Environmental Engineering Reference
In-Depth Information
space is affected by evaporative cooling and the PV-driven air heating system provides
the necessary regeneration of air. With such systems, it is possible to achieve a solar
fraction of 75% with an average COP of 0.52. Such hybrid systems have proven to
be most effective to offset the capital costs involved with BIPV. Detailed studies on
such systems have been carried out by several researchers. For instance, Ricaud and
Capthel (1994) have recommended improved air heat extraction methods and Yang
et al. (1994) have exclusively worked on roof integrated air-cooled systems. Infield
et al. (2006) presented a methodology to evaluate the thermal impact on building
performance of an integrated ventilated PV facade. This was based on an extension of
the parameters to take account of the energy transfer to the facade ventilation air. Four
terms describing ventilation gains and transmission losses in terms of irradiance and
temperature components were defined to characterize the performance of the facade in
total. Steady state analysis has been applied in order to express these four parameters
in terms of the detailed heat transfer process within the facade. This approach has been
applied to the ventilated facade of the public library at Mataró, Spain and was used
for validating their developed model.
Several researchers (Posnansky et al., 1994; Ossenbrink et al., 1994; Moshfegh
et al., 1995) have worked extensively on the building integrated PV/T systems. Later,
Brinkworth et al. (1997), Brinkworth (2000), Brinkworth et al. (2000) and Krauter
et al. (1999) presented design and performance studies regarding air type building
integrated hybrid PV/T systems. In addition, Eicker et al. (2000) have presented on
the performance of a BIPV PV/T system which was operated during winter for space
heating applications and during summer for active cooling.
Yet another comprehensive examination of PV and PV/T in built environments
has been presented by Bazilian et al. (2001). The study highlighted the fact that PV/T
systems are well suited to low temperature applications. Furthermore, they pointed
out that the integration of PV systems into the built environment could achieve “a
cohesive design, construction and energy solution''. However, it should be noted that
there exists a need for further research in the said field, before combined PV/T systems
become a successful commercial reality.
The building integrated photovoltaic is going to be a sector which would serve
as a wider PV module application. The works of Hegazy (2000), Lee et al. (2001)
and Chow et al. (2003) as well as Ito and Miura (2003) have given interesting mod-
eling results on air-cooled PV modules. Recent work on building integrated air-cooled
photovoltaic includes the study on the multi-operational ventilated PVs with solar air
collectors (Cartmell et al., 2004), the ventilated building PV facades (Infield et al.,
2004; Guiavarch and Peuportier, 2006; Charron and Athienitis, 2006) and the design
procedure for air cooling ducts to minimize the loss in PV module efficiency. On the
other hand, according to Elazari (1998), smaller size PV and PV/T systems, using an
aperture surface area of about 3-5 m
2
and a water storage tank of 150-200 l, could
be installed for small (one family) domestic houses, while large sized systems of about
30-50 m
2
and 1500-2000 l water storage are more suitable for multi-flat residential
buildings, hotels, hospitals and various food processing industries. Further, Charalam-
bous et al. (2007) suggested that the building-integrated PV/T collectors are most
suited for climatic regions with low ambient temperatures so that the heat from PV
surface can be put into effective use for space heating. Battisti and Corrado (2005)
investigated the EPBT (energy payback period) for a conventional multi-crystalline
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