# Psychrometric Chart

Component Index > Ladybug > 2 | VisualizeWeatherData > **Psychrometric Chart**

### Use this component to draw a psychrometric chart in the Rhino scene and evaluate a set of temperatures and humidity ratios in terms of indoor comfort. Connected data can include either outdoor temperature and humidty ratios from imported EPW weather data, indoor temperature and humidity ratios from an energy simulation, or indivdual numerical inputs of temperature and humidity. The input data will be plotted alongside polygons on the chart representing comfort as well as polygons representing the efects of passive building strategies on comfort.

The specific human energy balance model used by the psychrometric chart is the Predicted Mean Vote (PMV) model developed by P.O. Fanger. PMV is a seven-point scale from cold (-3) to hot (+3) that is used in comfort surveys. Each interger value of the scale indicates the following: -3:Cold, -2:Cool, -1:Slightly Cool, 0:Neutral, +1:Slightly Warm, +2:Warm, +3:Hot. The range of comfort is generally accepted as a PMV between -1 and +1 and this is what defines the range of the comfort polygon on the psychrometric chart.

Accordingly, this component will also output the PMV of the occupant for the input conditions as well as an estimated percentage of people dissatisfied (PPD) in the given conditions.

The comfort models that make this component possible were translated to python from a series of validated javascript comfort models developed at the Berkely Center for the Built Environment (CBE).

Specific documentation on the comfort models can be found here: https://code.google.com/p/cbe-comfort-tool/wiki/ComfortModels

Special thanks goes to the authors of the online CBE Thermal Comfort Tool who first made the javascript models in order to power the tool:

Hoyt Tyler, Schiavon Stefano, Piccioli Alberto, Moon Dustin, and Steinfeld Kyle, 2013, CBE Thermal Comfort Tool.

Center for the Built Environment, University of California Berkeley, http://cbe.berkeley.edu/comforttool/

The information for the polygons representing passive strategies comes from the climate consultant psychrometric chart. Further information on how these polygons are calculated can be found here:

http://apps1.eere.energy.gov/buildings/tools_directory/software.cfm/ID=123/pagename=alpha_list

## Inputs

## Outputs

Name | ID | Description | Type |
---|---|---|---|

out | readMe! | ... | String |

------------------------- | ------------------------- | ... | Goo |

totalComfortPercent | totalComfortPercent | The percent of the input data that are inside all comfort and passive strategy polygons. | Goo |

totalComfortOrNot | totalComfortOrNot | A list of 0's and 1's indicating, for each hour of the input data, if the hour is inside a comfort or strategy polygon (1) or not(0). | Goo |

strategyNames | strategyNames | A list of names for the comfort polygons and strategeis that corresponds to the numbers in the following outputs. | Goo |

strategyPercentOfTime | strategyPercentOfTime | The percent of the input data that are in each of the comfort or passive strategy polygons. Each number here corresponds to the names in the "strategyNames" output above. | Goo |

strategyOrNot | strategyOrNot | A list of 0's and 1's indicating, for each hour of the input temperature and humidity ratio, if the hour is inside a given comfort or passive strategy polygon (1) or not(0). If there are multiple comfort polyogns or passive strategies connected to the passiveStrategy_ input, this output will be a grafted list for each polygon. Each list here corresponds to the names in the "strategyNames" output above. | Goo |

------------------------ | ------------------------ | ... | Goo |

chartCurvesAndTxt | chartCurvesAndTxt | The chart curves and text labels of the psychrometric chart. | Goo |

psychChartMesh | psychChartMesh | A colored mesh showing the number of input hours happen in each part of the psychrometric chart. | Goo |

legend | legend | A colored legend showing the number of hours that correspond to each color. | Goo |

legendBasePt | legendBasePt | The legend base point, which can be used to move the legend in relation to the chart with the grasshopper "move" component. | Goo |

comfortPolygons | comfortPolygons | A brep representing the range of comfort for the input radiant temperature, wind speed, metabolic rate and clothing level. IF multiple values have been hooked up for any of these inputs, multiple polygons will be output here. | Goo |

strategyPolygons | strategyPolygons | A brep representing the area of the chart made comfortable by the passive strategies. If multiple strategies have been hooked up to the passiveStrategy_ input, multiple polygons will be output here. | Goo |

------------------------- | ------------------------- | Script variable PsychChart | Goo |

chartHourPoints | chartHourPoints | Points representing each of the hours of input temperature and humidity ratio. By default, this ouput is hidden and, to see it, you should connect it to a Grasshopper preview component. | Goo |

hourPointColors | hourPointColors | Colors that correspond to the chartHourPoints above and can be hooked up to the "Swatch" input of a Grasshopper Preview component that has the hour points above connected as geometry. By default, points are colored red if they lie inside comfort or strategy polygons and are colored blue if they do not meet such comfort criteria. In the event that you have hooked up annualHourlyData_ this output will be a grafted list of colors. The first list corresponds to the comfort conditions while the second list colors points based on the annualHourlyData. | Goo |

hourPointLegend | hourPointLegend | A legend that corresponds to the hour point colors above. In the event that annualHourlyData_ is connected, this output will be a grafted list of legends that each correspond to the grafted lists of colors. | Goo |