Topic Discussion: Elevator innovation trends

Current trends in elevator/lift innovations

In this quarterly report we discuss the major innovations taking place in the elevator (or lift) space. Most commercial buildings have at least one elevator so innovation in this area is paramount to making buildings smarter, more efficient, and less expensive. Furthermore, as taller and taller buildings are designed and built, the importance of elevator systems only increases. In a high rise office, the elevator system must not only provide fast service so employees can efficiently get to and from their workspace, but also must not take up too much of the leasable space in the building or consume too much electricity. Every square meter of space taken up by the elevator is space that otherwise could have been rented to a tenant. Thus, reducing elevator system size is important for real estate owners. To address these needs, the major elevator manufacturers have begun to rethink traditional elevator systems and are now pushing the envelope with new designs and technologies.

The major innovations seen in the market today can be grouped into four primary categories. The first involves modifications to traditional elevator systems that increase the speed of the lifts. Another type of innovation focuses on increasing the maximum height of elevator shafts. Third, some innovations focus on utilizing multiple elevator cabs within the same shaft to increase passenger throughput. Lastly, companies are pushing to improve elevator scheduling systems and to implement advanced algorithms that reduce passenger wait times. The hope is that these innovations will reduce wait and travel times for tenants and reduce the number of elevator shafts needed to service a given building. Many of these innovations also help decrease the electricity usage of elevator systems.

Increasing elevator speed

One of the innovations that has taken place in the elevator industry over the past 5 years is that firms have begun to increase the speed of elevators. Japanese manufacturers Toshiba, Mitsubishi, and Hitachi have installed several high speed elevator systems in high rise buildings. The goal of these ultrafast systems is to reduce transit times to high floors and also to attract tourists to the building.

Ultrafast elevators can travel at up to 20 meters per second, which is twice as fast as the elevator systems installed in the One World Trade Center in New York and in the Burj Khalifa in Dubai.[1] Ultrafast systems have already been installed in the CTF Finance Centre in Guangzhou and in the Shanghai Tower in Shanghai. To reach these high speeds, manufacturers not only improved the electric motors used to lift the elevators, but also modified many other system components to ensure rides are safe and comfortable. As an example, Hitachi implemented new innovations in nearly every part of the ultrafast elevator system in the CTF Finance Centre building. They developed a new slim drive permanent magnet electric motor, improved the strength of the steel elevator lift rope by 30% to reduce weight, designed a new system to suppress vibrations in the elevator cab, altered the design of the cab to improve aerodynamics and reduce noise, and developed a new air pressure control system to prevent passenger ear discomfort.[2]

Figure 1. Elevator speed in a variety of famous high rise building around the world. [1]

Figure 1. Elevator speed in a variety of famous high rise building around the world.[1]

The stated advantage of a fast elevator is that it can reduce wait times and transit times for tenants in high rise offices. As a result it becomes less of a hassle to reach an office on a high floor. Ultrafast elevators can also be useful in emergency situations where tenants on high floors need an express route to the ground level. Some within the elevator industry are skeptical that ultrafast speeds are truly advantageous in the long run, and believe these elevator systems may be more useful for marketing purposes and tourism.[3] It is possible, however, that the technology advances needed to implement an ultrafast system will eventually trickle down and be implemented into more mainstream elevator systems and provide more comfortable, quiet, and efficient elevator rides. Whether or not this is the case remains to be seen. It should be noted, however, that elevator speeds are not expected to increase much further. At some point increasing speed has diminishing returns because the elevator can only accelerate and decelerate so quickly or it will be unsafe and uncomfortable for passenger. In fact, elevator descent speeds are typically limited to 10 meters per second because descending any faster can make passengers feel like they are falling.[3]

Taller elevator shafts

A major limitation of traditional elevator technologies is that their height is limited to roughly 500 meters. Above this height, the steel rope that raises and lowers the elevator cab risks snapping under its own weight.[4] To get around this fundamental limit in steel strength, architects have incorporated “sky lobbies” in high rise buildings taller than several hundred meters. At the sky lobby, passengers transfer from one elevator system that services the lower section of a building to a second elevator system that services the upper portion of a building. While sky lobbies technically allow tenants to reach the highest floors in a high rise, this solution is by no means elegant. Incorporating a whole second elevator system into the building and dedicating space for a sky lobby takes up valuable space that otherwise could be leased to tenants. Furthermore, maintaining two elevator drivetrains and control systems can be costly over time. However, a benefit of the sky lobby technique is that such an elevator system may be able to provide lower wait times because the elevator cab in the lower shaft does not need to repeatedly travel all the way to the top of building. In the end, an ideal elevator system in a high rise may be composed both innovative express elevators capable of traveling from the ground floor to the top floor of a high rise and more traditional elevators that provide passenger service the bulk of the lower floors that receive the most traffic.

Figure 2. A section of Kone UltraRope sitting next to traditional steel cables.

Figure 2. A section of Kone UltraRope sitting next to traditional steel cables.

To make the idea of express elevators over 500 meters tall a reality, Kone and thyssenkrupp have developed two very different technologies. Kone, a Finnish firm, has developed a new type of elevator lift rope that will replace traditional steel ropes. The Kone UltraRope is a carbon fiber composite-based elevator rope that has a significantly higher strength to weight ratio when compared to steel. Using the UltraRope, architects can safely design elevator shafts that reach up to 1,000 meters tall.

The lower weight of the UltraRope (compared to steel) also means that elevator systems using UltraRope have lower energy consumption. By not carrying an exceedingly heavy steel cable up and down, the UltraRope system reduces the load on every elevator ride.  Furthermore, the strong composite UltraRope requires no lubrication over its lifetime, has twice the operating lifetime when compared to a steel rope, does not stretch over time (steel ropes must be replaced or shortened over time), and reduces elevator sway during strong winds.[5] Thus, in buildings up to 1,000 meters tall the use of the UltraRope may play an effective role as part of a high throughput elevator system. The Kone Ultrarope technologies will be utilized in a 660 meter tall elevator shaft in the Jeddah Tower, which is under construction in Saudi Arabia.

Figure 3. A MULTI elevator cab on a test track at thyssenkrupp’s testing facility.

Figure 3. A MULTI elevator cab on a test track at thyssenkrupp’s testing facility.

thyssenkrupp has developed an entirely different solution to the elevator shaft height problem. The MULTI elevator system from thyssenkrupp will completely eliminate the need for elevator lift cables. This system places a guide track within the elevator shaft and uses linear magnetic motors connected to the elevator cab to propel the cab up and down the shaft.[6] Such a system is analogous to a Maglev train, except the elevator track is perpendicular to the ground instead of parallel to the ground (as with a train). The primary advantage of such a system is that there is effectively no height limit since the system does not use a rope. The motors used to propel the cab are attached to and travel along with the elevator cab. The MULTI system is also very exciting for architects because it opens up the possibility of horizontal elevator travel in addition to vertical travel. With the proper guide track design, a MULTI elevator could have an elevator cab first travel upwards many floors and then travel horizontally some distance (either to reach a different area of the building or to temporarily move so another elevator cab can pass). This freedom of design will allow architects to explore new building shapes and designs. The MULTI system from thyssenkrupp has been in development for several years and the first commercial installation is expected to be in OVG Real Estate’s East Side Tower Berlin in 2020.

Figure 4. Example of the split lobby used for a double-deck elevator system.

Figure 4. Example of the split lobby used for a double-deck elevator system.

Multiple cabs within the same elevator shaft

One way to reduce the overall footprint of the elevator system in a building is to increase the passenger throughput of the system so that fewer elevator shafts are needed to service the entire building. To increase the throughput of a given elevator system, manufacturers have developed ways to place multiple cabs within a single elevator shaft. The first instances of such systems are known as double-deck elevators, which have two elevator cabs stacked on top of each other. These two cabs are connected together and move in concert. A double deck elevator is able to increase passenger throughput because it can serve two floors at the same time. Often one cab will serve the odd numbered floors in the building and the other cab serves the even numbered floors. When passengers arrive at the building they enter their destination floor and are directed to either board the elevator on the lobby floor or to go up a flight of stairs and board the top elevator cab. Double-deck elevators have been in service in a variety of buildings for years and manufacturers like Otis and Schindler (among others) supply these systems. While double-deck systems do indeed increase passenger throughput, they have limitations. Because the elevator cars are physically connected, both cars must stop each time a passenger requests to stop at a floor. This means that while twice as many passengers can board the elevator at once, each elevator ride will take longer and wait times may be increased. Furthermore, the need to have both a main lobby and upper lobby (to board the upper elevator) may lead to suboptimal building designs, which reduce the amount leasable space in the building.

Figure 5. Example of a thyssenkrupp TWIN elevator system

Figure 5. Example of a thyssenkrupp TWIN elevator system

To get around these limitations, thyssenkrupp has designed the TWIN elevator system. The TWIN system places two independently controlled cabs within the same elevator shaft. Each cab has its own lift rope and motor and thus the cabs can independently move (e.g. the top cab can be moving up while the bottom cab moves down). The only constraints are that the different elevator cabs cannot pass each other within the shaft. Thus, if the top cab needs to travel down to the lobby, the lower cab must be lowered one floor below the lobby. Alternatively, the lower cab would only be able to reach the top floor of the building if the upper cab was raised above the top floor (alternatively, top floor access could be restricted to the upper elevator cab only). To make the TWIN system work, thyssenkrupp had to develop an innovative control system that prevents the two elevator cabs from running into each other. Furthermore, they had to develop the technology needed to fit and operate two separate lift systems within the same shaft. The TWIN system is quite innovative and provides a higher passenger throughput when compared with more traditional double-deck elevators. Another advantage is that the TWIN system can put one elevator to sleep to save power when elevator demand is low. In a double-deck system, this is not possible because both cabs are needed to access odd and even floors.

Figure 6. Proof of concept drawing of a MULTI elevator system.

Figure 6. Proof of concept drawing of a MULTI elevator system.

As discussed previously, thyssenkrupp also is developing the MULTI elevator system. Because MULTI elevator cabs are propelled by motors on the cab rather than by lift ropes, you can operate many MULTI cabs within the same elevator shaft. It is even possible to connect different elevator shafts using horizontal elevator tracks. This type of elevator system has the potential to be incredibly high throughput. Additionally, the MULTI elevator cabs can be dispatched on an as needed basis. At times of low demand, only one or two cabs may be needed. The other cabs can be put to sleep to save energy.

 

Figure 7. Example of a modern elevator control from thyssenkrupp.

Figure 7. Example of a modern elevator control from thyssenkrupp.

New control systems and algorithms

Nearly every elevator manufacturer is developing new innovative control systems. Going forward, elevators will be much less likely to have simple up/down buttons and will increasingly ask passengers to input their destination floor before setting foot inside the elevator. By collecting data on which floors passengers are travelling to, the elevator system can more intelligently select which elevators should pick up which passenger in order to minimize wait and transit times.

A modern control system is especially useful in buildings which have several elevators in their lobby. Such a control system can direct passengers traveling to different floors into different elevators. Batching passengers into different elevators reduces the number of stops each elevator must take and reduces transit times. These control systems also collect data on where passengers travel during different times of the day. Using this data, more efficient elevator schedules can be developed to reduce wait times at peak travel hours.

Much of innovation in these control systems resides within the software and algorithms used to dispatch the different elevators. By utilizing more sophisticated algorithms, manufacturers can improve the overall experience for tenants in buildings. Innovative control systems will increasingly become more important as more sophisticated elevator systems like MULTI are implemented. Elevator systems with multiple cabs and routes will have many more degrees of freedom in how they are operated and thus optimizing the elevator schedule and maintaining safety will be paramount.

Conclusion

We see a wide variety of innovations making their way to the market in the elevator/lift space. The vast majority of these innovations are being led by the major players in the elevator space (Kone, Otis, thyssenkrupp, Hitachi, Mitsubishi, etc.). We believe this is due to the high price of prototyping and testing new elevator technologies. However, these industrial players appear to be competing with each other in a very competitive market. As a result, several innovative systems are coming to market and will help reduce wait and transit times for building tenants. Saving as little as 1-3 minutes of time per day per passenger in a building can yield very large productivity gains for an organization as a whole. Furthermore, increasing the throughput of elevator systems and reducing elevator system size, allows tenants to densify rented space and building owners to increase leasable space and increase the yield from their real estate investment.

Going forward, we see major potential in rope-less elevator systems (e.g. MULTI from thyssenkrupp). By eliminating the lift rope and moving to elevator cabs with linear motors, architects will be able to rethink how elevators fit into modern building designs. Assuming the first installations of these rope-less elevators are successful, we believe several companies will compete to build even more innovative rope-less systems. The hope is that new high passenger throughput elevator systems that take up very little physical space will be incorporated into future buildings. If this vision comes to fruition, both tenants and building owners will benefit because wait and transit times will decrease and rental yields will increase.


References:

[1] https://ig.ft.com/worlds-fastest-lifts/

[2] https://www.hitachi.com/rev/archive/2017/r2017_03/06/index.html

[3]https://www.washingtonpost.com/world/asia_pacific/the-surprisingly-cutthroat-race-to-build-the-worlds-fastest-elevator/2017/01/03/8f6a83ae-8910-4786-b1da-dd049b702f20_story.html?utm_term=.65a46a459caa

[4] https://www.economist.com/science-and-technology/2013/06/15/the-other-mile-high-club

[5] https://www.kone-major-projects.com/Images/7655_KONE_high-rise_solutions_tcm118-50235.pdf

[6] https://multi.thyssenkrupp-elevator.com/