Energy renovation and healthy indoor environment in green buildings -Impact of dynamic shading and demand controlled ventilation on occupant health and comfort

Examensarbete för masterexamen
Bergström, Gunnar
A number of measures exist that can help to reduce the energy use of existing buildings, such as demand controlled ventilation and dynamic shading. However, when they are implemented they can also have an on impact the comfort and health of the building’s occupants. Discomfort in the domains of thermal comfort, visual comfort and air quality can cause health issues ranging from mild to severe and can significantly impact the performance of office workers with resulting economical losses for employers. Increased awareness of occupant comfort in the design and operation of office buildings can have both health-related and economical benefits. A case study was carried out for a newly renovated office building where occupants have reported some amount of thermal and visual discomfort. A possible explanation for the discomfort was found in imbalances in the implementation and operation of the demand controlled ventilation and dynamic shading systems. The case study building, which has been awarded a Miljöbyggnad Silver certification, was studied in detail and it was found that thermal discomfort was likely to arise due to the intricate interplay between heat added by the sun and the occupants and heat taken away by the ventilation air flow. Since occupants are also a source of air pollution, ventilation and shading needs to be carefully balanced to ensure that thermal and visual comfort and acceptable air quality are maintained under all circumstances. The geometry of the shading device and the colour of the shading fabric can also be configured to further improve visual comfort and thermal performance. In general it was found that occupant comfort can be improved by detailed and holistic study of the building, how it behaves and how conditions vary in both space and time. The more time and effort is spent on identifying issues and customizing the building, the better the outcome for occupant comfort. However, increased customization means increased complexity and cost, making it more difficult to successfully implement the intended design. If significant causes of occupant discomfort are identified more clearly and methods are developed to address them in a streamlined and efficient way, it is more likely that the health, comfort and well-being of occupants will be put into focus when designing office buildings.
Demand controlled ventilation, dynamic shading, indoor environmental quality, thermal comfort, visual comfort, air quality, energy efficiency, building renovation, health
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