Sandia National Laboratories has developed and documented a performance
model for photovoltaic power systems. The model requires detailed
performance parameters determined using a specific outdoor testing
procedure also developed by Sandia. The performance model and outdoor
measurement procedures have also been validated by the National
Institute for Standards and Testing (NIST). A Microsoft Access database
of module performance parameters has been initiated by Sandia, and
is now widely used by system integrators and in commercial PV system
design tools such as PV-DesignPro by Maui Solar Software Corporation.4
The photovoltaic industry is in need of a commercial laboratory
that will conduct outdoor performance characterization using the
Sandia procedure, and provide the performance parameters required
by the system performance model. The technical expertise at ASU-PTL
and the weather in Mesa, AZ, provide an ideal combination for this
capability.
Sandia personnel will provide technical assistance, software for
data analysis (Microsoft Excel macro), and the photovoltaic modules
and reference cell required to facilitate this technology transfer
activity. The test procedure will be performed at both Sandia and
ASU/PTL using photovoltaic modules of two different types with the
goal of demonstrating comparable test results. ASU personnel are
expected to conduct daylong performance measurements on the two
PV modules in accordance with Sandia guidance. The performance measurements
include sequential current-voltage (I-V) scans using a DayStar DS-100
curve tracer with modules mounted on a solar tracker, as well as
simultaneous measurements of solar irradiance and module temperature.
These daylong tests should be performed on more than one date for
each module in order to demonstrate the repeatability of the procedure.
All recorded performance data will be analyzed at both ASU-PTL and
Sandia using the same Excel macro. After the completion of the collaborative
testing and analysis, the results of the effort are to be documented
in a paper co-authored by ASU-PTL and Sandia.
