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ADVANTAGES OF CoolGreenLighting QUICKSILVER REFLECTORS

  EXPLAINING THE PROBLEM.

Fluorescent lamps emit light in all directions, many luminaires are inefficient and allow the light to bounce around and be dissipated without ever leaving the fitting. However efficient the lamp and control gear the total package will be inefficient.

An efficient luminaire must:

Reduce the proportion of lamplight absorbed by the luminaire interior surfaces.

Minimise the proportion of lamplight uselessly reflected back and forth inside the luminaire.

Maximise the proportion of lamplight directed towards the working area.

Provide quality lighting.

  THE SOLUTION

A reflector within the light fitting is a way to make an inefficient luminaire efficient. But the reflector must be carefully designed to provide optimum performance. The white painted surface that is there for the physical construction of the luminare is not sufficient.

   WHAT WILL IT DO?

The increase in efficiency that can be achieved by fitting a purpose designed silver specular reflector to an existing light fitting, and incorporating triphosphor lamps, is such that in most cases even though the number of lamps is reduced by 50% the illumination within the space is increased.

  THINGS TO WATCH FOR

There are different kinds of reflective materials, and types of reflection. Not all are economic even though initially they may seem cheap.

Specular reflectance is mirror-like reflectance where the light ray is not scattered but is reflected perfectly. Specular reflectors are best for precise control of light.

Diffuse reflectance is where the light reflected from a surface comes off at all angles with essentially no control on the direction of light leaving the surface. This what would happen with a matt white surface.

Total reflectance is the combination of specular and diffuse reflectance; this is what occurs with real surfaces, with varying proportions of each.

  THE IMPORTANCE OF THE REFLECTIVE SURFACE

For optimum control and efficiency the best reflector is specular.

The best material is polished silver as it is highly specular, it reflects evenly across the entire visible spectrum, and does not vary in reflective performance through life.

To make reflectors from solid silver is economically impractical. In practice a specular silver film is aggressively bonded to an aluminium substrate.

The surface must be protected by a scratch resistant coating (this also prevents the surface from oxidation), for additional protection during handling and installation the surface must be covered with a protective liner that is removed once the reflector has been installed.

Make sure the reflector will maintain its specular reflectance throughout life.

  A small decrease in specular reflectance has a great effect on overall efficiency. With just two reflections the intensity of light from a 95% efficient specular reflector will drop to 90% of the original. This compares to only 72% of the original intensity for an 85% efficient specular reflector.