Abstract
Regarding the thermal resistance of the external envelop of buildings, windows are the weakest
places. This is especially true for historic windows with original single pane glazing in historic
buildings. To reduce the energy consumption and to improve thermal comfort of historic buildings,
replacing these windows by modern double glazed windows would be a logical choice. The
authentic character of these buildings, however, would be affected too much. Therefore, special
effort has to be given to this kind of windows. There are a number of ways to improve the thermal
performance of these windows. One approach is to add a single glazing pane from the inside or
outside to the existing single pane glazing, making use of a (ventilated) cavity. Apart from that,
special glazing has been developed, e.g. vacuum glazing, to replace the single glazing pane, with a
vacuum glazing with comparable thickness. To predict the thermal performance of these windows,
a multi-physical simulation approach is necessary. The paper will deal with the modeling approach
of these types of glazing. The typical total thermal transmittance of these windows will be
calculated, making use of the three-dimensional thermal bridge coupling effects on the thermal
performance of the glazing panes. COMSOL will be used to solve the multi-physical coupling of
the differential equations for Heat, Air and Moisture (HAM). The results of the three-dimensional
simulations are compared with relatively simple 1-dimensional calculations by hand and
measurements in a so-called hot-box measurement laboratory device and also with in-situ
measurements. Generally, good results are obtained by numerical simulation, compared to
measurement results. For a number of glazing types, 1-dimensional calculations by hand give a
good impression of the thermal performance of rather complex glazing configurations. Surface
temperatures of the glazing panes, risks on condensation and energy losses can be estimated with a
reasonable accuracy. If the boundary conditions are more complex and if ventilation of air in the
cavity is introduced, calculations by hand are not sufficient or possible anymore and more complex
computer simulations are necessary.
| Original language | English |
|---|---|
| Title of host publication | Presentation held at the Comsol Conference, 10-12 October 2012, Milan, Italy |
| Place of Publication | Milan |
| Publication status | Published - 2012 |
| Event | 2012 European COMSOL Conference, 10-12 October 2012, Milan, Italy - Milan, Italy Duration: 10 Oct 2012 → 12 Oct 2012 |
Conference
| Conference | 2012 European COMSOL Conference, 10-12 October 2012, Milan, Italy |
|---|---|
| Country/Territory | Italy |
| City | Milan |
| Period | 10/10/12 → 12/10/12 |
| Other | Comsol conference europe 2012 |
