It's estimated there are over 300 million streetlights in the world, so it's good to see they're constantly being improved, with CityTouch connectivity, glare reduction and even pole-less systems springing up over the last few years. Considering taxpayers are footing the bill, it pays to improve their efficiency, so a team at the Karlsruhe Institute of Technology (KIT) in Germany has developed an array of low-power LEDs that are more efficient, safer, cooler, and easier on the eyes.
LED streetlights are being fitted many cities across the globe as a more efficient alternative to HID lamps, but they aren't without their own issues. Chaining the diodes together means that if one goes out, the whole circuit does, and the more there are on one connection, the higher the voltage needed to power them. With the maximum permissible contact voltage being set at 120 volts, that limits the number of connected LEDs to 40.
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To overcome that, a team at KIT's Light Technology Institute developed a method to inter-connect the LEDs that allows for the circuit to stay lit up if individual diodes fail. In doing so, many more LEDs can be installed in the array, with the KIT prototype consisting of 144, and it can run much more efficiently, at a tested 20 volts. These low-power LEDs are also cheaper to run, and although they'd need to be installed in greater numbers, they should cost about the same as existing systems.
With great power comes great heat, and the KIT prototype tries to strike a balance there, too. The creators claim the array can distribute heat more efficiently and cheaply, reducing local overheating and improving the service life of the device. The new lights are also apparently simple enough to be retro-fitted into existing frameworks and tone down the glare a little.
"Many small LEDs are perceived as panel radiators from a certain distance," says Michael Heidinger, inventor of the new system. "Their glaring effect is smaller than that of high-performance LEDs that are perceived as spot-like light sources."
The new technology is already in the hands of industry partners like Gratz Luminance, and products built around it may be out later in 2017.
"For the first time, we can now construct glare-free lamps of high efficiency, which meet highest safety standards," says Klaus Müller, Managing Director of Gratz Luminance. "Before the end of this year, we will make available our lamp to customers for testing purposes."