Daylight Availability Study

Continuing from the Daylight Precedence Study, this design exercise will test the annual daylight availability in your three massing models. You will then refine the façade concept by adopting the window-to-wall-ratio (WWR) and glazing type.

Task A Daylight Massing Study

Build 3D models of your three daylight massing ideas from the Daylight Precedence Study. You may initially assume that all building envelope surfaces are infinitely thin. Unless you already have a specific idea regarding the window to wall ratio (WWR) for the different façade orientations, start with a generic WWR of 40%. To account for the window frame and wall thickness, pick a glazing with a visual light transmittance of 50%. For interior surfaces, assume diffuse reflectances of 50% for walls, 20% for floors and 80% for ceilings. (You can search for the relevant opaque materials in ClimateStudio by filtering “LM83”.) The grid of sensors should be between 0.75m and 0.85m above the floor with a spacing of 2m or less. You should specify some type of dynamic shading for each window unless you can provide a specific reason as to why shading is not required (e.g. in the case the window unit broders an atrium or circulation area).

Calculate the spatial daylight autonomy with a target illuminance of 300lux (sDA) for all three variants and decide which variant you want to continue working on going forward. For circulation areas you can set the target illuminance to 150lux. You may of course introduce new variants as you learn the pros and cons of your previous ideas. Show visualizations of your sDA calculations and report the percentage of your building that  is “daylit” as well as potential for glare and overheating using the Annual Solar Exposure (ASE). An example is shown in Figure 1.

Note that ASE only gives you a first sense of where you might have thermal or visual comfort issues. In future exercises you will refine this analysis using the daylight glare probability metric.

Figure 1: Example daylight availability study of the massing models from Figure 1. All massings are fully daylit but the fabric variant has the lowest Annual Solar Exposure (ASE) (S Aulgur, S Ajienka and J Berglund-Brown)

Task B Façade Study

For your favorite massing variant from Task A, explore at least three different window/ skylight configurations. Consider actual wall and roof thicknesses as well as window frames and add some interior walls where you deem them appropriate. In case you are working on the Multi-Unit Residential project, you should draw all interior walls separating apartment units and circulation areas. Improve the daylight availability throughout all regularly occupied spaces within the building while also trying to limit Annual Solar Exposure (ASE) levels. Feel free to pick any glazing of your liking from the ClimateStudio material database. Discuss your findings. During the next design exercise (Glare and Electric Lighting), we will , we will tackle dynamic shading and visual comfort.

Figure 2: Example façade study of three design variants based on the Fabric massing from Figure 2. The brick screen with lightshelf has the lowest ASE (S Aulgur, S Ajienka and J Berglund-Brown)

Figure 3: Example daylight availability study for a multi-unit residential floor

Task C Allocate Space for HVAC

At this point you should start thinking about where your HVAC equipment is going to fit into your building. The Area Requirement Matrix spreadsheet from the buildVAV GitHub repository provides you with typical area requirements for an office building for the roof and each floor for MEP (Mechanical, Electrical and Plumbing), Elevators and Egress Stairs. Please mark for your final daylight massing where these area are going to be located in your building. An example sketch for a three story 5000m2 office building is shown below.

Figure 4: MEP, elevator and egress requirements and placements for an office building

For a 2000m2 multi-unit residential building, the overall proportional areas are smaller since IT, electrical closets, restrooms, janitor closets, etc. are not needed.

Figure 5: MEP, elevator and egress requirements and placements for a multi-unit residential building

Related Video Tutorial/Handbook Chapter