Development of a method for estimating radiant temperature and radiant exergy within outdoor space

Abstract

This paper describes a method for estimating radiant temperature and its associated with radiant exergy within outdoor space, which is one of the key factors in micro-climatic design of pedestrian paths and park space in summer. Measurements of outdoor air temperature and humidity, wind velocity, small grey-globe temperature and surface temperature were carried out for one day during daytime of a hot summer day in August, 2015 at Sapporo Art Park. Firstly, the radiant exergies emitted from outdoor ground, buildings, trees, grassy plane, water surface of the pond and sky, were evaluated for quantifying the radiant environmental characteristics outdoors. Secondly, the measured grey-globe temperatures were compared with those obtained theoretically using solar radiation, long-wavelength mean radiant temperature taken from infra-red thermal image camera, out temperature and wind velocity. Lastly, on the basis of the measured results together with the theoretical investigation, we discussed the "coolness" to be available from pedestrian paths and park space.