Planificación urbana en ciudades dispersas de clima desértico: la densificación vertical como estrategia para la mejora ambiental. El caso de hermosillo (méxico)
- Autores: Carlos Fernando López Ordóñez
- Directores de la Tesis: Isabel Crespo Cabillo (dir. tes.), Jaime Roset Calzada (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2020
- Idioma: español
- Materias:
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- Resumen
By 2050, the world's population will have doubled and will be mainly urban. This perspective generates the need to think about the present and the future of cities, especially those located in mid-latitudes, where a large part of that population accumulates. Many of these cities are in regions with hot semi-arid and hot-dry climates.
Traditionally, desert cities were designed in compact shapes in response to various climatic factors. Today, these cities have adopted the dispersed city model, driven by car use, the emergence of cooling systems, and a steady decline in energy costs. This form of growth raises a series of problems from an environmental point of view: poor habitability of the public space, long distances, an elevated land use, high demand for cooling.
The goal of this thesis is to evaluate the energy repercussions of the increase in urban density in dispersed and low-density cities with a hot-dry climate in the northwestern region of Mexico. The city of Hermosillo in Sonora, a medium-sized city in expansion, is taken as a case study. This thesis analyzes the effects of urban densification on three different scales: city, neighborhood, and building.
Based on a city-scale cartographic analysis, this thesis shows that Hermosillo presents a dispersed pattern of low-density growth with two main characteristics: low centrality and high fragmentation. The low centrality is due to the loss of population and economic weight of the urban center in favor of the periphery. The urban fragmentation is a result of the existence of a large number of vacant lots (35% of the urban area). Therefore, two urban strategies are identified and could be followed to slow down the growth of the urban area: the infill of vacant lots and the densification of existing fabrics (stacking) for the creation of high-density sub-centers.
The historic center of Hermosillo is selected to carry out the analysis on a neighborhood scale. The impact that a densification process of an existing urban fabric has on the habitability of the urban space is assessed. Currently, this fabric has a high pedestrian potential, but low population and building density, and high levels of solar radiation. In this thesis, the study area is rethought through a densification process employing the mixed-use lot and the stacking of houses. It is shown that by following the current regulations is possible to achieve building density values similar to those of urban centers and tissue of cities with compact morphology. Also, by allowing an increase in density allows achieving streets with an aspect ratio of around h/w= 1, a ratio that, at this latitude, permits the creation of "shadow corridors" spaces protected from radiation.
Finally, the impact of stacking on energy performance at the building scale is analyzed using dynamic thermal simulations. To this end, this thesis compares the thermal behavior of free-running homes and the energy demand for cooling during the hot season of isolated single-family homes and multi-family homes in height. The conclusion is that the higher the stacking level, the better the thermal and energy performance. Furthermore, this study demonstrates that in homes without refrigeration, the use of solar protection on windows achieves a slightly superior improvement than that of thermal insulation.
Therefore, this thesis allows us to demonstrate that an increase in density (building and population) has advantages at different scales, especially in cities with a hot-desert climate. Stacking allows the creation of shade in the public space and, at the same time, an improvement in the internal energy consumption of refrigerated homes.
