Gulf Construction Online - Al Imtiaz turns down the heat with RetroSolar

Renovation & Refurbishment

Al Imtiaz turns down the heat with RetroSolar

01 March 2006

At the gulfBID exhibition to be held in Bahrain this May, Kuwait-based Al Imtiaz company will display a new range of sun-protection systems from German manufacturer RetroSolar, which can be used to bring in natural light while at the same time help reduce the load of heat on buildings in both new-build and renovation projects.

“The novel retro-systems constitute a basic innovation, which replaces not only external sun protection by internal systems, but also improves internal Venetian blinds in favour of reduced outer heat load of buildings,” says a spokesman for Imtiaz.
“Simultaneously, it improves the natural day-lighting of the inner space and the visibility through the glass façade. Diminution values of the energy transmission of FC < 0.5 in case of an internal system, up to FC < 0.08 in case of an insulating glass-integrated system, are to be achieved,” he adds.
Developed and patented by Dr Helmut Koster, architect and lighting designer – who has specialised in day-lighting and artificial lighting as well as façade planning – the novel technique has two basic retro systems:
• micro-structured with microprismatic surface; and
• macro-structured with two-fold louvre.
Both systems are to be used as venetian blinds interior or as insulation-glass integrated systems.

Micro RetroFlex
“The advantage of the system – which has drawn its design concept based on the idea of a Fresnel mirror-like surface created by a prismatic micro-structured mirror system – is the possibility to position the Venetian blinds horizontally, which allows an improved visibility through the curtain. Furthermore, the natural daylighting of the inner space is improved,” he points out.

Macro: RetroLux
Using conventional Venetian blinds with a mirror surface, daylight can be directed into the depth of an inner space. The disadvantage of this simple technique is the danger of overheating in summer or – in case of a closed Venetian blind – the lack of light inside the rooms.
The RetroLux-invention avoids these obvious disadvantages by dividing a louvre into two portions: the first, w-formed, which reflects the light, and the second, formed as a light shelf, which directs the diffused light with lower angles of incidence into the depth of the room and onto the ceiling. What makes the system ‘intelligent’ is its ability to automatically control light by making use of the different angles of incidence. With high angles of incidence in summer the blinds always remain in a horizontal position helping achieve greater levels of visibility in the interiors.
W-formed portion of the Retrolux system
Through the development of the RetroLux structure, it has become possible to control the direction of the reflected sunlight exactly and hence control the following functions:
• Retro reflection of the overheating high summer sun and;
• Light inflection for flat and diffused light radiation.
The advantage of RetroLux is an enhanced natural daylighting of the interior space, which in turn results in enormous energy savings. Simultaneously, the working area is not in the direct glare and the light influx is dimmed down to a comfortable level between 700 and 1,000 lux.
In the absence of harsh sunlight, the system increases the influx of light by making use of the lower angles of solar incidence.
Dr Koster succeeded in developing the contour of light guiding louvres in order to use them as normal Venetian blinds. Further applications are glass roofs.
A new software – developed by Dr Koster – gives detailed information about the energy and light transmission of every system at every single day and time of a year at every possible position of the façade fixed in any location worldwide.
This calculation-programme helps the architect and planner to decide, what systems to use in order to reduce the energy input in buildings, he says.
gulfBID will be held at the Bahrain Exhibition Centre from May 16 to 18. Al Imtiaz will be present at Stand IC 49 at the exhibition.