Lighting & control
Without light, there is no life. 80% of our life is spent inside. This is why lighting has a major influence on our life quality. Light is a key aspect of modern architecture and the energy efficiency of a building. Light triggers a lot of biological effects and has a considerable impact to enhance and maintain our health. Bright light, if applied correctly can improve the quality of work dramatically.
The eyes performance declines with increasing age. In easy adaptation of light level for different kind of work and age is a mandatory feature of a good lighting solution.
Light source quality:
There are three main parameters which describe the quality of a good light source.
Lumens (lm)… means how much light you are getting from a light source. For comparison an old light bulb delivers approximately 12lm/W. That means a 40W lamp delivers 480lm.
Colour temperature K … tells if the light spectrum is warmer or cooler. The old incandescent lamp or the sun at Sunrise has a colour temperature between 2700 to 3300°K. Day light has a spectrum of a correlated temperature off 5000 to 6500°K. A blue sky at December up has up to 10.000 °K.
CRI the Colour Rendering Index measures the ability of a light source to reveal the colours of objects faithful in comparison with a natural light source. The best possible CRI is 100. Good LED’s have a CRI of 80 or higher.
Daylight: The best light source is daylight. But daylighting openings and solution can hardly be changed once a construction has been completed. Most important of using daylight inside the building, is to prevent glare and overheating. Intelligent reflectors which guide the sunlight to the rooms ceiling, light pipes and heliostats are the best high tech solutions.
LED: Today LED’s are the best source for artificial lighting. Fast advancing progress in LED technologies opens new avenues for controlling colour temperature and therefore for adjusting light according to the time of day. The time for old light bulb with a performance of around 12lm/W has passed. The light performance of LED’s reach in laboratory already more than 300lm/W. Today (2014) good LED’s commercially available deliver already a performance of more than 100lm/W and is constantly increasing every year. With a lifetime of currently 50.000h at an average use of 3h a day LED’s will work for more than 40 years. Beside the reduced energy cost, it reduces also the need for cooling.
Beside a high energy efficient light source, a good and convenient light control system is a must in a sustainable and quality building. A good lighting system should automatically react, in conjunction of the outside daylight level, on the presence of a person. It should, depending on the situation, adapt light intensity and colour temperature. Light programs complement the functionality for planned situations like presentations, gala events or just to simulate presence for anti-burglary needs. Light programs could also be used to give guide lighting for evacuation reasons or simple be used for garden sprinkler systems. The system also should be capable to measure or calculate and protocoll actual power consumption. In connection with the sound system even light guided tours could be implemented. A good light control system could increase comfort and well feeling in a building dramatically and also reduce power consumption by more than 40% in addition to the energy saving of a good LED system.
Today there are several ways to control light sources, either by cable or by radio frequency. Most common cable based light busses are DALI and DMX. Both have their advantages:
DALI Digital Addressable Lighting Interface allows controlling of up to 64 individual devices and receiving status information like lamp broken. A single 5 core power cable supplies power and data to the DALI lamps. This allows a very simple cabling. Because of its low data speed of 1200 Baud it could use star and multi drop configuration.
DMX512 Digital Multiplex is a standard for digital communication used to control lights and also theatre special effects devices. DMX is based on a daisy chain RS485 two wire bus with a maximum length of 1200m and a termination resistor at its end.
Wireless lighting control:
Beside the use of standard IR control there are two major wireless lighting standards which allow flexible control and easy installation of light control systems, even in existing and old buildings and will replace cable based systems in the long run. RF enabled lamps are just connected to the main power. On, off, dimming, and change of colour temperature is done by RF signal.
EnOcean is based on miniaturized energy converters, ultra-low-power electronic circuitry and reliable wireless. This allows to use light switches and sensors without battery and cabling. Energy is just produced by energy harvesting. When a switch is pressed, the temperature alters or the luminance level varies. All these operations generate enough energy to transmit wireless signals.
EnOcean wireless components are used already in over 250.000 buildings worldwide. The wireless signal uses the 868 MHz, 902 MHz, 928 MHz and 315 MHz frequency bands, making it suitable for use worldwide.
Zigbee Light Link is a new standard for interoperable and very easy-to-use consumer lighting and control products, allowing consumers to gain wireless control over all their LED fixtures. Zigbee standard uses license-free 2.4GHz frequency band with a 250 kbps physical data rate.