due to the huge volumes that have inundated Caribbean, West African, and northern Brazil shorelines in recent years. As a solid biofuel, Sargassum spp. has a potential energy the order of 0.203 gigajoules (GJ)/m3. In the energy matrix of the residential sector in Mexico, its potential use as an energy source is comparable to the national consumption of firewood. The volume of beachcast Sargassum spp. that was removed from ~8 km of coastline around Puerto Morelos, Mexico in 2018&ndash, 2019, could have generated over 40 terajoules/year of solid biofuel. more...

Instituto de Investigaciones Metalúrgicas. Doctorado en Ciencias en Metalurgia y Ciencias de los Materiales The processing and characterization of carbon soot, commercial (Soot Carbon Fullerene) and forest biomass, is presented to identify its functional properties and apply it as a coating in solar thermal technologies. The material identified with the best functional properties is intended to be of low environmental impact, and low cost. The development of the coatings is shown in four phases: (a) the collection and processing of the material by means of low and high energy mechanical grinding (b) the characterization of the functional material of the material (soot), by means of ray diffraction techniques, scanning and transmission electron microscopy, X-ray photoelectron electron spectroscopy (XPS), raman and infrared spectroscopy, (c) evaluation of the coating: by optical characterization, evaluating solar absorption; thermal evaluation, through thermogravimetric tests to determine the maximum operating temperature of the coating, and flash laser analysis to determine thermal conductivity; in addition, analysis of surface morphology through atomic force microscopy and scanning electron microscopy, and (d) the evaluation of the coating in three solar thermal technologies, evaluating the thermal parameters of these technologies. The resulting solar absorbent coating is made from a binder consisting of grapefruit peel essential oil and expanded polystyrene, both obtained from waste materials; it also has soot (variant, in some cases of forest biomass and in others commercial), the latter as a photothermal functional material; The result of this combination is a paint that can be applied on metallic substrates, to form absorbent surfaces of solar energy. The results show that the coating developed with both types of soot can be used in solar thermal technologies with more than 250 ° C of operation; it also has a high solar absorption greater than 94%. Se presenta el procesamiento y caracterización de hollín de carbono, comercial (Soot Carbon Fullerene) y de biomasa forestal, para identificar sus propiedades funcionales, y aplicarlo como recubrimiento en tecnologías solares térmicas. Se pretende que el material identificado con mejores propiedades funcionales sea de bajo impacto ambiental, y bajo costo. El desarrollo de los recubrimientos se muestra en cuatro fases: (a) la recolección y procesamiento del material mediante molienda mecánica de baja y alta energía (b) la caracterización del material funcional del material (hollín), mediante técnicas de difracción de rayos x, microscopía electrónica de barrido y transmisión, espectroscopía de electrones foto emitidos por rayos-X (XPS), espectroscopía raman e infrarrojo, (c) evaluación del recubrimiento: mediante la caracterización óptica, evaluando la absortancia solar; evaluación térmica, a través de pruebas termo-gravimétricas para determinar la temperatura máxima de operación del recubrimiento, y análisis láser flash para determinar la conductividad térmica; además, análisis de la morfología de la superficie a través de microscopía de fuerza atómica y microscopía electrónica de barrido, y (d) la evaluación del recubrimiento en tres tecnologías termosolares, evaluando los parámetros térmicos de estas tecnologías. El recubrimiento absorbente solar resultante, está elaborado a partir de un aglutinante formado por aceite esencial de cáscara de toronja y poliestireno expandido, ambos obtenidos de materiales de desecho; posee también hollín (variante, en algunos casos de biomasa forestal y en otros comercial), éste último como material funcional fototérmico; el resultado de esta combinación es una pintura que se aplicó en sustratos metálicos, para formar superficies absorbentes de energía solar. Los resultados, muestran que el recubrimiento desarrollado con ambos tipos de hollín puede ser utilizado en tecnologías termosolares de más de 250 °C de operación; posee también una alta absortancia solar mayor al 94 % more...

Este documento presenta un marco de evaluación para las cocinas solares con base en tres parámetros: eficiencia energética, facilidad de uso y accesibilidad económica. Cada parámetro evalúa diversos indicadores cuantificables: a) eficiencia energética: potencia de cocción estándar, tiempo de calentamiento, el rendimiento térmico; b) facilidad de uso: la masa en relación al área del colector, orientaciones por hora y capacidad de carga de la olla y; c) accesibilidad económica: el coste por vatio generado y la durabilidad del reflector y/o acumulador térmico. A cada indicador se le asigna una escala máxima y mínima de la evaluación y los datos obtenidos de estos indicadores se integran en un gráfico radial. La suma de los indicadores constituye el aspecto que debe compararse, pero el gráfico también nos permite interpretar las fortalezas y debilidades descritas. Este marco no se puede analizar una sola cocina solar, ya que es una herramienta comparativa que requiere dos o más dispositivos que deseen evaluarse. more...

This paper introduces a new methodology for the development of appropriate technology that allows satisfying energy needs in rural communities. The methodology integrates the technological development, taking particularly into account the assessment of environmental impacts as well as evaluation of the functionality of the technology. Therefore, it is implemented as a case study in the development of a solar wood-dryer in an artisan community in Mexico. Relevant issues were identified for the success of the methodology, which includes identifying key participants in the community, as well as the use of specialized simulation- and computer-based design tools, and a prior evaluation of the potential environmental impacts through Life-Cycle Assessment (LCA) of the solar wood-dryer. Three geometries of a solar wood-dryer prototype were proposed and analyzed with computer-based simulations, which showed better interior heat transfer than the traditional wood brick-dryer. LCA revealed that the new solar wood-dryer prototype has environmental impacts in all analyzed categories that are 5% or smaller than those of the traditional dryer. Therefore, it was demonstrated that the solar wood-dryer developed with our introduced methodology leads to less environmental impacts compared to those of the traditional wood brick-dryer previously used by the rural community. more...

This paper presents a project of technology adoption, initially with the development of three prototypes of solar cookers; ofour own design. The main charact...

This study describes the exploitation of wood waste (Pinus spp.) in the form of sawdust and shavings generated during the production of furniture and artisanal items in a community in the state of Michoac&aacute, n, western Mexico. A process is described to densifying this raw material, to produce solid-type biofuel briquettes that can be used to satisfy the need to generate low-power heat for residential sectors. Briquette production involved six stages: (a) gathering samples of sawdust and shavings from artisanal workshops in the community, (b) proximal characterization of the samples, (c) elaborating the briquettes, (d) physicochemical characterization of the briquettes, (e) evaluation of the physical-thermal combustion of the briquettes, and (f) an economic evaluation of briquette production to determine viability. Finally, we performed a comparative analysis of the energy, economic, and environmental indicators of the briquettes produced and conventional pine and oak firewood (Pinus spp., Quercus spp.) in the study community. The results show the viability of using biomass residues to make briquettes, which are efficient, economic and easy to make and use. more...

In this paper, it's presented an integral project of technology transfer. Based in the development of several prototypes of solar cookers, all of them with our own design and construction, whose functionality is to compound parabolic concentrators of revolution, this project performed how to implement this ecotechnology. The prototype implemented uses mirror polished aluminum reflectors, aluminum pressure cooker manual tracking device and solar tilt. With the help of social programs, 70 solar cookers were implemented in an indigenous community in Michoacan, Mexico; previously it was implemented a diagnostic of timber resources consumption to each beneficiary family. Also, firing tests were performed with various prototypes plots to select the best one with thermal and ergonomic characteristics. The project expects to reduce the consumption of timber as fuel used for cooking by 30%; to encourage the use of renewable energy, to mitigate respiratory diseases caused by the inhalation of combustion smoke and help the family's economy. Currently we are working with the monitoring to quantify the improvements achieved in consumption-appropriation. There is already an user manual of maintenance and construction of solar cookers in the indigenous language and the project wants to be the basis for future Eco technologies’ implementations. more...

Facultad de Ciencias Físico Matemáticas. Maestría en Ciencias en Ingeniería Física This work shows the development of a coating based on the mixture of soot and resin matte black acrylic for the construction of an absorber surface low cost, aluminum substrate 3003-H14, to pots of solar cookers small dimensions. Also, a theoretical-experimental methodology is proposed to determine the thermal behavior of the surface (plate-coating). This methodology is performed in the laboratory with the presence of a light source 200 w, and can predict the thermal behavior of absorbing surfaces for solar cookers, for example the cooking power. The use of this methodology allows varying the substrate and the coating of the absorber surface, without use a solar cooking, optimizing the use of materials and avoiding tests of cooking power, heating time and cooking tests, they are difficult to carry out. Thermally, the most functional coating in laboratory tests by varying the concentration by weight of soot-acrylic mixture was 40% soot-60% acrylic; the surface with this coating was compared to a commercial coating for high temperature. In tests of effectiveness, power cooking standardized and times heating and cooking, calculated in a solar cooking, the methodology data were corroborated; higher temperature in both cases was observed in a shorter time interval on the surface with the proposed coating; this translates into less time cooking, about 20 minutes less. Therefore, the methodology is functional and opens up many possibilities for research considering varying substrates and coatings, in order to generate an optimal combination of these parameters for solar cookers of small dimensions and solar thermal technologies. El presente trabajo muestra la elaboración de un recubrimiento con base en la mezcla de hollín de resina y acrílico negro mate para la construcción de una superficie absorbedora de bajo costo, con sustrato de aluminio 3003-H14, para almacenadores de alimentos de sistemas de cocción solar de pequeñas dimensiones. Así mismo, se propuso una metodología teórica-experimental para conocer el comportamiento térmico de la superficie (Placa-Recubrimiento). Esta metodología se realiza en laboratorio con la presencia de una fuente de luz de 200 w, y puede predecir el comportamiento térmico en campo de superficies absorbedoras para cocinas solares. El uso de esta metodología permite variar el sustrato y el recubrimiento de la superficie absorbedora, sin necesidad de hacerlo en un sistema de cocción solar, optimizando el uso de materiales y evitando las pruebas de potencia de cocción, tiempo de calentamiento y tiempo de cocción, pruebas que son difíciles de llevar a cabo. Térmicamente, el recubrimiento más funcional en las pruebas de laboratorio, variando en peso la concentración de la mezcla hollín-acrílico, fue 40% hollín-60% acrílico; la superficie con este recubrimiento fue comparada con un recubrimiento comercial para alta temperatura. En las pruebas de efectividad, potencia de cocción estandarizada y tiempos de calentamiento y tiempo de cocción en un sistema de cocción solar, se corroboraron los datos de la metodología sugerida. En ambos casos se observó mayor temperatura en un intervalo de tiempo menor en la superficie con el recubrimiento propuesto; lo anterior se traduce en tiempos de cocción menores, alrededor de 20 minutos menos. Por lo tanto, la metodología es funcional y abre muchas posibilidades de investigación para considerar la variación de sustratos y recubrimientos, con la finalidad de generar una combinación óptima de estos parámetros. more...

Se presenta la estimacion de la potencia de coccion de la estufa solar Jorhejpatarnskua, palabra en lengua purhepecha que significa estufa solar. El dispositivo resulta de la aplicacion de optica de no imagen, usando un concentrador parabolico compuesto (CPC) de revolucion en 3 dimensiones. Para el calculo se ha usado el Protocolo de Funk. La potencia o poder de coccion no estandarizada esta estufa solar, es de aproximadamente 136 Watts.We present the estimation of cooking power of the solar stove Jorhejpatarnskua, word in language purhepecha that means solar stove. The device is from the application of non image optics, using a composed parabolic concentrator (CPC) of revolution in 3D. For the calculation the Protocol of Funk has been used. The cooking power not standardized of the solar cooker is approximately 136 Watts. more...