A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Influence of Optical Characteristics of Façades on Pedestrian Thermal Comfort Within the Streets of Manhattan
Since the first glass tower in Manhattan, the Lever House, was built about 70 years ago, entire neighborhoods of smooth façades have appeared in every major city in the world. The juxtaposition of tall glazed towers generates multiple reflections, mainly specular, which strongly influence the radiative exchanges. In thermal comfort, these exchanges are often expressed by the mean radiant temperature. This radiative phenomenon can be handled by raytracing in multiple steps. Within a model of more than 10,000,000 faces, a first raytracing identifies all surfaces that exchange with a point, thus limiting the mesh to the area of interest. Then, a second raytracing is used to calculate the radiative exchanges between the surfaces. For each face observed from a point located at the foot of the Lever House, we calculate the shortwave irradiance up to the 60th reflection. In longwave we assign a surface temperature according to the shortwave radiation absorbed by any element. Both results are then projected on panoramic images from which we can analyze the spatial distribution of energy and deduce the mean radiant temperature. This calculation is done to compare the influence on the thermal comfort of pedestrians of a radical change in the composition of New York’s façades, from black to white and from perfectly diffuse, to perfectly specular. The simulations proposed here make it possible to rapidly identify the zones of interest in a very large urban model. This could guide a measurement campaign, which in turn should provide the necessary boundary conditions for finer simulations of existing and possible urban transformation projects.
Influence of Optical Characteristics of Façades on Pedestrian Thermal Comfort Within the Streets of Manhattan
Since the first glass tower in Manhattan, the Lever House, was built about 70 years ago, entire neighborhoods of smooth façades have appeared in every major city in the world. The juxtaposition of tall glazed towers generates multiple reflections, mainly specular, which strongly influence the radiative exchanges. In thermal comfort, these exchanges are often expressed by the mean radiant temperature. This radiative phenomenon can be handled by raytracing in multiple steps. Within a model of more than 10,000,000 faces, a first raytracing identifies all surfaces that exchange with a point, thus limiting the mesh to the area of interest. Then, a second raytracing is used to calculate the radiative exchanges between the surfaces. For each face observed from a point located at the foot of the Lever House, we calculate the shortwave irradiance up to the 60th reflection. In longwave we assign a surface temperature according to the shortwave radiation absorbed by any element. Both results are then projected on panoramic images from which we can analyze the spatial distribution of energy and deduce the mean radiant temperature. This calculation is done to compare the influence on the thermal comfort of pedestrians of a radical change in the composition of New York’s façades, from black to white and from perfectly diffuse, to perfectly specular. The simulations proposed here make it possible to rapidly identify the zones of interest in a very large urban model. This could guide a measurement campaign, which in turn should provide the necessary boundary conditions for finer simulations of existing and possible urban transformation projects.
Influence of Optical Characteristics of Façades on Pedestrian Thermal Comfort Within the Streets of Manhattan
Innovative Renewable Energy
Sayigh, Ali (editor) / Beckers, Benoit (author) / Paz y Miño, Jairo Acuña (author) / de Bort, Inès (author)
2023-09-08
10 pages
Article/Chapter (Book)
Electronic Resource
English
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