DesignBuilder daylighting enables designers and assessors to check for good use of natural daylight and visual comfort in their building models by providing a wide range of daylight performance data. The results can be used to help guide the building design process and assess eligibility for credits with various rating schemes.
The Daylighting module is fully integrated with the core DesignBuilder thermal simulation feature, so, in general, no extra data needs to be added following previous energy simulation or certification project work. In particular building geometry, zone layouts, surface reflection, and glazing visible transmission properties from the thermal model are used in the daylighting calculations.
There are 4 main types of daylighting calculations in DesignBuilder:
Point-in-time illuminance simulations involve multi-zone physics-based calculation of illumination levels for static sky conditions using the Radiance simulation engine. Radiance applies a backward ray-tracing method to generate a map of illuminance on the working plane(s) in each zone. Point-in-time calculations allow you to generate Daylight Illuminance, Daylight Factor, and Uniformity results and other related reports.
Reports generated include: Daylight factor (DF and ADF), illuminance, uniformity etc. Standard reports for commonly used rating systems are also created, detailing eligibility for LEED v4, v4.1 (and older versions), BREEAM (HEA 01 4a) and Green Star (Credit IEQ4).
Annual Climate Based Daylight Modelling (CBDM, aka "dynamic daylighting") is the calculation of illuminance on the working plane using realistic sun and sky conditions and real climate data. Annual daylight simulations are run for a full year at a time-step of an hour to capture the daily and seasonal dynamics of natural daylight. The Radiance daylighting engine is also used in these simulations.
Results generated include: sDA, ASE and UDI distribution plots and summary grid reports. Standard formatted reports are also generated for: LEED (v4, v4.1); BREEAM HEA option b.
Right to Light calculations help check that new building developments meet planning requirements with regard to their impact on daylight availability in neighbouring buildings.
Results generated: Annual probable sunlight hours (APSH), Vertical sky component (VSC), No sky line (NSL) and Average daylight factor (ADF). VSC, APSH, ADF are calculated using Radiance while NSL calculations use an internal DesignBuilder ray tracing method.
Daylighting integrated within EnergyPlus simulations allow savings in electric lighting to be calculated based hour-by-hour on daylight availability throughout the year.
More information on Radiance daylighting calculations can be found in the Introduction to Daylighting Tutorial