High Performance Elevators

Summary

High Performance Elevators

Elevators: High Performance vs. Conventional

Passenger and freight elevators with efficiency features such as gearless permanent magnet synchronous motors, traction belts instead of steel ropes, dispatch control, and motors with regenerative braking.

Synopsis:

Losses in an elevator system include hydraulic and gear, friction, transmission, motor, controller, and brake losses. Recent advances are directed towards loss reduction. KONE developed a gearless vector drive that uses a permanent magnet synchronous motor (PMSM) that can be made in a compact, disc-like shape that allows it to be integrated into the traction sheave. No machine room is necessary, resulting in space and weight savings. Variable speed PMSM motors provide high efficiencies in multi-pole slow speed/high torque designs resulting in no need for gears. Kone claims energy savings of up to 40% compared to geared elevators and over 60% when compared to hydraulic lifts. Kone now offers a gearless traction design for the low-rise applications (up to 7 stories) that previously were served by hydraulic systems. Replacement of hydraulic system at their time of renovation saves a great deal of additional energy as these systems do not employ counterweights to offset the lifting requirements for the car.

Otis developed their Gen2 system, replacing steel ropes with a flexible traction belt consisting of ultra-thin (3-mm) steel fibers encapsulated in a polyurethane sheath. Sheave diameter was limited by the bending radius of the steel ropes, but advanced materials and innovative rope construction has resulted in reducing sheave size and rope weight. Flat traction belts allow the use of a four-inch rather than a 30-inch diameter drive sheave for the company's geared or gearless traction elevator systems. A smaller motor can be used to meet system power requirements. Otis claims as much as a 50% reduction in energy use with a gearless machine and a variable speed permanent magnet (PM) motor with advanced traction belts as compared to a conventional geared machine.

Magnetek also introduced their Quattro AC and DC elevator drives with regenerative braking, which they claim will produce energy savings of 40% compared with DC motor generator sets and 25% when compared with DC-SCR (silicon-controlled rectifier) drives. Regeneration is not always cost effective, especially in mid-rise buildings with low traffic.

While simple payback for these elevators is at least 50 years, the non-energy benefits of speed and comfort as well as reduced maintenance and space requirements (no penthouse or elevator room) are attractive to some buyers. The simple payback for installing high performance elevators in taller buildings is longer due to the higher efficiency of standard practice.

Energy Savings: 80%

Energy Savings Rating: Extensive Assessment What's this?

Level	Status	Description
1	Concept not validated	Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.
2	Concept validated:	An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.
3	Limited assessment	An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline.
4	Extensive assessment	Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions.
5	Comprehensive analysis	Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.
6	Approved measure	Protocols for technology application are established and approved.

Simple Payback, New Construction (years): 46.8 What's this?

Simple Payback, Retrofit (years): 121.2 What's this?

Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:

Simple Payback = Incremental First Cost / Annual Savings

The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.

For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.

For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.

Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.

The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.

TAG Technical Score: 3.5

Details

High Performance Elevators

Elevators: High Performance vs. Conventional

Item ID: 471

Sector: Commercial

Energy System: Transportation--Elevators & Escalators

Technical Advisory Group: 2014 Commercial Building TAG (#9)
Average TAG Rating: 2.71 out of 5
TAG Ranking Date: 03/17/2014
TAG Rating Commentary:

Unless this is combined with integrated PV I think there are better solutions.
Technology is commercially available but with very low penetration.
How new are these technologies?
Also offer several non-energy benefits such as increases comfort, less waiting and travel time.

Synopsis:

Baseline Example:

Baseline Description: Traditional Hydraulic Low-Rise Elevator
Baseline Energy Use: 16227 kWh per year per unit

Comments:

Energy savings from improving elevator efficiency depend heavily upon the baseline technology plus usage and traffic patterns. Critical assumptions include the weight (capacity) of the elevator, loading (persons or weight per trip), the number of trips, and the average lift or height per trip. Generally, a hydraulic elevator is assumed for low-rise applications with a DC traction motor drive is taken as the baseline case for mid and high-rise buildings.

Assumptions for energy savings estimates are: hydraulic elevator with a DC-traction motor a load of 3500 pounds, an elevator speed of 300 feet per minute, 200,000 starts per year, and an average travel height of 37 feet in a four-floor building.

Kone estimates an annual energy consumption of 16,227 kWh/year for the upgrade of a traditional hydraulic elevator with a gearless traction unit requiring only 3,308 kWh/year for an energy savings of 12,919 kWh annually (79.6%). The advanced elevator is equipped with their permanent magnet synchronous motor with regenerative braking.

Manufacturer's Energy Savings Claims:

"Typical" Savings: 30%
Savings Range: From 12% to 63%

Comments:

These claims are from Kone.

Best Estimate of Energy Savings:

"Typical" Savings: 80%
Low and High Energy Savings: 12% to 80%
Energy Savings Reliability: 4 - Extensive Assessment

Comments:

Elevators account for 2% to 4% of a building's energy consumption. Studies conducted for the European Commission indicate that energy savings of up to 63% are obtainable through use of "best available technology" instead of conventional hydraulic or a geared traction lift powered by a DC motor.

In actual operation, energy savings are dependent upon a number of variables including the baseline technology, car capacity (nominal load), travel speed (feet per minute), travel distance, number of floors served, and number of starts per year. Savings increase when the new technology includes regenerative braking. The "typical" 79.6% savings cited is due to the use of a Kone EcoSpace gearless traction design instead of a traditional geared traction system in a 3,500 lb capacity elevator in a 4 floor building.

Kone mocked up a number of "Elevator Energy Calculation Reports" in March of 2014 that examine potential savings from low-rise, mid-rise, and high rise elevator applications. The low rise elevator improvement produces an energy savings of 12,920 kWh/year per elevator (a 79.6% savings). The savings come from replacement of a hydraulic elevator with an EcoSpace Gearless traction unit. Basic assumptions include a 4-story building, 3500 pound nominal load, speed of 150 fpm, travel distance of 37 feet, and 200,000 starts per year. The mid-rise scenario produces an energy savings of 5,801 kWh annually (42.2%) through use of a MonoSpace gearless traction design instead of a geared traction system. Assumptions include a 16-story building, nominal travel speed of 350 fpm, a travel distance of 147 feet, and 200,000 starts per year. The high-rise comparison produces an annual energy savings of 1,745 kWh per year (12.8%). Assumptions for this analysis included an EcoSystem MR for the more efficient elevator versus a gearless traction system with a SCR static converter. The 32-story high-rise elevators have a speed of 700 fpm with an average travel distance of 300 feet. Again, a 3500 pound nominal load is assumed with 200,000 starts per year. In all cases, the Kone solution featured regenerative drives.

Energy savings come not only from changing the hoisting motor/drive system to permanent magnet motors with regenerative drives but also from reducing or eliminating standby losses due to elevator control systems, lighting, ventilation, floor displays, and operating consoles on each floor and inside the elevator cabin. Elevator car lighting can be changed from incandescent or fluorescent to LED lighting technologies. LEDs can be dimmed or cycled on/off without impacting operating lifetime. Elevators can be put in a low energy mode when not in use. During low demand periods, one or more elevators within a group can be shut down without compromising service quality. Controls for multiple elevators can be optimized to enhance both service effectiveness and energy efficiency.

Energy Use of Emerging Technology:

3,245.4 kWh per unit per year What's this?

Energy Use of an Emerging Technology is based upon the following algorithm.

Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))

Technical Potential:
Units: unit
Potential number of units replaced by this technology: 9,000
Comments:

According to the National Elevator Industry, Inc., there are 900,000 elevators in the U.S (NEII, 2014). If we take 4% of that, assuming the number of elevators is proportional to the population, that equals approximately 36,000 elevators in the Northwest. During the time that most existing elevators were installed, the dominant technology has been hydraulic. Assuming that 25% of existing elevators in the Northwest are hydraulic and serve 3 or more floors (see WA state breakout of elevators by type, below), yields a potential retrofit population of approximately 9,000 hydraulic elevators.

Note: The WA Department of Labor and Industries performs elevator safety inspections and maintains an elevator database for the state. Of the 26,474 elevators in their database, 11,094 are passenger hydraulic elevators and 6,023 of these operate to serve 3 or more floors. (The remainder are freight elevators, wheelchair lifts etc.). All could be upgraded to gearless traction elevator drives at their time of replacement or upgrading.

Also note that ACEEE states that the U.S. installs about 15,000 to 20,000 elevators annually (Sachs, 2015). Prorating by population yields about 5% x 17,500 = 875 elevator installations per year.

Regional Technical Potential:
0.12 TWh per year
13 aMW
What's this?

Regional Technical Potential of an Emerging Technology is calculated as follows:

Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)

First Cost:

Installed first cost per: unit
Emerging Technology Unit Cost (Equipment Only): $116580.00
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $24968.00
Baseline Technology Unit Cost (Equipment Only): $61890.00

Comments:

Elevator modernization may require six figures per elevator. The time to upgrade is when ordering elevators for a new facility or when modernization, renovation, or upgrading is required. Indicators that modernization is required include elevators no longer meeting code requirements, when they are no longer supported by the manufacturer, when the elevator no longer meets service expectations, or when maintenance costs and frequency increase and reliability suffers.

From RS Means Facilities Construction Cost Data (2014) the total cost of a geared traction passenger elevator with 3500 lbs capacity is $141,550, including equipment, installation, overhead, and profit. A hydraulic passenger elevator with a speed of 150 fpm, 4 stops, and a 3500 lb capacity car would have a total cost of $88,925 including equipment, installation, overhead and profit.

Cost Effectiveness:

Simple payback, new construction (years): 46.8

Simple payback, retrofit (years): 121.2

What's this?

Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.

Reference and Citations:

Anibal de Almeida, 05/14/2010. Energy Efficient Elevators and Escalators
University of Coimbra (Portugal)

ENEA, 01/01/2010. Options to Improve Lift Energy Efficiency
Italian National Agency for New Technologies

Harvey Sachs, 05/04/2005. Opportunities for Elevator Energy Efficiency Improvements
American Council for an Energy-Efficient Economy

Jonathan Bullick, 12/01/2011. Elevator Drives, Power Quality and Energy Savings
Elevator World

Karen Kroll, 09/01/2013. How to Know When It's Time to Modernize Elevators
Building Operating Management

NEII, 04/03/2014. Elevator And Escalator Fun Fact
National Elevator Industry, Inc.

Harvey Sachs, 01/27/2015. Advancing Elevator Energy Efficiency
ACEEE

Rank & Scores

High Performance Elevators

2014 Commercial Building TAG (#9)

Technical Advisory Group: 2014 Commercial Building TAG (#9)
TAG Ranking: 18 out of 44 Technologies (2014 Commercial TAG strategies ranked separately)
Average TAG Rating: 2.71 out of 5
TAG Ranking Date: 03/17/2014
TAG Rating Commentary:

Unless this is combined with integrated PV I think there are better solutions.
Technology is commercially available but with very low penetration.
How new are these technologies?
Also offer several non-energy benefits such as increases comfort, less waiting and travel time.

Technical Score Details

TAG Technical Score: 3.5 out of 5

How significant and reliable are the energy savings?
Energy Savings Score: 3.4 Comments:

I would definitely suggest exploring the addition of regenerating elevators to further improve the performance.
Elevators are a small part of overall building consumption so the targeted savings will be a small portion of the building total. When comparing hydraulic and traction elevators, the percent savings (savings divided by baseline elevator consumption) is high, but that is only a fair comparison for short buildings; in tall buildings traction elevators are the norm except in very old or low-income buildings. There is good savings available for going from the old motor generator sets to the solid state traction motors with variable speed control, so these baseline conditions--increasingly rare--should be replaced.

How great are the non-energy advantages for adopting this technology?
Non-Energy Benefits Score: 3.2
Comments:

Speed is the main benefit of going from hydraulic to traction (huge difference in speed), and for going from the old motor generator sets to solid state (modest difference). Dispatch control--when it is working properly--seems to reduce the time required for an elevator to arrive. It can be alienating for new users unless the user interface is friendly and transparent.
It always helps when you can market the energy efficient technology as a better product, rather than just one that happens to save energy while suffering from other drawbacks.

How ready are product and provider to scale up for widespread use in the Pacific Northwest?
Technology Readiness Score: 3.8
Comments:

All of the technologies you have listed appear to be ready for widespread use. Regenerative braking is a relatively recent introduction, but is routinely considered in new construction. Dispatch control is not uncommon in Seattle.

How easy is it to change to the proposed technology?
Ease of Adoption Score: 4.3
Comments:

If there is more than one elevator serving the building, it's a fairly easy change to make.
"Difficult / expensive for renovationeasy for new construction"
As noted above, dispatch control requires user-friendly user interface.
"New Construction projects tend to take advantage of several of the key EE measures as presented by Sameer. And the comment during the webinar regarding code requirement vs what a utility program can incentive on are very real challenges. The adoption rate in existing buildings is low (and likely to remain) low due to a few key barriers: 1) The life cycle of an elevator is very long, so unless there is a major renovation effort being undertaken for an old building the business case to upgrade just the elevator is a loosing proposition. 2) There is a key issue of elevators being managed and serviced under long term contracts, the process of influencing and financing an elevator upgrade is not a simple endeavour"
Sounded like the effort involved in retrofitting is not trivial, but it makes more sense in new construction

Considering all costs and all benefits, how good a purchase is this technology for the owner?
Value Score: 2.8
Comments:

"Excellent for new constructiondepends for renovation (poor to good)"
In an existing building, elevator upgrades (depending on the baseline equipment) can have a very long payback. For this reason, it is my impression that the upgrades are typically pursued largely for other reasons...probably speed, but advanced elements could be considered as an incremental improvement. In new construction, regenerative braking and dispatch controls can and should be considered, and in short buildings, where hydraulics are still sometimes used, the customer should consider using a high-efficiency traction elevator instead of hydraulic to obtain speed and efficiency.
Reduced maintenance costs being a bigger driver than energy

Completed:
5/2/2014 8:47:35 AM
Last Edited:
5/2/2014 8:47:35 AM