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DAYLIGHT DRIVEN OFFICE BUILDING DESIGN AT HIGH LATITUDES Case study in St. Petersburg

DAYLIGHT DRIVEN OFFICE BUILDING DESIGN AT HIGH LATITUDES Case study in St. Petersburg

Category
Daylight in buildings - Region 1: Western Europe.

Students
Evgenii Varlygin

School
Technical University of Munich

Country
Germany

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Through the master thesis, it was proven that daylighting is an integral part of a whole visual comfort topic and mid-rise office building design at high latitudes needs a unique approach to incorporate optimal daylighting. This design is different from the strategies applied for climate responsive building designs in other latitudes. Thus, five visual comfort driven design principles were found from research and simulations specifically for the urban context of high latitudes. These principles were applied to the case study office building project in St. Petersburg. Their functional advantages in comparison to a fully glazed base case were demonstrated in urban, building, detail, and layout scales. The holistic architectural approach took into account aesthetic as well as regulatory and social aspects.

Glare

Glare issues are considered as one of the most important factors while designing an office building at high latitudes due to the low sun angles. The final simulations results show the decrease of views with disturbing glare by 61,3% thank to contextual fenestration and seasonal exterior shading. The exterior shading devices, which are usually not in use in this climate showed themselves if they are used in a seasonal way, as a very powerful tool for glare reduction. The further improvements in desks layouts helped to even more reduce the DGP at critical places and periods while also enriching the indoor environment through diversifying the floor plans. The blind states simulations show the increase in the time when they are open by 12,8%, which means that the potential time throughout the year with closed blinds is only 8,1%. The reason is the reduction of direct sunlight, which also allows more natural light to penetrate the spaces.

Daylighting

With the help of Low sky angle and Pitched roof principles, the daylight availability is ensured for the neighbouring office buildings. At high latitudes, obstructions are especially tangible, that is why in selecting daylighting strategies it is important to take into account Sky angles and volumetry of the future development. The designer must consider the degree whereby the proposed construction would block existing buildings, thus reducing their access to daylight.

Despite the challenging natural lighting provision at high latitudes is thought of as the main argument for the fully glazed buildings, it is not completely true. The case study project reaches just slightly lower sDA results. The use of contextual fenestration, careful placement of roof windows, the implication of details such as splayed reveals, and slopping ceiling keep the daylight levels at very high results, that fulfil the LEED requirements. In cold high latitudinal climates, windows can be allies and foes at the same time: too many of them will cause glare and lose heat, too little and space will not have enough daylight and outdoor views. Sufficiently daylit space does not demand a 50-90 percent glazed facade. Careful consideration of the glazing positioning will provide plenty of daylight while decreasing the required amount of glazing. The professor of Center for Energy and the Design of Environments David Coley emphasized: “Cutting back on glass would be an easy win. Windows need to be sized, not glorified, and sized for a purpose. … We need to build buildings with windows, rather than buildings that are one big window.”

Views

The view availability to the outdoors and scenery plays a big role in the design and commercial decisions. It is also one of the main aspects for the occupants and hence it cannot be ignored in fenestration design. Views are often significant arguments for designing tall panoramic windows. However, thoughtful design regarding the occupant’s points of view and perspectives to the scenery, like greenery or city skyline, created a visually interesting user-oriented working environment. The results of horizontal view analysis, which is accredited by LEED, show the decrease in results just by 1,6% compared to a fully glazed base case. Furthermore, as all visual comfort aspects are interconnected, the significant decrease of disturbing glare provides more time with open blinds, hence the access to the views.

Relevance and significance of the study

The most research for the topic of daylight and visual comfort is done for middle latitudes, so designers of high latitudes currently try to apply inappropriate for their climate strategies. The case study in St. Petersburg set the stage for the integration of visual comfort design principles in mid-rise office buildings for other high latitudinal cities.

In order to achieve sustainable goals, it is imperative that architects maximize daylight in the projects. Entering visual comfort driven principles at an early stage of the design process will help to use more consciously daylighting, as well as create a comfortable and pleasurable working environment, keeping the occupants healthy, happy and productive.