A luminaire is a complete lighting unit, comprised of a light source (lamp or lamps), together with the parts that distribute the light, position and protect the lamps, and connect the lamps to the power supply. Good luminaire can distribute light well, separate task lighting with ambient lighting, provide controllability, etc. Choosing luminaires that efficiently provide appropriate luminance patterns for the application is an important part of energy efficient lighting design. One of the main current and future research trend is innovation in luminaire to enhance the lighting experience and ensure design flexibilities in different functional requirements. The reflectivity of the material and the maintenance factor of luminaire is dependant on the material selection and robust design.
A performance of a luminaire is significant for estimating the energy efficiency of the overall lighting system and design. It is defined in terms of light output ratio (LOR), i.e. the ratio of lumens emitted by the luminaire to lumens emitted by that luminaire’s lamps. The efficiency of a luminaire is subject to the lamp type, control gears, optical components, and material of reflective surface. High reflective surfaces have improved the LOR enabling the luminaire to transfer more than 70% of lamp output.
For an efficient design, LOR is considered along with the room index to estimate the co-efficient of utilization. The CU accounts not only for light losses within the luminaire, but also for the effects of room configuration and surface reflectance. Each lamp type and luminaire manufacturer have different co-efficient of utilization for their product. Better the ratio, lesser the number of luminaires required in a space to lit the area as per the desired lux level. Most general lighting luminaire manufacturers provide co-efficient of utilization data for different room index value for their respective luminaire product. In case where, the co-efficient of utilization ratio of less than 0.5, it is recommended to either upgrade the light source to more efficient lamps or use controls for indirect reduction of lighting capacity.
Luminaires come in variety of size, shapes and wattage, etc.
Type of Luminaires
The luminaire system consists of the luminaire itself along with its reflectors, lenses and housings, as well as the lamps and ballasts. System performance depends on how well all these components work together, as well as many other factors including room finishes, daylight contribution, room geometry, and task components.
An efficient luminaire optimizes the system performance of each of its components.
Regulated current to a lamp is a key component of any lighting system. Ballast is used in lighting technologies to ensure regulated current. Many types of ballasts are available in the market. The selection of ballast type should be done considering the functional requirement of light source and the efficiency of the ballast itself. Two of the commonly used ballast types are electro-magnetic ballast and magnetic ballast.
Key advantages of electronic ballast:
Key disadvantages of electronic ballast:
Key advantages of electro – magnetic ballast:
Key disadvantages of electro – magnetic ballast: