Symbol
|
Definition
|
Page Links
|
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Anisotropy Index [unitless] |
Hay and Davies Sky Diffuse Model, Reindl Sky Diffuse Model |
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Air Mass [unitless] |
Air Mass |
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Absolute Air Mass [unitless] |
Perez Sky Diffuse Model, Sandia PV Array Performance Model |
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Angle of Incidence [degrees] |
POA BeamAngle of IncidenceHay and Davies Sky Diffuse ModelReindl Sky Diffuse ModelPerez Sky Diffuse Model |
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Diffuse Horizontal Irradiance [W/m2] |
Global Horizontal Irradiance, Diffuse Horizontal IrradianceIsotropic Sky Diffuse ModelSimple Sandia Sky Diffuse ModelHay and Davies Sky Diffuse ModelReindl Sky Diffuse Model
Perez Sky Diffuse Model |
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Direct Normal Irradiance [W/m2] |
Irradiance and Weather – Definitions and OverviewDirect Normal IrradianceGlobal Horizontal IrradiancePOA BeamHay and Davies Sky Diffuse ModelReindl Sky Diffuse Model |
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Day of Year |
Extraterrestrial Radiation |
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reference irradiance, typically 1000 W/m2 |
Sandia Cell Temperature Model, Effective IrradianceSandia PV Array Performance ModelPVWatts |
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Extraterrestrial Irradiance [W/m2] |
Extraterrestrial RadiationDISC ModelHay and Davies Sky Diffuse ModelReindl Sky Diffuse ModelPerez Sky Diffuse Model |
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beam component of plane-of-array irradiance [W/m2] |
Plane of Array (POA) IrradiancePOA BeamSandia PV Array Performance Model |
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sky diffuse component of plane-of-array irradiance [W/m2] |
Plane of Array (POA) IrradianceSimple Sandia Sky Diffuse ModelHay and Davies Sky Diffuse ModelReindl Sky Diffuse ModelPerez Sky Diffuse ModelSandia PV Array Performance Model |
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effective irradiance [unitless] |
Effective IrradianceSandia PV Array Performance ModelPVWatts |
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irradiance incident on the plane of the array [W/m2] |
Plane of Array (POA) IrradianceFaiman Module Temperature ModelSandia Cell Temperature ModelPVsyst Cell Temperature ModelEffective Irradiance |
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Equation of Time |
Simple Models |
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Solar Constant |
Extraterrestrial Radiation |
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efficiency of PV module |
PVsyst Cell Temperature Model |
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fraction of diffuse light used by PV module |
Sandia PV Array Performance Model |
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Global Horizontal Irradiance [W/m2] |
Direct Normal IrradianceDISC ModelGlobal Horizontal IrradianceSimple Sandia Sky Diffuse ModelReindl Sky Diffuse Model |
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Current [amps] |
Module IV CurveSingle Diode Equivalent Circuit Models |
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Saturation current |
Single Diode Equivalent Circuit Models |
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Incidence angle modifier |
Incident Angle Reflection Losses |
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Incidence angle modifier for beam component of irradiance |
Incident Angle Reflection Losses |
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voltage-dependent current lost to recombination |
Single Diode Equivalent Circuit Models |
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light-generated current produced within PV cell |
Single Diode Equivalent Circuit Models |
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current of module or array |
Single Diode Equivalent Circuit Models |
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current at maximum power |
Sandia PV Array Performance Model |
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short circuit current |
Sandia ModelEffective IrradianceSandia PV Array Performance Model |
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|
Effective IrradianceSandia PV Array Performance Model |
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|
Effective Irradiance |
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|
Effective Irradiance |
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current lost due to shunt resistances |
Single Diode Equivalent Circuit Models |
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glazing extinction coefficient |
Physical Model of IAM |
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Direct Normal Transmittance |
DISC Model |
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Global Horizontal Transmittance |
DISC Model |
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glazing thickness |
Physical Model of IAM |
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Longitude of the observer |
Simple Models |
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Longitude of standard meridian of observer’s time zone |
Simple Models |
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air mass modifier |
De Soto Model |
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number of cells in series |
Single Diode Equivalent Circuit Models |
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AC output power |
Sandia Inverter Model |
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maximum AC power rating |
Sandia Inverter Model |
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DC input power |
Sandia Inverter Model |
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normalized DC power |
Driesse Inverter Model |
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|
Driesse Inverter Model |
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maximum power point power |
Point-value ModelsPVWatts |
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|
PVWatts |
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daily AC performance ratio |
Performance Ratio |
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elementary charge (constant) |
Single Diode Equivalent Circuit ModelsSandia PV Array Performance Model |
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mean Sun-Earth distance |
Extraterrestrial Radiation |
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series resistance |
Single Diode Equivalent Circuit Models |
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shunt resistance |
Single Diode Equivalent Circuit Models |
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|
PVsyst Model |
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total absorbed irradiance [W/m2] |
De Soto ModelPVsyst Model |
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soiling factor; ranges from 0 (no soiling)to 1 (complete soiling) |
Effective Irradiance |
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reference temperature, typically 25 degrees Celsius |
Effective IrradianceSandia PV Array Performance ModelPVWatts |
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cell temperature [°C] |
Sandia Cell Temperature ModelPVsyst Cell Temperature ModelEffective IrradianceDe Soto ModelPVWatts |
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|
Effective Irradiance |
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local time |
Simple Models |
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module temperature [°C] |
Sandia Module Temperature ModelFaiman Module Temperature ModelSandia Cell Temperature Model |
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solar time |
Simple Models |
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constant heat transfer component |
Faiman Module Temperature ModelPVsyst Cell Temperature Model |
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convective heat transfer component |
Faiman Module Temperature ModelPVsyst Cell Temperature Model |
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voltage [V] |
Module IV Curve |
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DC input voltage [V] |
Sandia Inverter Model |
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DC voltage level at which AC power rating is achieved [V] |
Sandia Inverter Model |
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normalized DC voltage |
Driesse Inverter Model |
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voltage of module or array [V] |
Single Diode Equivalent Circuit Models |
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maximum power point voltage [V] |
Sandia PV Array Performance Model |
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open circuit voltage [V] |
Sandia PV Array Performance Model |
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thermal voltage |
Single Diode Equivalent Circuit Models |
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wind speed [m/s] |
Sandia Module Temperature ModelFaiman Module Temperature ModelPVsyst Cell Temperature Model |
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AC system yield |
Performance Ratio |
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ratio of plane-of-array irradiance to reference irradiance |
Performance Ratio |
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absorption coefficient of PV module |
PVsyst Cell Temperature Model |
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temperature coefficient for maximum power point current |
Sandia PV Array Performance Model |
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temperature coefficient for short circuit current |
Effective IrradianceDe Soto ModelSandia PV Array Performance ModelPVsyst Model |
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|
Effective Irradiance |
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temperature coefficient for module; open circuit voltage |
Sandia PV Array Performance Model |
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temperature coefficient for module; open circuit voltage at reference irradiance |
Sandia PV Array Performance Model |
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temperature correction for Pmp |
PVWatts |
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temperature difference parameter |
Sandia Cell Temperature Model |
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bins of clearness |
Perez Sky Diffuse Model |
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azimuth angle |
Sun PositionAngle of Incidence |
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declination of the sun |
Simple Models |
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solar elevation angle |
Sun Position |
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hour angle |
Simple Models |
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angle of refraction |
Physical Model of IAM |
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solar zenith angle |
Sun PositionAir MassAngle of IncidenceSimple Sandia Sky Diffuse ModelPerez Sky Diffuse Model |
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constant |
Perez Sky Diffuse Model |
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latitude of the observer |
Simple Models |
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weighted transmittance |
Incident Angle Reflection Losses |