Abstract:The present study's main objective was to determine the applicability of organic phase change materials (PCMs) in a building's envelope construction system for the passive provision of comfortable indoor thermal conditions over one year based on thermal inertia in Mexico City. Research on PCMs relate mainly to their use in building envelope construction systems to reduce energy consumption for mechanical indoor thermal conditioning-not in passive systems. Computer simulation results of mean indoor temperature variations are presented with the objective of evaluating these construction systems' thermal inertia properties. In the present study, dynamic thermal simulations (DTS), using EnergyPlus software, of ten 1 m 3 test units with envelope construction systems combining organic PCMs of different fusion temperatures with conventional materials were performed. Based on the results, it is concluded that the implementation of organic PCMs with a fusion temperature around 25 • C in combination with aerated concrete in a space envelope results in the highest number of hours the indoor temperatures remain within the comfort range throughout a typical year, due to the decrement of indoor temperature oscillations and, to a large extent, to thermal lag.

Recent research indicates that not only blue and green monochromatic light stimulates our circadian system, but polychromatic light as well. Recent work also suggests that the human circadian system also changes its spectral sensitivity with different light levels and spectrum. Usually, indoor architectural spaces are dynamic in light color and quantity, and to a certain extent, the architect is able to modulate these light characteristics to benefit not only of the visual system but the circadian system as well. The purpose of this work was to redirect the three main spectral components (RGB) of indirect light towards different directions and in different quantities as an approach to an understanding of how the spectral composition of an indoor light environment can be modulated by passive methods. In the present work, reflections of blue-enriched polychromatic light off different surface materials with different optical properties and textures were simulated. Spectral radiance values were measured at a specific point in space in order to evaluate how the three main spectral components of the reflected light changed in quantity.

The urban heat island (UHI) is mostly due to urbanization. This phenomenon in concert with the high temperatures caused by global climate change may profoundly affect human thermal comfort, which can influence human productivity and morbidity especially in spring/summer period. The main objective of this investigation was to determine changes in degree of thermal comfort of Mexico City’s inhabitants and compare it with the physiological equivalent temperature (PET) to evaluate whether PET and its categorization are adequate to be applied in Mexico City. A series of microclimatological measurements to estimate PET were made at four sites including the city’s center. Concomitantly, a series of surveys of thermal perception were applied to 1300 passersby. The results show that PET has increased from 1990 to 2020 from 0.1208 °C/year to 0.1498 °C/year in the study sites, in addition to overestimating the degree of thermal comfort of people according to the stablished categories or classes. It is concluded that it is necessary to adjust thermal stress categories. Knowing the percentages of people without thermal comfort will lead us to determine different ranges in environmental parameters to define an acceptable environment for most people.

The urban heat island (UHI) is mostly due to urbanization. This phenomenon in concert with the high temperatures caused by global climate change may profoundly affect human thermal comfort, which can influence human productivity and morbidity especially in spring/summer period. The main objective of this investigation was to determine changes in degree of thermal comfort of Mexico City’s inhabitants and compare it with the physiological equivalent temperature (PET) to evaluate whether PET and its categorization are adequate to be applied in Mexico City. A series of microclimatological measurements to estimate PET were made in four sites including the city´s center. Concomitantly, a series of surveys of thermal perception were applied to 1300 passersby. The results show that PET has increased from 1990 to 2020 from 0.1208 °C/year to 0.1498 °C/year in the study sites, besides overestimating the degree of thermal comfort of people according to the stablished categories or classes. It is concluded that it is necessary to adjust thermal stress categories. Knowing the percentage of people without thermal comfort will lead us to determine different ranges in environmental parameters to define an acceptable environment for most people.

In the past three decades, nanotechnology has attracted extensive attention. People have many expectations on the utilization of nanotechnology in medicine, but unfortunately, these expectations are unlikely to be realized. In the field of nanotechnology, the niche for building commercial products has not been developed yet. However, metal nanoparticles have attracted people’s attention since ancient times because of their optical properties, which are very different from those of bulk metals. By understanding the origin of these optical properties and using current technology, these nanoparticles can be manipulated to build a palette. Using micro measurement equipment, the palette can be printed with very good resolution.