UTCI Comfort Map
Last updated
Last updated
Compute spatially-resolved Universal Thermal Climate Index (UTCI) and heat/cold stress conditions an EPW and Honeybee model.
This recipe uses EnergyPlus to obtain surface temperatures and indoor air temperatures + humidities. Outdoor air temperatures, relative humidities, and air speeds are taken directly from the EPW. The energy properties of the model geometry are what determine the outcome of the simulation, though the model's Radiance sensor grids are what determine where the comfort mapping occurs.
Longwave radiant temperatures are obtained by computing spherical view factors from each sensor to the Room surfaces of the model using Radiance. These view factors are then multiplied by the surface temperatures output by EnergyPlus to yield longwave MRT at each sensor. For outdoor sensors, each sensor's sky view is multiplied by the EPW sky temperature to account for longwave radiant exchange with the sky. All outdoor context shades and the ground are assumed to be at the EPW air temperature unless they have been modeled as Honeybee rooms.
A Radiance-based enhanced 2-phase method is used for all shortwave MRT calculations, which precisely represents direct sun by tracing a ray from each sensor to the solar position. To determine Thermal Comfort Percent (TCP), the occupancy schedules of the energy model are used for indoor sensors if no schedule_ is input. Any hour of the energy model occupancy schedule that is 0.1 or greater will be considered occupied. If no schedule_ is input, all hours of the outdoors are considered occupied.
model [Required]
A Honeybee Model for which UTCI comfort will be mapped. Note that this model should have radiance grids assigned to it in order to produce meaningful results.
epw [Required]
Path to an EPW weather file to be used for the comfort map simulation.
ddy
Path to a DDY file with design days to be used for the initial sizing calculation of the energy simulation. Providing this input is important when there are conditioned Room geometries in the model, in which case the sizing of the building heating/cooling systems is important for modeling the heat exchange between indoors and outdoors. Otherwise, it can be ignored with little consequence for the simulation.
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).
run_period
An AnalysisPeriod to set the start and end dates of the simulation. If None, the simulation will be annual.
wind_speed
A single number for meteorological wind speed in m/s or an hourly data collection of wind speeds that align with the input run_period_. This will be used for all outdoor comfort evaluation. This can also be the path to a folder with csv files that align with the model sensor grids. Each csv file should have the same name as the sensor grid. Each csv file should contain a matrix of air speed values in m/s with one row per sensor and one column per timestep of the run period. Note that, when using this type of matrix input, these values are not meteorological and should be AT HUMAN SUBJECT LEVEL. If unspecified, the EPW wind speed will be used for all outdoor sensors and all sensors on the indoors will use a wind speed of 0.5 m/s, which is the lowest acceptable value for the UTCI model.
schedule
A schedule to specify the relevant times during which comfort should be evaluated. This must either be a Ladybug Hourly Data Collection that aligns with the input run_period_ or the path to a CSV file with a number of rows equal to the length of the run_period_. If unspecified, it will be assumed that all times are relevant for outdoor sensors and the energy model occupancy schedules will be used for indoor sensors.
comfort_par
Optional comfort parameters from the "LB UTCI Comfort Parameters" component to specify the temperatures (in Celcius) that are considered acceptable/comfortable. The default will assume a that the comfort range is between 9C and 26C.
solar_body_par
Optional solar body parameters from the "LB Solar Body Parameters" object to specify the properties of the human geometry assumed in the shortwave MRT calculation. The default assumes average skin/clothing absorptivity and a human subject always has their back to the sun at a 45-degree angle (SHARP = 135).
radiance_par
Text for the radiance parameters to be used for ray tracing. (Default: -ab 2 -ad 5000 -lw 2e-05).
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.
env_conds
A folder containing CSV matrices with all of the environmental conditions that were input to the comfort model. These can be loaded into Grasshopper using the "HB Read Environment Matrix" component. This includes the following.
utci
A folder containing CSV maps of Universal Thermal Climate Index (UTCI) temperatures for each sensor grid at each time step of the analysis. This can be connected to the "HB Read Thermal Matrix" component to parse detailed results into Grasshopper. Values are in Celsius.
condition
A folder containing CSV maps of comfort conditions for each sensor grid at each time step of the analysis. This can be connected to the "HB Read Thermal Matrix" component to parse detailed results into Grasshopper. Values are as follows.
category
A folder containing CSV maps of the heat/cold stress categories for each sensor grid at each time step of the analysis. This can be connected to the "HB Read Thermal Matrix" component to parse detailed results into Grasshopper. This can be used to understand not just whether conditions are acceptable but how uncomfortably hot or cold they are. Values indicate the following.
TCP
Lists of values between 0 and 100 for the Thermal Comfort Percent (TCP). These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize spatial thermal comfort. TCP is the percentage of occupied time where thermal conditions are acceptable/comfortable. Occupied hours are determined from the occuppancy schedules of each room (any time where the occupancy schedule is >= 0.1 will be considered occupied). Outdoor sensors are considered occupied at all times. More custom TCP studies can be done by post-processing the condition results.
HSP
Lists of values between 0 and 100 for the Heat Sensation Percent (HSP). These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize uncomfortably hot locations. HSP is the percentage of occupied time where thermal conditions are hotter than what is considered acceptable/comfortable. Occupied hours are determined from the occuppancy schedules of each room (any time where the occupancy schedule is >= 0.1 will be considered occupied). Outdoor sensors are considered occupied at all times. More custom HSP studies can be done by post-processing the condition results.
CSP
Lists of values between 0 and 100 for the Cold Sensation Percent (CSP). These can be plugged into the "LB Spatial Heatmap" component along with meshes of the sensor grids to visualize uncomfortably cold locations. CSP is the percentage of occupied time where thermal conditions are colder than what is considered acceptable/comfortable. Occupied hours are determined from the occuppancy schedules of each room (any time where the occupancy schedule is >= 0.1 will be considered occupied). Outdoor sensors are considered occupied at all times. More custom CSP studies can be done by post-processing the condition results.
