It is hard to determine, without considerable research, who first conjured the idea of the machine-room-less elevator. It could have been an architect looking for design freedom, developers urging suppliers to reduce construction costs, or building owners trying to maximize rentable space. Anyway you look at it, the result is the same – elevators without machine rooms are now, if only on a limited scale, available to the market and are worthwhile considering for new construction and retrofits.
Some of the systems referred to here are not yet available in Canada, because the revolution in and enthusiasm for this technology first took hold in Europe and Asia. It is only now attracting significant attention in this part of the world.
The selling points for the technology are that it reduces construction costs, is very energy efficient, and is environmentally friendly. The only down side is that it has limited applications right now due to speed and height restrictions.
Changes were heralded in the elevator industry when noisy generators that often caused leveling problems and emitted carbon dust were eliminated. They were replaced by variable voltage, variable frequency (VVVF) drives. The complete drive system includes the main motor, the power supply to it, the monitor and control of speed (acceleration and deceleration) as well as the position of the elevator in the hoistway.
When the VVVF drive is used in concert with a gearless hoist machine, the result is an alternating current (AC) gearless system, the basic elements of an elevator without a machine room.
Reduced Construction Costs
Such an elevator reduces building construction costs by requiring less material and less space. For example, the Fujitec Eceed elevator uses a slightly different format. It is designed with the hoist machine in the hoistway pit and the control system adjacent to the elevator entrance on the second landing. According to the company’s marketing material, which focuses on installations in Japan, this configuration reduces elevator installation space by about 36 per cent of a conventional roped elevator, and about 31 per cent of a hydraulic elevator.
The cost benefit also extends to the construction of the elevator. Without machine rooms, cranes for hoisting heavy machinery to build those rooms are unnecessary.
Greater Energy Efficiency
Building owners should enjoy long-term savings with these installations, because they are more energy efficient. Kone Inc., the leader in the race to market the technology (with approximately 23,000 units installed worldwide) claims that its MonoSpace system, using the EcoDisc AC Gearless machine, provides “up to 60 per cent reduction in energy consumption compared to traditional traction and hydraulic elevators.”
Kone is not unique in this boast, however, because the energy savings come from the efficiency of the AC gearless drive technology, used by most companies in their products.
There is always a risk that the hydraulic elevator cylinder of a standard elevator, buried in the ground, will develop a leak and thus contaminate the soil. This has become less of a concern with the protection of polyvinyl chloride (PVC) cylinder encapsulation, or holeless installations. However, the threat still exists. With a machine-room-less elevator, this concern is eradicated.
Although it’s not a significant environmental threat, noise pollution is also reduced with a machine-room-less elevator. I have had the opportunity to view a Kone MonoSpace elevator that was installed in a residential building in North Toronto. The site visit verified that the system operates very quietly, with none of the noises caused by hydraulic pumps, generators or geared machines. In fact, even though the gearless machine was located directly inside of the hoistway at the top landing, only metres from the front door of a residential suite, no disruptive noise of any sort was witnessed.
The gearless machinery that powers this innovation has become known throughout the industry for its exceptional performance. Unfortunately, the gearless machines used in typical elevator installations are very expensive, hence are most often only used in tall commercial building applications that require high-speed elevators.
Technical innovations have now allowed manufacturers to design and manufacture gearless machines that are much smaller. Some manufacturers claim that they can reduce the size by 70 per cent and the production price substantially. These machines should also have a long performance life, as there are a reduced number of moving parts that could wear and cause operational problems.
Hoisting the Load
Otis Elevator has incorporated another new technology with their Gen2 system. For this model, Otis uses polyurethane-coated steel belts rather than traditional steel hoist ropes to support the load of the elevator cab and counterweight. Otis must be credited for their efforts to take the design of these elevators one step further. One advantage of the coated steel belts is their tremendous flexibility and enhanced traction control, which allow for a more efficient power transfer, further reducing the size of the machine required to operate the elevator.
Although this may seem far-fetched, perhaps the next step in this process will be complete freedom from hoisting ropes – a self-propelled elevator. Such a device would eliminate the restrictive nature of the ropes and remove the requirements for load bearing supports almost completely, placing all of the loads directly on the foundations of the building.
Speed and Height Restrictions
The down side to machine-room-less elevators, as mentioned before, is that they are still limited in their application due to height and speed restrictions. KONE Inc. is currently installing models in Canada with rises of up to 90 feet and speeds of 200 feet per minute. Also, because they are new they have yet to prove their longevity.
Despite the limitations, one must wonder why these are not being installed whenever viable. It would stand to reason that architects and developers would enjoy the design freedom offered by it, and the additional space gained, particularly with a substantial number of luxury condominiums are being built.
It is probably because they are only beginning to become available in North America. Some manufacturers have only just added them to their portfolio here, while some are years away from entering this market.
Given the benefits of the technology, it is certainly worth considering this type of elevator for a new facility or a full retrofit.
Michael Morgenstern is a partner at National Elevator Consulting, based in Toronto, Ontario.