Measured Performance of Building Integrated Photovoltaic Panels.
Measured Performance of Building Integrated Photovoltaic
Fanney, A. H.; Dougherty, B. P.; Davis, M. W.
ASME Journal of Solar Energy Engineering, Special Issue:
Solar Thermochemical Processing, Vol. 123, No. 2,
187-193, August 2001.
amorphous silicon; building integrated; efficiency;
electrical performance; single-crystalline; silicon
film; photovoltaic cells; polycrystalline; predicted
The photovoltaic industry is experiencing rapid growth.
Industry analysts project that photovoltaic sales will
increase from their current $1.5 billion level to over
$27 billion by 2020, representing an average growth rate
of 25%. To date, the vast majority of sales have been
for navigational signals, call boxes, telecommunication
centers, consumer products, off-grid electrification
projects, and small grid-interactive residential rooftop
applications. Building integrated photovoltaics, the
integration of photovoltaic cells into one of more of
the exterior surfaces of the building envelope,
represents a small but growing photovoltaic application.
In order for building owners, designers, and architects
to make informed economic decisions regarding the use of
building integrated photovoltaics, accurate predictive
tools and performance data are needed. A building
integrated photovoltaic test bed has been constructed at
the National Institute of Standards and Technology to
provide the performance data needed for model
validation. The facility incorporates four identical
pairs of building integrated photovoltaic panels
constructed using single-crystalline, polycrystalline,
silicon film, and amorphous silicon photovoltaic cells.
One panel of each identical pair is installed with
thermal insulation attached to its rear surface. The
second paired panel is installed without thermal
insulation. This experimental configuration yields
results that quantify the effect of elevated cell
temperature on the panel's performance for different
cell technologies. This paper presents the first set of
experimental results from this facility. Comparisons are
made between the electrical performance of the insulated
and non-insulated panels for each of the four cell
technologies. The monthly and overall conversion
efficiencies for each cell technology are presented and
the seasonal performance variations discussed. Daily
efficiencies are presented for a selected month.
Finally, hourly plots of the power output and panel
temperatures are presented and discussed for the
single-crystalline and amorphous silicon panels.