Slim building envelopes using vacuum glazing and high-performance insulation

To get a slim building envelope with low thermal transmittance, and hence a low energy consumption, vacuum glazing and high-performance insulation material have been combined. Preliminary investigations both experimental and numerical have been carried out to determine thermal, hygric and mechanical properties of these building components according to either existing standards or to best knowledge procedures. This includes measurement of the center-of-glass U-value, the simulation of the influence of support pillars on the glass surface temperature and comparison of measured and calculated results. Several specimens were measured under different temperature gradients to get more information about accuracy and deviation in the production of the vacuum glazing elements. Further, mechanical stability of larger specimens was tested by the standard pendulum tests for flat glass and compared to identical tests on conventional double-glazing elements of the same size. Finally, a onedimensional hygro-thermic analysis has been conducted to determine the temperature and moisture distribution within a thin wall construction containing high-performance insulation when submitted to climatic conditions in the Swiss Midlands.