Green Roofs versus Ponds and High Albedo Materials as Passive Cooling Techniques of Urban Spaces

In this paper the effect of vegetation, water and high albedo of materials is examined in the built environment. The high capacity and low albedo urban building materials are mostly responsible for the formation of raised urban temperatures. If these materials are covered with materials of low heat capacity and high albedo, this phenomenon of excessive heat gains in the built environment could be moderated. The necessity of covering existing or new urban structures with high albedo materials, with plants or water is investigated. With the use of dynamic, heat and mass transfer algorithms these techniques are investigated for three cities in hot climates; Athens (hot and dry), Mumbai (hot and humid) and Riyadh (hot and arid). A comparison is done between the techniques and the different climates and conclusions are drawn, regarding which technique could prove more beneficial for mitigating raised urban temperatures for each climate.

Keywords:

urban temperature , microclimate of buildings