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Content archived on 2024-04-19

Development and investigation of evacuated windows based on monolithic silica xerogel spacers


Normally, the weak part of the thermal envelope of a building is the window area. In order to improve the window area thermally and maintain a good solar transmittance, monolithic silica xerogel will be applied as transparent insulation material in glazings.
The objectives of this project are to develop and investigate highly insulating glazings with evacuated monolithic silica xerogel, and to improve the production process of monolithic silica xerogel for this purpose.
The deliverables of the project will be different sets of samples and glazing units at prototype level, periodic progress reports and a final report covering all the work done, objectives achieved and conclusions.

Brief Description of the research project: Until now the thermal improvements of glazings have been obtained e.g by the use of extra layers of glass and low-e coatings. However the solar transmittance will decrease. To a great extent, this can be avoided by application of transparent insulation. The project focus on the application of monolithic silica xerogel as transparent insulation material in glazings. The work is organized in the three task:
Task 1 - Material and process,
task 2 - Characterization and
task 3 - Application.

Task 1 deals with production process and improvements of xerogel. In order to optimize and scale up the production process studies of the chemical reactions during the process and of the structure of xerogels will be carried out. The improvements of the material concerns mainly optimization of the optical (solar transmittance and clarity) and the thermal properties. Task 2 deals with characterization of xerogel with respect to mechanical, optical and thermal properties. The results will be used in task 1 at the optimization of the process and in task 3 at the optimization of evacuated glazings with xerogel.
Task 3 deals with the development and investigation of glazings with evacuated xerogel. A major topic will be the rim seal of the xerogel glazing with respect to durability, airtightness and cold bridge effect. Furthermore full scale prototypes of xerogel glazings will be tested and towards the end of the project a xerogel window will be tested in a PASSYS Test Cell according to the common European test procedure for characterization. The energy saving potential for the use of xerogel windows in typical buildings will be calculated. Xerogel windows are expected to be able to replace existing windows. And such a replacement in the existing housing stock are expected to give a saving of up to about 20 % of the energy consumption for space heating.

Call for proposal

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Danmarks Tekniske Universitet
EU contribution
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2800 Lyngby

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Participants (7)