Energizing Efficiency Minnesota

Improved technologies designed into some of today's power, lighting and lighting control equipment are successfully cutting energy consumption. Here is a look at some of the technology for three different product segments:

Power

Transformers on the market now are more energy efficient than any other time in the last 30 years—a return to efficiency levels of the 1950s to 1970s, when they were about 98 percent efficient.

In the 1980s, manufacturers bowing to competitive price pressures lowered the quality of electrical steel used in the construction of transformer cores in order to lower the price of manufacture. Consequently, energy efficiency fell to about 95 percent.

Some years ago, in the early 1990s, the federal government estimated that about 61 billion kWH of electricity was wasted annually in transformer losses. Manufacturers began offering more energy efficient products at that time, but the industry did not accept the products at the premium price, so the market did not obtain the benefits of the higher efficient products.

Recently, transformer manufacturers—now impelled by federal law to counter those losses— made changes in how they build their products to comply with the U.S. government's Energy Policy Act of 2005, which mandates that all low voltage dry-type distribution transformers manufactured on or after Jan. 1, 2007 meet Class l Efficiency Levels and conform to recommended transformer efficiency levels as stated in standard TP-1-1996. They must now be at least 98 percent efficient.

The most significant changes are the return to the use of higher grade electrical steel in the core and in how manufacturers configure the core. For example, Square D Lean Power Energy Efficient Low-Voltage NEMA Transformers from Schneider Electric use high-grade electrical steel for the cores, instead of constructing the core with butt lap joints, and mitered joints, which improved the magnetic flux and energy efficiency.

With these changes, "transformers, in effect, went from approximately 95 percent efficient to 98 percent efficient, which equates to some serious energy savings and returns transformers to levels achieved in the 1960s and 1970s," explains Thomas Patzner, LV transformer product marketing manager, Schneider Electric.

Motors

Electric motors consume about two-thirds of the electricity produced in the United States, with a great deal of energy wasted from losses in diecast aluminum rotors and electrical resistance in stator windings. Recently, manufacturers have addressed these issues and introduced refinements in new or upgraded premium motors that cut those losses measurably. (Generally, premium motors meet or exceed nominal energy efficiency levels as agreed upon by National Electrical Manufacturers Association (NEMA) and the Consortium for Energy Efficiency.)

For example, Siemens' three new lines of NEMA premium AC motors, available in sizes from 1 hp to 20 hp, feature a very energy efficient design incorporating new technology that enabled use of diecast copper rather than diecast aluminum rotors, resulting in efficiency levels that exceed the NEMA premium standard efficiency levels by 10 percent.

"Despite the technical difficulty imposed by the fact that copper has about twice the melting point of aluminum, new technology enabled the development of a process, machinery, and tooling that can successfully mass produce copper rotors," notes Tony Giambra, product marketing consultant at Siemens.

Other enhancements in premium efficiency motors that boost energy efficiency include thinner core laminations and reduced windage designs.

Lighting

Though the lighting industry has been improving on energy-efficient products for four decades, advances in lighting components continue to provide increased efficiency.

For example, the pairing of new high efficiency T8 or T5 lamps, which feature a refined blend of phosphors. This enables more lumens per watt with improved high-efficiency electronic ballasts that support dimming, which saves installations measurable energy when used in systems taking advantage of occupancy sensors, daylight harvesting, energy management systems and load shedding.

Sylvania's Quicktronic PowerSense high-efficiency electronic dimming ballasts for T8 and T5 lamps, for example, feature microcontroller technology that contributes to energy efficiency lamp performance. At light levels of greater than 75 percent, unnecessary lamp-coil power is turned off, delivering energy efficiencies comparable to non-dimming instant start electronic ballasts, explains Susan Anderson, energy relations, Osram/Sylvania. When used in conjunction with lighting sensors that respond to daylight, the ballasts support automatic dimming (100 - 5 percent in T8s and 100 - 1 percent in T5s), maximizing energy efficiency.

Fixture manufacturers also design with energy efficiency in mind. For example, Cooper Lighting's new Metalux F-Bay MB Series (Micro-Bay) narrow profile fluorescent high-bay luminaire is a high system efficacy alternative to outdated fluorescent or HID systems that may be operating at 60 percent to 70 percent of their original light output and consuming 25 percent to 40 percent more energy than an equivalent fluorescent product.

Designed for T5 and T8 fluorescent technology, the series is suited for continuous row mounting in narrow aisle applications. The Specular MIRO reflectors allow precise light control and three optical distribution patterns are available. The combination of the reflector design with a minimum 95 percent total reflectivity, electronic ballast and energy efficient fluorescent lamps provide energy savings and excellent performance. An occupancy sensor is available, as well.

Lighting control

Until recently, system-wide lighting control relied on a central database operating basically dumb devices. However, that does not deliver optimized energy efficiency.

In comparison, intelligent relay based-lighting control panels can save energy. The panel houses relays turn circuits on and off on a schedule, and are able to automatically override the schedule in response to detection of the presence of a person or by action of that person.

The devices—the switch, the occupancy sensor, and the photocell—collaborate within a space, with the devices "talking" to each other and interoperating based on the information they are sharing, explains Tom Braz, general manager, Hubbell Building Automation.

Lutron's intelligent EcoSystem fluorescent lighting control system combines "plug and play" components, including occupancy and daylight sensors, wall controls, personal handheld remotes, and software with a network of "smart" microprocessor-based dimming ballasts that communicate via low voltage wires.

Suitable for commercial applications, the enhanced control can generate energy savings of 50 percent to 70 percent by combining occupancy sensing, daylight harvesting, space tuning, personal control, scheduling, and load shedding, notes Michael Jouaneh, marketing manager, Lutron. The system is scalable—it can control the lights for one room to an entire building. And as building needs change, facilities managers can reprogram the system with a PDA—no rewiring necessary.

Hubbell's LX Networked Lighting Control Panel System uses distributed intelligence communicating to individual devices with microprocessors and transceivers on the printed circuit board. The products in the series use LonWorks open system architecture as an intelligent protocol to make decisions based on information passing between devices. Using this systems approach, it is possible to connect up to 32,000 devices yet still achieve speed of transmission without any delay.

Bill Feldman is a freelance writer.