Energy-efficient urban design guidelines for warm-humid cities: strategies for Colombo, Sri Lanka

This paper develops a set of energy-efficient urban design guidelines for an equatorial tropical city (Colombo, Sri Lanka), on the basis of a survey of energy-conserving urban design guidelines developed and applied principally in temperate regions. A total of twenty-two urban design guidelines currently enforced in various U.S. cities and six from the U.K are analyzed. These address one or more of the following urban energy requirements: space-conditioning, transportation and embodied energy needs. Problems related to excessive energy use in Colombo, Sri Lanka, are then identified by critically analyzing the "Colombo Development Plan" which legally binds all its urban development. Key factors analyzed are: floor area ratio, plot size, building height, open space, waterfront development, and landscaping. Finally, a hypothetical proposal is made for Colombo. It includes eight design guidelines (amendments to existing legislation as well as new) for the reduction of cooling needs and three for the reduction of transportation needs. These are presented within two broad policy options: prevention of parceling of urban land, use of existing railroad as a Mass Rapid Transportation system.