Inverted Slat Aluminum Blinds
High rises peppering the skyline, sunlight glinting off shiny surfaces, sunglasses a part of the visage as much as noses and lips – this is the facade of city life! And we debate the veracity of global warming! Tsk, tsk. Each building absorbs and dissipates massive amounts of energy, warming the air that surrounds it, and radiating it onward. Is it any surprise then, those summers are warmer than they were 50 yrs ago? And we curse at the ensuing floods and blizzards without a thought for the damage we’ve wrought with our unquenchable thirst for ‘the better life’!
The puzzle is no longer how to make buildings more energy efficient, but how to change minds set on instant gratification rather than long-term gains. Countless studies have been conducted to show how buildings can be made more energy efficient, with a minimum impact on the environment. A study was conducted at the Lawrence Berkeley National Laboratory on aiding building professionals in choosing ‘daylighting’ systems to direct daylight into interiors to optimize the usage of natural light to save energy. They studied both fixed and movable systems that shade windows from the exterior of a building as well as the interior. This study answered questions such as
1. The usefulness of a daylighting system vis a vis a building in question
2. What sort of lighting issues can be resolved with a daylighting system
3. The benefits that can be achieved with such a system, and
4. The best system to use
The comprehensive analysis of the performance of the various systems shed light on the important objectives to be focused on, such as redirecting daylight to under-lit areas; improving daylighting for task illumination; improving visual comfort by controlling the glare; achieving solar control or thermal control.
For daylighting systems with shading, it was evident that though this is designed primarily for solar shading, it also takes care of protection from glare and redirection of direct or diffuse daylight. Shading options such as pull-down shades reduce the admission of daylight in a room, but to increase daylight while providing shade, advanced shading systems need to be applied to protect the window area from sunlight and to send direct and/or diffuse daylight into the interior of a room.
One of the movable interior shading systems under study was Aluminum Venetian blinds, which is defined as a system comprising horizontal, vertical or sloping slats that are flat or curved, made of small or medium-sized PVC or painted/brushed aluminum. The slats are evenly spaced at a distance smaller than the slat width so that they can overlap when closed. Interior blinds usually have slats that are 10 to 50 mm wide.
Blinds partly or wholly obscure directional view to the outside, depending on the angle of the slat – vertical blinds make for a vertical view of the sky while horizontal blinds reduce the vertical height of the exterior view. As blinds obstruct the exterior view, they are designed to be partially or fully retracted to enhance exterior view if desired.
In sunny conditions, glossy Venetian aluminum blinds cause glare even while horizontally positioned; tilting the slats upwards increased glare and view; tilting the slats downward reduced the glare and provided shading. Problems of glare can be diminished with the use of diffuse surfaces – painted, brushed, a variety of polishes.
Polished aluminum auto-controlled, static horizontal blinds can be used in all orientations and latitudes, and can increase penetration of light – In the horizontal position, they can receive light from the sun, the sky, and the ground; upward tilted slats direct light from the sun and sky; downward tilted slats transmit light from the ground. It was studied that auto controlled aluminum blinds perform well in all climates provided it’s adjusted to accommodate he heating/cooling-load-to-daylighting balance for the building location; they should also be timed to maximize on available daylight.
In terms of illuminance provided by blinds with semi-silvered inverted slat blinds (slats with a silvered upper/concave side, the system was studied with the slats angled at three positions fully closed, horizontal, and 45-degree downward tilted, under both clear and overcast conditions. It was found that compared to conventional blinds, inverted silvered blinds gave more light when the slats were in a horizontal position, especially when the sun was high in the summer sky; the inverted slats combat glare, and the spacing between slats obscure exterior view as desired.
As a viable solution to reducing power consumption in commercial buildings during daylight hours, the sky being overcast or clear, the inverted slat polished aluminum mini blinds from Graber seem to be the ideal option to use for illuminance of interiors, so that working comfort can be maintained without disruption of efficiency; natural lighting is enhanced by a whopping 38% than with conventional aluminum blinds……
So, help reduce the harmful emissions released into the atmosphere when energy is used and use the inverted slat aluminum blinds from Graber with automatic vane controls to optimize lighting in offices housed in large commercial buildings. Operated on a radio frequency that can be timed to work to your advantage, there’s really no argument for any support to the contrary!
