Innovative solutions for good daylighting and low energy use in multi-family dwellings: MKB Greenhouse, Malmö, Sweden

This is the report of the work for project Dagsljuskrav i miljöcertifierade byggnader" of the Swedish Energy Agency, project number: 39682-1. The study was focused on the energy use and daylight conditions in the multi-family building Greenhouse located in Malmö, Sweden. The aim of the study was first to analyze and develop innovative design solutions for multi-family dwellings with good daylighting and low energy use thereby solving the conflict between these two aspects. The second objective was to validate the simulation tools normally used in the practice of a large architectural office (White architects). The third objective was to verify the adequacy of the current minimum daylight factor requirement in relation to subjective assessments by building inhabitants of Greenhouse. These objectives were met by using a research method based on measurements, advanced lighting and energy simulations and subjective assessments. The results indicate that the simulations allow predicting the measured values with a reasonable accuracy. The results also show that the presence of a glazed sunspace and balcony has a significant impact on daylighting indoors, reducing the daylight factor by at least 50% in adjacent spaces under overcast sky conditions. The simulations also validated the relevance of having larger window sizes on the south orientation, intermediate sizes on the east and west orientations and smaller sizes on the north orientation, when highly insulated windows are considered. However, overheating issues need to be addressed at the early design stage with provision of efficient solar shading protections. The study also shows that daylighting is generally preferred over electric lighting by the inhabitants and that although the highest daylighting level criteria was used for the certification of the building, a significant portion of tenants found the daylight level to be ‘neither bright nor dark’ or ‘dark’, which was an unexpected result. Overall, the research allows establishing relations between measurements, simulations and subjective assessment.