With the advancement of renewable power technologies (solar PV, battery storage, wind generation), the imminent growth of DC-microgrids, and continuous threats of lighting downtime caused by electric utility outages, DC lighting is a key component to addresses the evolving need for renewable, load-sharing, modular structure, and off-grid infrastructure solutions…
Why DC and LED Lighting?
In a traditional Alternating Current (AC) electric system, an AC to DC conversion is necessary to use the DC power, and the power produced by renewable power sources, such as solar PV and battery storage. The opportunity to save 15% electrical consumption in a commercial building by eliminating unnecessary AC/DC conversions with the addition of a modern renewable electrical infrastructure is a logical opportunity for renewable-energy buildings.
As the risk of lighting downtime caused by AC grid failure, outages, and other threats has created new organizational safety and financial risks, DC power is poised to explode in the building industry, similar to how LED lighting became positioned in 2007-2010. As we move towards more localized energy resiliency in ever more turbulent times, a most interesting revolution is poised to transform our electrical infrastructure.
DC lighting takes DC power directly from the DC source (i.e. solar photovoltaic, battery storage) and directs it to the standard DC or LED DC loads. While LED has proven to be the replacement for incandescent lamps, DC LED lamp fixtures are manufactured with LED lamps included, offering convenience, significantly longer life spans, and greater efficiency than standard fluorescents.
Lighting downtime caused by more recent AC grid failure, outages, and other threats has created publicly reported organizational safety and financial risks that have created an imminently growing need for DC-powered emergency, back-up, remote-site, and off-grid lighting, powered by renewables. Additionally, the cost of AC building power continues to increase, and lighting costs represent an average of about 50% and may represent as much as 70% of power usage.
The DC Solution
DC promotes cost savings and reduced carbon footprint benefits via direct connect-ability with renewable and sustainable DC power sources and further expands electric control costs and efficiency capabilities. By offering the flexibility of sharing lighting power consumption among various power sources, this further optimizes control of electric source usage and costs. Additionally, DC to DC is “clean” & efficient; in many processes where consistency and lighting quality is priority, and AC lighting circuits are “noisy” and inconsistent, causing flicker and pulsing.
DC Lighting & Renewables
There is a bright future for low voltage DC LED Lighting; with the continued advancement of DC power generation and distribution and renewable power sources like solar PV, battery storage, fuel cell, and wind power generating solutions, low voltage DC LED fixtures deliver the most energy efficient solution, offering direct interface with 24, 48, and 125 volt DC supply power.
Lighting is finally moving towards DC power inputs, aligning nicely with solar PV panels and battery storage systems. Net-zero energy buildings will generate, store and consume power all in DC format, and researchers forecast that commercial buildings will save 15% of total power by foregoing the DC-AC-DC inversion process. New infrastructure developers are creating electrical infrastructures for commercial buildings that use DC as the primary backbone throughout the building, whereby AC is only provided for convenience outlets or legacy devices. This notion represents an imminent evolution poised to transform the electrical infrastructure.
With DC power, power waste can be substantially reduced, while reducing electronic hardware, associated maintenance, and e-waste issues, and opening the door to advanced energy management. Moreover, end-devices in construction projects are switching to DC power.
DC Building Lighting
The DC lighting system is typically comprised of a DC distribution network, specified to supply DC power to at least a portion of the building to supply ample power to the DC lighting load(s). The system also includes a DC power source or sources having a DC power output (typically 24DC, 48DC, 125DC), such as a rechargeable battery and/or solar PV array, directly-coupled to the DC distribution network to provide DC power to the lighting grid. The system will also include a switching mechanism coupled to the DC distribution network, to switch the lights “on” and “off”.
Project Example – Off-Grid Community Center, Ghana Africa
Solar PV Array / Battery Storage / DC Light Fixtures
- Off-grid structure (600 SF)
- 24VDC interior & exterior light fixtures
- Battery Storage (2 x 200 AH)
- Solar PV Array (5.4 KW)
- Load sharing
- DC-powered ice maker