Comfort in urban spaces: defining the boundaries of outdoor thermal comfort for the tropical urban environments

With rapid urbanisation, often without climate responsive guidelines, cities in the Tropics are progressively falling short of sustaining outdoor life. While at the building level such inadvertent climatic modifications have lead to a remarkable demand on the urban energy resources. The rationale for developing a thermally desirable outdoor ambience in such a context has implications that go beyond the requisites of urban design and well into the design of buildings. In order to re-establish and sustain life outdoors it is important that we try to make urban spaces comfortable as far as the ambient climate permits. In order to ascertain conditions of comfort for outdoor spaces we need to define comfort for outdoors. This paper presents findings on outdoor comfort based on field investigations conducted in Dhaka, a city in the wet-Tropics. Findings from a survey conducted on a large number of randomly selected people from urban spaces are presented. The findings include factors affecting comfort outdoors for Dhaka and a comfort regime based on environmental parameters for urban outdoors is presented. Interestingly, comfortable ambient climate leads to comfortable indoor environment particularly with regard to free running buildings. With regard to mechanically controlled indoor environments a comfortable outdoor produces lesser strain on energy environment relationship. By defining conditions of comfort for outdoor environments an important step towards achieving sustainability of our urban environments can be made. (C) 2003 Elsevier Science B.V. All rights reserved.