The impact of greenery and surface reflectances on solar radiation in perimeter blocks

Abstract

The paper discusses the importance of greenery in cities. It considers the presence of green elements inside a typical urban perimeter block and deliberates about their impact on the solar radiation level on the facades and the yard. A series of computer simulations have been done using six combinations of surface reflectance (façade/yard) for six perimeter block configurations. The simulations were performed with DIVA, a plug-in for Rhino for Oslo (59.91273, 10.74609). The results confirm that a modest amount of greenery causes only a small reduction of the radiation, up to 11% in the yard and up to 13% in the lower parts of facades. Surface reflectances are important. The increase of façade reflectance from 22% to 66% is more than enough to compensate for adding green elements, e.g. one large birch and three smaller ever-green conifers.