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As stated Light tubes or
light pipes are used for transporting or distributing natural or
artificial light. They are by design the most energy efficient way of
lighting an area. In their application to day-lighting, they are also
often called sun pipes, solar pipes, solar light pipes,
or daylight pipes.
Day-Lighting
Day-lighting is the practice of placing windows, or other transparent
media, and reflective surfaces so that, during the day, natural light
provides effective internal illumination.
Within the overall architectural design of a building, particular
attention is given to day-lighting when the aim is to maximize visual
comfort, productivity, or to reduce energy use. Energy savings from
day-lighting are achieved in two ways--either from the reduced use of
electric lighting, or from passive solar heating or cooling.
Electric lighting energy savings can accrue because occupants choose
not to switch their lights on, or because an automatic lighting control
system ("photocontrol system") switches the lights off or dims them to a
lower level.
In passive solar technique, buildings are designed such as to account
for local climate, in particular the luminance of the sky. For instance,
in cooler parts of the globe with largely overcast skies, a house will be
designed with minimal windows on the polar side but more and larger
windows on the equatorial-side. This is because there is no direct
sunlight on the polar-side wall of a building from the autumnal equinox to
the spring equinox in parts of the globe north of the Tropic of Cancer and
in parts south of the Tropic of Capricorn. Equatorial-side windows receive
at least some direct sunlight on any sunny day of the year, so they are
effective at day-lighting areas of the house adjacent to the windows. One
disadvantage of relying on conventional window space for day-lighting is
that, especially during mid-winter, it tends to be highly directional
light that casts deep shadows. This may be partially ameliorated through
light diffusion and somewhat reflective internal surfaces. |
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