Page 72 - Glass-Technology International no. 1-2019

SPECIAL GLAZING APPLICATIONS

heating on the exterior glass exterior glass, which Finn-
is on only when it snows, glass provided to meet re-
making it energy efficient quirements.
and highly reactive to chang- Electrical heating on the
ing weather conditions. interior glass brought in-
Electrically heated glass is credible comfort indoors
the only architectural solu- from glass wall to glass
tion that can prevent con- wall. It optimized the util-
densation and convection, ity of indoor space with-
provide unobstructed views out the need for additional
at all times, and maintain space-consuming radiators There are no wires criss-crossing glass. Instead, electricity is conducted via
customer comfort even if or fan coil units in proxim- a low-E coating. The only way to tell that the glass is electrically heated
is that it is always clear, even in cold climates. This example shows a
the outside temperature ity to the glass to prevent
double-glazed window, however, triple-glazing is predominant in Finland
drops 15 degrees in less convection.
than an hour. When constructing sky-
Construction costs in- scrapers in cold climates,
creased with the use of heat- the prevention of ice and
ed glass, but the investment snow build-up on rooftops
paid back within a year is crucial in ensuring the
thanks to the international safety of all people around.
attention brought by incred- Snow and ice must be melt-
ible comfort in arctic condi- ed with heating on exterior
tions that in the end, led to glass to prevent it from fall-
a new, very profitable busi- ing to street level from over
ness. Pictures of the arctic 300 meters above.
resort have been viewed on- We built roofs with sen-
line over a billion times. sors to detect snowing,
which turned the heating
COMFORT AND on to melt snow. Water Convection is caused by the air temperature close to the window being lower
SAFETY IN HIGH from melted snow and ice than in the room. Cold air descends, moves across the floor and rises back up,
ALTITUDES causing a sensation of draft and cold radiation. When glass is heated just one
is directed to gutters, also or two degrees higher than room temperature, it stops convection and draft
Josef Gartner GmbH (a featuring heating, to en-
Permasteelisa company) sure that water gets all the
contracted Finnglass to way down without freezing
manufacture glass for Mer- on the way, blocking pas- panes with the interior ing glass evenly all across
cury City Tower’s crown. sageways. glass installed with heat- the pane.
At 338 meters, it is the sec- Since the heating is on only ing. However, heating can The second low-E coat-
ond-tallest skyscraper in all when it snows, costs are also be installed on the ex- ing on the exterior glass
of Russia and Europe, situ- minimized, windows are terior glass, or even both, reflects escaping heat back
ated in Moscow. kept unblocked, and day- depending on customer towards the indoor space.
Sloped roofs at lower levels light gets in. requirements, climate and According to a study by
were built by Yuanda, also THE SECRET IS conditions. the Technical Research
using Finnglass products. IN THE COATING Both glass panes feature Center of Finland (VTT),
Once again, the cold cli- low-E coating, but in the 100 per cent of electric
mate played a role in chal- Electrically heated glass example, only the inte- power is converted to heat
lenging energy efficiency, differs from normal glass rior coating is connected when using heated glass
indoor conditions and both in structure and fea- to electricity, making it a and over 90 per cent of it
health and safety. Weather tures. In the example pro- heating coating. Low-E can be directed indoors,
conditions called for heat- vided, the window con- coating acts as a uniform making heated glass su-
ing on both interior and sists of two tempered glass resistance element warm- perior in efficiency to any

70 Glass-Technology International 1/2019