Insulating liquid project boosts energy efficiency


Researchers are developing windows that provide highly efficient solar energy and heat by using insulating liquid…

The European Commission’s flagship research fund Horizon 2020 is supporting researchers to develop large-area fluidic windows to harvest solar energy and manage heat exchange.

The project, LAWIN (large-area fluidic windows), aims to build upon the energy efficiency performance of triple-glazed windows through this novel approach.

The windows use fluid contained in microchannels to control the temperature. The fluid is able to automatically adjust the amount of light or to harvest exterior heat, which is then transported to a heat pump.

Current prototypes use aqueous solutions, but researchers said any fluid with heat exchange properties could be used. In the future, it is hoped further functionalities, such as polychromatism (the fluid’s optical absorption properties in relation to the magnitude of incident relation) could be used.

Coordinator of the project Professor Lothar Wondraczek, of the University of Jena’s Otto Schott Institute of Materials Research (OSIM) said: “Essentially, we want to enclose a building in a layer of liquid and control the temperature.”

The project’s windows and façade are based on four types of new materials:

  • Low-cost thin and strong cover glasses
  • Microstructured rolled glasses of architectural quality
  • A glass-glass compound comprising microfluidic channels
  • A heat storage liquid designed for transparency and/or active functionality in façade and window implementation

It is hoped the design will reduce embodied energy and CO2 levels to zero for window surfaces after four months of usage.

Additionally, LAWIN hopes to improve thermal insulation figures for window surfaces by at least 20 per cent, while reducing the energy used during the life cycle of a building by 10 per cent.

Professor Wondraczek said: “The most important thing is the large-scale production process.

“Integrating the technology into the conventional process used to manufacture triple glazed windows is a key objective.”

A final prototype will be produced on a semi-industrial scale by 2017 to test the technology. In the meantime the researchers need to overcome one issue: wavy glass.

The method to create the product comprises of embossing one millimetre wide microchannels in glass and then laminating the glass to another piece. However, the rolling process that does this creates inherently wavy glass. The project’s researchers are overcoming this by developing a new processing equipment that can create a high quality piece of flat glass.

“A big challenge is to provide the windows at very low cost in a large size,’ added Professor Wondraczek.

Currently, the demonstration prototype is 0.25-0.5 m2, but it is hoped the final product would be nearer 2m2.

In 2017, the prototype will be installed in model buildings in north and southern Europe to test it in different climates.

While it is expected the high-end version of the product would cost 2.5 times more than top quality triple glazed windows, the researchers said the energy savings would offset this.

Members of LAWIN consortium said the windows could reduce CO2 levels by at least 123,000 tons and replace at least two per cent of window furnaces across Europe.


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