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Previous issue date: 2012-11-26 === The main objective of this work was to fabricate and to characterize static
concentrator photovoltaic modules (MEC-P) with bifacial solar cells and diffuse
reflector. PV concentrator modules and PV standard modules with the same solar
cell area were installed in a stand-alone PV system at 1.5 years and these were
electrically characterized after the solar radiation exposure. The PV systems were
monitored, measuring the irradiance (total and ultraviolet) at the same plane of PV
modules, the voltage of battery, the electric current to the load and the electrical
voltage and current of PV modules. Two PV concentrators were manufactured with
dimensions of 775 mm x 690 mm x 70 mm (length x width x thickness) and with 36
bifacial solar cells with 80 mm x 80 mm, soldered in series. With cells whose average
efficiency was (13.8 ? 0.2) % and (13.2 ? 0.2) % for front and rear mode illumination,
respectively, one module with efficiency of 7.8 % was fabricated. By using solar cells
of (13.7 ? 0.2) % / (13.1 ? 0.3) % for front / rear illumination mode, the efficiency
achieved by the PV module was 7.6 %. It was estimated that the temperature of the
solar cells in PV module concentrators was about 5 ?C to 9 ?C higher than that of PV
standard modules with the same type of glass and similar lamination materials. The
PV concentrators were subjected to total radiation of around 1.9 MWh/m? (6.84 x 109
J/m?) for 1.5 years and presented no degradation of their visual appearance as well
as its electrical characteristics. The PV stand-alone system installed with MEC-P
modules showed a monthly average efficiency of (6.5 ? 1.0) % in the period in which
the load was held constant. The efficiency was 1.0 % lower than that obtained with
the modules MEC-P was due to the higher operating temperature, the higher
reflectance of solar radiation when the PV modules are installed on the tilted plane
and has variation of the angle of incidence during the day, the resistive losses in the
system and because in the calculation of system efficiency it was considered the
electrical energy produced and stored. === O objetivo principal deste trabalho foi fabricar e caracterizar m?dulos fotovoltaicos
concentradores est?ticos (MEC-P) com c?lulas solares bifaciais e refletor difuso.
M?dulos fotovoltaicos concentradores e m?dulos convencionais com a mesma ?rea
de c?lulas foram instalados em sistemas fotovoltaicos isolados por aproximadamente
1,5 anos e os mesmos foram caracterizados eletricamente ap?s o per?odo de
exposi??o ? radia??o solar. Os sistemas fotovoltaicos foram monitorados, medindose
a irradi?ncia (total e ultravioleta) no plano dos m?dulos, a tens?o do banco de
baterias, a corrente el?trica na carga, a tens?o e a corrente el?tricas dos m?dulos
fotovoltaicos. Dois m?dulos fotovoltaicos concentradores foram constru?dos com as
dimens?es de 775 mm x 690 mm x 70 mm (comprimento x largura x espessura) e
com 36 c?lulas solares bifaciais de 80 mm x 80 mm, soldadas em s?rie. Com c?lulas
cuja efici?ncia m?dia foi (13,8 ? 0,2) % e (13,2 ? 0,2) % para ilumina??o pela face
frontal e posterior, respectivamente, fabricou-se um m?dulo com efici?ncia igual a
7,8 %. Com c?lulas de (13,7 ? 0,2) % / (13,1 ? 0,3) % para ilumina??o
frontal/posterior, a efici?ncia alcan?ada pelo m?dulo foi de 7,6 %. Estimou-se que a
temperatura das c?lulas solares nos m?dulos concentradores foi da ordem de 5 ?C a
9 ?C maior que a de c?lulas solares em m?dulos convencionais com o mesmo tipo
de vidro e materiais de encapsulamento similares. Os m?dulos concentradores
foram submetidos ? radia??o total de aproximadamente 1,9 MWh/m2 (6,84 x 109
J/m?) durante 1,5 anos e n?o apresentaram nenhuma degrada??o de seu aspecto
visual bem como de suas caracter?sticas el?tricas. O sistema fotovoltaico isolado
instalado com m?dulos MEC-P apresentou uma efici?ncia m?dia mensal de (6,5 ?
1,0) % no per?odo em que a carga foi mantida constante. A efici?ncia de 1 % abaixo
da obtida com os m?dulos MEC-P foi devida ? maior temperatura de opera??o, a
maior reflet?ncia da radia??o solar quando os m?dulos s?o instalados no plano
inclinado e h? varia??o do ?ngulo de incid?ncia durante o dia, ?s perdas resistivas
no sistema e porque no c?lculo da efici?ncia do sistema foi considerada a energia
el?trica produzida e armazenada.
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