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remove Cv value, switch to C = hub height (clearance at zero tilt) > 0.5
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Update trackingBFvaluescalculator to take hub_height
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@cdeline
cdeline committed Oct 6, 2017
1 parent bf7634b commit ee1b914
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Showing 3 changed files with 31 additions and 41 deletions.
58 changes: 24 additions & 34 deletions bifacialvf/bifacialvf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -25,29 +25,29 @@
import csv
import pvlib
import os
#import sys
#sys.path.insert(0, '../BF_BifacialIrradiances')

from vf import getBackSurfaceIrradiances, getFrontSurfaceIrradiances, getGroundShadeFactors
from vf import getSkyConfigurationFactors, trackingBFvaluescalculator, rowSpacing
from sun import hrSolarPos, perezComp, solarPos, sunIncident
import pandas as pd


def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
def simulate(TMYtoread, writefiletitle, beta = 0, sazm = 180, C = 0.5, D = None,
rowType = 'interior', transFactor = 0.01, cellRows = 6,
PVfrontSurface = 'glass', PVbackSurface = 'glass', albedo = 0.62,
tracking = False, backtrack = True, rtr = None, Cv= 0.05, offset = 0):
PVfrontSurface = 'glass', PVbackSurface = 'glass', albedo = 0.2,
tracking = False, backtrack = True, rtr = None, Cv = None, offset = 0):

if tracking == True:
axis_tilt = 0 # algorithm only allows for zero north-south tilt with SAT
max_angle=90 # maximum tracker rotation
axis_azimuth=sazm # axis_azimuth is degrees east of North
beta = 0
beta = 0 # start with tracker tilt = 0
hub_height = C # Ground clearance at tilt = 0. C >= 0.5

if (D == None) & (rtr != None):
D = rtr - math.cos(beta)
D = rtr - math.cos(beta / 180.0 * math.pi)
elif (rtr == None) & (D != None):
rtr = D + math.cos(beta)
rtr = D + math.cos(beta / 180.0 * math.pi)
elif (D == None) & (rtr == None):
raise Exception('No row distance specified in either D or rtr')
else:
Expand All @@ -69,7 +69,7 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
print "Running Simulation for TMY3: ", TMYtoread
print "Location: ", name
print "Lat: ", lat, " Long: ", lng, " Tz ", tz
print "Parameters: beta: ", beta, " Sazm: ", sazm, " Height: ", C, " D separation: ", D, " Row type: ", rowType, " Albedo: ", albedo
print "Parameters: beta: ", beta, " Sazm: ", sazm, " Height: ", C, " rtr separation: ", rtr, " Row type: ", rowType, " Albedo: ", albedo
print "Saving into", writefiletitle
print " "
print " "
Expand All @@ -94,23 +94,12 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
sw = csv.writer(csvfile, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL)
# Write Simulation Parameters (from setup file)

if tracking==True:
Ctype='Vertical GroundClearance(panel slope lengths) Cv'
Dtype='Row-to-Row-Distance rtr'
Ctypevar=Cv
Dtypevar=rtr
else:
Ctype='GroundClearance(panel slope lengths)'
Dtype='DistanceBetweenRows(panel slope lengths)'
Ctypevar=C
Dtypevar=D

outputheader=['Latitude(deg)','Longitude(deg)', 'Time Zone','Tilt(deg)',
'PV Azimuth(deg)',Ctype, Dtype, 'RowType(first interior last single)',
'PV Azimuth(deg)','GroundClearance(panel slope lengths)', 'Row-to-Row-Distance rtr', 'RowType(first interior last single)',
'TransmissionFactor(open area fraction)','CellRows(# hor rows in panel)',
'PVfrontSurface(glass or AR glass)', 'PVbackSurface(glass or AR glass)',
'CellOffsetFromBack(panel slope lengths)','Albedo', 'Tracking']
outputheadervars=[lat, lng, tz, beta, sazm, Ctypevar, Dtypevar, rowType, transFactor, cellRows, PVfrontSurface,
outputheadervars=[lat, lng, tz, beta, sazm, C, rtr, rowType, transFactor, cellRows, PVfrontSurface,
PVbackSurface, offset, albedo, tracking]


Expand Down Expand Up @@ -139,6 +128,7 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
print " ***** IMPORTANT --> THIS SIMULATION Has Tracking Activated"
print "Backtracking Option is set to: ", backtrack
outputtitles+=['beta']
outputtitles+=['sazm']
outputtitles+=['height']
outputtitles+=['D']

Expand Down Expand Up @@ -187,8 +177,8 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
#solpos = pvlib.solarposition.get_solarposition(myTimestamp, lat, lng)
#aazi= solpos['azimuth']
#azen= solpos['zenith']
aazi = pd.Series([azm*180/math.pi], index =[myTimestamp])
azen = pd.Series([zen*180/math.pi], index =[myTimestamp])
aazi = pd.Series([azm*180.0/math.pi], index =[myTimestamp])
azen = pd.Series([zen*180.0/math.pi], index =[myTimestamp])



Expand All @@ -205,7 +195,7 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
#sazm = sazm+180 # Rotate detectors
beta = -beta;

[C, D] = trackingBFvaluescalculator(beta, Cv, rtr)
[C, D] = trackingBFvaluescalculator(beta, hub_height, rtr)
[rearSkyConfigFactors, frontSkyConfigFactors, ffConfigFactors] = getSkyConfigurationFactors(rowType, beta, C, D); ## Sky configuration factors are the same for all times, only based on geometry and row type


Expand Down Expand Up @@ -278,6 +268,7 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,

if tracking==True:
outputvalues.append(beta)
outputvalues.append(sazm)
outputvalues.append(C)
outputvalues.append(D)

Expand All @@ -294,8 +285,8 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
return;

if __name__ == "__main__":
import time
start_time = time.time()
#import time
#start_time = time.time()


beta = 10 # PV tilt (deg)
Expand All @@ -314,16 +305,15 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
# Tracking instructions
tracking=False
backtrack=True
rtr = 1.5 # row to row spacing in normalized panel lengths. This input is not used (D is used instead) except for in tracking
Cv = 0.05 # GroundClearance when panel is in vertical position (panel slope lengths).
rtr = 1.5 # row to row spacing in normalized panel lengths.

TMYtoread="data/724010TYA.csv" # VA Richmond
writefiletitle="data/Output/TEST.csv"

simulate(TMYtoread, writefiletitle, beta, sazm,
C, D, rowType= rowType, transFactor= transFactor, cellRows= cellRows,
simulate(TMYtoread, writefiletitle, beta, sazm, C, rtr= rtr,
rowType= rowType, transFactor= transFactor, cellRows= cellRows,
PVfrontSurface= PVfrontSurface, PVbackSurface= PVbackSurface,
albedo= albedo, tracking= tracking, backtrack= backtrack, rtr= rtr, Cv= Cv)
albedo= albedo, tracking= tracking, backtrack= backtrack)

#Load the results from the resultfile
from loadVFresults import loadVFresults
Expand All @@ -336,5 +326,5 @@ def simulate(TMYtoread, writefiletitle, beta, sazm, C = 1, D = None,
# Print the annual bifacial ratio.
frontIrrSum = data['GTIFrontavg'].sum()
backIrrSum = data['GTIBackavg'].sum()
print('The bifacial ratio for ground clearance {} and row gap {} is: {:.1f}%'.format(C,D,backIrrSum/frontIrrSum*100))
print("--- %s seconds ---" % (time.time() - start_time))
print('The bifacial ratio for ground clearance {} and rtr spacing {} is: {:.1f}%'.format(C,rtr,backIrrSum/frontIrrSum*100))
#print("--- %s seconds ---" % (time.time() - start_time))
8 changes: 4 additions & 4 deletions bifacialvf/vf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1396,9 +1396,9 @@ def rowSpacing(beta, sazm, lat, lng, tz, hour, minute):
return D;
# End of RowSpacing

def trackingBFvaluescalculator(beta, Cv, r2r):
def trackingBFvaluescalculator(beta, hub_height, r2r):
'''
C, D = trackingBFvaluescalculator(beta, Cv, r2r)
C, D = trackingBFvaluescalculator(beta, hub_height, r2r)
1-axis tracking helper file to calculate C = ground clearance of PV panel and D = row-to-row distance
(each in PV panel slope lengths)
Expand All @@ -1413,7 +1413,7 @@ def trackingBFvaluescalculator(beta, Cv, r2r):
#rtr = D + x1; # Row-to-row distance (in PV panel slope lengths)
D = r2r - x1; # Calculates D DistanceBetweenRows(panel slope lengths)
hm = 0.5*math.sin(beta); # vertical distance from bottom of panel to top of panel (in PV panel slope lengths)
C = 0.5+Cv-hm # Ground clearance of PV panel (in PV panel slope lengths).
#Adding a 0.5 for half a panel slope length, since it is assumed the panel is rotating around its middle axis
#C = 0.5+Cv-hm # Ground clearance of PV panel (in PV panel slope lengths).
C = hub_height - hm #Adding a 0.5 for half a panel slope length, since it is assumed the panel is rotating around its middle axis

return C, D;
6 changes: 3 additions & 3 deletions docs/bifacial viewfactor model - HOW TO USE.ipynb
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Original file line number Diff line number Diff line change
Expand Up @@ -55,7 +55,7 @@
"tracking=False\n",
"backtrack=True # backtracking optimization as defined in pvlib\n",
"rtr = 1.5 # row to row spacing in panel lengths. This input is not used (D is used instead) except for in tracking\n",
"Cv = 0.05 # GroundClearance when panel is in vertical position (panel slope lengths)\n",
"\n",
"\n",
"\n",
"\n",
Expand Down Expand Up @@ -87,7 +87,7 @@
"bifacialvf.simulate(TMYtoread, writefiletitle, beta, sazm, \n",
" C, D, rowType=rowType, transFactor=transFactor, cellRows=cellRows,\n",
" PVfrontSurface=PVfrontSurface, PVbackSurface=PVbackSurface, albedo=albedo, \n",
" tracking=tracking, backtrack=backtrack, rtr=rtr, Cv=Cv)\n",
" tracking=tracking, backtrack=backtrack, rtr=rtr)\n",
" "
]
},
Expand All @@ -109,7 +109,7 @@
"# Print the annual bifacial ratio\n",
"frontIrrSum = data['GTIFrontavg'].sum()\n",
"backIrrSum = data['GTIBackavg'].sum()\n",
"print('The bifacial ratio for ground clearance {} and row gap {} is: {:.1f}%'.format(C,D,backIrrSum/frontIrrSum*100))\n",
"print('The bifacial ratio for ground clearance {} and rtr spacing {} is: {:.1f}%'.format(C,rtr,backIrrSum/frontIrrSum*100))\n",
"\n"
]
},
Expand Down

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