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M. Schuss, U. Pont, M. Wölzl, P. Schober, A. Mahdavi:
"In-situ performance evaluation of historic box-type windows with vacuum glazing";
Talk: 8th International Building Physics Conference IBPC2021, Copenhagen, Denmark; 2021-08-25 - 2021-08-27; in: "Online Portal of presentations and papers of the 8th International Building Physics Conference - IBPC2021", C. Rode et al. (ed.); (2021), Paper ID 21.02, 8 pages.

Climate protection objectives and energy efficiency targets imply stricter performance
expectations from both new and retrofit building projects. Given the related important role of the
building envelope, there is a need for a holistic approach to the design, construction, as well as
laboratory and field testing of buildings' window and wall systems. In this context, the present
contribution reports on recent efforts regarding the thermal retrofit of box-type windows. In the
course of an actual research project, vacuum insulated glass (VIG) elements were integrated with
ten existing box-type windows at six locations in Austria. To facilitate empirical testing and
evaluation of these windows, a detailed concept for a continuous in-situ performance monitoring
concept was designed and implemented together with the required monitoring infrastructure.
This infrastructure involves the deployment of regular state-of-the-art IoT (Internet of Things)
technology and enables the continuous monitoring of the salient performance indicators
(including temperature, relative humidity, and heat flow). The derived values of performance
indicators (such as the fRsi-value) can facilitate, among other things, the assessment of water
vapor surface condensation risk. Collected data since mid-2020 cover both hot and cold weather
periods have been analysed to capture performance differences between alternative vacuum glass
settings at the testing locations. The alternative implementations pertain to different positions of
the glazing layer (inside versus outside), different opening directions of the casements, and
different positions of box-type within the opaque wall. Moreover, for comparison purposes,
monitoring equipment was integrated into a comparable regular box-type window (with float
glass or insulation glass) at each of the demonstration sites. Occurrences of potential visible or
functional defects (including surface condensation) have been documented as well. The paper
presents, analyses, and discusses the preliminary findings of this effort in detail.

(no german abstract)
Climate protection objectives and energy efficiency targets imply stricter performance
expectations from both new and retrofit building projects. Given the related important role of the
building envelope, there is a need for a holistic approach to the design, construction, as well as
laboratory and field testing of buildings' window and wall systems. In this context, the present
contribution reports on recent efforts regarding the thermal retrofit of box-type windows. In the
course of an actual research project, vacuum insulated glass (VIG) elements were integrated with
ten existing box-type windows at six locations in Austria. To facilitate empirical testing and
evaluation of these windows, a detailed concept for a continuous in-situ performance monitoring
concept was designed and implemented together with the required monitoring infrastructure.
This infrastructure involves the deployment of regular state-of-the-art IoT (Internet of Things)
technology and enables the continuous monitoring of the salient performance indicators
(including temperature, relative humidity, and heat flow). The derived values of performance
indicators (such as the fRsi-value) can facilitate, among other things, the assessment of water
vapor surface condensation risk. Collected data since mid-2020 cover both hot and cold weather
periods have been analysed to capture performance differences between alternative vacuum glass
settings at the testing locations. The alternative implementations pertain to different positions of
the glazing layer (inside versus outside), different opening directions of the casements, and
different positions of box-type within the opaque wall. Moreover, for comparison purposes,
monitoring equipment was integrated into a comparable regular box-type window (with float
glass or insulation glass) at each of the demonstration sites. Occurrences of potential visible or
functional defects (including surface condensation) have been documented as well. The paper
presents, analyses, and discusses the preliminary findings of this effort in detail.

Vacuum insulated glass, historic box-type windows, performance monitoring

https://publik.tuwien.ac.at/files/publik_299290.pdf