Page 302 - A Comprehensive Guide to Solar Energy Systems

306 A ComPreHenSIVe GuIde To SolAr enerGy SySTemS

layers with potentially shorter life expectancies can be easily replaced or removed from
the design based on the sustainability measurement criteria, which can be applicable to
other sustainable building materials and systems for building construction.

14.3.3 Integration of a Multifunctional Roofing System

A multifunctional roofing system can be easily assembled by using the proposed BI-
PVT panel, which is sized to be easily integrated with the industry standard structural
framing spacing of 304.8 mm on center. Custom panels can also be easily developed
for longer spans. The length of the panel can be either 1219 or 2438 mm, based on the
weight and thickness requirements (1219 mm is illustrated for demonstration). The
prototype design references the International Building Code (IBC 2015) [33] for the
roof assembly requirements for weather protection, such as flashings to prevent mois-
ture penetrations at all roof interruptions and terminations. The proposed panelized
system will employ a field-applied joint system while gasketed design alternatives can
also be developed. Both electrical and fluid connections will be made between the
individual panels.
The manufacture of this panel will not be more complex than the existing combination
of a traditional roof and PV panels. The proposed BIPVT panel can be integrated into a
building’s skin with relevant system components such as water circulation, flow control,
and heat storage. The innovations of the proposed BIPVT technology are summarized as
follows:

• Due to the ability to control temperatures through the water flow, the PV modules can
work at lower temperatures in the summer resulting in a higher PV efficiency.
• The collected hot water can be directly utilized by water heating systems for indoor or
for external use.
• Due to the temperature control on the roof, better thermal comfort in the building
can be achieved in the summer time, a cooler room temperature can be obtained, and
the energy demand for cooling can be reduced.
• In winter, a warm water flow can be used to remove frost or ice on the roof, clean solar
panels, and thus restore and enhance solar energy utilization.
Traditional solar panels are rebuilt on the rooftop or attached to structural elements
of the building skin, which is less than optimal. Firstly, the power generating elements
of such panels are typically adhered to a structural substrate, supported by a structural
framework that penetrates the building’s water proofing system. Secondly, traditional so-
lar panels cannot shield the building skin from wind loads and conventional configura-
tions necessitate redundancies as the panel substrate and frame must be designed to resist
the same wind and snow loads as the building envelope. However, the present BIPVT is not
a simple superposition of individual structural component and PV module, but provides a
viable solution to significantly increase overall energy utilization efficiency while alleviat-
ing the disadvantages of a traditional approach.