Regenerative Drive: Save Money & Energy

Regenerative Drive

Elevator regenerative drives are gaining popularity due to their numerous advantages. Utilizing the kinetic energy harnessed during the elevator’s downward movement, these mechanisms aid in raising the building to greater heights, thereby preserving energy, reducing operational costs, and enhancing efficiency levels.

Elevator regenerative drives are mechanisms enabling elevators to generate power while traversing the shaft. This generated power can be utilized to assist in operating the elevator or other building devices. The increasing adoption of regenerative drives is attributed to their potential to curtail energy expenses.

Regenerative drives save money and energy, but compared to basic dynamic braking systems, their capital cost is comparatively high. Consequently, when there is a significant quantity of energy to be recovered or when the cost of the recovered energy is high, the case for regeneration is most convincing financially.

What do regenerative drives do?

When a traction elevator lifts a fully-loaded car, electrical power is supplied from the building utility to the elevator system. However, during descent, the same fully-loaded car regenerates energy. Essentially, the stored energy in the mechanical system is converted back into electrical energy.

Regenerative drives are capable of controlling the speed and direction of rotation of an AC or DC dynamometer, as well as the torque direction of the dynamometer. The term “regenerative” describes the drive’s ability, particularly under braking conditions, to convert the mechanical energy of the motor and the connected load into electrical energy, which is then returned (or regenerated) to the AC power source. This process effectively returns energy and helps reduce operating costs, especially in elevator systems.

How Regenerative Drives Work

Energy Conversion

Regenerative drives convert kinetic energy into electrical energy during the elevator’s operation. When the elevator descends, the motor acts as a generator, producing electricity. This electricity can then be reused, reducing the overall energy consumption.

Energy Storage

The generated energy is stored within the building’s electrical system. It can power other devices or even the elevator itself when it ascends. This process significantly enhances energy efficiency.

Traditionally, in Variable Frequency Drive (VFD) applications, this regenerated energy was diverted across a braking resistor and dissipated as heat. This led to two main issues: Firstly, the heat represented wasted energy, potentially resulting in significant costs for building owners depending on factors like size, duty, and the number of elevators in the building. Secondly, the additional heat generated in the machine room often led to increased cooling expenses.

It revolves around the capability to reclaim energy during certain phases of operation. Basic AC drives lack this ability, as they cannot send energy back to the power source. While the AC motor and the inverter possess inherent regenerative potential, the input rectifier of the drive does not. Consequently, when mechanical energy is returned to the motor, exceeding motor loss, a brake resistor is typically required to absorb and dissipate surplus energy. Failure to do so results in a rise in DC voltage, triggering a protective trip to prevent damage.

It gets benefit from frequent starts and stops, steady deceleration, or loads that undergo overhauling. They’re ideally suited for regenerative drives. Instances include downhill conveyors, elevators, and flywheels.

Benefits of Regenerative Drives

Cost Savings

By reusing energy, regenerative drives reduce the need for external electricity. This leads to lower energy bills. Over time, the cost savings can be substantial, making the initial investment worthwhile.

Environmental Impact

Reducing energy consumption lowers the building’s carbon footprint. This is beneficial for the environment. Adopting regenerative technology contributes to sustainability goals.

Enhanced Performance

Elevators equipped with regenerative drives operate more smoothly. This improves user experience. Additionally, the drives reduce wear and tear on the elevator’s components, extending its lifespan.

Implementation of Regenerative Drives

Retrofitting Existing Elevators

Regenerative drives can be installed in existing elevators. This retrofit process is straightforward and does not require extensive modifications. It is a cost-effective way to upgrade your elevator system.

New Installations

For new buildings, integrating regenerative drives from the start is ideal. It ensures maximum efficiency and cost savings from day one. Architects and builders are increasingly considering this technology in their designs.

Considerations for Installation

Cost vs. Benefits

While the initial cost of installing a regenerative drive can be high, the long-term benefits outweigh the expense. Calculating the return on investment (ROI) can help in decision-making.

Conclusion:

Regenerative drives offer the advantage of energy conservation by recycling otherwise wasted energy, thus decreasing overall energy consumption. Additionally, it enhances elevator system efficiency by minimizing wear and tear on system components, leading to a prolonged equipment lifespan and reduced maintenance expenses. So you can install a regenerative drive after consulting with your facility manager or elevator technician.