Building typologies in northern European cities: daylight, solar access, and building energy use

How does urban form and density, as expressed in different building typologies, affect energy use and daylight? Architects and planners should ask themselves this question at the very beginning of the design process, and the answer is a matter of great importance because once a typology has been decided, its basic form and structure are likely to remain relatively unchanged during the buildings life cycle.

The effects of building typologies are long term. If we think of entire districts as being characterized by certain prevalent typologies, it is crucial that we understand the properties of those typologies when developing design guidelines for better, more energyefficient cities with generous daylight availability.

This study develops a framework for urban analysis, the "urban shearing layers," and analyzes the potential of passive solar energy and daylight and their impact on the total energy performance of typical urban typologies found in northern Europe, using Copenhagen, Denmark, as a reference. A comprehensive suite of climatebased dynamic thermal and daylight simulations shows how the passive energy properties of buildings are affected by increases in urban density and urban form design choices.

We analyze both traditional and contemporary typologies, and the results show that the relative impact of choosing a specific typology may affect up to 16% of the total energy performance and up to 48% of the daylight autonomy in buildings at similar urban densities. This indicates that the design of urban building typologies is a key factor affecting energy consumption and daylight levels, as the impacts are long term.

It also suggests that there is a quite specific range of optimal urban density, where energy efficiency and daylight availability are ensured, for a given regional climate. Daylight should be understood as a common resource. Since it is affected by urban form more radically than energy use, we conclude that daylight should receive particular attention in planning and the first stages of building design, particularly in northern Europe, where daylight can be scarce.

To this end, urban daylighting strategies should be developed.