Untitled - Journal of Lighting Engineering

have been used for few years mostly for
façade lighting or architainment
(architectural entertaining lighting) with the
scope of projecting non-white effects, the
tunable sources are used to display various
white color temperatures to suit the
occasion. Research has shown that different
colors of light affect more than just our
conscious vision system. The newly
discovered intrinsically photosensitive
retinal ganglion cells (ipRGC) in our eyes
respond to blue light by suppressing
production of sleep-inducing melatonin, so
the naturally blue-rich light of daytime
keeps us alert, while reddish evening light
lets us ease into sleep. With LEDs it would
be possible to adapt light color for different
activities such as alertness, which in turn
can affect circadian rhythm positively.
The controllability of LED light color,
intensity and direction allows novel lighting
system designs that can deliver a wide
range of social benefits. In schools, for
example, an LED lighting system with three
color/intensity settings (red-rich "relax",
blue-infused "energy", yellowish-mild
"concentrate") has been shown to
dramatically improve student performance.
NASA is developing similar lights for the
International Space Station because
astronauts have trouble sleeping more than
6 hours a night. The lights will switch from
blue-rich to keep the astronauts alert during
their working day to red-rich light when
they are relaxing before bed. Just recently,
Philips and Apple launched the Hue bulb,
which can be tuned using smartphones or
tablet computers to provide any desired
light color or white CCT using RBG LEDs.
• Integral Controls – the example of
the Hue bulb is the best example of how
Information
controls could actually change the old
lighting (lamp-switch) paradigm. Wired or
wireless but for sure digital, controls can
now co-exist in synergy with the SSLs and
be the motor not an afterthought of the
lighting design, adapting dynamically for
convenience. Diming drivers cost a fraction
of the fluorescent or HID diming electronic
ballasts and will become a default feature,
while the miniaturization of sensors will
economically enable their integrations with
LED luminaires. In a not-so distant future
(SSL) lights will comprise a complex
communication network where sensors and
controls join forces to maximize
convenience, safety and save energy,
resulting in such features as road lights that
brighten when a fire engine approaches and
interior lights that react in a similar fashion
when someone enters the building.
Cristian ŞUVĂGĂU
Dr., P.Eng., LC, CEM,
MIES, MCIE
BC Hydro PowerSmart,
Burnaby, BC, V5H4TB
Canada
e-mail: cristian.suvagau@bchydro.com
Cristian holds a Ph.D. from the Technical
University of Construction in Bucharest,
Romania. He has been practicing and
teaching architectural lighting design and
energy efficiency in Europe and North
America for over 25 years. He is also a
member of the Canadian NC of the CIE and
Past President of the BC chapter of IESNA.
70 Ingineria Iluminatului 2012; 14, 2: 67-70