Numerical Simulations and Empirical Data for the Evaluation of Daylight Factors in Existing Buildings in Sweden
Journal article, 2019

Point Daylight Factor (DFP) has been used for daylighting design in Sweden for more than 40 years. Progressive densification of urban environments, in combination with stricter regulations on energy performance and indoor environmental quality of buildings, creates complex daylight design challenges that cannot be adequately solved with DFP. To support a development of the current and future daylight indicators in the Swedish context, the authors have developed a comprehensive methodology for the evaluation of daylight levels in existing buildings. The methodology comprises sample buildings of various use and their digital replicas in 3D, detailed numerical simulations and correlations of diverse DF metrics in existing buildings, a field investigation on residents' satisfaction with available daylight levels in their homes, and a comparison between the numerical and experimental data. The study was deliberately limited to the evaluation of DF metrics for their intuitive understanding and easy evaluation in real design projects. The sample buildings represent typical architectural styles and building technologies between 1887 and 2013 in Gothenburg and include eight residential buildings, two office buildings, two schools, two student apartment buildings, and two hospitals. Although the simulated DFP is 1.4% on average, i.e., above the required 1%, large variations have been found between the studied 1200 rooms. The empirical data generally support the findings from the numerical simulations, but also bring unique insights in the residences' preferences for rooms with good daylight. The most remarkable result is related to kitchens, typically the spaces with the lowest DF values, based on simulations, while the residents wish them to be the spaces with the most daylight. Finally, the work introduces a new DF metric, denoted DFW, which allows daylighting design in early stages when only limited data on the building shape and windows' arrangement are available.

daylight simulations

existing buildings

daylight survey

daylight factor

daylight

Author

Sara Eriksson

Bengt Dahlgren AB

Lovisa Waldenstrom

Bengt Dahlgren AB

Max Tillberg

Bengt Dahlgren AB

Magnus Österbring

NCC AB

Angela Sasic Kalagasidis

Chalmers, Architecture and Civil Engineering, Building Technology

Energies

1996-1073 (ISSN)

Vol. 12 11 2200

Subject Categories

Architectural Engineering

Architecture

Building Technologies

Driving Forces

Sustainable development

DOI

10.3390/en12112200

More information

Latest update

9/11/2019