Passive solar design: Where urban and building design meet

Abstract

Urban layout has a significant impact on the outdoor microclimate in the city. The urban fabric can limit solar access, but also has the ability to store and trap heat. This may lead to uncomfortable or even unhealthy situations outdoors. The indoor thermal environment can be controlled independent of dynamic outdoor conditions. However, this is undesirable from a comfortable and sustainable point of view. It is therefore preferable to find passive building strategies to support a comfortable thermal environment outdoors as well as indoors. In temperate climates, buildings facing south are preferable, as they yield the largest solar gain in the heating season and the smallest in summer. However, south facing row houses imply east-west running streets, which have larger street irradiance in summer - possibly leading to heat stress - and a smaller street irradiance in winter compared to north-south running streets. In addition to orientation, the height to width ratio of streets is also of great importance since it defines the obstruction angle; buildings may cast shadows on the street or on the opposite building facade resulting in reduced solar gains. The full paper discusses the viability of passive solar heating strategies in residential buildings in The Netherlands under the influence of typical urban density and layout. In addition, the paper gives some guidelines for the integration of passive solar heating strategies for dwellings in different urban situations. The effects of orientation and street width of an urban canyon on the percentage of irradiated street and facade areas, for different seasons in The Netherlands, will be discussed in another paper by the authors. © 2010 WIT Press.