The internal mechanism of a twilight switch
The switches they are a 'basic ingredient' of the lighting system by regulating the on-off phase of the lights. With the switches right, that is, suitable for the particular use of light in that particular type of environment, you can save a lot of electricity and deflate your bill.
Save where? Considering that lighting consumption accounts for 14% of total electricity consumption in the residential sector, 8.70% in industry and 28.30 in the tertiary sector (offices, hospitals, schools, shops ...) especially in the latter sector that the switches turn out to be important.
Mind you, even at home switches of light are important, but more for the sake of comfort than savings (good rules of conduct are worth more to save at home) while it is in large mixed-type environments that they are indispensable to avoid waste.
It certainly isn't just with the switches that the cost of lighting an environment and perhaps an entire building is faced, where it makes more sense to think in terms of the 'lighting system' (from the lighting bodies to the sensors to the management software), but the on-off phase remains decisive.
The switches most common are of four types: switches turn on turn off; switches in time; switches that detect sunlight; switches that detect the presence of people.
On-off switches. Devices of this type should be sufficient in number to illuminate individual parts of the environment rather than the entire environment (the so-called zone lighting). It is advisable that the zones controlled by a switch are parallel to the windows, so as to make better use of natural light.
Time switches. They are especially convenient when the environment is used little and for short periods, typically in warehouses. They can be equipped with motion detectors which, according to experience, can save up to 70 percent in very large warehouses. The obstacle to adoption is the cost, which makes them convenient only when the energy involved is considerable. Also in warehouses, the possibility of installing capturing systems should be evaluated.
Switches that detect sunlight. Devices of this type also cost a lot and are only worthwhile in very large buildings. They generally work in three different modes: on / off; with gradual shutdown; with continuous control. There are no solar switches that regulate the switching off of a single lamp at a time.
Switches that detect the presence of people. They turn on if there is someone in the room, they turn off if there is no one. They certainly save a lot of energy, but their installation is convenient only if the building is under construction or the subject of a major renovation.