Lighting : LIGHTING-February-2017
26 LIGHTING MAGAZINE | February/March 2017 February/March 2017 | LIGHTING MAGAZINE 27 TECHNICAL FEATURE Stand-by of “smart lamps” can be larger than their energy use for lighting Edited by Warren Julian from IEA material “Smart” lamps combine technology breakthroughs in wireless communications with light emitting diodes (LEDs) to provide many exciting consumer benefits. However, the standby energy use of “smart lamps” can be larger than the energy used for providing lighting, according to a new report from the International Energy Agency (IEA) 4E Solid State Lighting Annex. Smart lamps are an exciting new family of products that provide an opportunity for the consumer to benefit from smart services, better product quality and energy savings. Combining wireless communication, intelligent controls and light emitting diodes (LEDs), these lamps offer end-users features like colour-tuning, dimming, changing lighting scenes, remote control, motion-sensing control, daylight control and other features. But these features require energy even when the lamps are not providing light but are instead waiting for a wireless instruction from a smartphone or remote control unit. A new SSL Annex report explores this topic of smart lighting and new features that impact energy consumption. POLICY MAKERS CONCERNED OVER LOST SAVINGS “Policy-makers who are looking at lighting products are concerned that these ‘smart’ lamps may end up creating new, high levels of standby power consumption in households.” said Dr Peter Bennich, chairman of the SSL Annex’s Management Committee and representative of the Swedish Energy Agency, one of the Annex’s member countries. “We are concerned that these ‘smart’ features will offset some of the energy-efficiency gains from switching to LED technology.” In order to better understand smart Figure 1. Luminaires can be controlled by smart phones but the standby energy used can exceed that of the time the luminaire is alight. (Photo credit: www.aliexpress.com) lighting and provide policy guidance for governments, the IEA 4E SSL Annex has launched a study on the energy performance of smart lighting. This report offers the initial findings from this body of work. Tests conducted on a limited number of smart wireless LED lamps used in the domestic sector reveal that these products can have substantial standby power use which, depending on hours of use, can even be higher than the energy consumed when the light is switched on (Figure 1). These test results are similar to experiences with standby consumption for other products where manufacturers initially focused on new features before turning their attention to reducing the standby power consumption. For some of the lamps, manufacturers also provide a gateway (with its own energy consumption) for wireless Figure 2. Annual energy consumption for 27 smart lamps models in operation for one hour/day. (This is Figure 13 in the IEA report.) communication between the lamps and other devices using protocols such as Zigbee, Z-wave or 6LoWPAN (a low- power wireless mesh network where every node has its own IPv6 address, allowing it to connect directly to the Internet using open standards). LARGE VARIATIONS IN STANDBY ENERGY INDICATE POTENTIAL FOR IMPROVEMENT When the lamp is not emitting light, the power is still connected as the lamp switches to a standby mode waiting for a signal from the end-user to switch-on again or the lamps may in commercial buildings also serve as part of a local wireless network. This means that the lamps are consuming energy even when they are not emitting light; and the standby power consumption for domestic products varies widely, from 0.15 to 2.70W – indicating that design improvements or a shift of protocol to reduce standing losses are possible (Figure 2). Domestic light sources in IEA 4E SSL Annex member countries, as well as in many other countries, typically operate 1-2 hours per day. The smart lamps producing 200 to 1000 lumens, tested in this project, had an average standby energy consumption representing 51% of the total daily energy consumption when these lamps are operated one hour per day. That corresponds to an overall efficacy of 9 to 51 lumens per watt, meaning some smart lamps had the equivalent performance of incandescent lamps. If the lamps are switched on for two hours per day, standby energy represented 35% and the efficacy is approximately 16 to 64 lumens per watt, much lower than the non-smart LED lamps on the market today.
Lighting December 2016