Daylight compliance of multi-dwelling apartment blocks : Design considerations, evaluation criteria and occupant responses

This thesis examines the daylight compliance of residential spaces, in particular apartments in multi-dwelling building blocks, and provides knowledge that may prove useful for the development of future daylight criteria for dwellings. The implications of design choices on daylight compliance of spaces and the effect of daylight criteria on the level of compliance are at the core of this work. Daylight simulations were performed to evaluate a large sample of representative apartment buildings according to past and present daylight criteria. Self-administered questionnaires were also used to investigate occupant preferences and subjective impressions of daylight conditions in the dwellings. The simulations and questionnaires divide this work into two parts, which are connected on the basis of the same study object: multi-dwelling buildings.The first part includes a review of daylight regulations in Sweden from the time the term “daylight” first appeared in 1960. It proceeds with compliance testing results for a large sample of multi-dwelling blocks, evaluated according to the current Swedish daylight compliance criteria. Several criteria commonly used internationally are assessed for the same spaces, to evaluate compliance differences when using different criteria. The review concludes that there has been no significant progress in Swedish daylight regulations since 1975, when the basis for the current daylight factor criterion was first formulated. It also argues that the current geometric criterion has limitations due to spatial implications deriving from its formulation. The compliance testing results indicate that Swedish daylight criteria have not been successful in safeguarding daylight access for residential spaces historically, especially in denser urban areas, perhaps because they were expressed as “general recommendations” instead of “mandatory provisions”. To this end, several buildings built prior to the introduction of daylight criteria, and built only by architectural intuition, perform better than regulated buildings. A more detailed assessment of the investigated rooms using additional criteria indicated which building types perform better overall, which geometric attributes are more significant for compliance, and the effect of urban density on compliance.The second part includes results from a questionnaire survey carried out in the city of Malmö, the third largest city in Sweden. The questionnaires were distributed in buildings of the same block typologies as the buildings evaluated via simulations in the first part of this research. This second part concerns daylight perception, electric lighting use, and occupant preferences with respect to daylighting among room types. The questionnaire rating scales were validated for their suitability as a form of measurement for daylight surveys. The reported electric lighting use was compared between different room types, geometries, and facade orientations to evaluate whether there is less use of lighting in rooms with specific characteristics. The relation between reported daylit area and electric lighting use was analysed to assess whether daylight availability can yield reductions in electric light use, to what extent, and under which conditions. The survey also revealed clear occupant preferences, indicating the room types where daylight availability is prioritised

Daylight compliance of Swedish residential blocks according to past and current performance criteria

The importance of daylight to occupants’ health and wellbeing has been extensively documented, as well as its role in reducing electric lighting use. As a result, most countries have today some form of regulatory framework, specifying minimum daylight requirements for built spaces. The present Swedish building code (BBR – BFS 2011:6) includes general recommendations for daylight provision of residential spaces, which stipulate a minimum window area relevant to the floor area or a minimum point daylight factor within rooms “inhabited more than temporarily”. Currently, policy makers in Sweden are considering the possibility of updating the current regulation, in light of the new European Daylight Standard (EN-17037), recently adopted by the Swedish Standards Institute. The challenges for policy makers include the extensive ongoing development of housing projects and the resulting impact of urban densification on daylight levels. Given this context, this paper investigates the compliance of residential developments, located primarily in Stockholm, for different daylight performance criteria. A sample of 10.888 rooms belonging to 3.151 apartments in 25 multi-family urban blocks was selected to represent different construction eras and major architectural typologies in Swedish urban planning history. All rooms were assessed by Radiance simulations according to the current Swedish regulation, the EN-17037 standard and other, commonly used, international compliance criteria. Results indicate that the implementation of different daylight criteria deem different building typologies better or worse performing, depending mainly on urban density and building height. A consistent finding is that all evaluated developments achieve lower compliance rates when standard 17037 is applied. Finally, policy implications on design and compliance are discussed, along with the necessary future investigations

Chapter 12: Introduction to lighting simulations

This is one the 13 chapters included in the book titled "Daylighting and Lighting under a Nordic sky". The chapter focuses on daylight simulation for buildings. It begins with the fundamental elements existing in every daylight simulation scenario, i.e. the scene geometry, the sky model, the ground, the areas of interest, the space usage and the simulation engine. The reader is introduced to different daylight simulation techniques developed over the past decades, and which are deployed in available simulation tools today. Eventually, procedures to conduct annual daylight simulations are presented, alongside the implications of different methods and aspects of daylight simulation control

Association between Perceived Daylit Area and Self-reported Frequency of Electric Lighting Use in Multi-dwelling Buildings

This paper examines the association between daytime electric lighting use and perceived indoor daylight availability in residential spaces. In addition, occupant preferences were evaluated, in particular which rooms are prioritized in terms of daylight availability. The study deployed a questionnaire survey that was carried out in typical multi-dwelling apartment blocks in Malmö, Sweden (Latitude: 55.6 °N). Occupants were asked to report how often they use electric lighting during daylight hours (EL) in their kitchen, living room and main bedroom, and how much of the floor area they perceive as adequately daylit (DA) throughout the year. Responses EL and DA were measured in seven-point semantic differential scales, and were correlated (Spearman) to evaluate their association for different room groups. Groups were based on age, room function, façade orientation, balcony obstruction and fenestration geometry. In addition, occupants were asked which room they would choose if there had to be one underlit room. Results indicate that EL is strongly associated with DA in the overall room sample (rS = −0.588, p <.01, n = 225). The association is persistent across room groups of different characteristics, with the Spearman rank correlation coefficient ranging between −0.4 and −0.8, and not differing significantly between groups. In terms of preferences, a significantly high proportion of participants would choose the bedroom if there had to be one underlit room (62%, p <.05), while the kitchen was selected by only 5 out of 108 respondents

Daylight utilization in the dense Swedish city : Benchmarks, metrics and tools securing good daylighting, low energy use and user acceptance

Scientific Poster titled “Low-energy daylit dwellings in the dense city - Benchmarks, metrics and tools securing good daylighting, low energy use and user acceptance”, Velux Academic Forum, Berlin, 2 May 2017. This dissemination illustrates the research questions and key aspects of a PhD research project regarding daylight utilization in Swedish apartment blocks, which was initiated in February 2017. The overall aim of the PhD research is to provide findings to help update current regulations and certification systems according to user acceptance, health and the well-being, all while accounting for the Swedish urban fabric and the different architectural choices

Workflow for the generation of multiple illuminance files for distinct daylit spaces in apartment blocks : Abstract and oral presentation

This work presented the working scheme developed and used in order to conduct multiple daylight simulations for distinct rooms in a wide range of apartment buildings within the urban grid. The objective was to generate 3D models of the rooms under study and their urban surroundings, and to obtain the corresponding illuminance files and geometry information in a time-efficient, automated manner. The workflow utilized commercial and free software, all widely used by practitioners in the field of architecture and daylight simulation. At the core of this workflow was an algorithm used to seamlessly generate 3-dimensional geometry out of CAD plan layouts, assign visual properties, conduct lighting simulations and export resulting data in spreadsheet form. The workflow also allowed for the export of the simulations in batch files, for use with available compute resources of multiple nodes. This work was awarded with the IBPSA-Nordic Simulation Award (2017) for outstanding implementation work in building simulation

Daylight compliance of Swedish residential blocks according to past and current performance criteria

The importance of daylight to occupants’ health and wellbeing has been extensively documented, as well as its role in reducing electric lighting use. As a result, most countries have today some form of regulatory framework, specifying minimum daylight requirements for built spaces. The present Swedish building code (BBR – BFS 2011:6) includes general recommendations for daylight provision of residential spaces, which stipulate a minimum window area relevant to the floor area or a minimum point daylight factor within rooms “inhabited more than temporarily”. Currently, policy makers in Sweden are considering the possibility of updating the current regulation, in light of the new European Daylight Standard (EN-17037), recently adopted by the Swedish Standards Institute. The challenges for policy makers include the extensive ongoing development of housing projects and the resulting impact of urban densification on daylight levels. Given this context, this paper investigates the compliance of residential developments, located primarily in Stockholm, for different daylight performance criteria. A sample of 10.888 rooms belonging to 3.151 apartments in 25 multi-family urban blocks was selected to represent different construction eras and major architectural typologies in Swedish urban planning history. All rooms were assessed by Radiance simulations according to the current Swedish regulation, the EN-17037 standard and other, commonly used, international compliance criteria. Results indicate that the implementation of different daylight criteria deem different building typologies better or worse performing, depending mainly on urban density and building height. A consistent finding is that all evaluated developments achieve lower compliance rates when standard 17037 is applied. Finally, policy implications on design and compliance are discussed, along with the necessary future investigations

Swedish daylight regulation throughout the 20th century and considerations regarding current assessment methods for residential spaces

Daylight availability for buildings has been an integral part of architecture since ancient times, yet for the vast majority of countries, criteria for daylight provision were not normative until the 20th century. This article examines the case of Sweden, where the term “daylight” first appeared in regulations in 1960, and assesses the daylight compliance of multi-dwelling buildings before and after that, in the timespan between 1920 and 2000. Firstly, the study evaluates whether the introduction of daylight criteria improved building performance. Secondly, the two current assessment methods are compared, as a disagreement was expected given that one method is formulated based on the glass-to-floor ratio scheme (GFR-method) while the other on a daylight factor scheme (DFP). Thirdly, the applicability and limitations of each method are evaluated. Results indicate that dwellings built following the introduction of daylight criteria do not necessarily outperform their predecessors. With respect to assessment methods, it was shown that the GFR-method is of limited applicability due to geometric constraints stipulated in its formulation, primarily due to the violation of the fenestration width condition. When comparing methods, the GFR-method yielded higher compliance compared to DFP, but only marginally. Eventually, the study highlights methodological flaws in the formulation of each criterion. Overall, the work contributes to knowledge supporting the development of daylight requirements for residential spaces. It provides background information suitable for planners and policy makers in their endeavors to define daylight performance criteria

Multi-objective optimization of fenestration design in residential spaces – The case of MKB Greenhouse, Malmö, Sweden : Abstract and oral presentation

This work presented and optimization scheme for daylighting, heating and thermal comfort objectives in a highly insulated apartment, while varying different geometrical aspects of external windows (number, shape, size, position). To satisfy all objectives simultaneously, a large number of design iterations was evaluated by the use of the SPEA2 genetic algorithm as it is implemented on the Octopus explicit components used in the visual programming environment of Grasshopper. The latter was used to connect the validated simulation engines of EnergyPlus, Daysim and Radiance with the generated designs governed by the optimization algorithm. Overall, it was shown that the use of genetic algorithms can accelerate the optimization process in building simulation scenarios, while evaluating a representative part of the solution space (total of solutions). The results indicate that the optimization process can lead to a good set of solutions for designers to work with in the initial design stage

Multi-objective Optimization of Fenestration Design in Residential spaces. The Case of MKB Greenhouse, Malmö, Sweden

This thesis investigates the optimization of fenestration design for multi-family apartments, considering the heating demand, daylight autonomy as well as overheating. A literature review was conducted to situate the thesis focus within the broader academic field of façade optimization, and a specific apartment located in the city of Malmö was chosen as the study object. The results presented are the outcome of climate-based daylight modelling (CBDM) simulations and dynamic thermal modelling (DTM) simulations, all of which were integrated in a single script definition within the visual programming environment of Grasshopper (2016). A significant part of the study involved the use of an optimization algorithm, to assess multiple fenestration designs based on their daylighting and heating performance. The optimum window position, size and shape were assessed as a function of the achieved daylight levels, the energy required for heating, the impact of solar gains and the amount of overheating time for the studied spaces. Overall, it was shown that the objectives of heating and daylighting are in conflict in the Swedish context, when the aim is to satisfy both luminous and thermal needs. In addition, it was shown that the window-to-wall ratio is not sufficient as information regarding the building performance, as different geometrical aspects of windows and their position can lead to different results for the same glazing area