Climatic Urban Design: configuring the urban fabric to support daylighting, passive cooling, and solar heating

Access to site-based energy resources is a prerequisite for natural lighting, solar heating, and natural ventilation in buildings. This paper describes design methods and proposals developed for the City of Chattanooga, Tennessee, USA,to simultaneously address access to daylight, solar radiation and wind for as many buildings as possible in the urban core. The study area is the entire downtown district. Results include specific design proposals as part of the city’s Downtown Plan along with portable design patterns that may be employed in other cities. The organization of buildings, streets and open spaces in higher density areas can either preserve or block access to sun, wind, and light resources. I developed a composite technique, ‘Climatic Envelopes,’ which regulates the shape of buildings on a block or site for the purpose of protecting access to both daylight from the sky and direct radiation from sun. It combines the ‘Daylight Envelope’ with the ‘Solar Envelope’. This technique was applied to the existing pattern of blocks and buildings in the downtown core. Results show that existing buildings were not designed to consider other sites’ rights to light and sun. My team developed building configurations that satisfy the criteria for composite climatic envelopes and follow several design patterns for daylighting, while maximizing development potential. The resulting calculated floor area ratio for the proposed pattern was twice the existing density. The team developed proposals for modifications to cool the city by creating additional shade, channeling winds to bring ventilation to more buildings, and working with the existing topography, resulting in a ‘Downtown Cooling Plan.’

Source: University of Tennessee

Publication Date: January 2015

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