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Take Elevator Efficiency to the Next Level
Chronically neglected in favor of lower-hanging fruit, elevators are nowhere near the top of most FMs’ energy upgrade priorities.
These machines represent 3-7% of your building’s energy consumption, however – so while elevators may not be your biggest energy consumer, they offer potential for considerable cost and energy savings.
Target the major sources of elevator energy waste with a solution tailored to your budget.
Smart Tracking Strategies
Start your elevator efficiency upgrades by first getting a handle on how much energy each machine uses. Submetering involves installing data logging equipment in the entire bank of elevators to measure current and voltage in incoming electrical lines. This practice results in the most accurate measurements, and some utilities will subsidize energy efficiency upgrades depending on the results, notes Jack Tornquist, vice president of the elevator consulting group for the consultancy Lerch Bates.
The initial investment can be significant, which discourages many building owners from tracking energy consumption closely despite the possible savings, says Andy Kohl, president of The Elevator Consultants.
“The meters themselves are anywhere from $2,500 to $6,000,” adds Brad Nemeth, vice president of sustainability for ThyssenKrupp Elevator Corp. “The minimal investment is about $4,000, and then you’re replicating that across however many elevators you have.”
Not comfortable monitoring consumption in-house? Consider bringing in a third party to conduct an audit, recommends Bill Lippman, vice president of modernization sales for Schindler Elevator Corporation.
“An elevator audit will evaluate the age of the equipment, when it was installed, and if or when it was modernized,” Lippman explains. “If the system is over 15 to 20 years old, there are huge potential gains to be had in energy efficiency and reliability simply because of the technological advancements that have taken place in that time.”
Where to Find Waste
To determine where the most cost-effective improvements can be made, your next step is examining components responsible for the most energy use.
“One of the largest sources of energy waste in elevators is the drive system,” says Lippman. “Older drives, such as motor generator sets, are continuously running, which can be very inefficient and contribute to a large waste of energy. They can also contribute to hidden energy costs in a building because they generate a lot of heat, which can require additional energy from HVAC to cool the equipment.”
Still have a hydraulic elevator? Its motor likely uses 40-60 HP, compared to the 6-8 HP motor typical of a modern machine room-less (MRL) elevator, says Kellie Lindquist, marketing manager for KONE Elevators and Escalators. That means whenever the elevator is actively working, it’s expending energy, Kohl adds, whether it’s hoisting the car or just leveling as it approaches the right floor.
“For hydraulics, there are some new products out that can do a really good job because they cut down on the floor-to-floor time,” Kohl explains. “If it takes 12 seconds to get to your floor in a hydraulic elevator and you can take that to 9 to 10 seconds, that three seconds every time the elevator runs can add up pretty quickly. If the motor’s not running, you’re saving energy.” PageBreak
If your budget won’t allow a full-scale modernization, don’t worry – there are several incremental changes that will help increase efficiency without incurring large expenses.
Lighting is a great place to start, Nemeth says. For roughly $2,000-3,000, you can replace the older lighting system in one elevator with a more energy-efficient version.
“The majority of older elevator cabs have T12 fluorescent lights that may have been upgraded to T8s, and a lot of them have halogen downlights that consume a lot of energy and give off heat,” Nemeth says. “Many retrofits can be done with a small controller drive that mounts on the top of the cab. It’s almost plug-and-play to switch out the fluorescents with more modern LED lights.”
Replacing the starter could cost as little as $2,500 and offers other benefits in addition to roughly $300-500 in energy savings per year, Kohl adds.
“If you have an across-the-line starter and install one of the new starters today, it dramatically changes the elevator’s energy consumption,” Kohl says. “You can pick up some energy efficiency with a new starter, but you also save on brownouts. If you ever have a brownout, a newer starter keeps your controller from getting fried.”
Consider pairing the starter with a new landing system for additional savings, Kohl recommends.
“Landing systems typically utilize magnets or tape. The elevator starts to slow down as it gets to the landing and starts to level,” Kohl says. “With a more sophisticated landing system, you can slow down and stop a lot faster, which means less draw and less runtime on the motor.”
The landing system will cost about $4,000-5,000 if you’re not installing it during a modernization; if you wrap it into a large modernization project, the new landing system typically represents just a few hundred dollars in extra costs.
That modernization might be necessary if you’re looking to carve out steeper energy savings, but also comes with a much larger investment.
Phase In Larger Improvements
Contrary to popular belief, you don’t have to take on these large projects all at once, Lippman stresses – you can implement them in phases to make them more affordable.
“The costs of an elevator modernization can range from a few thousand dollars to the multimillion dollar range, depending on the scope,” Lippman notes. “A wide variety of factors, including the number of elevators, traffic requirements, and the amount of floors, fixtures, and architectural elements are all relevant when determining the cost.”
“If you’re purely looking at energy efficiency vs. ride quality, there are different levels of modernizations or retrofits. One investment is to look at the elevator machine itself – the motor, the gearbox, and so on,” Nemeth adds. “Many of these older pieces of equipment were state-of-the-art back in the ‘60s and ‘70s, and we have many options to modernize those. The simplest one would be replacing the DC motor with an AC motor and changing out the drive mechanisms for it – you can see anywhere from 30 to 50% savings by just changing out the motors in your drive systems.”PageBreak
A full modernization can cost upwards of $120,000-130,000 and essentially replaces everything but the shaft, Nemeth says. This investment brings the entire elevator up to the latest code requirements, replaces the cab interior, and generally results in what looks like a brand new elevator.
Though energy efficiency isn’t the sole focus of a full modernization, you can still make it a priority by specifying any of the many energy-cutting features possible with a larger investment:
Standby mode, a controller option that’s most useful in facilities where the elevator periodically sits idle, powers down lighting, signaling, and other non-essential operations after the elevator hasn’t been used for a preset period of time. The elevator then powers back up and responds whenever someone pushes a button to request a ride.
Destination dispatch is another smart control technology available with a full modernization and allows the elevator bank to group passengers in the most efficient way, reducing the number of stops for all riders, Nemeth says.
Regenerative drives reclaim the energy created while braking or slowing down and fuel it back into the building.
Got an older geared elevator? A geared to gearless modernization eliminates the motor generator, reducing noise levels and power consumption.
Elevator improvements offer precious few LEED points and require high investment costs, so why spend the money? For one thing, an inefficient elevator isn’t just an energy hog – its wasteful operation is a red flag for bigger, more expensive problems waiting to happen, from pollution to annoyed tenants and customers.
“There are always ripple effects with older equipment. Carbon dust goes through not only your machine room, but can also go through your whole building and get carried out into the hallways,” Kohl says. “If the motor generators or controllers aren’t maintained properly, they can start on fire.”
The oil required to operate a hydraulic elevator also presents a potential environmental hazard, adds Lindquist.
“Right now, there are over 1 million elevators in operation. Around half of those are over 20 years old and ready to hit the end of their lifecycle. About half of those are hydraulic, so there’s an opportunity to make some changes,” Lindquist says. “Many hydraulic elevators were installed with in-ground pistons and jacks – if you need to replace the jacks, it could cost $30,000 to $40,000. The hydraulic fluid also creates the potential for contamination if the oil leaks and gets into the ground and local rivers.”
Absent a catastrophic health or environmental hazard of this type, a poorly functioning elevator can still cause headaches in both the short and long term by inconveniencing building occupants. Tenant satisfaction – or the lack of it – is at risk if elevator maintenance and periodic upgrades are ignored, Nemeth adds.
“The problem that strikes fear into most people is entrapments, where the elevator gets stuck and that person can’t get out of the cab,” Nemeth says. “Most of the time they can be solved very quickly, but it depends on where the building is located. Is it in downtown LA in the middle of rush hour? It may be two hours before someone can get there and help the person out, rather than 20 minutes. It starts becoming a trust issue.”
CASE STUDY #1:
Grand Avenue Courtyard
El Segundo, CA
Building: 12-floor office building
Elevators: Five, 23 years old
Problem: Inefficient operation and energy use
Solution: Energy audit followed by modernization. Changes included a 23.3 HP AC motor to replace the old 30 HP AC motor, as well as new microprocessor controllers.
Energy Reduction: 61.9% (an average of 227.03 kW, compared to the old machine’s average of 595.9 kW)
CASE STUDY #2:
Hyatt Place Waikiki Beach
Building: 20-story hotel
Elevators: Two, over 30 years old
Problem: Outdated and inefficient elevators coupled with high utility rates resulted in steep operating costs. Additionally, the hotel had to continue running throughout the renovation, requiring care to avoid inconvenience.
Solution: Modernization with aesthetic improvements. Changes included a permanent magnet AC motor replacing a 20 HP DC one, the elimination of the generator, TAC50 controllers to replace relay logic models and the elimination of group controllers, and LED lighting to replace incandescent lamps.
Energy Reduction: 56% overall (from an annual demand of 52,418 kW pre-renovation), including 86% less energy for lighting
Janelle Penny email@example.com is associate editor of BUILDINGS.