Page 18 - ZEB Final Report 2009-2017

18 | ZEB Zero Emission Buildings | Final Report 2017

Multilayered Windows for

Zero Emission Buildings

There is increasing interest in coupled multi-layer

window structures which optimize thermal properties

and feature solutions with a more climate protected

solar shading system. The windows may also be part

of the ventilation strategy.

Silje Asphaug Birgit Risholt Philipp Müller
Researcher, SINTEF & Research Manager Head Wicona, Sapa
PhD Candidate Klima SINTEF and Work Development
2050, NTNU Package Leader, ZEB

The risk of condensation on the exterior air gap between the inner and outer part in the ZEB Living Lab pilot building.
glass layer in multi-layer windows can must be ventilated with outdoor air to This is a double window with an
be a challenge which is often addressed. give the window a “drying out” capacity. outer frame with a single pane of glass
Net long-wave radiation from the The U-value of the window and thus the in the sash and an inner fixed frame
glass surface to the atmosphere during moisture conditions in the air gap both with a three layer insulated pane of glass.
cloudless nights results in exterior glass depend on the ventilation of the air gap. Solar shading is mounted between the
temperatures lower than the outdoor air Decreasing the ventilation improves the frames. The air gap between the frames is
temperature, thus increasing the risk U-value but increases the desiccation ventilated and can be incorporated in the
of condensation on both sides of the time. Small openings at the top and ventilation strategy of the building as an
exterior glass. The actual condensation bottom of the outer part are sufficient, air inlet or outlet.
will depend on window properties and and the negative influence on U-value is The prototype has been developed in
indoor and outdoor climate conditions. small. collaboration with Sapa. Sapa primarily
Good airtightness in the inner part of A prototype of a multilayer window works with aluminium building envelope
the window is very important to reduce has been optimized for ventilation and components.
the risk of moisture from indoor air. The thermal properties and is demonstrated