Page 126 - Alternative Energy Systems in Building Design

102 SOLAR POWER SYSTEM PHYSICS AND TECHNOLOGIES

Figure 3.51 Structural concrete roof-mounted solar support railing system
assembly detail using double-sided UNISTRUCT railing. Photo courtesy of Vector Delta
Design Group, Inc.

BUILDING-INTEGRATED PHOTOVOLTAIC (BIPV) SYSTEMS
As discussed in Chap. 1, custom-designed and manufactured PV modules are called
building-integrated photovoltaic (BIPV) modules. These types of solar panels are con-
structed by laminating individual solar cells in a desired configuration, specifically
designed to achieve some special visual effects. They are typically deployed in solar-
ium or trellis-type of structures. Owing to the separation gap between the adjacent
cells, BIPV modules, when compared with standard PV modules, produce less ener-
gy per square feet of area.
Under operating conditions, when solar power systems actively generate power, a
line carrying current at several hundred volts could pose the threat of serious burns or
bodily injury and electric shock if exposed during the roof demolition process. To pre-
vent injury under fire hazard conditions, all roof-mounted equipment that can be
accessed must be clearly identified with large red-on-white labels. Additionally, the
input to the inverter from the PV collector boxes must be equipped with a crowbar dis-
connect switch that will short the output of all solar arrays simultaneously.
Another design consideration is that, whenever economically feasible, solar array
groups should incorporate shorting contacts (normally closed) that can be activated
from a multicontact relay that can by engaged during emergency conditions. Crowbar
circuitry is not needed.