Three grid-connected monocrystalline silicon arrays on the National Institute of Standards and Technology (NIST) campus in Gaithersburg, MD have been instrumented and monitored for 1 yr, with only minimal gaps in the data sets. These arrays range from 73 kW to 271 kW, and all use the same module, but have different tilts, orientations, and configurations. One array is installed facing east and west over a parking lot, one in an open field, and one on a flat roof. Various measured relationships and calculated standard metrics have been used to compare the relative performance of these arrays in their different configurations. Comprehensive performance models have also been created in the modeling software pvsyst for each array, and its predictions using measured on-site weather data are compared to the arrays' measured outputs. The comparisons show that all three arrays typically have monthly performance ratios (PRs) above 0.75, but differ significantly in their relative output, strongly correlating to their operating temperature and to a lesser extent their orientation. The model predictions are within 5% of the monthly delivered energy values except during the winter months, when there was intermittent snow on the arrays, and during maintenance and other outages.

References

References
1.
Peel
,
M. C.
,
Finlayson
,
B. L.
, and
McMahon
,
T. A.
,
2007
, “
Updated World Map of the Köppen-Geiger Climate Classification
,”
Hydrol. Earth Syst. Sci.
,
11
(
5
), pp.
1633
1644
.
2.
NREL
,
2016
, “
NREL: Dynamic Maps, GIS Data, and Analysis Tools
,” National Renewable Energy Laboratory, Golden, CO, accessed Sept. 19, 2016, https://www.nrc.gov/docs/ML1409/ML14093A281.pdf
3.
Dougherty
,
B.
, and
Boyd
,
M.
,
2016
, “
Model (at Least) Twice, Build Once: Experiences With the Design-Bid-Build Process for Solar Photovoltaic Arrays
,”
ASME J. Sol. Energy Eng.
,
139
(3), p. 035001.
4.
Boyd
,
M.
,
2016
, “
High-Speed Monitoring of Multiple Grid-Connected Photovoltaic Array Configurations and Supplementary Weather Station
,”
ASME J. Sol. Energy Eng.
,
139
(3), p. 034502.
5.
Boyd
,
M.
,
2015
, “High-Speed Monitoring of Multiple Grid-Connected Photovoltaic Array Configurations,”
National Institute of Standards and Technology
, Gaithersburg, MD, Technical Note No.
1896
.http://nvlpubs.nist.gov/nistpubs/TechnicalNotes/NIST.TN.1896.pdf
6.
Boyd
,
M.
,
2016
, “
NIST Weather Station for Photovoltaic and Building System Research
,” National Institute of Standards and Technology, Gaithersburg, MD, Technical Note No.
1913
.https://www.nist.gov/publications/nist-weather-station-photovoltaic-and-building-system-research
7.
Smith
,
R. M.
,
Kurtz
,
S.
, and
Sekulic
,
B.
,
2011
, “
Back-of-Module Temperature Measurement Methods
,”
SolarPro
,
4
(6), pp.
90
104
.http://solarprofessional.com/articles/products-equipment/modules/back-of-module-temperature-measurement-methods#.WgGQv1uCzZ4
8.
Dierauf
,
T.
,
Growitz
,
A.
,
Kurtz
,
S.
,
Cruz
,
J. L.
B.,
Riley
,
E.
, and
Hansen
,
C.
,
2013
, “
Weather-Corrected Performance Ratio
,” National Renewable Energy Laboratory, Golden, CO, Technical Report No.
NREL/TP-5200-57991
.https://www.nrel.gov/docs/fy13osti/57991.pdf
9.
Marion
,
B.
,
Adelstein
,
J.
,
Boyle
,
K.
,
Hayden
,
H.
,
Hammond
,
B.
,
Fletcher
,
T.
,
Canada
,
B.
,
Narang
,
D.
,
Shugar
,
D.
,
Wenger
,
H.
,
Kimber
,
A.
,
Mitchell
,
L.
,
Rich
,
G.
, and
Townsend
,
T.
,
2005
, “
Performance Parameters for Grid-Connected PV Systems
,” IEEE Conference Record of the Thirty-First Photovoltaic Specialists Conference (
PVSC
), Lake Buena Vista, FL, Jan. 3–7, pp. 1601–1606.
10.
Mermoud
,
A.
,
2016
, “
PVsyst v6.4.1
,” PVsyst SA, Satigny, Switzerland.
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