Exploring Sustainable Service Solutions for Elevators

This article discusses sustainable solutions that increase energy efficiency and extend the lifecycle of elevators.

With a continually increasing emphasis on green building practices globally, many building owners, facility managers, engineers and architects are seeking ways to reduce the environmental impact of existing elevators by exploring innovative sustainable service solutions. Among the environmental challenges they are encountering are energy efficiency, indoor air quality and oil requirements. In response, experienced technicians and engineers can recommend cost-effective sustainable products and practices that help achieve reductions in material use, energy and waste. The following sustainable solutions can be implemented to increase energy efficiency, reduce toxins, eliminate unnecessary waste and extend the lifecycle of your elevator.

Sustainable Solutions for Traction Elevators

Upgrading the Motor

Upgrading from a motor-generator (MG) drive to a variable-voltage, variable-frequency (VVVF) drive could save approximately 40% on energy consumption, depending on the elevator type and size. Because of required power conversion, MG sets require one motor to run solely as a generator to power another hoisting motor. More current technologies, like VVVF drives, have eliminated the need for this unnecessary redundancy, thus greatly reducing the amount of energy needed to power elevators. Moving away from the old MG sets also eliminates potential indoor air-quality issues associated with carbon dust created by the use of carbon brushes in the motors themselves and waste heat.

Regenerative Drives

Building owners can implement technical advances, like installing regenerative drives, which revert some of the elevator’s unused energy back into the building. The power transferred back into the building would traditionally be dissipated via heat into the machine room. With the regenerative drive, the excess energy is captured and reused, and the system reduces costly traditional cooling of the elevator machine room. Building owners, facility managers, elevator consultants and architects can utilize energy calculators to help customers identify estimates of energy savings from regenerative options.

Destination-Control Software

Installing destination-control software can create more efficient passenger transportation, ultimately improving building efficiency – not to mention the “cool” factor – which can increase the building’s overall property value. Destination-control software, like ThyssenKrupp Elevator Americas’ Destination Dispatch™, improves routing by grouping elevators by the floor the passengers intend to travel to in a building.

Buttons are not required inside each elevator car, because passengers designate which floor they are traveling to using a centralized screen input system in the building’s lobby. The touchscreen directs passengers to their designated elevator as determined by a formula that considers requested destinations and estimated time to destination. Riders are evenly dispersed to their appropriate elevators. The software groups all passengers traveling to the same floor in the same cab, reducing the number of stops and improving the elevator’s efficiency. This practice can increase handling capacity up to 30%. Systems equipped with destination-control software also allow building owners to accommodate tenants with high traffic needs during peak travel times. 

Sustainable Solutions for Hydraulic Elevators

Readily Biodegradable Oil

Recently developed canola-based hydraulic oil represents the most environmentally preferable hydraulic option available today. It differs from traditional soy-based hydraulic oils, which are typically 50% vegetable-based with synthetics added to compensate for deficiencies. It has a more stable viscosity throughout its heat range, requiring fewer valve adjustments in extreme temperatures and may eliminate the need for a viscosity control device, which requires energy in order to keep the oil fluid and avoid thickening. Traditionally, a viscosity-control device is required to keep an elevator’s oil at its optimum operating temperature around the clock, even when the elevator is not in use. Eliminating the need for this device reduces the amount of electricity a building’s elevator is consuming. And by replacing existing petroleum-based oil with this product, you can rejuvenate your system’s lubricity, which will allow you to maintain your elevator at peak operating performance and make the system more environmentally preferable.

Power Units and Valves

Another improvement in hydraulic-elevator technology can be achieved through the updating of power units. Normal wear and tear on older pump units means seals can begin to leak or valves might not seal tightly, permitting system pressure to decrease over time. Decreased pressure requires the unit to unnecessarily power up in order to re-level, even in off-peak hours. Constant leveling throughout a unit’s downtime can mean unnecessary use of electricity for the building owner and more wear and tear on the seals and pump parts.

Sustainable Solutions for All Elevator Types

LED Lighting

Installing LEDs can reduce energy costs by up to 80%, as well as dramatically reduce the number of bulbs owners need to replace each year. Typically, LED lights last up to 10 years. The choice to move to LED can reduce heat loss (typical in other lighting options) and disposal issues (common with other mercury-containing bulbs). It also increases the lifespan, in some cases up to 10 years per light. Finally, LEDs do not emit ultraviolet light, which can cause fading to elevator cab interiors over time and is common in other bulbs.

Econolight™

Based on lifecycle analysis, it is common knowledge that an elevator’s largest environmental footprint comes from the energy used during its use phase, and most of that phase is spent sitting idle. Programming the elevator controller to shut off the elevator’s lights and fan when the cab meets certain parameters will increase energy savings. Econolight is a sustainable solution that eliminates approximately 60% of wasted energy in an idle elevator. For instance, if the elevator is stopped on the lobby floor and has not been used within a certain timeframe, the elevator system would be programmed to shut off the cab’s lights and fans. With Econolight, energy use could go from 24 hr. a day to less than 9.5 hr. a day, reducing CO₂ emissions by 193,000 T per year.

Features and benefits include:

• Installation in less than 2 hr.
• Energy conservation
• Increased value of the elevator and building
• Money savings due to fewer bulb replacements
• Five-year or less payback period in energy savings
• Cooler cabs (when lighting has been off between calls)

Solid-State Starters

A solid-state starter supplies a motor with smooth and steady current, eliminating the large influx of current typically created by older mechanical starters. Conventional motors, when energized, create power surges (spikes). These spikes may be noticed by momentary dimming of the lights in the cab and may hamper optimal performance of sensitive equipment, such as computers. This sustainable solution also provides savings, because the starters reduce spikes, which utility companies may bill at higher rates.

Features and benefits include:

• No starter contacts used during normal operation
• Less severe starting
• No light flicker or spikes that can interfere with a building’s equipment
• Reduced stress on the motor windings
• Prolonged motor life
• Quieter operation

Battery Lowering

Battery lowering ensures that in the case of an emergency, all elevators are lowered to the nearest point of egress, thereby avoiding entrapments. It also reduces the demand on a building’s backup generator, permitting reduced energy demand in an emergency. This can reduce the need to include elevator systems, while sizing the building’s backup generator, and represents an efficient use of resources.

Conclusion

The largest impact the industry can have on energy reduction is through the modernization of outdated and energy-inefficient technology, one building at a time. According to the U.S. Green Building Council, buildings are using approximately 71% of all electricity in the U.S., making finding means to reduce this usage paramount to sustained operations.

Because older elevators consume up to 3% of all electricity globally, it has become increasingly important for companies to provide best-in-class sustainable solutions that reduce customers’ environmental impacts and operating costs. There is an opportunity for energy and emissions reductions in drives, lighting and fans, with potential energy savings ranging 50-94% for each element.^[1] It is estimated that regenerative drives, in particular, reduce 3,800 lb. of greenhouse gas emissions per year per elevator. The reduction can be substantial for customers measuring, documenting and reporting the CO₂ footprint of their building portfolio. In short, by choosing sustainable service solutions, building owners benefit both building occupants and the environment.

References
[1] ThyssenKrupp Elevator Americas.. “2009/ 2010 Corporate Sustainability Report” (www.thyssenkruppelevator.com/Sustainability/Report2010/index.asp).