strategy was used when establishing the buildings’ energy use
patterns. As far as PV technologies are concerned, it should be
noted that Brazil is a tropical country, and operating
temperatures of these dark-colored PV surfaces under full
sun can reach 65 8C and over [20]. The strong negative
coefficient of power of some of the PV technologies shown
should be taken into consideration in the choice of technologies
and in the sizing of PV systems.
Our results demonstrate that at the three sites studied there is
a considerable potential for solar energy generation. Even
during the worst possible scenarios (highest energy demand
week and lowest irradiation week), energy demand per m2 was
only a fraction of the incoming radiation available. Using
hourly averages of energy demand and irradiation, the buildings
studies showed average energy demands in the range from 6 to
10 kWh/m2, while global horizontal irradiation ranged from
195 to 268 kWh/m2.
A further hourly analysis demonstrated that along the year
there is a considerable amount of hours when the PV system
generates more energy than the building demands. For the
particular building model selected, some 30% of the time the
building is feeding energy to the public grid.
It was demonstrated that the integration of PV elements to
vertical fac¸ades in Brazil, even at low-latitude sites, is not
negligible and should always be considered. In some instances,
local climatic conditions can lead to considerable deviations in
the expected solar energy distribution, resulting in unexpected
contributions from the various surface orientations in a
building.