The thesis is an outcome of a collaborative work between the author and an architect. It aims to answer design questions that were posed in the early stages by the team of a student architect and the author himself relating to the daylighting performance of the building located in Stockholm, Sweden. Two design elements of interest that were to be evaluated were decided: the orientation of the building and the effect of introducing an atrium in the building. Annual daylighting performance simulations were carried out and these two design elements were parametrically varied to see the effect on the daylight distribution inside the building for the given architectural model. For the same design parameters, an energy model was created and simulated to see the effect of these design alteration on the cooling loads of the building. The importance of early stage collaboration between engineers and designers have also been discussed which sets the contextual scene of the thesis.

This thesis investigates the design of atria for daylighting in large scale buildings. Athree dimensional test building with a central atrium was constructed and various parameters of the atrium altered. The impact of these changes was studied through computer simulations of annual daylight distribution by implementing state of theart software. Daylight autonomy is simulated for an annual climate file for Stockholm, Sweden. In the thesis, notion is made of basic daylighting concepts, the importance of bringing daylight into buildings is argued, and the daylighting criteria of three environmental certification tools introduced. Furthermore, a detailed comparison is made on several well known daylight simulation tools. A newly developed, state of the art, daylight simulation tool called Honeybee, is used in the simulation process. The tool utilizes the calculation engines of wellknown daylight simulation software Radiance and Daysim, which apply backward ray-tracing to reach accurate results. Honeybee is coupled to the graphical algorithmeditor Grasshopper for Rhinoceros 3D, which allows for an efficient way of parametric modelling. The comparison of five different daylight simulation tools showed that Honeybee outweighs the capabilities of many of them by offering a wast range of simulation capabilities and also giving the user exceptional control of result data within multiple zones of the test building. The results of the daylight study have been compiled into a document which purpose is to serve as early stage design guidelines of atria for architects. Many factors have been shown through simulation to have a dramatic impact on daylighton an annual basis, and several suggestions have been made on how to maximize the quantity of daylight within buildings containing atria.

Contribution of daylight to employees in terms of health, productivity, and overall wellness in the office spaces are undeniable. Apart from the psychological and biological benefits of employees, embracing daylight in office spaces increases the energy-efficiency of the building which leads to the sustainable development of a city. However, a considerable number of employees in Sweden lack daylight in their workspaces according to a report by the Swedish Work Environment Authority [Arbetsmiljöverket (Swedish)] (Lowden, 2019). Professionals like Architects, Lighting Designers, and students of architecture and lighting design across Sweden were asked their opinions pertaining to lack of daylight in a considerable number of office spaces in Sweden based on their experience through online questionnaires/ interviews to get to know the overview of this subject. Out of all the possible reasons, window design and economy were the two macro factors according to them that influenced daylight in an office building in Sweden but often, obstruction angle in a building due to urban densification is overlooked when it comes to daylight in an office building. This thesis discusses the influence of obstruction angles with an illustrated office building in Stockholm. Diva for Rhino was the software used for the modelling and daylight simulation.