RENSHADE – SUMMER AND WINTER BENEFITS Aug 2011
Please view http://www.concertinafoilbatts.com/renshade.htm RENSHADE is
designed for use on internal surfaces of windows and under transparent
roofing or skylights.
RENSHADE
with airspaces stops approximately 85% of all incoming radiation. This is by
either 97% reflection
outwards as well as 3% low re-radiation/emission inwards, allowing for holes
constituting 11% of the
surface area. It is not
essential for a clear airspace to exist between the glass and the RENSHADE –
the inward surface always functions independently because it
always has a clear airspace facing into the room. The ideal minimum width airspace for vertical foil surfaces is 20mm. See also http://www.concertinafoilbatts.com/fact12.pdf RENSHADE can
be made into Holland Blinds but we do not organize this, rather we sell the
base material alone to the
blind manufacturers who deal direct with customers. Perfectly functioning
chain driven blinds are on
display at our showroom in Cheltenham - and they really work well. Blinds are
the ultimate application
because the view and amount of light can be controlled. RENSHADE is
paper-based double-sided foil laminate, not a flexible fabric and will have a
potentially long life as blinds so long as handling is
minimized.
99% of sales
to date have been for direct velcro application to inside of glazing. Results:
greatly reduced incoming summer heat, no glare, view is maintained and
significantly reduced cooling
costs. RENSHADE is not an external use
sun shield. It is ideal for protected use applications, namely fixed
(by velcro) against inside glazing, under skylights and stapled beneath
transparent roofing. One of the
best RENSHADE velcro applications is when combined with slim-line venetian
blinds producing attractive optical variations throughout the day while the RENSHADE is largely hidden and obscured. A successful
result was achieved at Brunswick South-west Primary School(Melbourne) in Nov
2003 with RENSHADE
fixed directly to inside of windows (4.5m high ceilings) with velcro, which
was commented in the
Community Power News write-up Spring 2004. Air-conditioning as well as external
blinds were cost prohibitive
and so RENSHADE blinds were first considered but we advised this would be
unsuitable long term as
damage would readily happen in a school environment. In this
school application RENSHADE fixed to glass will remain permanently in place
for all of the year, and
wintertime would let less light in but electric lighting remains on
regardless in institutional buildings – winter or
summer. RENSHADE fixed to glass will very easily be the cheapest option for
residential, commercial
or institutional buildings and the summer benefit is quite literally
enormous. The news
articles http://www.concertinafoilbatts.com/press.htm
provide further background to why incoming radiation
must be identified and stopped. Aluminium insulations such as RENSHADE, CONCERTINA
FOIL BATTS and conventional roll foils do this. For comfort in hot climates,
these foil insulation
products combined with natural ventilation and air movement by ceiling fans
will often be sufficient
with the avoidance of expensive refrigerative air-conditioning. The key step
is to remove the sources of
incoming radiation. RENSHADE
testimonial letters and data files can be viewed: http://www.concertinafoilbatts.com/renshade.htm RENSHADE - WINTER HEAT RETENTION
RENSHADE will have an impact in
keeping in winter heat. We predict that if the RENSHADE was left in place for the duration of winter,
then heavy drapes would not be needed for either summer or winter - and then a lightweight blind, curtain
or drape may be sufficient, eg venetian or vertical tilting blinds, sheer
fabric. We expect what is happening with winter heat is
that there is an 11% surface area of holes and each hole is 2mm wide. It might just be that convected heat
cannot make sufficient contact to the cold glass. If some type of
blind exists, then a reflective airspace has been formed which will have
thermal resistance. Aluminium
backed drapes (which still exist on the market and are very expensive) also
create greater thermal value than if there was no aluminium
present. Trapped airspaces create insulation. Still airspaces are more effective than ones with air movement, and
still reflective aluminium
airspaces have greater thermal value. Vertical foil airspaces are known to have
approximately the same thermal resistance HEAT FLOW IN(summer) or HEAT FLOW OUT(winter). So
if the RENSHADE works in summer, then it must also be working in winter. But the RENSHADE
was invented so as to be in place for the duration of summer and in many cases removed in winter.
However, if made into Holland Blinds and combined with well
fitting drapes, logically there will be aluminium foil airspaces on either
side of the RENSHADE with more thermal value than if it were just RENSHADE
stuck to the glass with velcro with one airspace - but an airspace against the glass is not essential. It is a complicated technical subject, but the
existence of the RENSHADE foil will enhance thermal resistance of the window, with or without an additional drape
or curtain, in either summer or winter. |