Our cities are getting taller. Today there are more than 250 million elevators in use worldwide. So what are some of the vertical transportation trends and technologies helping designers reach new heights?
A potential game-change is ThyssenKrupp’s cable-free elevator system. The MULTI technology places linear motors in elevator cabins, allowing multiple cars and horizontal movement in a single shaft transforming how people can move inside a building.
“After 160 years, we are moving away from the cable-dependent elevator. Buildings can now evolve, reach new heights, shapes and purposes,” said Patrick Bass, CEO of ThyssenKrupp North America, Inc. “As the world’s population continues to migrate into urban areas, efficient mobility in buildings is no longer a luxury, but an absolute necessity.”
By mid of 2015 the firm plans to have a scaled 1:3 model in their R&D center in Gijon, Spain and by the end of 2016 a running prototype will be installed in a new test tower in Rottweil, Germany.
The advancements afforded by MULTI stand to impact a new era for cities by decreasing elevator wait times for inhabitants to 15 -30 seconds, adding rentable space by decreasing the elevator footprint by up to 50%, and conserving energy use within buildings.
Energy conservation, of course, is no longer an added value it is a prerequisite. Buildings are responsible for 40% of the world’s energy consumption. Elevators and escalators make up 2 to 5 percent of the energy used in most buildings, but can reach as high as 50 percent during peak operational times
On average, new elevator technologies such as the ThyssenKrupp TWIN elevators can save up to 27% of energy when compared with other technologies, and reduce the electrical power required by half. This leads to lighter and simpler power supply systems required for buildings and, according to the energy efficiency guidelines for elevators established by the Association of German Engineers in 2009 (VDI 4707), the most efficient elevator technology configurations can save up to 70% on energy consumption of a building.
In addition, elevators can also operate as power generators. Regenerative drives, which use energy created when the cabins slow down (converted into electricity and fed back into to the building’s power grid), reduce energy needs for the building by approximately 30%.
Taking into consideration the higher initial costs of constructing a green building, the impact that new elevator technologies can have on the overall operating costs of existing buildings is significant. This is especially true for older buildings, where maintenance costs escalate as structures get older. These regenerative technologies can be introduced in almost any existing elevator providing immediate benefits.
Although more energy-efficient elevators can significantly reduce the costs of operating a building, the information needed to help building owners identify the appropriate elevator system — and the savings associated with it — aren't readily available, according to a new study published by the American Council for an Energy-Efficient Economy (ACEEE)
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 says the report.
"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.
The study lays out a framework for industry leaders to set common standards for measuring elevator efficiency, which could potentially lead to a rating system, along the lines of those already in place for heating, ventilating and air-conditioning systems, and many home appliances.
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.
Speed & Comfort
As buildings become taller, there is also growing demand for elevators that travel faster. Mitsubishi Electric, for example, has developed an ultra-high-speed elevator capable of travelling 1,080m/min, a considerable step-up from their traditional 750m/min. With increased speed comes increased challenges.
“The development of faster elevators means we have had to contend with issues not previously faced before by lift designers, particularly when it comes to comfort levels,” said Masaji Iida and Yoichi Sakuma from Mitsubishi Electric.
Vibration, noise and compression are three critical issues they explain:
“To suppress vibration inside the car, we have developed an active roller guide which uses acceleration sensors installed on both the car and car frame to enable the same degree of riding comfort as by conventional active control.”
“To reduce noise inside the car, the shape of the air rectification cover has been optimized and noise reduction measures in the vicinity of the car and noise-proofing of the car itself carried out to attain acceptable noise value levels for speeds of 1,080m/min.”
“For a building that is 500m tall, the difference in compression levels between the top and bottom floors is about 6,000 Pa. To mitigate the sensation of compression in the ears experienced by passengers, air pressure change lines and an atmospheric pressure control unit have been developed and commercialized.”
An additional challenge, which from a solution perspective is still evolving, comes with size. A motor driving a typical 500-foot-a-minute elevator can fit in about 27 cubic feet. On the other hand, a high-speed motor like those in a super tower takes up about half a room
Indeed, reducing the space needed for services is a real challenge for mechanical engineers; less service space means more lettable space.
Machine Room-Less (MRL) solutions are helping to return leasable space to the project owners by eliminating planned overhead machine rooms that were typically required with conventional traction elevator models.
KONE was the first to deliver an MRL elevator solution in the early 1990s. Fast forward today and their new EcoDisc technology eliminates the need for a machine room by utilizing the guide rail to support the hoisting machine, and placing all control and logic systems in an integral control space. It also uses less power which helps save on general construction.
Elsewhere, the development of the machine room-less hydraulic elevator additionally allows for petroleum-free operation, without the weight and capacity restrictions associated with traction machine room-less products. All the components to run the elevator are housed within the elevator hoistway space.
Then, as referenced above, there is the MULTI technology which expands upon ThyssenKrupp’s TWIN elevator system, which was the first system to offer two cabins per shaft to increase transport capacity and reduce the elevator footprint in buildings.
Innovative vertical transportation technologies are transforming the city of tomorrow. They are increasing transport capacities and efficiency while reducing the elevator footprint and peak loads from the power supply in buildings. They are transforming how people are able to move and enabling buildings to adopt potentially limitless heights, shapes and purposes.