ClearVue’s luminescent solar concentrators create clear PV windows

The lure of building integrated photovoltaics continues to attract entrepreneurs and startups.

April 14, 2020 Eric Wesoff

Last year, the Perth-based company completed a pilot project – an energy-generating glass atrium at the entrance of a nearby shopping center.

Image: Vicinity Centres and ClearVue Technologies

ClearVue is a small ASX-listed Western Australia-based solar company looking to generate power from clear windows. It’s another attempt at building integrated photolvoltaics (BIPV).

However, this company’s solar power generation method is very different from conventional silicon or thin-film solar approaches to BIPV.

ClearVue’s transparent luminescent solar concentrator is a spectrally selective polyvinyl butyral interlayer sandwiched between two panes of glass. Most visible light is transmitted through the glass, but infrared light is deflected by inorganic particles in the interlayer to solar cells in the frame. UV light is converted to infrared and also deflected to cells on the window perimeter via total internal reflection.

In 2019, pv magazine Australia reported that ClearVue signed a memorandum of understanding with Taiwanese thin-film CIGS solar manufacturer BeyondPV to supply PV strip modules for use in its insulated glass units and windows.

The CIGS solar strips are applied to the permeter of the integrated glass window units.

Luminescent solar concentrator

A luminescent solar concentrator (LSC) is made from plastic or glass with fluorescent materials or quantum dots in or on it. The hope for the LSC is that cheap dyes or phosphors can make the system inexpensive as well as tolerant of defects or angle.

The luminescent ingredients can be dialed-in to absorb and re-emit at selected wavelengths. Luminophores used in LSCs can be quantum dots, rare-earth ions, nanoclusters and organic molecules. There has been a recent move away from organic dyes towards more stable inorganic phosphors.

pv magazine USA spoke with ClearVue’s CEO Victor Rosenberg and senior staff last week.

Rosenberg said that the window product is absolutely clear and claims:

Solar conversion efficiency of the window is 3.3%
The 1.1 X 1.2 meter unit has been tested to UL 61730
Two OEMs in China are in production

ClearVue wants to license its technology to big glass companies, like Ubiquitous Energy, another clear solar window technology startup.

The glass and window industries are conservative and risk adverse. As Ubiquitous Energy told pv magazine, “It has to work, be efficient and durable — and they still need to see large-size product before they move.”

ClearVue’s path to commercializing an integrated solar window facade is not just an engineering problem. The company has to drive a completely new type of window and curtain wall product through the very conservative building channel — and that’s a daunting marketing challenge — especially for a lossy, pre-product company with limited sales and cash in the bank.

According to an investor presentation, $9 million has been invested in ClearVue over the last eight years.

VC-funded companies such as Israel’s Pythagoras Solar and California’s Solaria tried and failed to commercialize solar windows. Other companies still in the fray include:

Heliatek’s organic solar cell technology is focused on windows and facades
Ubiquitous Energy is working on transparent solar window films using organic solar cells.
Onyx uses amorphous silicon to create facades and curtain wall
SolarGaps builds solar blinds
Physee’s solar facades
eni – developed with MIT, eni builds plastic-based luminescent solar concentrators

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