Thermal Comfort and Longwave Radiation over Time in Urban Residential Complexes

You Jin Kwon and Dong Kun Lee
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You Jin Kwon: Interdisciplinary Program in Landscape Architecture, Seoul National University, Seoul 08826, Korea
Dong Kun Lee: Department of Landscape Architecture and Rural System Engineering, Seoul National University, Seoul 08826, Korea

Sustainability, 2019, vol. 11, issue 8, 1-19

Abstract: Large cities with a high concentration of high-rise buildings are shaded by urban canyon. This brings a cooling effect compared to the space exposed to the sun, but is not always cool due to the longwave radiation emitted from buildings and the built environment. We tested the micro-scale effects of major external spatial factors, trees, and buildings, under shade on longwave radiation shifts to understand the effects of large shaded areas in megacities. Incoming and outgoing longwave radiations (ILR and OLR, respectively) were found to decrease the overall observation by time zone. Longwave radiation on a micro-scale was also inversely proportional to the tree volume. From mean radiant temperature (MRT) analysis, we found that about a 10% decrease in MRT could be achieved by increasing tree volume by around 50%. Larger tree volumes corresponded to greater blocking effects on longwave radiation. Considering the tree volume, a multilayer urban tree canopy composition can more favorably improve the thermal environment and energy sustainability of a city compared to a single-layer canopy. Larger trees planted with harmonious shrubs are the most effective in reducing longwave radiation.

Keywords: thermal comfort; mean radiant temperature; tree volume; energy balance; longwave radiation (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

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