Did you ever think about producing energy
from the window of your home to meet up with the energy needs? An Israeli
company named Pythagoras Solar invented the World’s first transparent
Photovoltaic glass unit (PVGU) which will produce energy from sunlight
directly. Pythagoras Solar beat out nearly 5000 entrants to win this year’s
$100,000 GE Ecomagination Challenge, which recognizes the most promising green
energy building innovations, for its unique solar window. According to the CEO of
Pythagoras Solar, the window will produce benefits such as power generation and
reducing the building energy needs, while allowing light in. The technology is
its optical design uses direct light to generate energy, while optimising
daylight inside the building. Photovoltaic Glass Units (PVGUs), are compatible
with standard glazing systems, combine energy efficiency, high density solar
power generation and transparency.
PVGUs employ a prism system that steers most of the so-called
direct sunlight striking its surface to an integrated silicon solar cell while
allowing the indirect light that contains visual information to pass through
it. The result is a window that produces up to 140W/square meter of electrical
power, dramatically reduces a building’s cooling requirements, and still
provides its occupants with a clear view of the world.
The module's prisms divert most of the so-called direct
sunlight, but they still provide up to 75% transparency for the reflected light
from the scenery so that occupants still enjoy a great view.
The prisms also serves as a concentrator that makes efficient use of the costly silicon cell and allows the modules to be as tall as 4” while still remaining thin enough (typically 1”) to drop directly into commercial window frame designs. Since the concentrated sunlight can cause significant heating of the solar cell, it is mounted on an integral heat sink that dumps captured heat to the outside.
The prisms also serves as a concentrator that makes efficient use of the costly silicon cell and allows the modules to be as tall as 4” while still remaining thin enough (typically 1”) to drop directly into commercial window frame designs. Since the concentrated sunlight can cause significant heating of the solar cell, it is mounted on an integral heat sink that dumps captured heat to the outside.
One of the few downsides with the Pythagoras PVGUs is that
while they are excellent at reducing solar-related heat gain, they are not as
good at reducing heat loss as non-PV glazing options. The thickness of
Pythagoras’s modules will vary by applications, so it’s impossible to pin down
the window’s actual R value but, given a nominal 1” thickness, it’s safe to
assume it will be in the neighbourhood of R-3. While this is fairly good for a
standard double-pane window, today’s triple-glazed or vacuum pane glazing
systems are much better than this. In its defense, Pythagoras says that once the
initial products are launched it will be relatively easy to tweak the design to
deliver higher R values for applications in Northern latitudes. But even the
existing system’s thermal performance should be more than adequate to justify
its use in many applications in moderate and cool climates.
The idea is to maintain the work environment
at a comfortable temperature without massive, energy guzzling, cooling &
heating systems. Imagine a commercial facade if you could replace the normal
glass that can improve energy efficiency; the advantages are multiple.
