Smart Lighting – SPGTC 2011
May12,2011, Smart Power Grid Technical Conference, Santa Clara, CA—Stewart Findlater from Redwood Systems talked about the need to connect the smart grid to smart loads. The smart loads are especially important in commercial buildings which use more power than homes.
Commercial buildings are responsible for about 40 percent of all primary energy use, 72 percent of all electricity consumption, and 39 percent of CO2 emissions in the United States. Of this energy use, lighting consumes over one third of the electricity, but offers some very intriguing characteristics. It is the only major load that can be dynamically shifted, can be accurately measured, and upgrading lighting systems is one of the most cost-effective, energy-efficient projects possible.
By combining an intelligent delivery system with smart loads, users and utilities can prioritize sources of power based on most desired user characteristics, such as cleaner or cheaper. To achieve these benefits requires intelligent systems and higher efficiency light sources. One candidate technology for lighting is LEDs. These devices are high-efficiency, low heat output, environmentally clean, longer life, instant on, and dimmable on standard systems.
Comparing lighting technologies shows that LEDs produce more illumination per watt than all the available alternatives. White LED lamps can produce 130 lm per watt. LED packaging is suitable for many commercial installations and comes in standard form factors like 2’x2′, 2×4, linear, down, and track. Although the lights are compatible with standard controls, smart controllers can add functions like timers, control panels, occupancy detectors, zone lighting, day lighting minimization, wall or scene controls, and many others.
In comparison, conventional controls operate relays through some software control. There is little automation and many sensors are just overlays to the existing structure. All modifications are manual and the lighting systems are difficult to provision, set up, and integrate with the building management systems. There is no feedback from the lights to the system and all of the operations are high-voltage analog.
In comparison, changing to a LED system makes everything digital. The lights operate on low voltages from a centralized DC supply that includes the controls, networking, and sensors for parameters like light output, temperature, color, and other environmental conditions. The building infrastructure goes from conduit and heavy wires to light-weight 24 AWG wire pairs to each light and to the sensors.
The integration of multi-variable sensor systems enables lighting to be integrated with the building air conditioning for localized provisioning, commissioning, and planning. The systems can automatically group light and air functions from the sensor inputs. By installing addressable fixtures, very fine grain control is possible, as in one installation in a server farm where the light moves with a person to the area where work is going on. All other areas remain unlit.
The integration of sensors into the lighting systems facilitates building management and opens up the ability to analyze the occupancy patterns and other operating characteristics to improve energy management. These types of systems are most applicable for new construction and major renovations.
