PVWatts Results
===============

The PVWatts performance model displays the following results in :doc:`Tables <../results/data>` and :doc:`Time Series <../results/timeseries>` graphs. For details about how the model calculates these results, see Dobos, A. (2014). PVWatts Version 5 Manual (`PDF 714 KB <https://docs.nlr.gov/docs/fy14osti/62641.pdf>`__).

Hourly Data
~~~~~~~~~~~
.. list-table::
   :width: 100%
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   * - Variable Name
     - Units
     - Description
   * - AC inverter power
     - W
     - The output power of the inverter(s)
   * - Ambient temperature
     - ºC
     - Ambient temperature (dry-bulb) from the weather file
   * - Angle of incidence
     - degrees
     - The angle between the beam irradiance and a line normal to the photovoltaic array surface.
   * - Beam irradiance
     - W/m\ :sup:`2`\ 
     - Direct normal solar irradiance data from the weather file
   * - DC array power
     - W
     - The output power of the photovoltaic array
   * - Diffuse irradiance
     - W/m\ :sup:`2`\ 
     - Diffuse horizontal solar irradiance data from the weather file
   * - Global horizontal irradiance
     - W/m\ :sup:`2`\ 
     - Global horizontal solar irradiance data from the weather file
   * - Module temperature
     - ºC
     - Operating temperature of the photovoltaic cells in the modules
   * - Plane of array irradiance
     - W/m\ :sup:`2`\ 
     - Solar irradiance incident on the photovoltaic array
   * - Power generated by system
     - kW
     - The output power of the system (equal to the AC inverter power converted from W to kW)
   * - Shading factor for beam radiation
     -  - 
     - Factor applied to beam irradiance to represent reduction due to shading
   * - Sun up over horizon
     -  - 
     - Indicates whether the sun is up for the given time step (1 = sun over horizon, 0 = sun below horizon)
   * - Transmitted plane of array irradiance
     - W/m\ :sup:`2`\ 
     - Plane of array irradiance transmitted through the module cover to the photovoltaic cells
   * - Wind speed
     - m/s
     - Wind speed data from the weather file

Monthly Data
~~~~~~~~~~~~
.. list-table::
   :width: 100%
   :align: center
   :header-rows: 1

   * - Variable Name
     - Units
     - Description
   * - Monthly DC energy
     - kWh
     - Monthly total of hourly array DC output.
   * - Monthly AC energy
     - kWh
     - Monthly total of hourly inverter AC output.
   * - Monthly AC energy in Year 1
     - kWh
     - Monthly total of hourly inverter AC output. This is the same as Monthly AC Energy.