Modeling and Design of Net ZEBs as Integrated Energy Systems - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 54

thermal and electrical energy strongly affects the economics of BIPV/T
systems. The design of BIPV/T systems usually requires the participation
of the building designers to ensure that the systems are properly integrated
with the building envelope design and with the HVAC system. Special
considerations are also needed for retrofit applications.
Semitransparent PV (STPV)
Semitransparent PV is another type of BIPV system that can replace
conventional windows and skylights in both commercial and residential
buildings. In most commercial buildings, where reduction of cooling energy
costs is important, double glazing with low-emissivity coatings is generally
adopted to reduce heat transfer by longwave radiation. The outer glass
layer often includes a tint to reduce transmission of solar radiation. Rather
than having a tint or using ceramic frit on the outer glass to reduce solar
transmittance, a STPV glazing may be used to reduce solar heat gains and
generate solar electricity, while providing adequate daylighting and views
to the outdoors. In residential buildings, STPV modules can be used in
skylights or adjacent solaria and greenhouses. Commercially available STPV
products use different PV cell technologies, from spaced opaque crystalline
silicon cells to thin-film transparent PV cells ( Figure 2.13 ), with the latter
creating a uniform coverage on the window surface.
Fig. 2.13 (a) Micromorph (thin film transparent) STPV module; (b)
poly-Si (spaced opaque cells) STPV module; (c) retrofit STPV installation at
the Enwave theater (Toronto, Canada) (Image courtesy of Internat Energy
Solutions Canada)
2.2.1.2 Modeling
In addition to electricity generation, BIPV systems can produce useful heat
(BIPV/T) and/or possibly provide natural daylight (STPV). Various models