python, configuration factor model
Original code by Bill Marion Python translation by Silvana Ayala Updates by Chris Deline
Based on the publication: "A Practical Irradiance Model for Bifacial PV Modules" B. Marion, S. MacAlpine, C. Deline, A. Asgharzadeh, F. Toor, D. Riley, J. Stein, C. Hansen 2017 IEEE Photovoltaic Specialists Conference, Washington DC, 2017 URL: https://www.nrel.gov/docs/fy17osti/67847.pdf
bifacialvf is a self-contained view factor (or configuration factor) model which
replicates a 5-row PV system of infinite extent perpendicular to the module
rows. The function returns the irradiance profile along the middle (interior)
row by default, but user interface options include 'first'
, 'interior'
,
'last'
, and 'single'
. Single-axis tracking is supported, and hourly output
files based on TMY inputs are saved. Spatial nonuniformity is reported, with
multiple rear-facing irradiances collected on the back of each module row.
This software is written for Python 2 or 3. NREL recommends Anaconda Python.
bifacialvf is at the Python Package Index (PyPI). Use pip to install the latest release in your conda environment or virtualenv:
(myenv)$ pip install bifacialvf
For those interested in contributing to bifacialvf:
- Clone the bifacialvf repository:
$ git clone https://github.com/NREL/bifacialvf.git bifacialvf-master
- Navigate to the repository directory where
setup.py
is located:$ cd bifacialvf-master
- Install via pip in development mode:
$ pip install -e .
import bifacialvf
bifacialvf.simulate(inputTMY, outputfile, tilt, azm, clearance, rowspacing)
(data, metadata) = bifacialvf.loadVFresults(outputfile)
For more usage examples, see the Jupyter notebooks in \docs\
bifacialvf.simulate(
TMYtoread, writefiletitle, beta, sazm, C=1, D=0.5,
rowType = 'interior', transFactor=0.01, cellRows=6,
PVfrontSurface='glass', PVbackSurface='glass', albedo=0.62,
tracking=False, backtrack=False, r2r=1.5, Cv=0.05, offset=0)
This is the main runfile. Hourly TMY3 inputs are read, and an outputfile is saved with
a number of irradiance points along the module chord specified by cellRows
.
loadVFresults.loadVFresults(filename=None)
read in saved file from bifacialvf.simulate
. If no filename is passed, a tkinter GUI opens for file selection
sun.py
:
Solar position and irradiance-related helper files including
hrSolarPos
, perezComp
, solarPos
, and sunIncident
vf.py
:
View Factor helper files to help with configuration-factor calculation
1-axis tracking and self-shading calculation.
Subroutines include:
getBackSurfaceIrradiances
, getFrontSurfaceIrradiances
, getGroundShadeFactors
,
getSkyConfigurationFactors
, trackingBFvaluescalculator
, rowSpacing