Sky vault partition for computing daylight availability and shortwave energy budget on an urban scale

Abstract

The objective of this work is to propose to the urban physics community an optimal sky vault partition able to support most existing applications, either in daylight availability evaluation or in shortwave energy budget estimation. This partition is explained and justified. Its refinement is examined and analysed with respect to the studies performed today at urban level. The solution of the analyses is obtained in two steps: the heaviest part is the solution of the urban interreflection problem, while the second step is very fast and can be achieved in interactive mode. It consists in computing the thermal or illumination loads which will be used as coefficients of a recombination of the first step results. The urban interreflection problem is independent of this process and can be obtained with various existing techniques, such as the radiosity method.