Form Over Function
A New Way to Look at the Function of BIPV
by Teodor Galitev
Building integrated photovoltaics (BIPV): the name
itself may sound complicated and daunting, but this term for one of the
most logical uses for solar electric systems, or photovoltaics (PV), is
a term glass companies should get to know.
PV is a natural match with buildings. Energy-efficiency can go only so
far and the rest (or most of it) of the energy can be supplied by a solar
electric system. A PV system can bring the building down to net-zero electric
energy consumption—the true and complete definition of energy independence.
One of the greatest disadvantages of the modular designs for solar electric
systems is the aesthetics. This can be solved by hiding or masking the
solar panels so they are not visible. This option is not always possible,
however, and the solar modules may very well be seen as potentially obtrusive
to the aesthetic design on your roof or facade.
Solar module designers have made repeated efforts to change the appearance
of the standard PV panel design, but without modifying the purpose of
the product itself, it is impossible to create this desired BIPV product.
BIPV in general needs to serve a double purpose: (1) to be an aesthetic
feature of the building and (2) to generate power.
BIPV can be defined as a building material that generates electricity
and has the same structural and physical characteristics as the material
that is being offset. With this in mind, the most important function of
the BIPV material is to serve as a building material.Generating power
is a secondary function.
This single point of power generation as a secondary function is why BIPV
is so fundamentally different from the PV solutions that have come before
"This single point
of power generation as a secondary function is why BIPV is
so fundamentally different from the PV solutions that have come before
In general, any building material that can be replaced with a solar module
with the same structural characteristics as the building material qualifies
for use as BIPV. There already are a vast number of applications of this
technology, and it’s my personal opinion that many more have not been
discovered yet. Because this is a paradigm shift for PV design, there
exists vast potential within the glazing world to come up with beautiful
and innovative BIPV applications that fit seamlessly into architectural
design criteria—while also moving us toward conditions where a structure
is able to generate it’s own power.
Recognizing that power generation is the secondary function of BIPV we
can qualify these building components as follows: roofing, facades, glazing,
and art and architecture.
Roofing is one of the earliest and most common applications of BIPV. The
goal is to match the roofing materials, including slates, shingles, tiles
and other materials, to provide a seamless transition from one roof surface
to the other. Any such transition has to be done in a way that does not
compromise the integrity of the roof. The BIPV roofing material should
provide adequate weather protection and a long-lasting roof. A BIPV warranty
typically is the same as the regular solar panels warranty—generally 25
years at 20 percent less power. Since we can expect the solar portion
of the BIPV roofing material to last 25 years or more, the roof integrity
needs to be built to withstand at least 25 to 30 years. You do not want
to replace the roof while under warranty.
In some cases, hot water collectors are mounted under the roofing material
to add to the overall energy-efficiency of the building. Using PV with
hot water collectors is not a new idea, however, hiding all of the ugly
materials without compromising integrity and aesthetics is a revolutionary
move. We will be seeing many more such applications as BIPV continues
to grow in market share.
Facades are most commonly seen in commercial applications such as high-rises
and other large buildings. Typically the façade material is replaced
with a glass solar module that is mounted the same way as the offset material.
Glass has fantastic characteristics and is one of the most cost-effective
building materials. Making the solar module does add cost, but compared
to some of the materials that can be used—such as granite, sandstone and
marble—a façade BIPV solar module is cheaper and has the double
function of generating power. Facades will work everywhere, however they
will see more sun and be more efficient in places such as the Northern
U.S., Canada and Europe.
Glazing, or the use of glazing to mount the solar module, is a fast-growing
application. We have seen glass companies, mullion extruders and fabricators
promote and invest in such products. The glazing industry is well able
to handle both small and large BIPV projects. Since glass is one of the
most cost-effective building materials, the applications for this industry
are vast. There is no denying that we are continuing to see more and more
all-glass facades on buildings.
Any of the glass units can be replaced with a BIPV module that has the
same structural and energy efficiency characteristics as the original
glass. The BIPV glazing module is suitable for vertical, sloped and horizontal
glazing applications. Insulating glass (IG) units can be used in locations
that are adjacent to conditioned spaces.
The typical module is custom-designed with a specific size, strength and
efficiency in mind. The designer has to make sure that the electrical
connections are protected and to code. Typical electrical output boxes
can be mounted on the back of the module, but with wider IG usage of BIPV
we are seeing edge connections that are made while installing the BIPV
module, and the installer hides the wires into the mullion. These kinds
of systems are safer and, in my opinion, represent the direction that
BIPV inevitably is going to take.
Art and architectural BIPV is a category that covers all of the other
possible applications for BIPV. From artistic outdoor shower glass to
shading and loggia type applications, it’s clear that where there is glass
and glazing, there can be BIPV. To build such a project all of the above
methods are utilized in an artistic and architectural manner.
The operation of these integrated systems generally is the same as a standard
module system. A solar module array is configured in some manner and connected
to an inverter that then converts the DC to AC and connects to the electrical
circuits of the building. There is one major difference, however: here
the solar module’s primary function is to perform as a structural and
aesthetical building material.
Up until now, BIPV materials have been considered too inefficient to warrant
the cost. Yet this way of thinking does not represent the reality of the
value one sees in BIPV upon a closer look. Manufacturers often compare
the BIPV materials to the their standard module, omitting the obvious
“next level” of design, aesthetic and structural benefits and features
that BIPV provides.
In my experience, BIPV materials are non-comparable to the standard module
since you can never have a standard module that performs as a building
material. The standard module is built only with power generation in mind
and makes no provision for a structural contribution to the design.
The economics of this BIPV building material is relatively simple: it’s
the cost of the offset building material plus the power generation.
is the vice president of design and engineering of NEOptions in Fountain
Valley, Calif., and has been responsible for the design, development and
installation of more than 250 BIPV systems. Mr. Galitev’s opinions are
solely his own and not necessarily those of this magazine.
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