Integrate and Save
November 01, 2005
Appeared in Lowe's ForPros
When it comes to saving big money on a building's operating costs, little steps can slice energy bills by double digits, says Carlos Petty, group manager in the New York office of Syska Hennessy Group, a national consulting engineering and construction firm. Lighting, for instance, usually amounts to about 25 percent of a building's energy costs. But those bills can be slashed by half with just a few savvy steps that include daylight harvesting and heavier use of focused, task lighting.
Matters quickly can get complicated because, as Lindsay Audin, one-time energy manager for Columbia University and now a consultant based in Croton-on-Hudson, N.Y., points out, a change in one part of the energy system design may trigger unexpected, even unwanted, changes in other parts of the system. This is precisely why system integration is a top goal for many buildings' energy managers.
Introduce a more efficient lighting system, for example, and that may throw off a building's heating system, which had been developed under the assumption that it could capture stray degrees of heat from light bulbs. Remove that source of heat, and either office occupants will need to learn to like cooler temperatures or more fuel will be consumed, raising temperatures, in the building. "Whole building analysis is the key to making systems work together," Audin says.
The other part of the news is that "we are seeing more technologies that easily and inexpensively integrate and control a building's energy use," Petty says. "We are seeing much more use of occupancy sensors in rooms." Some detect motion, others detect carbon dioxide, but however it is done, occupancy sensors increasingly are used to turn off lights when they aren't needed, to control variable frequency drivers and the use of fans to pump energy into a room, and together this means real reductions in energy use. In the summer, for instance, we'll let an unoccupied room go up to perhaps 79 degrees," Petty says. In the winter that unoccupied room might be permitted to dip to 65 degrees. Real savings result because less energy is consumed, both in heating/cooling and lighting.
Software and programming keep getting smarter, too. If a conference room is never used on Fridays—"we'll build that into the energy design," Petty says. That means both HVAC output and lighting will be diminished every Friday. If the room is put into service on a Friday, manual overrides allow occupants to control their comfort level.
Another integration trend: "We are seeing more energy consumption switched to off-peak hours," Audin says. Every homeowner has heard the injunction to run dishwashers at night in the summer, for instance, but there are two problems: most dishwashers lack timers and few homeowners are on an energy billing plan that charges more in peak hours, less in off-peak. Many large buildings do have variable-hour billing plans, however, and, importantly, "we are seeing more systems that are smart enough to activate themselves at off-peak times," Petty says. That may mean delaying large photocopy or print runs until the morning's earlier hours, when costs are lowest. This time shifting isn't fully implemented in energy management just yet, although it's on the horizon.
A big takeaway: the focus on energy efficiency and the tighter system integration that helps deliver it is here to stay, says Mike DeNamur, an expert with Minneapolis-based Honeywell Building Solutions. "Integration is a trend. We know how to do it, we have the technologies, and there are clear values that arise from integrating multiple systems such as lights and HVAC."
Expect the velocity of this trend to grow stronger. As energy bills leap higher—and many experts predict double-digit increases in this winter's heating bills alone—a focus on efficiency will become intense. And it's not just for new construction. "In many areas of the country, whenever there is substantial renovation, upgrading the energy systems has to be built into the plan," Audin says. The upshot will be mounting pressures to implement comprehensive energy plans that leave nothing to chance and that tie multiple energy-consuming systems together into an efficient whole. The benefit will be more control over energy bills for building management and tenants alike.