Presentation at the Low Carbon Research Institute Conference, Cardiff, SWALEC Stadium, 18th November 2014 on Building Integrated Photovoltaics Solar Glazing:Current & Emerging Technologies

1. BIPV Solar Glazing:
Current & Emerging Technologies
Gavin D. J. Harper
g.harper@glyndwr.ac.uk
@gavindjharper
www.gavindjharper.com
http://orcid.org/0000-0002-4691-6642
Low Carbon Research Institute Conference,
SWALEC Stadium,
Cardiff, Wales,
18th November 2014

2. BIPV – the global market
• Navigant Research estimate the BIPV market to be worth $2.4 Billion by 2017
• They expect the BIPV total capacity to quintuple in the same time
• Other sources (Accenture Plc) see the solar glass market alone being worth
$4.2 Billion
• New markets continue to emerge and existing markets expanding. Middle
East is placing more onus upon energy and Far East is following close behind
• As energy prices continue to rise and LEED and BREEAM become more
mainstream (as well as Zero Carbon buildings), the appeal of BIPV will
continue to grow. More mainstream BIPV will become more the norm and
newer versions will help create signature buildings with their novel properties

4. Solar Roadmap Part II (page 28)
•The UK has a vibrant Building Integrated PV (BIPV)
sector, where the building fabric is made from solar PV
materials.
•Technology is starting to provide us with the
opportunity to install PV directly into the fabric of
building glass and cladding material.
•These products will allow architects designing new
buildings to maximise the energy generation of the
fabric of the building.
•Costs of BIPV products have fallen at a similar rate to
conventional modules, as they share the same solar
cells.
•BIPV looks set to be an exciting area of growth.

5. Wales: Competing with China?

6. PV in Wales
Regional Strengths
Commercialisation
& Manufacture
Centre for Solar Energy
Research (CSER) @ OpTIC
Glyndwr
Expertise in thin-film,
Cadmium Telluride cells.
Expertise in novel MOCVD
process & advanced optics.
GB Sol, PV Module
manufacture. Mounting
Systems Manufacture.
G24i Manufacturer of dye
sensitised solar cells.
Bangor University
Dye sensitised cell
research Sharp Silicon Module
Manufacture.
SPECIFIC, Swansea University
Ser Solar, Swansea University
PV Research
Pure Wafer (Reclaimed Silicon
Wafers)
Dyesol BIPVCo
IQE Multijuction PV (Concentrators)

7. Adding Value To Glass With Solar Control
• Whilst not a ‘PV’ technology, Solar Control glass demonstrates
how “value” can be added to glazing products through specialist
coatings.
• Market for innovative glass products – e.g. Smart Glass.
• High value niches where the UK can compete?

8. A look at Solar Glazing
Technologies

9. Bifacial PV Cells
• Bifacial PV Cells are
encapsulated in a clear
material on both sides
(e.g. laminated glass).
• This allows them to
capture light from both
sides of the module.
• Lends the technology to
glazing applications
where the visual
intrusion is not a
problem.

10. Pythagoras Solar Windows
Image from: Pythagoras Solar, www.pythagorassolar.com

11. Pythagoras Solar Windows
Image from: Pythagoras Solar, www.pythagorassolar.com

12. Pythagoras Solar Windows
• Stacked its solar cells.
• Appears like venetian blinds inside a window pane, so you can
still see the view while generating electricity.

13. Solar
Windows
Images from:
Pythagoras Solar

14. Solar Concentrators
• Solar concentrators collect sunlight from a very wide area, and
concentrate it down to a much smaller area.
• A smaller quantity of photovoltaic material can be located at the
smaller area.
• This makes more efficient use of the photovoltaic material.
• This could potentially lead to cost reductions in photovoltaic devices.
• There are “large scale” solar concentrator technologies – e.g.
“mirrors in the desert”, but technologists are also investigating
whether the principle could apply on a smaller scale for BIPV.

15. Organic Solar
Concentrators
(OSC’s)
• A variation on this
technology
developed at MIT is
known as
“luminescent solar
concentrators”
(LSC’s)

16. Integrated Concentrator Solar Facade
• Array of concentrating cells.
• Fresnel lens and optics concentrate
light onto small PV cell.
• Allows diffuse light to pass through.
• Glass structures suspended on a
tensioned wire system that allows
orientation to be adjusted to track
the sun.
• Developed by New York based
Centre for Architectural Science &
Ecology.

17. Integrated Concentrating Solar Facade

18. Integrated Concentrating Solar Facade

19. Organic Solar Concentrators
• OSC’s consist of a sheet of plastic,
surrounded by photovoltaic devices on their
edges.
• The plastic is “sprayed” with a dye.
• The combination of dye and plastic act as a
“waveguide”.
• A waveguide is a device which captures light
and directs it along a path to a particular
location.
• The edges of the sheet appear bright as the
light is concentrated.
• It is this concentrated light that the photovoltaic
device captures.

20. Organic Solar Concentrators
• Light hits the plastic, the dye absorbs the light.
• The energy is thereby transferred to the dye, causing the electrons in
those molecules to jump to a higher energy level.
• When the electrons fall back to a lower energy level, the dye
molecules release that energy into the plastic sheet, where it gets
stuck.
• The light can’t escape the plastic, this is known as total internal
reflection.
• (This is the same principle used to transmit data using light over fibre optic
cables).
• It just bounces around in the material, ultimately making its way to
the outer surface. At the outer surface, the solar cells are waiting to
absorb the light and generate electricity.

21. Drawbacks to OSC’s
• While the light energy bounces around in the plastic, it
sometimes gets reabsorbed into the dye molecules and ends up
emitted as heat. This energy, then, never makes it to the solar
cells.

22. Luminescent Solar Concentrators
• Luminescent Solar Concentrators are an
evolution of the Organic Solar
Concentrator.
• The plastic of an Organic Solar
Concentrator is replaced with a sheet of
glass coated with a dye.
• A type of aluminum called tris(8-
hydroxyquinoline) is added to the dye
molecules.
• These aluminum molecules cause the
dyes to emit light waves at frequencies
the dyes can't absorb.
• This stops light loss through re-absorption
as the light makes its way to
the solar cells at the concentrators edge.
An image of a Luminescent Solar Concentrator under test.
Image: Viktoria Levchenko
http://www.researchgate.net/profile/Levchenko_Viktoria/publications

23. Device Durability
• At the moment, this technology is one to consider for the future.
• The challenge is that the dyes used within the device are unstable
and over a period of three months or so degrade.
• Work is ongoing to improve the performance of these devices.

24. Dye Sensitised
Solar Cells
The modern version of a
dye solar cell, also known
as the Grätzel cell, was
originally co-invented in
1988 by Brian O'Regan and
Michael Grätzel at UC
Berkeley

25. Dye Sensitised Solar Cells
• Simple to make using conventional roll-printing techniques
• This could allow for “continuous” rather than “batch” production.
• Semi-flexible and semi-transparent which offers a variety of uses
not applicable to glass-based systems
• Utilises many low cost materials.
• HOWEVER, uses small amounts of platinum and ruthenium which are
expensive and have proven very hard to eliminate from the process.
• Challenges with dye stability / degradation mechanisms.
• European Photovoltaic Roadmap suggests that these degradation
mechanisms can be overcome and DSC’s will make a significant
contribution to the solar generation mix by 2020

26. Honeycomb Patterned Thin Film Devices
• Honeycomb patterned thin film devices capture some sunlight
from PV material deposited in a “honeycomb” pattern, but allow
light to pass through the middle of the hexagons.
• The material blends “Fullerenes” (carbon) and semiconductor
materials.
Images Brookhaven / Los Alamos National Laboratory

27. Honeycomb Patterned Thin Film Devices
• “The material stays transparent because the polymer chains pack
densely only at the edges of the hexagons, while remaining loosely
packed and spread very thin across the centers…The densely
packed edges strongly absorb light and may also facilitate
conducting electricity…while the centers do not absorb much light
and are relatively transparent.”
• “Combining these traits and achieving large-scale patterning could
enable a wide range of practical applications”
Lead scientist Mircea Cotlet, Brookhaven’s Center for Functional Nanomaterials

28. Standalone Window for Low Voltage DC
• Developed by Nihon
Telecommunication System Inc.
• ‘Stand Alone’ does not require
interconnection with circuits in
building.
• Growing use of low voltage DC in
consumer electronic devices.
• Avoids the losses associated with
converting DC-AC with an inverter, and
then back from AC-DC.

29. Standalone
Window for
Low Voltage
DC
• Many portable electronic
devices have converged
around USB as a charging
standard.

30. If you found any of this interesting…
Please stay in touch
Gavin Harper
g.harper@glyndwr.ac.uk
www.gavindharper.com
http://www.cser.org.uk/
https://www.westproject.org.uk/
@gavindjharper
@CSER_PV
@LCRI_WEST