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  Energy efficiency in hospitals - Lighting (part 5)   How to optimize the lighting in hospitals and achieve energy efficiency? Lighting  is one of the major energy consumers in hospitals, as in many other types of utility buildings. Various studies have shown that the lighting installation represents about 20% of the total energy consumption of a hospital. As for  energy-saving ,  this can be done on lighting, these can be divided into two main categories, each of which is discussed below. . Smart switching The fastest savings can be achieved with “smart switching” of lighting. The lighting is often turned on unnecessarily when, for example, there is  sufficient daylight  or there is no one in the room. With manually operated systems, in particular, the lights tend to be left on unnecessarily. The advice is therefore to make the best possible use of automatic light control equipment. Examples include:  </ p> Daylight sensors Presence sensors Connection

  Depreciation of light emissions Illumination: Illumination initially provided by a lighting installation will gradually fade over the course of its use due to reduced number of lamps, lamp burning, and dirt build-up in lamps, fixtures and room surfaces.   Dirty surface of fluorescent lamp However, it is possible to keep the illumination equal to or above the minimum allowable value (called the maintenance value), clean lighting fixtures and room surfaces, as well as replace burnt out or worn lamps at suitable intervals, according to a previously agreed maintenance program. The value of this maintenance schedule is shown in  Figure 1 . Clearly, in the case illustrated, the illuminance in the unmaintained system will decrease to 40% of the initial value during the first three years and continue to decrease. But with an annual cleaning, a paint change and a paint change every three years, the shine reaches 60% of the original value. In three years, the updated system pr

Brightness, lamp life and efficiency of LED luminaires Introduction A typical  LED luminaire  has four main components: an  LED Emitter ,  the device's heat sink ,  driver  and  dimming control , and  dimmer optics . The transmitter consists of the matrix, a heat sink, a lens, and an external housing. The chip is the actual LED chip in the transmitter. The color of light is determined by the energy gap in this semiconductor. The heat sink that is part of the transmitter keeps the chip away from heat and leads it to the device ground (larger the device  heat sink  ). The electronics in the power supply are designed to limit the drive current to the specifications of the LED. In this regard, LEDs are very sensitive;  too much current can shorten their useful life from 50,000 hrs. to nothing in an instant . This is why manufacturers warn that the light  should not be used above a certain temperature . Control of the drive current is critical to the brightness and lifespan