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The Best Path To Lighting And HVAC Efficiency
There is no question that lighting and HVAC systems are the largest energy users in commercial and institutional facilities. Lighting systems account for an estimated 30 percent of the electrical energy used in commercial buildings.
The building’s chiller is the single biggest user of electricity in a typical facility. Add in the heating system, and the energy used to distribute the heating and cooling to the building, and it is no surprise that most successful energy management programs have focused on lighting and HVAC.
Fortunately, facility executives have many options when it comes to conserving energy in lighting and HVAC systems. By applying new lighting technology, facility executives can cut lighting energy use by an average of 30 to 50 percent, while improving the performance of the lighting system. Lamps with electronic ballasts, lighting controls, high efficiency replacements for incandescent lamps – all are being widely used in lighting system upgrade programs.
Similar improvements are being made in the operation of HVAC systems. New technologies allow facility executives to reduce the energy use of their HVAC systems by 25 to 50 percent, without sacrificing comfort or indoor air quality. High efficiency chillers, direct digital controls, energy management systems – these and other new technologies are being widely applied in building HVAC system upgrades.
Individual Projects or an Integrated Plan?
One of the biggest questions facility executives face when looking at upgrading lighting and HVAC systems is how much should they do. Some technologies offer a fast payback. Other technologies, while reducing energy use and improving the quality of the services provided to the facility, have much longer paybacks, often two or three times longer. Should facility executives focus only on those items that offer a rapid payback, or should they only be concerned with the payback for the overall upgrade program? While the available level of funding can be a limiting factor, other factors must also be considered.
Start with the reasons why the upgrade program is being implemented. Energy conservation, while a driving factor, is not the only issue. The primary purpose of any lighting or HVAC system is to meet the needs of building occupants. When looking to upgrade existing systems, facility executives must focus on the quantity and quality of light and space conditioning needed to meet those needs. Unfortunately, limiting system upgrades to items with a quick payback usually fails to take into account occupant needs. And when occupant needs are overlooked, facility executives risk jeopardizing productivity and morale to the point where tenants may move or the energy management measures that were implemented may be defeated by the occupants.
Another problem with limiting system upgrades to components with quick paybacks is the effect it has on overall system performance. Implementing quick payback projects tends to produce a series of upgrade patches.
But simply replacing the lamps does not address the issue of how much light is actually needed in the space. If the space is overlit, additional energy could have been saved by examining the lighting requirements, changing the number of fixtures installed, using a ballast with a lower ballast factor or installing lighting controls. Similarly, the original chiller may have been oversized for normal operation. Additional savings could have been achieved by installing a smaller chiller, or two smaller chillers whose operation can be staged to match the building load, or by installing a variable speed drive on the new chiller. Even more energy could have been saved by installing a high efficiency cooling tower.
Finally, programs that are implemented in a patchwork fashion are more expensive and more disruptive to building occupants. When the entire system is upgraded, all work in a given area can be performed at the same time. When th