Zbornik - SDR

“IEA ECBCS Annex 45 – Energy Efficient Electric Lighting for Buildings” R-2
cables and damage walls. In this sense it is also possible to integrate such a system into existing
buildings. On the other hand is it impossible to realize an intelligent lighting system without a lot of
sensors and actuators to capture and control the environment.
Directive 2000/55/EC gives energy efficiency requirements for ballasts for fluorescent lamps.
The maximum power of ballast-lamp circuit, for example, of a 36 W fluorescent lamp should be less
than 45 W after 21 May 2002 and less than 43 W after 21 November 2005. [6]
High pressure discharge lamps are very energy-efficient lamp types. Their small discharge body
allows an efficient reflector design for luminaires so that the luminous flux leaving the luminaire can
be distributed effectively in the room. Typically, it takes 3 minutes to reach 80% of the nominal
luminous flux of a high pressure discharge lamp. For automotive lamps, this time has been reduced
to 3 seconds already [7]. At present, high pressure discharge lamps cannot replace other lamp types.
Reasons are given in the start performance and in restricted dimming performance. Research on the
interaction of ballast electronics and high pressure discharge lamps may significantly improve the
performance of this lamp type.
LEDs (Light Emitting Diodes) are new alternative light sources, which are foreseen to
revolutionise the lighting technology in the near future. According to Agilent Technologies the
lumens/package value of red LEDs has been increasing 30 times per decade whereas the price is
decreasing 10 times per decade [8]. The use of LED based lighting could decrease the lighting energy
consumption by 50 % by 2025 [9]. The future entrance of LEDs in the lighting market is dependent
on improvements in conversion efficiency and optical power per package. Although most of the
high-power LEDs (HP-LEDs) nowadays convert between 15 to 20% of the input power into light,
their efficiency potential is far better. In fact the best AlInGaP (aluminum indium gallium phosphide)
red LED and InGaN (indium gallium nitride) green and blue LEDs can have internal quantum
efficiencies which can reach almost 100% and 50%, respectively. To achieve external quantum
efficiencies close to that magnitude, the light extraction has to be improved. By allowing more
photons to escape from the LED chip without been absorbed by the surrounding structure, is one of
the main design challenges which has to be addressed in order to increase the device conversion
efficiency and the radiant power per device. New technologies have been developed in order to
address this issue. The most promising one is the use of quantum dots or nanoparticles. Quantum
dots are characterized by having a large absorption spectral range characteristic and a tunable
spectral emission. This makes them ideal to substitute conventional and inefficient phosphors used
on today white LEDs. However improvements have to be done especially in the quantum efficiency
of quantum dots.
The importance of LED lighting was acknowledged this year also by the Millennium Prize
Foundation. The 2006 Millennium Technology Prize of one million euros, the world’s largest
technology award, was awarded to Professor Shuji Nakamura for his invention of the blue LED. [10]
4 Objectives
The goal is to identify and to accelerate the widespread use of appropriate energy efficient highquality
lighting technologies and their integration with other building systems, making them the
preferred choice of lighting designers, owners and users.
The aim is to assess and document the technical performance of the existing promising, but
largely underutilized, innovative lighting technologies as well as future lighting technologies and
their impact on other building equipment and systems (ie: daylighting, HVAC). These novel lighting
system concepts have to meet functional, aesthetic, and comfort requirements of building occupants.
“Lighting engineering 2006” stran 7