Cities are becoming smarter day-by-day: This is the modern trend of the smart grids of energy distribution. The main reason is clearly exposed in Keith Dawson’s blog, When Utilities Fight LED Street Lights: “For cities, the upside of replacing energy-guzzling street lights with efficient LEDs is evident. But there is a downside for utility cash flow”
This makes it easy to understand that the new strategy for street illumination is mainly focused on LED (light-emitting diode) lights. The main reason is the good lighting in terms of energy conversion efficiency and the easy control of the brightness of the light emitted by LED lights, which can be done in a smart modality by an automated protocol of a smart integrated system. The long-term cost savings of this solution are really promising.
It’s clear that an automated system cannot control the quality of the light emitted from the LED; this can be done by a good design of the LED lamp. An integrated solution to control the light emitted by LED lights has to take into consideration that, basically, the tone of the light emitted from the LED depends, not directly on the electrical power absorbed, but on the concentration of the emitted light. The light concentration is the ratio of the total light flux (measured in lumens) and the surface that is exposed to that light, hence the effect of the light emitted from an LED depends essentially on the lens used.
Although the quality of the light emitted by the LED is not directly related to the electric power supplied to the LED lamp, the electric current supplied to the LED is the key parameter to control automatically the brightness of the LED light, and this control can be implemented automatically by a smart system.
This is the basic idea of the smart lighting solution: The brightness of the LED light can be dimmed by controlling the current flowing into the LED, so the controller is able to regulate the energy consumption, depending on the feedback signal coming from a control sensor. This feedback may be, for example, the output of a light intensity sensor (a photodiode for instance), hence this design strategy makes the overall system really effective by leading to an auto-regulating process.
In Part 2 of this series, I will describe some solutions for smart street illumination, adopted by some companies that are major players in the semiconductor market.
What do you think of smart LED lighting? Is this solution appealing to the accounting departments of the administrations of the big cities?