The Ups and Downs of Energy Efficiency

MORE energy-efficient elevators significantly reduce the costs in a building, but building owners struggle to identify the elevator system and the savings associated, according to a new study.

The study, by the American Council for an Energy-Efficient Economy (ACEEE), and looked at elevators and escalators, which make up 2-5% of the energy used in most buildings, but can reach as high as 50% during peak operational times. At 5%, that means the yearly energy consumption of U.S. elevators is approximately five times of that used in all of Washington D.C. The technology exists today to reduce that consumption by 40% or more, especially by cutting energy use between trips, when an elevator is idle, according to the study.

Some technologies have been found to reduce consumption by as much as 75%, but without a standard way to measure energy savings and a rating system to distinguish more efficient elevators, building owners may be unaware of the benefits of upgrading to a more efficient system or choosing a more efficient system for new construction.

“Enhanced visibility when it comes to elevator efficiency can help customers grasp the full value package of better controls, improved performance, reduced sound, and increased comfort,” said Harvey Sachs, ACEEE senior fellow, and the study’s lead author. Sameer Kwatra of ACEEE presented the study at the 2015 American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Winter Conference in Chicago.

The study lays out a framework for industry leaders to set common standards for measuring elevator efficiency. Those standards could lead to a rating system, such as the U.S. Environmental Protection Agency’s ENERGY STAR® ratings already in place for heating, ventilating and air-conditioning systems, and many home appliances. Clear standards also could lead energy utilities and government agencies to offer incentives, such as rebates, for very efficient models. And building label programs, such as the U.S. Green Building Council’s LEED® program, could include elevator efficiency as a factor in certifying buildings. Right now, the LEED program considers elevators a part of unregulated “process loads,” and there are no direct credits for installing more efficient systems.

“Owners see elevators as an extension of the building lobby — a way to include their personality and values in the building,” said John Mandyck, chief sustainability officer, UTC Building & Industrial Systems. “As consumers and tenants better understand and value the effects green buildings have on the health and productivity of inhabitants, clear standards for measuring elevator efficiency can provide a great opportunity to reduce operating costs and showcase the environmental attributes of a building.”

The report identified energy-efficient elevator technologies that can be included in building codes and factored in elevator rating and labeling systems. As almost all elevators are idle far more than they are moving, reducing standby power, such as by turning off lights and cab ventilation systems, can be relatively inexpensive and dramatically cut total energy use. In addition, new technologies, such as coated steel belts that replace cable ropes in some elevators, allow for more efficient operation. Advanced dispatching software can improve the customer experience by reducing wait time while cutting energy use in half compared to traditional systems, according to the report.

Picture of a glass elevator by Dieselducy, reproduced under CCL.

Tuesday 3rd February 2015


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