Modelado termodinámico de una planta solar térmica hibrida de ciclo Brayton en Colombia

Introducción: Actualmente en Colombia, existe gran interés por la aplicación de energías renovables y la diversificación de la matriz energética. Por lo tanto, en el presente trabajo se muestran los resultados de la simulación de una planta solar térmica hibrida de ciclo Brayton cerrado en Colombia, que recibe calor de un sistema de concentración de torre central y heliostatos. El recurso solar se estima por un modelo horario, adicionalmente cuenta con una cámara de combustión que utiliza gas natural como combustible, la cual garantiza la estabilidad del calor suministrado a la planta. La ubicación de la planta se selecciona en función de la radiación global y difusa media diaria mensual, y adicionalmente, se realiza una simulación de los principales parámetros de operación, optimizando la potencia y el rendimiento global en función de la relación de presión. Por último, se realiza un análisis exergético de la planta, especialmente de los componentes afectados por la variación de la radiación en el día. Objetivo: Evaluar una planta solar térmica de concentración de ciclo Brayton cerrado, desde el punto de vista energético y exegético bajo las condiciones ambientales de Colombia. Metodología: Integrar en lenguaje modélica, por medio de un compilador Dymola un modelo de recurso solar, un modelo energético y un modelo exergético aplicado a las condiciones ambientales de Colombia. Resultados: Se presenta el análisis correspondiente a la evolución de los principales parámetros de operación de la planta a lo largo del día, la variación del rendimiento y la potencia en función de la relación de presiones. Conclusiones: Es viable técnicamente la operación de una planta solar térmica de concentración de ciclo Brayton en algunos lugares de Colombia, dado el recurso solar disponible y el ahorro de combustible que genera a pesar del detrimento del rendimiento energético y exergético.Introduction− Actually in Colombia, there is great inter-est in the application of renewable energy and the diversi-fication of the energy matrix. Therefore, in this work, are presented the results of the simulation of a hybrid solar thermal plant of closed Brayton cycle in Colombia, that re-ceives heat from a concentration system of central tower and heliostats. The solar resource is estimated by a time model validated initially, additionally with a combustion chamber that uses natural gas as fuel, which guarantees the stability of the heat supplied to the plant. The location of the plant is selected based on the global and diffuse average monthly radiation per day, and additionally, a simulation of the main operating parameters is carried out, optimizing the power and overall performance as a function of the pressure ratio. Finally, an exergy analysis of the plant is developed, especially of the components affected by the variation of the radiation during the day.Objective−Evaluate a thermal solar plant of closed Brayton cycle concentration, through an energetic and exegetical analysis under the environmental conditions of Colombia.Methodology−Integrate a model of solar resource, an energetic model and an exergy model applied to the envi-ronmental conditions of Colombia in model language in a Dymola compiler.Results− The evolution of the main operating parameters of the plant throughout the day, the variation of the perfor-mance and the power depending on the pressure ratio are presented and analyzed.Conclusions−It is technically feasible the operation of a solar thermal plant of concentration of Brayton cycle in some places of Colombia, given the available solar resource and the fuel saving that it generates despite the detriment of the energetic and exegetical performance

Energy losses study in solar hybrid gas turbine in Colombia

Due to decrease of oil reserves, the international commitment for the reduction of pollutant emissions and environmental protection, renewable energy sources are intensively studied, including solar energy applications. However, solar energy is not constant and one possible alternative are solar hybrid thermosolar power plants. A hybrid solar gas turbine has three subsystems: a solar concentrator with heliostat field and central tower receiver, a combustion chamber, and a regenerative gas turbine. A previous thermodynamic analysis allowed shows an energy and exergy study of the plant, from a thermodynamic model of the system that has a method of solar resource estimation. However, this analysis did not allow evaluation of the energy losses in the system components, although the original model considered the typical irreversibilities of these cycles. This work aimed to develop a thermodynamic model that estimates the energy losses in the subsystems and the solar hybrid gas turbine components from a few parameters. The model estimated the energy losses for a Brayton cycle hybrid solar thermal plant throughout the day July 20 in Barranquilla, Colombia. A Dymola compiler in Modelica language was used to evaluate the model, which facilitates the estimation of the results at different times of the day. In this case, the computations were performed hourly throughout the day. In the results, energy losses were 16 % in the solar concentrator when the solar resource was the maximum at noon and close to 1 % in the combustion chamber. Therefore, the hybrid solar Brayton cycle system is technically feasible and reduces fuel consumption. Consequently, it is important to continue developing concentration systems and reduce their energy losse

Influence of water electrolysis products on diesel engine performance in Colombia

Restrictions imposed by regulatory frameworks, the high cost of fuels, environmental impacts and the efficiency of internal combustion engines encourage research into reducing the consumption of fossil fuels. Additionally, to think about the alternative energy sources. In compression ignition engines, researchers around the world have been working for years on the use of biodiesel fuel, in order to reduce emissions and the consumption of diesel fuel. In other investigations, water electrolysis products obtained in an HHO gas generator and supplied to an internal combustion engine allow for improving performance, reducing fuel consumption and emissions. HHO gas is a mixture of hydrogen and oxygen resulting from the electrolysis process of water, with energy supplied by an electric source or accumulator. The main objective of this work is to evaluate the influence of an HHO generator products in a diesel engine that operates with diesel fuel produced in Colombia with 10 % biodiesel. The objective of this study is evaluated the influence of gas HHO on mechanical performance, fuel consumption, and polluting emissions in a single-cylinder diesel engine, performing a comparative analysis when the HHO generator operates with different amperages. The results showed a 25 % average reduction in fuel consumption between 1500 y 2500 engine revolutions when the HHO cell operated with 8 amperes. The breaking power maximum value increased a 10 %, and CO and PM10 emissions were reduced by 14 % and 53 %, respectively, at 1000 rpm. It is possible to conclude that supplying water electrolysis products in the fuel-air mixture increases the mechanical performance of a diesel engine and reduces polluting gas emissions. Additionally, research areas are opened in the development of HHO generators and standards for the application of this technolog

Proposal for improving of paddy rice drying process in dryers inclined pools: Propuesta de mejoramiento del proceso de secado de arroz paddy en secaderos tipo albercas inclinadas

The operation of inclined type dryers for paddy rice is studied to improve their operation and efficiency, considering the variables of drying time, humidity distribution in the rice layer after drying and air velocities within the plenum. Simulating the distribution and velocities of the air flow before crossing the rice layer, the outlet ducts to the plenum are relocated and dampers are placed to distribute the flow evenly. On the other hand, it is proposed to replace the flat-type mesh with a zigzag-type mesh.  To verify the proposed modifications, a scale model was built to determine the humidity and drying time variation inside the rice layer, obtaining more uniform moisture percentages within the rice layer and a decrease in drying time.  Se estudia el funcionamiento de los secaderos tipo inclinado para arroz paddy, con el fin de mejorar su operación y eficiencia, considerando las variables de tiempo de secado, distribución de la humedad en la capa de arroz después del secado y velocidades del aire dentro del plenum. Simulando la distribución y velocidades del flujo de aire antes de cruzar la capa de arroz se reubican los conductos de salida al plenum y se colocan dampers que distribuyan uniformemente el flujo. Por otro lado, se propone la sustitución de la malla tipo plana por una malla tipo zigzag.  Para verificar las modificaciones propuestas se construyó un modelo a escala para medir la variación del tiempo de secado y la humedad dentro de la capa de arroz paddy, obteniendo porcentajes de humedad más uniformes dentro de la capa de arroz y disminución del tiempo de secado

Proposal for improving of paddy rice drying process in dryers inclined pools: Propuesta de mejoramiento del proceso de secado de arroz paddy en secaderos tipo albercas inclinadas

The operation of inclined type dryers for paddy rice is studied to improve their operation and efficiency, considering the variables of drying time, humidity distribution in the rice layer after drying and air velocities within the plenum. Simulating the distribution and velocities of the air flow before crossing the rice layer, the outlet ducts to the plenum are relocated and dampers are placed to distribute the flow evenly. On the other hand, it is proposed to replace the flat-type mesh with a zigzag-type mesh.  To verify the proposed modifications, a scale model was built to determine the humidity and drying time variation inside the rice layer, obtaining more uniform moisture percentages within the rice layer and a decrease in drying time.  Se estudia el funcionamiento de los secaderos tipo inclinado para arroz paddy, con el fin de mejorar su operación y eficiencia, considerando las variables de tiempo de secado, distribución de la humedad en la capa de arroz después del secado y velocidades del aire dentro del plenum. Simulando la distribución y velocidades del flujo de aire antes de cruzar la capa de arroz se reubican los conductos de salida al plenum y se colocan dampers que distribuyan uniformemente el flujo. Por otro lado, se propone la sustitución de la malla tipo plana por una malla tipo zigzag.  Para verificar las modificaciones propuestas se construyó un modelo a escala para medir la variación del tiempo de secado y la humedad dentro de la capa de arroz paddy, obteniendo porcentajes de humedad más uniformes dentro de la capa de arroz y disminución del tiempo de secado

Influencia de productos de la hidrólisis en el desempeño de un vehículo que opera con gasolina y gas natural en la altura

Introduction: There is a great interest in reducing the use of fossil fuels due to the variation of prices and strong regulatory controls, which is why methods are being sought to reduce fuel consumption in internal combustion engines, such as the supply of products from the Hydrolysis of the water in the engine manifold. Objective: The objective of this paper is to present the results of an experimental methodology applied to estimate the mechanical and environmental performance of a vehicle fueled with gasoline and natural gas, when the engine is supplied with products resulting from the hydrolysis of water. Methodology: For the supply of said products to the vehicle, an external hydrolysis device was installed, and the vehicle has been instrumented with a fifth wheel, temperature and engine revolutions speed sensors, to perform acceleration tests on a flat road and a road with longitudinal slope angle. Additionally, torque and power tests with a chassis dynamometer, and pollutant emissions and fuel consumption tests were carried out. The tests were conducted in the outskirts of the city of Bogotá DC - Colombia, located at 2650 m above sea level. Results: The results show that the products of hydrolysis do not improve the mechanical performance of the vehicle, since they increase the time to arrive at the speeds defined in the acceleration tests up to 18% in the engine with gasoline and 7% in the engine with natural gas, and the torque and power are increase by around 1%. On the other hand, the results of the polluting emissions tests indicate that fuel consumption is reduced by about 7%. Conclusions: The results indicate that the performance of the vehicle does not improve, although fuel consumption decreases, the environmental performance does not decrease.Introducción: En la actualidad existe un gran interés en la reducción en el uso de combustibles fósiles por la variación de los precios y los fuertes controles normativos, por lo cual se buscan métodos para disminuir el consumo de combustible en los motores de combustión interna, tales como el suministro de productos de la hidrólisis del agua en la admisión del motor. Objetivo: El objetivo del este trabajo es presentar los resultados de una metodología experimental aplicada para estimar el desempeño mecánico y ambiental de un vehículo alimentado con gasolina y gas natural, específicamente cuando al motor se le suministran productos resultantes de la hidrólisis del agua. Metodología: Para el suministro de dichos productos al vehículo se le instalo un dispositivo hidrólisis externo, y el vehículo fue instrumentado con una quinta rueda, sensores de temperatura y velocidad de revoluciones del motor, para realizar pruebas de aceleración en una carretera plana y una carretera con pendiente longitudinal. Adicionalmente, se realizaron pruebas de torque y potencia con dinamómetro de chasis y pruebas de emisiones contaminantes y de consumo de combustible. Las pruebas fueron realizadas en las afueras de la ciudad de Bogotá DC - Colombia, ubicada a 2650 m sobre el nivel del mar. Resultados: Los resultados muestran que los productos de la hidrólisis no mejoran el desempeño mecánico del vehículo, ya que aumentan el tiempo para llegada a las velocidades definidas en las pruebas de aceleración hasta en un 18% en el motor con gasolina y 7% en el motor con gas natural, mientras que el torque y la potencia del motor se incrementa alrededor del 1%. Por otro lado, los resultados de las pruebas de emisiones contaminantes indican que el consumo de combustible se reduce aproximadamente en un 7%. Conclusiones: Los resultados indican que el desempeño del vehículo no mejora, aunque el consumo de combustible disminuye, el desempeño ambiental no disminuye