When researching before an elevator investment, you will quickly face the choice between two drive systems: hydraulic drive and the classic cable drive. In this article, we will show you which drive system is the best choice in different situations.
The hydraulic lift
The category of hydraulic lifts includes various types, such as the plunger elevator, the scissor lift or the column lift. What all these types have in common is that the lifting force is generated electrohydraulically.
Subtypes
Of the three possible variants, we produce two types: the elevator based on a scissor lift table and the elevator based on a column lift. Both systems are enhanced with the necessary safety features.
The scissor lift
In a scissor lift, the elevator cabin is raised by a hydraulic lift table. An electric motor drives a gear pump, which transports oil into the hydraulic cylinders. By extending the cylinders, the platform is lifted. For more information on how a hydraulic lift table works, please refer to our landing page under the section: How does a hydraulic lift table work?.
The column lift
In a column lift, the cabin is not guided by a scissor mechanism, but by side-mounted guide rails. The lifting mechanism is located in the lateral guides. Oil is pumped by a gear pump into the hydraulic cylinders, which are connected to the elevator cabin either directly or via a rope drum.
Which of the two variants is used depends on the installation situation and the geometries involved. The column lift has the advantage that installation without a pit is possible. However, it requires more space next to the platform.
Placement of the drive unit
The drive unit of a hydraulic lift can be placed flexibly. Since the unit is connected to the hydraulic cylinders via hoses and pipes, there are many possible installation locations: It can be integrated directly within the lift table or the shaft or placed in an unused space, such as under a staircase. Installation in a separate machine room is also possible but not strictly necessary.
Maintenance effort
A hydraulic lift requires relatively few components. The installed parts consist of electrical sensors with high switching cycles, purely mechanical steel assemblies or durable hydraulic elements. Apart from regular safety inspections, maintenance is mostly limited to visual checks of the lift columns and guides, as well as the replacement of hydraulic oil. Therefore, the maintenance costs of a hydraulic lift are relatively low.
Energy consumption
When considering only the lifting process, the hydraulic lift is less energy-efficient. The cable-driven elevator, especially a traction elevator, consumes significantly less energy during the lifting process.
However, the hydraulic lift shows its advantage during descent: Lowering occurs through its own weight, and simply opening the safety valves is enough to initiate the downward movement. This significantly improves the energy balance of the hydraulic lift over the entire movement cycle.
Nevertheless, the cable-driven elevator has a lower overall energy consumption during regular operation. Only when looking at the entire lifespan does it become clear that the hydraulic lift, especially in usage categories 1 and 2 (up to 150 lift cycles), is often the more economical choice (see the article The Comeback of the hydraulic lift in the LIFTjournal).
High lifting heights
For very large lifting heights, the hydraulic lift becomes increasingly uneconomical. As the lifting height increases, the risk of buckling for the hydraulic cylinders also increases, requiring larger piston diameters (see our article: How to choose a hydraulic cylinder).
Main application area
Hydraulically operated lifts are primarily used as simplified goods lifts for transporting goods or as special lifts with custom dimensions.
The cable-driven elevator
The cable-driven elevator is the standard for passenger elevators and is commonly used in high-rise buildings. There are two categories: drum elevators and traction elevators.
Subtypes
Drum elevator
In drum elevators, the drum is directly driven by an electric motor. Depending on the motor’s direction, the hoisting cable of the elevator is wound or unwound, raising or lowering the cabin. Since this design requires the electric motor to provide all the energy for both lifting and lowering the cabin, it is now mostly found in rare special cases and older systems.
Traction elevator
Traction elevators are more common. In this type of drive, the cabin is connected to a counterweight via pulleys, which is balanced to match the average load (e.g. the cabin weight plus two people). This way, the electric motor only needs to supply energy for the weight difference, significantly reducing energy consumption.
Placement of the drive unit
The drive unit of cable-driven elevators is usually located above the elevator shaft. Therefore, a sufficiently tall overhead clearance is necessary to accommodate the equipment.
Alternatively, all the equipment can be housed in a separate machine room. The space requirement for the technical equipment is generally larger than for hydraulic lifts, so additional room needs to be considered during the planning process.
Energy consumption
Although cable-driven elevators consume energy for both lifting and lowering, their energy usage during operation is lower than that of a hydraulic lift. In some cases, potential energy can be recovered through frequency converters. However, since feeding this energy back into the public grid can involve certain challenges, energy recovery is usually only worthwhile when multiple elevator systems are operated simultaneously. In such cases, the recovered energy from one elevator can be used to power another. Alternatively, the energy can be stored and used later for operation. It should be assessed whether the cost of a storage system makes this option viable.
When considering the entire manufacturing process, the hydraulic lift often has a better overall balance: The energy required during production is significantly lower, meaning the lower energy consumption of cable-driven elevators during operation only becomes significant after more than 16 years of use, depending on usage intensity (Source: The comeback of the hydraulic lift, LIFTjournal). Therefore, investing in a hydraulic lift can be particularly worthwhile for lifts in usage categories 1 or 2, where fewer than 150 cycles per day are performed.
High lifting heights
For large lifting heights, the cable-driven elevator shows its full strength. Since there are no cylinders subjected to buckling, but only cables under tensile stress, high lifting heights can be achieved much more economically than with a hydraulic lift. For this reason, cable-driven elevators are almost exclusively used in very tall buildings. The limit for these elevators is only reached when the hoisting cable becomes so long that it can barely support its own weight.
Main application area
Cable-driven elevators are primarily used as passenger elevators, as well as in systems with very high lifting heights or heavy traffic. Without this type of elevator, modern skylines as we know them today would not be possible.
Direct comparison of the elevator systems
Below you will find a brief overview of which elevator is best suited for different situations. Of course, in individual cases, personalized consultation may lead to a different result.
| Feature | Hydraulic lift | Cable-driven elevator |
|---|---|---|
| High lifting height | X | |
| Low number of lift cycles (< 150 cycles/day) | X | |
| Special installation situation | X | |
| Standard shaft dimensions | X |
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