A review of the state-of-the-art of solar thermal collectors applied in the industry

El consumo energético asociado al sector de la industria representa el 38 % de la demanda de energía a nivel global, siendo un aspecto importante que marca el desarrollo de un país. En este sentido, es sumamente importante diversificar las distintas fuentes de energía e incorporar el uso de fuentes renovables de energía, como la solar, no solamente con la idea de asegurar el suministro energético, sino también considerando como elementos que permitan la reducción de las emisiones generadas por el uso de combustibles fósiles. El presente trabajo aborda las principales tecnologías de colectores solares que pueden ser incorporadas a distintos tipos de industrias, basado en experiencias e investigaciones en otros países. Sobre la base de esta revisión, se ha visto que una buena parte de las industrias a nivel mundial requieren temperaturas en sus procesos hasta los 250 °C, lo que hace idóneo el uso de esta tecnología. En función de cada industria, se podrán usar colectores solares de placa plana, de tubos de vacío, del tipo Fresnel o cilindro parabólicos. Por último, se detallan los ahorros asociados a algunas instalaciones y se abordan los desafíos relacionados con este sector.The energy consumption associated with the industry sector represents 38% of the global energy demand, being an important aspect that marks the development of a country. In this sense, it is extremely important to diversify the different energy sources and incorporate the use of renewable energy sources, such as solar energy, not only with the idea of ensuring energy supply, but also as elements that enable the reduction of energy emissions generated by the use of fossil fuels. This work addresses the main solar collector technologies that may be incorporated into different types of industries, based on experiences and research in other countries. Based on this review, it has been seen that an important part of the industries worldwide requires temperatures up to 250 °C in their processes, which makes suitable the use of solar energy technology. Depending on each industry, flat plate, vacuum tube, Fresnel type or parabolic trough solar collectors may be used. Finally, the savings associated with some facilities are detailed and the challenges related to this sector are addressed

Design and Development of a Catalytic Fixed-Bed Reactor for Gasification of Banana Biomass in Hydrogen Production

Hydrogen produced from biomass is an alternative energy source to fossil fuels. In this study, hydrogen production by gasification of the banana plant is proposed. A fixed-bed catalytic reactor was designed considering fluidization conditions and a height/diameter ratio of 3/1. Experimentation was carried out under the following conditions: 368 °C, atmospheric pressure, 11.75 g of residual mass of the banana (pseudo-stem), an average particle diameter of 1.84 mm, and superheated water vapor as a gasifying agent. Gasification reactions were performed using a catalyzed and uncatalyzed medium to compare the effectiveness of each case. The catalyst was Ni/Al2O3, synthesized by coprecipitation. The gas mixture produced from the reaction was continuously condensed to form a two-phase liquid–gas system. The synthesis gas was passed through a silica gel filter and analyzed online by gas chromatography. To conclude, the results of this study show production of 178 mg of synthesis gas for every 1 g of biomass and the selectivity of hydrogen to be 51.8 mol% when a Ni 2.5% w/w catalyst was used. The amount of CO2 was halved, and CO was reduced from 3.87% to 0% in molar percentage. Lastly, a simulation of the distribution of temperatures inside the furnace was developed; the modeled behavior is in agreement with experimental observations

Design and Development of a Catalytic Fixed-Bed Reactor for Gasification of Banana Biomass in Hydrogen Production

Hydrogen produced from biomass is an alternative energy source to fossil fuels. In this study, hydrogen production by gasification of the banana plant is proposed. A fixed-bed catalytic reactor was designed considering fluidization conditions and a height/diameter ratio of 3/1. Experimentation was carried out under the following conditions: 368 °C, atmospheric pressure, 11.75 g of residual mass of the banana (pseudo-stem), an average particle diameter of 1.84 mm, and superheated water vapor as a gasifying agent. Gasification reactions were performed using a catalyzed and uncatalyzed medium to compare the effectiveness of each case. The catalyst was Ni/Al2O3, synthesized by coprecipitation. The gas mixture produced from the reaction was continuously condensed to form a two-phase liquid–gas system. The synthesis gas was passed through a silica gel filter and analyzed online by gas chromatography. To conclude, the results of this study show production of 178 mg of synthesis gas for every 1 g of biomass and the selectivity of hydrogen to be 51.8 mol% when a Ni 2.5% w/w catalyst was used. The amount of CO2 was halved, and CO was reduced from 3.87% to 0% in molar percentage. Lastly, a simulation of the distribution of temperatures inside the furnace was developed; the modeled behavior is in agreement with experimental observations

Design and implementation of a web-based residential energy assessment platform: a case study in Cuenca-Ecuador

Population confinement caused by the COVID-19 pandemic has led to an increase in household energy consumption. Electricity consumption in the residential sector in Latin America and the Caribbean increased by 20% during 2020 in comparison to 2019. An upsurge in electricity consumption at the residential level was observed between March and August of 2020 due to the emergency sanitary declaration in Ecuador. Viewed in this context, the residential customers of Cuenca have increased their consumption by around 13% during May 2020 in comparison to the same month of the previous year. Adopting energy efficiency and sufficiency measures could counteract this increase in energy and contribute to managing the demand in the residential sector. The present work aims to evaluate energy savings and emissions reduction in the residential sector in Cuenca through the design and implementation of a web-based platform for estimating electricity power savings. To develop the platform, information was gathered, through surveys, on the energy consumption of the average household. Power consumption of appliances was obtained from various sources, mainly from a database provided by a local appliance retailer. Energy-saving strategies for electrical and electronic appliances were taken from technical guidelines and academic sources. The functional and visual specifications of the platform were designed with specialized tools. The platform allows for calculating household electrical energy consumption and potential savings in energy, economic, and environmental terms in a simple and visually attractive manner. The study shows that 4 members of a family household consumes an average of 182 kWh/month, which is equivalent to 17.1 USD and an annual environmental footprint of 1068.9 kg of CO2. From this energy consumption, 57% is consumed by household appliances, 31% corresponds to technology and entertainment, and 12% represents lighting. Nevertheless, it is possible to reduce monthly energy consumption by 45% if energy sufficiency and efficiency measures are applied by consumers. This reduction will produce a monthly saving of 7.9 USD and an annual reduction of 485 kg of emissions. By implementing this web-based tool non-specialized users can analyze and decide the best way to reduce energy consumption, creating an appropriate energy culture with a positive impact on the household economy and promoting environmental sustainability.Guayaqui

Design and development of a catalytic fixed-bed reactor for gasification of banana biomass in hydrogen production

Hydrogen produced from biomass is an alternative energy source to fossil fuels. In this study, hydrogen production by gasification of the banana plant is proposed. A fixed-bed catalytic reactor was designed considering fluidization conditions and a height/diameter ratio of 3/1. Experimentation was carried out under the following conditions: 368 °C, atmospheric pressure, 11.75 g of residual mass of the banana (pseudo-stem), an average particle diameter of 1.84 mm, and superheated water vapor as a gasifying agent. Gasification reactions were performed using a catalyzed and uncatalyzed medium to compare the effectiveness of each case. The catalyst was Ni/Al2O3, synthesized by coprecipitation. The gas mixture produced from the reaction was continuously condensed to form a two-phase liquid–gas system. The synthesis gas was passed through a silica gel filter and analyzed online by gas chromatography. To conclude, the results of this study show production of 178 mg of synthesis gas for every 1 g of biomass and the selectivity of hydrogen to be 51.8 mol% when a Ni 2.5% w/w catalyst was used. The amount of CO2 was halved, and CO was reduced from 3.87% to 0% in molar percentage. Lastly, a simulation of the distribution of temperatures inside the furnace was developed; the modeled behavior is in agreement with experimental observations

Biodiesel Production by Transesterification of Recycled Oil Catalyzed with Zinc Oxide Prepared Starting from Used Batteries

The consumption of batteries and cooking oil have been increasing. Most used batteries are disposed of incorrectly, leading to health and environmental problems because of their composition. In a similar form, cooking oil, once used, is often released by the discharge reaching the wastewater, polluting soil, and water, which affects its treatment. In Ecuador, these environmental passives are recollected and stored without further treatment, which is a temporary and unsustainable solution. To address this issue, the circular economy concept has gained increasing attention. In this study, zinc oxide was prepared from discarded batteries using the hydrometallurgical method to use as a catalyst; it achieved 98.49% purity and 56.20% yield and 20.92% of particles presented a particle size of 1–10 nm. Furthermore, the catalyst morphology was investigated in an SEM, which showed that particle size ranged from 155.69 up to 490.15 nm and spherical shapes. Due to its characteristics, the obtained catalyst can be used in the industry instead of the zinc oxide obtained by mining processes. These processes are known to produce heavy contamination in the ecosystems and human health. Additionally, a zinc oxide lifecycle in the environment was analyzed through a material flow analysis (MFA), taking into consideration two paths, one assuming the disposal of used batteries and the other assuming the recycling of zinc. Biodiesel was produced with a heterogeneous catalyst. This took place with a transesterification reaction with used cooking oil, ethanol, and zinc oxide (ZnO) as catalysts. The biodiesel obtained had the following characteristics: 37.55 kJg−1 of heating power, 0.892 gcm−3 of density, 4.189 mm2/s of viscosity, 0.001% of water content, and a 70.91% yield. Furthermore, the energy consumption in biodiesel production was quantified, giving a total of 37.15 kWh. This kind of initiative prevents that waste from becoming environmental pollutants and potential health risks by giving them a second use as a resource. Moreover, turning waste into a valuable product makes the processes self-sustaining and attractive to be implemented

Evaluation of Nutritional Practices in the Critical Care patient (The ENPIC study) : Does nutrition really affect ICU mortality?

The importance of artificial nutritional therapy is underrecognized, typically being considered an adjunctive rather than a primary therapy. We aimed to evaluate the influence of nutritional therapy on mortality in critically ill patients. Methods: This multicenter prospective observational study included adult patients needing artificial nutritional therapy for >48 h if they stayed in one of 38 participating intensive care units for ≥72 h between April and July 2018. Demographic data, comorbidities, diagnoses, nutritional status and therapy (type and details for ≤14 days), and outcomes were registered in a database. Confounders such as disease severity, patient type (e.g., medical, surgical or trauma), and type and duration of nutritional therapy were also included in a multivariate analysis, and hazard ratios (HRs) and 95% confidence intervals (95%CIs) were reported. We included 639 patients among whom 448 (70.1%) and 191 (29.9%) received enteral and parenteral nutrition, respectively. Mortality was 25.6%, with non-survivors having the following characteristics: older age; more comorbidities; higher Sequential Organ Failure Assessment (SOFA) scores (6.6 ± 3.3 vs 8.4 ± 3.7; P < 0.001); greater nutritional risk (Nutrition Risk in the Critically Ill [NUTRIC] score: 3.8 ± 2.1 vs 5.2 ± 1.7; P < 0.001); more vasopressor requirements (70.4% vs 83.5%; P=0.001); and more renal replacement therapy (12.2% vs 23.2%; P=0.001). Multivariate analysis showed that older age (HR: 1.023; 95% CI: 1.008-1.038; P=0.003), higher SOFA score (HR: 1.096; 95% CI: 1.036-1.160; P=0.001), higher NUTRIC score (HR: 1.136; 95% CI: 1.025-1.259; P=0.015), requiring parenteral nutrition after starting enteral nutrition (HR: 2.368; 95% CI: 1.168-4.798; P=0.017), and a higher mean Kcal/Kg/day intake (HR: 1.057; 95% CI: 1.015-1.101; P=0.008) were associated with mortality. By contrast, a higher mean protein intake protected against mortality (HR: 0.507; 95% CI: 0.263-0.977; P=0.042). Old age, higher organ failure scores, and greater nutritional risk appear to be associated with higher mortality. Patients who need parenteral nutrition after starting enteral nutrition may represent a high-risk subgroup for mortality due to illness severity and problems receiving appropriate nutritional therapy. Mean calorie and protein delivery also appeared to influence outcomes. ClinicaTrials.gov NCT: 03634943