10 reasons the future of lighting is DC grids

THERE ARE a host of factors driving local – and regional – electricity distribution towards direct current, and with lighting installations going all LED, it’s time the lighting industry began supporting it. Here’s 10 reasons why it makes sense.

 

  • Lighting has effectively gone DC thanks to LEDs. Why have the expense of local drivers for each luminaire when they can all be run off the same local DC network?

 

  • The power industry is moving to distributed power generation, thanks to a switch to renewables such as solar panels and the advent of energy storage. 

 

  • It’s much easier to integrate battery packs such as those produced by Siemens and Tesla into DC systems and grids. DC to DC converters are up to 20 times smaller that AC/DC equivalents.

 

  • There’s a significant energy loss every time power is converted from AC to DC at each device. Removing a stage can improve system efficiency by 5 to 10 per cent.

 

  • System reliability will be improved. By removing AC/DC converters, especially those with electrolytic capacitors, we can dramatically improve the mean time between failures.

 

  • By using a relatively higher voltage such 380V DC rather than 48V DC, we can solve the challenges of direct current such as voltage drop and increased cabling sizes, while maintaining safety.

 

  • There’s less local heat at the luminaires when there is no power conversion electronics built into the housing, leading to cooler-running, more efficient and longer life LEDs and cooler ceiling voids and interiors.

 

  • A local DC grid opens up opportunities to connect other DC devices, such as sensors and cameras, to the lighting to create an network which can use data to deliver new services.

 

  • The technology is field proven and is used by blue-chip clients such as Carrefour and MaxMara.  Louis Vuitton, for instance, is using DC microgids for its lighting at 40 of its newer stores in both Europe and China.

 

 

Traditional versus a DC microgrid architecture. Pic: Encom Energy

 

  • Based on a presentation by Fabien Teissier of Encom Energy at the recent Lighting Fixture Design conference.

 

 

  • Learn more about DC microgrids for lighting at the LuxLive 2018 exhibition and conference taking place at ExCeL London on Wednesday 14 November and Thursday 15 November 2018. Entry is free if you pre-register HERE.

Comments 10

Pewter Milliken, Please visit this site; https://www.americanradiohistory.com/Popular-Electronics-Guide.htm Download these editions of the Popular Electronics magazine. They are all PDF's. PE-1971-01, PE-1971-03, PE-1972-01 and PE-1974-04. There are others on the same topic. Here you will find quite detailed information about electric shock and the human physiology. It is not voltage that does the harm. It is amperage, current, as little as 5 milliAmps. If that goes through the heart, it causes fibrillation and death. The heart is in fact driven by an electric current much smaller than that and 5 mA disrupts its function. 15 mA is generally considered fatal. The benefit of adapting power with transformers is the power isolation the circuit since the primary and secondary windings are insulated from each other. Adapting power by resistors means that your are directly vulnerable to the grid power should anything, like short circuits, go wrong. Transformers step down the voltage and at the same time step up the current. The wattage remains the same. The effect is similar to the rail gun. Small projectile at insane speed. Not the force, but the speed kills you.

Our company, Marshall DC Lighting, providers of 48DC & 125DC light fixtures, would like to add the above article to our website: www.dclightfixtures.com Robert Mandell dcman1962@gmail.com 602-777-0028

Great summary. Thanks. There are many DC standards to choose from. Each provides benefits and the improvements will keep coming. That's why LumenCache doesn't require a specific technology for the transmission and conversion of power or communications. Systems running beautifully around the world since 2012.

Thanks for the comments here! We do offer 0-10V, DMX and DALI controls on our 48V E-boxes and drivers. The 380V DC architecture and our rectifiers 380V to 48V include a built-in safety feature called HRMG (High Resistance Mid-point Ground) which corresponds to the earthing topology of IT equipment (IEC 61557) and follows the standards of the EN 301 605. The reason behind 380V DC is simply because of the limitations of 48V in terms of drop voltage and cabling. The 380V architecture has been popular in Data Centers and the Telecom industry for many years. With HRMG becoming a safety feature adopted by most of the main brands such as Bosch, Emerson, AEG.. And Encom Energy. This being said, we do also offer our E-boxes and drivers with a dual input 220V AC/ 380V DC, to be flexible and to promote LVDC 48V for Lighting no matter the distribution architecture running in the building. More info available by email: info@encom.energy

The concept of mini DC power grid is known for some time. I've published couple of articles related to this subject. Until now it is used largely in a retail stores, storage facilities and industrial premises. The grid's voltage value is around 200Vdc and is supplied by a AC/DC convertor stepped down from 380Vac to 200Vdc of max 26kW. It is using existing lighting reticulation (1.5mm) with a max of 2% voltage losses for a 200m line length. It is easy to be connected to a DC battery bank for emergency purpose and split-ed in various sub-circuits in order to fulfill task requirements. At the end the solution cost is about 23% cheaper.

Roland.... I'm not a 'techy guy', but... DC is easier to vary than AC? - my schoolboy physics told me that you can vary AC with a transformer, and then rectify to DC if necessary. To vary DC, unless you just use resistors, don't you use a bunch of semiconductors etc? - seems more complicated to me. And, regarding EMC....most LED devices are run/dimmed using PWM techniques - which are, I think, good generators of EMC... If my understanding is wrong, perhaps some electronics engineer out there would comment?

Using DC sounds very good, but using a value of 380V could be dangerous! When you receive a shock at 240V 50Hz AC which is the RMS voltage, the peak voltage is around 320 V, meaning you get a potential difference from 320V to to 320V at 50 times per second. When you receive a shock of 380V DC , chances of you being killed is higher. With AC electric shocks it has a point of 0V (100 times in a second in 50HZ) you get thrown away. Since in DC you do not have this 0V point, you get a constant 380V, you stick to the contact surface increasing the the chances of being killed. Admittedly you would not receive a shock to earth, but it does sound rather dangerous. Better to stay at 48V DC.

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Fabien Teissier: Stunningly brief yet thorough explanation. Kudos. Reprising some old food for thought: For Single Family Dwellings (SFD) I envision low voltage wiring in the upper reaches for lighting, entertainment, tech and sensor products. These low-energy-draw devices powered by homeowner's PV, battery, and control gear may also be part of a micro DC grid (below). The muscle of mains voltages for laundry and appliances may be necessary for the medium term. California's 2020 Zero-Net-Energy drive will catalyze this evolution in the States. ### In less affluent corners of the world I see PV powered homes connected via mini neighborhood DC grids. No mains current at all due to life/culture choices. With the miniaturisation and attendant economisation of current handling and sensor gear, small electrical cooperatives can be established where the monthly balance sheet is reconciled using micro-finance via cell phone. PV-Powered of course. The best solution for NICs/LDCs might help spark adoption in the rich world. Lovely irony.

At last, at least some people are getting common sense. I've been advocating this way to work for over a year and nobody was listening. This will at the same time eliminate harmful EMC radiation and flickering. Dimming will become even easier as like every techy guy knows, it's much easier to vary DC than AC.

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