Roberto Alvarado-Juárez

In indoor thermal analyses, the effect of humid air as a radiatively participating medium that absorbs and emits energy is often neglected. This simplification can underestimate important values in the results. This study presents a numerical investigation of the humid air that participates radiatively in the conjugate heat and mass transfer convection into a room modeled as a two-dimensional square cavity with a semitransparent wall (glass). The governing equations for mass, momentum, energy, species transport, turbulence, and radiative heat transfer were solved using the Finite Volume Method and coupled with the SIMPLEC algorithm. Two scenarios were analyzed: a radiatively participating medium (RPM) and a non-participating medium (NPM), under two climatic conditions (hot and cold). Results show that considering the radiatively participating medium breaks the symmetric patterns observed in the case of NPM. The energy absorbed by humid air enhances turbulent viscosity, buoyant forces, and indoor temperature. Humid air absorbs approximately 30–32% of the incident energy entering the enclosure. Finally, a correlation for the average temperature is proposed. The results provide insight into the influence of radiatively participating humid air on indoor-like thermal behavior. The study focuses on the analysis of fundamental transport mechanisms.

En la mecánica automotriz, particularmente en los trabajos de suspensión de vehículos, existe una problemática recurrente asociada a la falta de herramientas especializadas para controlar el movimiento de la horquilla de suspensión. En los servicios mecánicos se emplean frecuentemente herramientas improvisadas, lo que incrementa los riesgos de accidentes y daños tanto en el vehículo como en el operario. Esta situación afecta la eficiencia y la calidad del servicio, generando retrasos y costos adicionales En este contexto, el presente estudio aborda el diseño y la fabricación de una herramienta especializada que permite manipular la horquilla de suspensión de manera segura y precisa. Mediante el uso de técnicas de diseño mecánico y análisis estático, se desarrolló un prototipo funcional orientado a mejorar las condiciones de operación en talleres automotrices Los resultados obtenidos evidencian que la herramienta propuesta contribuye a reducir riesgos operativos, optimizar los tiempos de reparación y minimizar posibles daños en los componentes del sistema de suspensión. Asimismo, se demuestra su viabilidad técnica como alternativa eficiente dentro del mantenimiento automotriz. Finalmente, se destaca su potencial para la formación de recursos humanos especializados y su aporte al desarrollo tecnológico en el sector

I moduli termoelettrici [TEM] sono ampiamente utilizzati per il raffreddamento dei dispositivi elettronici grazie alle loro dimensioni ridotte e al fatto che non producono rumore, oltre che perché non richiedono refrigeranti, rendendoli quindi ecologici. Per garantire l'efficienza dei TEM, è necessario controllare la temperatura sul lato caldo. Questa ricerca riporta la simulazione effettuata su un dissipatore di calore di un TEM commerciale con un modulo Peltier. L'analisi è stata effettuata sull'aletta centrale per 4 casi di separazione delle alette sul lato freddo e caldo [p=5,08, 3,81, 2,54, 1,27 mm] e 6 casi di trasferimento di calore per convezione [h=5, 20, 50, 100, 150 e 200 W/m2∙K]. I risultati mostrano che il comportamento termico è simile per ogni separazione delle alette senza differenze significative di temperatura. Le differenze principali sono state osservate sul lato caldo, dove il caso p=1,27 mm e h=200 W/m2∙K è l'opzione migliore per ridurre la temperatura del dissipatore di calore sul lato caldo di un TEM. Infine, la comprensione di come la geometria e la convezione influenzano la temperatura consente di prendere decisioni nella scelta del dissipatore di calore adeguato.

This research reports the simulation done to a heat sink of a commercial TEM with a Peltier module. The analysis was done at the central fin for 4 cases of separation of the fins at the cold and hot side [p=5.08, 3.81, 2.54, 1.27 mm] and 6 cases of convective heat transfer [h=5, 20, 50, 100, 150 and 200 W/[m2K]]. Results show that the thermal behavior is similar for each separation of fin without significant difference of temperature. The main differences were observed at the hot side were the case of p=1.27mm and h=200 W/[m2K] is the best option to reduce the temperature of the heat sink in the hot side of a TEM.

Climate change, driven by natural factors and human activity, produces significant environmental changes worldwide. One consequence is increased rainfall, which leads to intense and increasingly frequent storms, sudden increases in river flows, and increased likelihood of emergencies linked to natural disasters. This framework proposes a model based on the System Dynamics (SD) approach that aims to monitor the increase in flow in rapid-response catchments (RRCs). The model evaluates humanitarian logistics strategies to manage supplies during emergency situations and it is based on dynamic simulation, whose advantages are the analysis of causal relationships between variables and their behavior over time, mathematical support during the creation of the simulation model, and the creation of a graphical interface that allows the user to carry out a visual analysis of the variables involved in the model. The results show, through a case study, the implementation of a containment plan based on early decision-making from rapid-response catchment monitoring to generate humanitarian logistics strategies preventing material and human damage. Therefore, the main contribution of this framework is the creation of a simulation model that involves the synergy between two different systems: the analysis of RRC behavior and the humanitarian logistics plan to establish provision policies (food, water and medicine) based on the number of people at risk.

A Net Zero Energy Building (NZEB) is a building with a highly reduced operational energy consumption where energy efficiency measures have been implemented that allow the energy demand to be supplied by renewable sources. To this end, this paper describes the adaptation and implementation of a methodology to transform an existing residential building into a net zero energy building and thus achieve a self-sustainable building, considering as a case study a warm sub-humid climate in the state of Morelos, since this climate predominates in 85% of the total area of the state. The types of feasible and affordable eco-technologies to be implemented in Morelos are analysed and discussed. The energy efficiency of the building is analysed considering the combination of construction techniques, suitable materials for the envelope, thermal loads, and electrical energy consumption, with the aim of reducing the high dependence on fossil fuels in the construction sector.

The effect of radiation of a gray gas in a square cavity with double diffusive natural convection is presented. The regime flow studied range from a thermal Rayleigh number of 104 to 1011 and buoyancy ratio from 0.5 to 2.0. The governing equations of fluid flow, heat transfer and radiative transfer equation are solved by the finite volume method. The results show the effect of radiatively participating media plays an important role in the heat and mass transfer study doing oblique stratification. The velocity and turbulent viscosity increases about 80% and 22%, respectively, and decreases the convective Nusselt number 13%. The increase of buoyancy ratio increases the mass transfer until 26%. Finally, a practical correlation for computing the convective and radiative Nusselt numbers as well as the Sherwood number is proposed.