building integrated photovoltaic solar glazing, current & emerging technologies
TRANSCRIPT
Gavin D. J. Harper
BIPV Solar Glazing:Current & Emerging Technologies
Low Carbon Research Institute Conference,SWALEC Stadium,
Cardiff, Wales,18th November 2014
[email protected]@gavindjharper
www.gavindjharper.comhttp://orcid.org/0000-0002-4691-6642
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
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.
Wales: Competing with China?
PV in WalesRegional StrengthsCommercialisation& Manufacture
Centre for Solar Energy Research (CSER) @ OpTIC
GlyndwrExpertise in thin-film,
Cadmium Telluride cells. Expertise in novel MOCVD process & advanced optics.
G24i Manufacturer of dye sensitised solar cells.
GB Sol, PV Module manufacture. Mounting Systems Manufacture.
Bangor UniversityDye sensitised cell
research Sharp Silicon Module Manufacture.
Pure Wafer (Reclaimed Silicon Wafers)
Ser Solar, Swansea UniversityPV Research
SPECIFIC, Swansea University
BIPVCoDyesol
IQE Multijuction PV (Concentrators)
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?
A look at Solar Glazing Technologies
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.
Pythagoras Solar Windows
Image from: Pythagoras Solar, www.pythagorassolar.com
Pythagoras Solar Windows
Image from: Pythagoras Solar, www.pythagorassolar.com
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.
SolarWindows
Images from:Pythagoras Solar
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.
Organic SolarConcentrators(OSC’s)
• A variation on this technology developed at MIT is known as “luminescent solar concentrators” (LSC’s)
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.
Integrated Concentrating Solar Facade
Integrated Concentrating Solar Facade
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.
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.
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.
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 Levchenkohttp://www.researchgate.net/profile/Levchenko_Viktoria/publications
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.
Dye SensitisedSolar 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
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
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
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
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.
StandaloneWindow for Low Voltage DC• Many portable electronic
devices have converged around USB as a charging standard.
Gavin [email protected]
http://www.cser.org.uk/
https://www.westproject.org.uk/
@gavindjharper
@CSER_PV
@LCRI_WEST
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