pv_system.py

"""
An open PV system specification
"""

import json
import pathlib
import yaml


def get_pv_spec(pv_spec_pathlib_file_or_buffer):
    try:
        f = pathlib.Path(pv_spec_pathlib_file_or_buffer)
    except TypeError:
        f = pv_spec_pathlib_file_or_buffer

    try:
        g = f.open()
    except AttributeError:
        g = f

    return yaml.load(g)


def test_pv_spec():
    x = get_pv_spec('pv_system.yaml')
    y = get_pv_spec(pathlib.Path('pv_system.yaml'))
    assert x == y
    with pathlib.Path('pv_system.yaml').open() as f0:
        z = get_pv_spec(f0)
    assert x == z
    assert y == z
    with pathlib.Path('test_pv_system.json').open() as f1:
        w = json.load(f1)
    assert x == w
    assert y == w
    assert z == w


if __name__ == '__main__':
    x = get_pv_spec('pv_system.yaml')
    with pathlib.Path('test_pv_system.json').open('w') as f2:
        json.dump(x, f2, indent=2)

pv_system.yaml

# Open PV system specification

# component specifications
PV module specs:
  <PV module ID>: <ModuleSpec>
  etc: <...>
inverter specs:
  <inverter ID>: <InverterSpec>
  etc: <...>
mounting type specs:
  <mounting type ID>: <RackSpec|TrackerSpec|...>
  etc: <...>
transformer specs:
  <transformer ID>: <TransformerSpec>
  etc: <...>

# site parameters
latitude: <float(degrees)>
longitude: <float(degrees)>
elevation: <float(meters)>
GIS shapefile path: <filepath>|<null>    # if null assume horizontal
HOR file path: <filepath>|<null>         # if null assume horizon incl. in weather
irradiance weather file path: <filepath(s)>
weather file formats: <enum>|<newspec>   # should be list if more than one weather file
albedo per month: <float|floats[12]>     # constant or monthly
soiling per month: <float|floats[12]>    # constant or monthly
etc: <...>

# layout parameters
transformers:
- transformer name: <str>
  transformer spec ID: <enum>            # transformer specs are enumerated by ID at top level
  transformer count: <int>               # identical transformers are scaled linearly
  etc: <...>
  inverters:
  - inverter name: <str>
    inverter spec ID: <enum>             # inverter specs are enumerated by ID at top level
    inverter count: <int>                # identical inverters are scaled linearly
    AC collection loss: <float(%)>
    etc: <..>
    layouts:
    - layout name: <str>                 # identical layouts are scale linearly
      layout coordinates: <point>        # (easting, northing) from (lat, lon)
      layout count: <int>                # use list to assign to different inverter inputs
      inverter input: <int|int[ct]>      # 0-based, must be less than number of inverter MPPTs
      PV module spec ID: <enum>          # PV module specs are enumerated by ID at top level
      mounting type ID: <enum>           # mounting system specs are enumerated by ID at top level
      system azimuth: <float(degrees)>   # fixed tilt: normal to surface, trackers: axes
      module tilt: <float(degrees)>
      gcr: <float>
      PV modules per string: <int>
      number of strings: <int>           # must be a multiple of strings per row
      row in front of PV system: <bool>  # is this in the middle of the system or not
      row in back of PV system: <bool>   # useful for bifacial
      number strings per row: <int>      # number of strings must be a multiple of this
      thermal parameters: '<thermal model: {Uc: <float>, Uv: <float>}>'
      DC collection loss: <float(%)>
      etc: <...>
    - layout name: <str>                 # next layout
      etc: <...>
  - inverter name: <str>                 # next inverter
    etc: <...>
- transformer name: <str>                # next transformer
  etc: <...>

# shade objects
shade objects: <shade object spec>       # buildings, trees, poles, overhead wires, etc.

# settings & options to toggle different calculations
calcultion settings:
- include thermal: <bool>
- include spectral: <bool>
- include bifacial: <bool>
- include IAM: <bool>
- include diffuse IAM: <bool>            # use interate IAM over diffuse
- include ground diffuse: <bool>
- include panel surface VF: <bool>       # can the panel surface see all ground & sky?
- include ground-sky VF: <bool>          # can the ground see all of the sky?
- always decompose GHI: <bool>           # ignore given DNI & DHI, and calculate from GHI
- use Erbs decomposition: <bool>         # if false then use DIRINT, may require more inputs
- use Hay-Davies transposition: <bool>   # if false then use Perez-Ineichen, may require more inputs
- use POA GTI-DIRINT: <bool>             # if true and POA is given, then ignore GHI and other inputs
- include shade objects: <bool>
- etc: <...>

test_pv_system.json

{
  "PV module specs": {
    "<PV module ID>": "<ModuleSpec>",
    "etc": "<...>"
  },
  "inverter specs": {
    "<inverter ID>": "<InverterSpec>",
    "etc": "<...>"
  },
  "mounting type specs": {
    "<mounting type ID>": "<RackSpec|TrackerSpec|...>",
    "etc": "<...>"
  },
  "transformer specs": {
    "<transformer ID>": "<TransformerSpec>",
    "etc": "<...>"
  },
  "latitude": "<float(degrees)>",
  "longitude": "<float(degrees)>",
  "elevation": "<float(meters)>",
  "GIS shapefile path": "<filepath>|<null>",
  "HOR file path": "<filepath>|<null>",
  "irradiance weather file path": "<filepath(s)>",
  "weather file formats": "<enum>|<newspec>",
  "albedo per month": "<float|floats[12]>",
  "soiling per month": "<float|floats[12]>",
  "etc": "<...>",
  "transformers": [
    {
      "transformer name": "<str>",
      "transformer spec ID": "<enum>",
      "transformer count": "<int>",
      "etc": "<...>",
      "inverters": [
        {
          "inverter name": "<str>",
          "inverter spec ID": "<enum>",
          "inverter count": "<int>",
          "AC collection loss": "<float(%)>",
          "etc": "<..>",
          "layouts": [
            {
              "layout name": "<str>",
              "layout coordinates": "<point>",
              "layout count": "<int>",
              "inverter input": "<int|int[ct]>",
              "PV module spec ID": "<enum>",
              "mounting type ID": "<enum>",
              "system azimuth": "<float(degrees)>",
              "module tilt": "<float(degrees)>",
              "gcr": "<float>",
              "PV modules per string": "<int>",
              "number of strings": "<int>",
              "row in front of PV system": "<bool>",
              "row in back of PV system": "<bool>",
              "number strings per row": "<int>",
              "thermal parameters": "<thermal model: {Uc: <float>, Uv: <float>}>",
              "DC collection loss": "<float(%)>",
              "etc": "<...>"
            },
            {
              "layout name": "<str>",
              "etc": "<...>"
            }
          ]
        },
        {
          "inverter name": "<str>",
          "etc": "<...>"
        }
      ]
    },
    {
      "transformer name": "<str>",
      "etc": "<...>"
    }
  ],
  "shade objects": "<shade object spec>",
  "calcultion settings": [
    {
      "include thermal": "<bool>"
    },
    {
      "include spectral": "<bool>"
    },
    {
      "include bifacial": "<bool>"
    },
    {
      "include IAM": "<bool>"
    },
    {
      "include diffuse IAM": "<bool>"
    },
    {
      "include ground diffuse": "<bool>"
    },
    {
      "include panel surface VF": "<bool>"
    },
    {
      "include ground-sky VF": "<bool>"
    },
    {
      "always decompose GHI": "<bool>"
    },
    {
      "use Erbs decomposition": "<bool>"
    },
    {
      "use Hay-Davies transposition": "<bool>"
    },
    {
      "use POA GTI-DIRINT": "<bool>"
    },
    {
      "include shade objects": "<bool>"
    },
    {
      "etc": "<...>"
    }
  ]
}