Christopher Lionel Heard

El estudio analiza el comportamiento de los habitantes de una vivienda típica en Villahermosa, Tabasco, México, frente al aumento de las temperaturas nocturnas. Para ello, se realizan simulaciones en una casa de dos pisos, con viviendas contiguas. En esta región, el clima actual exige el uso de aire acondicionado en las casas unifamiliares. Durante los meses más cálidos, que van de mediados de febrero a mediados de junio, la estrategia habitual es mantener el aire acondicionado encendido a una temperatura estable, sin aumentar la potencia de los equipos. La simulación parte del supuesto de que la temperatura interior nocturna de las viviendas es de 25 °C, mientras que la temperatura exterior es superior a la interior, lo que obliga a tener el aire acondicionado funcionando. Para llevar a cabo este estudio, se utilizará el programa ESP-r, una herramienta que permite determinar tanto el confort térmico dentro de la vivienda, como la cantidad de energía consumida para lograrlo, incluyendo la potencia de los sistemas de aire acondicionado actuales. Según los modelos y escenarios desarrollados, es probable que el crecimiento de esta región conlleve un aumento significativo en el uso de aires acondicionados en las viviendas unifamiliares, sobre todo, en horarios nocturnos. Esto, a su vez, se traducirá en un incremento considerable en la demanda y el consumo de energía eléctrica en la región de Tabasco. Esta situación plantea la necesidad de realizar una inversión sustancial en la infraestructura de transmisión y distribución de energía eléctrica en la región. Será necesario transportar energía desde fuentes más lejanas para satisfacer la creciente demanda. El año típico de referencia utilizado en este análisis fue desarrollado por WhiteBox Technologies, basándose en datos históricos horarios recopilados entre 1975 y 1989.

The construction sector is a significant contributor to global greenhouse gas emissions, primarily due to the embodied carbon of conventional materials, including concrete and steel. Timber offers a sustainable alternative, extending carbon storage and supporting circular economic strategies. This study assesses the potential of timber as a low-carbon building material in Mexico by combining a literature review with the perspectives of fifty stakeholders from forestry, wood processing, architecture, and academia. Data was collected through semi-structured interviews and an online snowball-sampled survey. Findings indicate that timber can reduce embodied carbon by 30–50%, lower onsite waste by up to 30%, improve energy efficiency, and sequester 1–1.6 t CO₂ m⁻³ over a building’s life cycle. However, adoption is hindered by regulatory gaps, limited technical expertise, cultural biases regarding durability and fire safety, and higher upfront costs of engineered wood. The study recommends updating building codes, establishing fire safety standards, promoting financial incentives, and strengthening education programs to enhance technical capacity. By addressing these barriers, timber construction can be mainstreamed in Mexico’s urban development, advancing circular economy goals and contributing to global climate mitigation.

The social acceptance of introducing an improved and sustainable roofing material in multicultural communities in Mexico was addressed. A case history of a community “La Cañada” in Huixquilucan, State of Mexico (19°19′02.81″ N, 99°22′23.21″ W, 3025 m above mean sea level), a village very close to the eastern edge of Mexico City and representative of strong social and transcultural pressures similar to surrounding communities in Mexico City, is reported. The approach considered developing a double-layered roof to reduce the energy demand for space heating in this predominantly cold region, thus significantly contributing to indoor thermal comfort, reducing the need for cutting wood and helping to alleviate the accelerating impacts of deforestation in the area. Two parallel studies were used, whereby the then-current awareness levels of citizens and the factors impacting their commitment to energy sustainability were analysed using multicriteria social parameters, while the second study focused on the analysis of improved comfort when the proposed double roof was implemented, based on the feedback received from a pool of citizens who experienced living in the improved prototype dwellings. Results showed that while the level of awareness on energy efficiency was still low, the influence of media on their decisions and aspirations was strong and this could be constructively used to support the shift towards a more sustainable society and a “solar culture”. Moreover, the developed sustainable double-roof prototype has significantly improved indoor comfort and energy savings for heating, while demonstrating a fast and easy replicability potential in similar dwellings.

Industrial liquid/solid fluidized bed heat exchangers are commonly used with particle recycling systems to allow an increased superficial velocity and higher heat transfer rates. Here, experimental results are reported on a novel helical flow channel geometry for liquid/solid fluidized beds which allow higher heat transfer rates and reduced complexity by operating below the particle transport fluid velocity. This eliminates the complexity of particle recycle systems whilst still delivering a compact heat exchanger. The qualitative character of the fluidization was studied for a range of particle types and sizes under several inclinations of the helices and various hydraulic diameters. The best fluidization combinations were further studied to obtain heat transfer coefficients and pressure drops. Improvements over the heat exchange from a plain concentric tube in an annulus were obtained to the following degree: vertical fluidized bed, 27%; helical baffles, 34 to 54%; and fluidized bed with helical baffles, 69 to 89%.

The present investigation analyzes the volatility of precipitation and temperature in Mesoamerican cities generated by climate change, using as a baseline the dynamics of the two observed climatic variables month by month; between 1971 to 1980 and 2001 to 2010, comparing them with future climate scenarios for the years 2061 to 2070. The Mesoamerican cities used in the analysis include the capital cities of the states of the Mexican southeast, Guatemala, El Salvador, Honduras, and Belize. Measuring climatic variables' volatility allows us to qualify if the distribution of rainfall and temperature is above or below the average ranges of the historical distribution of these variables. Understanding climate volatility provides a glimpse of a series of technical and political scenarios and generates concrete actions in the face of changes in long-term climate dynamics. Thus, it anticipates the effects of extreme climate events present in a region. The method empowers decision-making in public policy, particularly in urban areas where the tendency to dry and hot climates generate a series of consequences. Some consequences are i) the need to diversify drinking water sources and hydroelectric generation, ii) the effects of heat spells on the quality of life of the population, iii) the quality of sleep and productivity, and ultimately iv ) consumption of energy levels for air conditioning or refrigeration higher than current levels.

A two storey terraced house was modelled in ESP-r with a simple window opening control strategy to represent typical dwellings found in Mexico City and the adjoining municipalities. Future weather data was generated for years in this century based on morphing methods developed from the literature and by the authors and a TMY weather file developed from historical data between 1975 to 1989 by WhiteBox Technologies. The population in the region under consideration is a little over 20 million which represents 16% of Mexico’s population. The present day climate is such that air conditioning is rarely used in single family housing. The main cooling strategy in the hottest months (Mid February to mid June) is window opening. This was modelled considering that if the interior temperature was at or above 18°C and the exterior air temperature was below the interior air temperature then windows would be open. The air flow was modelled using the flow network model within ESP-r. It was found that in the latter part of the present century, this strategy would become increasingly ineffective. This is likely to lead to a considerable increase in installed air conditioning in single family dwellings and a consequent increase in electricity demand and consumption leading to a need for substantial investments in electricity transmission and distribution systems in the region to bring in power from distant sources.

The frequency of extreme weather events, such as severe floods, storms, hurricanes, and droughts, seems to have increased in recent years. The analysis of trends and other changes in the distribution of these phenomena uses the extreme value theory. This study proposes the use of the Weibull distribution for the evaluation of extreme events in precipitation. A correct assessment of probabilities of extreme precipitation events and their changes is important for stakeholders, particularly in agriculture, infrastructure, tourism, and insurance. This paper provides a simple approach in showing the trends in extreme precipitation in the western part of Mexico. The methodology has an additional virtue as it enables the calculation of probabilities of change in extreme events. With this, it is feasible to develop new methodologies for better understanding of climate change.