Annual Daylight
Last updated
Last updated
Run an annual daylight study for a Honeybee model to compute hourly illuminance for each sensor in a model's sensor grids.
By default, this recipe uses an enhanced 2-phase method, which accurately models direct sun by tracing rays from each sensor to the solar position at each hour of the calculation. This makes the result suitable for computing Annual Sun Exposure (ASE) and for modeling the effects of dynamic shades and apertures.
When the enhanced_ option is set to False, a standard 2-phase method for simulation, which is much faster because it simply determines the relationship between each sensor and sky patch and then multiplies the value of each sky patch at each hour by the relationship coefficient. However, this means that the direct sun is spread out across a few sky patches, making it unsuitable for ASE.
The resulting illuminance is used to compute the following metrics:
Daylight Autonomy (DA) - The percentage of occupied hours that each sensor recieves more than the illuminance threshold. * Continuous Daylight Autonomy (cDA) - Similar to DA except that values below the illuminance threshold can still count partially towards the final percentage. * Useful Daylight Illuminance (UDI) - The percentage of occupied hours that illuminace falls between minimum and maximum thresholds
model [Required]
A Honeybee Model for which Annual Daylight will be simulated. Note that this model must have grids assigned to it.
wea [Required]
A Wea object produced from the Wea components that are under the Light Sources tab. This can also be the path to a .wea or a .epw file. Note that the Wea must have a timestep of 1 to be used with this recipe.
north
A number between -360 and 360 for the counterclockwise difference between the North and the positive Y-axis in degrees. This can also be Vector for the direction to North. (Default: 0).
thresholds
A string to change the threshold for daylight autonomy and useful daylight illuminance. Valid keys are -t for daylight autonomy threshold,
schedule
An annual occupancy schedule, either as a Ladybug Hourly Continuous Data Collection or a HB-Energy schedule object. This can also be the path to a CSV file with 8760 rows or the identifier of a schedule in the honeybee-energy schedule library. Any value in this schedule that is 0.1 or above will be considered occupied. If not provided, a default schedule that runs from 8 AM to 5 PM on weekdays will be used.
grid_filter
Text for a grid identifer or a pattern to filter the sensor grids of the model that are simulated. For instance, first_floor_* will simulate only the sensor grids that have an identifier that starts with first_floor_. By default, all grids in the model will be simulated.
radiance_par
Text for the radiance parameters to be used for ray tracing. (Default: -ab 2 -ad 5000 -lw 2e-05).
enhanced
Boolean to note whether an enhanced version of the 2-phase ray tracing simulation should be used, which will more accurately account for direct sun at each time step. If False, only a 2-phase daylight coefficient calculation with sky patches will be used, which is much faster but spreads the direct sun out across a few sky patches, making it unsuitable for ASE. (Default: True).
run_settings
Settings from the "HB Recipe Settings" component that specify how the recipe should be run. This can also be a text string of recipe settings.
run [Required]
Set to True to run the recipe and get results. This input can also be the integer "2" to run the recipe silently.
report
Reports, errors, warnings, etc.
results
Raw result files (.ill) that contain illuminance matrices for each sensor at each hour of the simulation. These can be postprocessed using various components under the 4::Results sub-tab.
DA
Daylight autonomy results in percent. DA is the percentage of occupied hours that each sensor recieves equal or more than the illuminance threshold. Each value is for a different sensor of the grid. These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize results. These can also be connected to the "HB Spatial Daylight Autonomy" component to compute spatial daylight autonomy for each grid. Note that the resulting sDA is only compliant with LEED if dynamic blinds have been simulated using the methods in IES-LM-83-12.
cDA
Continuous daylight autonomy results in percent. cDA is similar to DA except that values below the illuminance threshold can still count partially towards the final percentage. Each value is for a different sensor of the grid. These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize results.
UDI
Useful daylight illuminance results in percent. UDI is the percentage of occupied hours that illuminace falls between minimum and maximum thresholds. Each value is for a different sensor of the grid. These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize results.
UDI_low
Results for the percent of time that is below the lower threshold of useful daylight illuminance in percent. Each value is for a different sensor of the grid. These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize results.
UDI_up
Results for the percent of time that is above the upper threshold of useful daylight illuminance in percent. Each value is for a different sensor of the grid. These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize results.
