New Multi-Functional Solar Window Generates Electricity by Reflecting Light

Sometimes, you stumble upon news that makes you raise an eyebrow—whether it's a strange new invention, an unexpected consequence of climate change, or a surprising display of human clumsiness. It leaves you thinking, "Well, that's remarkable."

A new type of window has been developed and tested that generates electricity while simultaneously regulating heat and light. This was done by researchers from the ZIEZO project, led by TNO. This window, the first of its kind, has special double-sided solar cells and built-in blinds that reflect sunlight. This allows more light to pass to the back of the cells, which increases energy yield and prevents overheating.

Higher energy efficiency of buildings

To be climate neutral by 2050, buildings need to become much more sustainable. Stricter energy performance standards for buildings are driving the market for building-integrated solar technologies (BIPV). It is also commercially interesting because, to our knowledge, this concept is not yet available on the market.

By making effective use of sunlight and solar heat, this window can have a major impact on the energy efficiency of buildings. For an average office building, these windows can reduce the carbon footprint of that building by at least 20%. It is also commercially interesting because, to our knowledge, this concept is not yet available on the market.

Three Modes

The new solar window, called Sun Shade Including Electricity Generating Solar Window, consists of double-sided crystalline silicon solar cells and built-in blinds. When the blinds are down, they reflect sunlight to the back of the solar cells, generating more energy.

It offers three modes:

• The blinds are stored in the top box (no boost)
• With the blinds down and horizontal (partial boost)
• With the blinds down but vertically so that all sunlight is blocked (max boost).

Users can automatically adjust the blinds to generate more energy or control the temperature and light in the room.

How does it work?

When the blinds are down, they act as a reflector and (part of) the sunlight is redirected to the back of the double-sided cells. In a vertical position, this results in a higher energy yield than in a horizontal position.

25% increase in energy

In addition to TNO, the research group also consists of TU/e, glass company Pilkington Nederland and W/E consultants. Over the past year, they have tested 12 small versions of this window at the outdoor research facility SolarBEAT in Eindhoven and installed 6 full windows in the Experience Center of Pilkington in Enschede.

On sunny days, the solar window increases the energy yield by up to 25% with the most reflective blinds, compared to a window with only single-sided solar cells without blinds. On average over the entire year, the energy increase is approximately 13%. The results of the system were recently published in an article for the solar energy magazine Solar RRL.

Next steps

In the near future, the group will further investigate the impact of the shading system on visibility and indoor temperature in the building. The project partners are also considering a follow-up project in a European context. In addition, they are developing a new tool to improve building designs.

This will optimize solar energy generation, indoor climate and CO? savings by reducing heating and cooling needs. This is challenging due to changing sun positions and changing office occupancy patterns (weekdays versus weekends), together with individual preferences for light and temperature behind the ZIEZO window. Pilkington is also taking steps to bring the product to market.

That's it for now. We'll be back soon with more Innovative and Sustainable news. Did you like this post? Interested in more? Feel free to like and/or share with your network.