Daylight optimization in an office building through atrium improvements

Abstract

Daylighting has become a fundamental measure not only to decrease the electrical energy demand in buildings, but also to provide good indoor comfort for the occupants. Atria have been implemented in buildings since old times as a space to foster interaction and provide indoor comfort through ventilation and daylight. However, the implementation of this feature can be complex if good natural light levels are to be achieved, especially in tall buildings. Bearing that in mind, this thesis reviewed the studies that were developed in the field of daylighting in atria and proposed an investigation about the atrium parameters that affected the most the daylight conditions in a building project located in Gothenburg. In order to evaluate the current atrium and propose modifications that fit the architectural design, simulations were carried out in different programs. This evaluation concentrated in two main aspects of the building, which were the geometry and the wall reflectance values. Due to the size of the study case, the evaluation grid is located only along the atrium and the results are translated in area, so it is possible to draw a comparison between the different modifications proposed. Results showed that the geometrical volume alterations were the ones to increase the most the daylight quantity in the rooms along the atrium. Nonetheless, some of the modifications on the original project were followed by a floor area addition to compensate the losses brought by the alterations, therefore daylighting and property value were also analyzed. Lastly, a few options were investigated when it comes to the daylight quantity in each floor. Overall, the outcomes demonstrated that shifting the atrium characteristic from an enclosed one to a semi-enclosed can double the daylight quantity in the adjacent rooms.

Popular Abstract

In the one hand, there are the benefits of daylight that range from a better employee productivity to the decrease of electrical lighting need in office buildings. On the other hand, many developers launch project competitions that generate a series of non-feasible projects construction and daylighting-wise. Atria have been long used as a strategy to bring daylight and ventilation into buildings, but their design must take a series of factors into consideration in order to successfully work. According to the literature, deep atria induce gloomy spaces in their bottom, while shallow ones tend to be well-lit. In this master thesis, a series of modifications were proposed in an office building in order to improve its existing atrium, so better daylight conditions could be achieved in its adjacent rooms.
Minimum daylight conditions in regularly occupied spaces are required by the Boverket’s Building Regulation (BBR) and different environmental certification systems. Bearing that in mind, the case study geometry was modified through parametric studies in order to evaluate their impact on the daylight conditions in the adjacent rooms. The main aim was to improve the natural light levels on the spaces in the atrium perimeter, so they could not only provide a better working environment, but also meet the required regulations. The geometry modifications were conducted by dividing the building block into different wings and suppressing each one of them at a time, so the atrium would shift from an enclosed to a semi-enclosed shape. It was also tested the potential of inclining the atrium walls to improve the daylight quantity in the adjacent spaces. Finally, different wall materials were changed in order to increase the reflectance in the void.
One of the hindrances of proposing these modifications is that they triggered space losses. To tackle that, the losses were compensated by distributing a newly built area over the existing building shape in many ways. In addition, the idea was to keep the architecture quality while building the compensations, so both the designer and the developer would have options to fit their aims. Therefore, the objective was to find an optimal atrium geometry that would increase the daylight quantity in the adjacent rooms, whilst diminishing the area losses.
The results of the investigation showed that the daylight quantity dramatically increased in the spaces along the atrium when the wings were suppressed, regardless of their cardinal orientation. However, some of the built area compensations can decrease the adjacent rooms daylight performance, depending on which part of the building they are being erected. As the building was divided into four different wings, the area compensation was distributed over one, two and three wings. Surprisingly, the last option showed the worst performance, even though it is the alternative that presented the shortest height.
In short, this investigation shed light on how different atrium shapes that are not square and rectangular react to different inner envelope configurations regarding the daylight quantity in their adjacent rooms. This work also shows that there are different ways of not only increasing the natural light levels in the these spaces, so they can meet the regulations, but also accommodating the requirements of the stakeholders involved in the project.

• author: Ferreira, Thiago
• supervisor: Marie-Claude Dubois
• organization: Division of Energy and Building Design
• course: AEBM01 20181
• year: 2018
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: atria, daylight, optimization, office, atrium
• language: English
• id: 8947933
• date added to LUP: 2018-06-13 14:44:43
• date last changed: 2018-06-18 08:54:50