Grasshopper

algorithmic modeling for Rhino

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1 | AnalyzeWeatherData
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Outdoor Solar Temperature Adjustor

Component Index > Ladybug > 2 | VisualizeWeatherData > Outdoor Solar Temperature Adjustor

Use this component to adjust an existing Mean Radiant Temperature for shortwave solar radiation. This adjusted mean radiant temperature can then be used in comfort studies.
Note that this component assumes that you have already accounted for longwave radiation in the form of the _baseTemperature input. If you do not hook up a _baseTemperature, this component will assume that the surrounding radiant temperature is the same as the air temperature, which is a decent assumption for someone standing in an unobstructed field. However, the more obstacles that surround the person (and the more "context" that you add), the more important it is to derive a starting mean radiant temperature from a Honeybee Energy simulation. Also note that this component is not meant to account for shortwave radiation passing through glass.
This component uses Radiance functions in order to determine the amount of direct and diffuse solar radiation falling on a comfort mannequin. The portion reflected off of the ground to the comfort mannequin is derived from these values of direct and diffuse radiation.
Lastly, the formulas to translate this radiation into an effective radiant field and into a solar-adjusted mean radiant temperature come from this paper:
Arens, Edward; Huang, Li; Hoyt, Tyler; Zhou, Xin; Shiavon, Stefano. (2014). Modeling the comfort effects of short-wave solar radiation indoors. Indoor Environmental Quality (IEQ).
http://escholarship.org/uc/item/89m1h2dg#page-4

Inputs

NameIDDescriptionType
_location_locationThe location output from the 'Ladybug_Import epw' component. This is used to determine the position of the sun.Goo
_cumSkyMtxOrDirNormRad_cumSkyMtxOrDirNormRadEither the output from a GenCumulativeSkyMtx component (for high-resolution analysis) or the directNormallRadiation ouput from the 'Ladybug_Import epw' component (for simple, low-resolution analsysis).Goo
_diffuseHorizRad_diffuseHorizRadIf you are running a simple analysis with Direct Normal Radiation above, you must provide the diffuseHorizaontalRadiation ouput from the 'Ladybug_Import epw' component here. Otherwise, this input is not required.Goo
_baseTemperature_baseTemperatureA number or list of numbers representing either the outdoor dry bulb air temperture (if the input below is set to 'True') or the long wave mean radiant temperature (MRT) of the surrounding surfaces in degrees Celcius (if the input below is set to 'False'). The former is useufl for computing outdoor MRT if you only have the air temperature while the latter is useful for indoor conditions when you can compute a starting long wave MRT from the indoor surface temperatures.Goo
_baseDryBulbOrMRT__baseDryBulbOrMRT_Set to 'True' to have the _baseTemperature above understood as the outdoor dry bulb air temperature, in which case this component will attempt to account for long wave radiation by computing sky temperature and assuming all other surfaces are at the specified _baseTemperature. Set to 'False' to have the input above interpreted as a starting long wave MRT, which will only be increased to account for short wave radiation. The latter is useful for indoor conditions where you can compute a starting long wave MRT from the indoor surface temperatures. The default is set to 'True' to interpret the input above as outdoor air temperature.Goo
_horizInfraredRad__horizInfraredRad_A number or list of numbers representing downwelling long wave infrared radiation from the sky. This input can also be the horizontalInfraredRadiation output of the Import EPE component. The values are necessary to calculate long wave sky temperature when the input above is set to 'True.'Goo
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bodyPosture_bodyPosture_An interger between 0 and 5 to set the posture of the comfort mannequin, which can have a large effect on the radiation for a given sun position. 0 = Standing, 1 = Sitting, 2 = Lying Down, 3 = Low-Res Standing, 4 = Low-Res Sitting, and 5 = Low-Res Lying Down. The default is set to 1 for sitting.Goo
rotationAngle_rotationAngle_An optional rotation angle in degrees. Use this number to adjust the angle of the comfort mannequin in space. The angle of the mannequin in relation to the sun can have a large effect on the amount of radiation that falls on it and thus largely affect the resulting mean radiant temperature.Goo
bodyLocation_bodyLocation_An optional point that sets the position of the comfort mannequin in space. Use this to move the comfort mannequin around in relation to contextShading_ connected below. Note that this point should be the center of gravity of your person. The default is set to a person just above the Rhino origin.Goo
contextShading_contextShading_Optional breps or meshes that represent shading or opaque solar obstructions around the mannequin. If you are using this component for indoor studies, windows or any transparent materials should not be included in this geometry. You should factor the transmissivity of these materials in with the windowTransmissivity_ input. Also, note that, if you have a lot of this context geometry, you should make sure that you input a starting _baseTemperature that accounts for the temperature of all the temperture of these shading surfaces.Goo
north_north_Input a vector to be used as a true North direction for the sun path or a number between 0 and 360 that represents the degrees off from the y-axis to make North. The default North direction is set to the Y-axis (0 degrees).Goo
groundReflectivity_groundReflectivity_An optional decimal value between 0 and 1 that represents the fraction of solar radiation reflected off of the ground. By default, this is set to 0.25, which is characteristic of outdoor grass or dry bare soil. You may want to increase this value for concrete or decrease it for water or dark soil.Goo
clothingAbsorptivity_clothingAbsorptivity_An optional decimal value between 0 and 1 that represents the fraction of solar radiation absorbed by the human body. The default is set to 0.7 for (average/brown) skin and average clothing. You may want to increase this value for darker skin or darker clothing.Goo
windowTransmissivity_windowTransmissivity_An optional decimal value between 0 and 1 that represents the transmissivity of windows around the person. This can also be a list of 8760 values between 0 and 1 that represents a list of hourly window transmissivties, in order to represent the effect of occupants pulling blinds over the windows, etc. Note that you should only set a value here if you are using this component for indoor analysis where the only means by which sunlight will hit an occupant is if it comes through a window. The default is set to 1 for outdoor conditions.Goo
analysisPeriodOrHOY_analysisPeriodOrHOY_An optional analysis period from the 'Analysis Period component' or an hour of the year between 1 and 8760 for which you want to conduct the analysis. If no value is connected here, the component will run for the whole year if using raw epw DirNormRad or will run for noon on the winter solstice if using cumSkyMtx.Goo
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parallel_parallel_Set to 'True' to run the component using multiple CPUs. This can dramatically decrease calculation time but can interfere with other intense computational processes that might be running on your machine. For this reason, the default is set to 'True.'Goo
bakeIt_bakeIt_An integer that tells the component if/how to bake the bojects in the Rhino scene. The default is set to 0. Choose from the following options: 0 (or False) - No geometry will be baked into the Rhino scene (this is the default). 1 (or True) - The geometry will be baked into the Rhino scene as a colored hatch and Rhino text objects, which facilitates easy export to PDF or vector-editing programs. 2 - The geometry will be baked into the Rhino scene as colored meshes, which is useful for recording the results of paramteric runs as light Rhino geometry.Goo
_runIt_runItThe legend base point, which can be used to move the legend in relation to the chart with the grasshopper 'move' component.Goo

Outputs

NameIDDescriptionType
readMe!readMe!...String
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effectiveRadiantFieldeffectiveRadiantFieldThe estimated effective radiant field of the comfort mannequin induced by the sun for each hour of the analysis period. This is in W/m2.Goo
MRTDeltaMRTDeltaThe estimated change in mean radiant temperature for the comfort mannequin induced by the solar radiation. This is in degreed Celcius.Goo
solarAdjustedMRTsolarAdjustedMRTThe estimated solar adjusted mean radiant temperature for each hour of the analysis period. This is essentially the change in mean radiant temperature above added to the hourly _baseTemperature input. This is in degreed Celcius and can be plugged into any comfort components for comfort studies.Goo
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mannequinMeshmannequinMeshA colored mesh of a comfort mannequin showing the amount of radiation falling over the mannequin's body.Goo
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