Energy Efficient Elevators | Green Building Design Strategies
In a world of climate change and limited fossil fuel resources, renewable energy sources are playing an increasingly important role. Due to industrializations and population growth our economy and technologies today largely depend upon natural resources, which are not replaceable. Approximately 90% of our energy consumption comes from fossil fuels (viz. coal, oil and natural gas). The irony is that these resources are depleting. Also, the huge consumption of fossil fuels has caused visible damage to the environment in various forms as global warming, acid rains etc.
Elevators contribute to the 4-5 % of Building energy consumption. Efficient elevators systems can be provided to conserve and produce energy for the building.
Elevators usually work using power from a power supply (powered operation); however, when they travel down with a heavy car load or up with a light car load (regenerative operation), the traction machine functions as a power generator. Although the power generated during traction machine operation is usually dissipated as heat, the Regenerative Converter transmits the power back to the distribution transformer and feeds into the electrical network in the building along with electricity from the power supply. Compared to the same type of elevator without a Regenerative Converter, this system provides an energy-saving effect of up to 35%. (Reduction in CO2 emissions: 1400 kg/year) In addition, the Regenerative Converter has the effect of decreasing harmonic currents.
Not only through regeneration operation, TWINN CABIN elevators also help to provide an efficient solution for green building design. The concept of twin cabin elevators is not new however the ideas have been greatly brought to reality by thyssenkrupp.
The TWIN elevator system has two cars, arranged on top of each other, that operate in one hoistway. Each elevator has its own traction drive, controller and safety features. They also share the same guide rails and landing doors. The cars move independently in the hoistway, with a minimum separation at all times for safety reasons. This is a big deal because elevators have a big physical footprint in a building. By putting two cars in one shaft, one can get away with few shafts, since stacking the cars increases capacity by 40 percent. It also saves a bit of energy.
Making use of the energy generated by the elevator when traveling downwards with a heavy carload or upwards with a light carload, the traction mechanism acts as a power generator and transmits power back to the electrical network in the building.
The efficiency of TWIN relies on the intelligent Destination Selection Control(DSC). DSC is like a concierge that directs passengers to the elevator that will get them to their destination fastest. It groups people traveling to the same floor together, making fewer stops and improving efficiency to keep tenants on the move.
Before passengers step on the elevator, they enter their destination floor on a Keypad in the elevator lobby. Next the DSC system groups passengers with the same destination to the same car. So interruptions from passengers who enter and exit the elevator at intermediate stops are kept to a minimum.
Elevator passengers can also benefit from pre-programming, which enables them to toSwipe an ID card or enter a numeric PIN code. Corporate branding can be added to touch screen terminals. VIP/emergency call overrides give tenants immediate access to an elevator. If you need to restrict access in your building, DSC can help with this too.
The most energy-efficient elevators now have:
- software- and microprocessor-based controls instead of electromechanical relays
- in-cab sensors and software that automatically enter an idle or sleep mode, turning off lights, ventilation, music, and video screens when unoccupied
- destination dispatch control software that batches elevator stop requests, making fewer stops and minimizing wait time, reducing the number of elevators required
- personalized elevator calls used with destination dispatch controls that eliminate the need for in-cab controls.
source : thyssenkrupp , Hitachi