Elevator - Organisational Measures

The building manager has several potential actions: improving the motorization system, using a variable speed regulation or modifying the lift driving mode:

1. The electronic variable speed regulation on AC motors    

They are the most efficient (30% savings) and allow to decrease the power subscription due to lower starting power peaks (- 30%).

The higher the building, the more competitive the variable speed regulation is.
The other advantages of this technology are:
- lower maintenance costs (no brakes)
- higher comfort (slower start and stop)

2. The different lift driving modes    

The starting of the lifts are the main source of their consumption due to the high peak power (3 to 4 times the nominal power).

The driving management is a way to improve the global energy consumption of the lifts.

The locking driving mode:

No regulation at all, the lift goes directly from the first called floor to the final destination of the first calling people, without any stop. This mode has a very bad energy efficiency and is only used with the one gear lifts models.

The collective driving mode:

- one way with a stop at every called floor
- the way back is made without any stop

The selective driving mode:

The lift stops at every called floor, going up and down.

When there are several lifts operating together, it is possible to use a supervision system to improve the combination of the driving modes.

Elevator- Procurement

The main criteria to define the kind of needed lift are:

- the speed (which is a parameter of the waiting time and of the flow of people during peak hours)
- the distance (height of the building)
- the nominal load
- the available room to install the lift

The research of good energy performances goes through the following points:
- Do not oversize the lift capacity which involves higher consumption during off-peak hours and when the lift is empty.
- Look carefully to the motorization and balancing systems.
- If there are several lifts working together, the best solution concerning the choice of the lifts automatic regulation has to be studied.

1. Lift capacity

To avoid lift over-sizing, an in-depth analysis of the needs (number of people on each floor, kind of activity) has to be carried out. In the case of a multi-lift building, equivalent solutions are coming from the peak hour flow calculation. Generally speaking, it is better to choose the lowest lift capacity option (with a higher number of lifts in that case). 

2. Motorization systems    

The hydraulic motorizations are not usual, the main advantage of this technology is its low size when not much room is available, but the specific energy consumption is very high and the height is limited to 15 m.

The electric motorization (AC or DC), defined by the couple capacity/speed

 a) Grip cable drives with AC asynchronous motors (1 or 2 gears) are used in small buildings because of their low speed (1,6 m/s). The stop precision is also not very good and the maximum load not very high. These basic models are well adapted in small buildings with low traffic.

 b) The electronic variable speed regulation on AC motors. They are the most efficient (30% savings) and allow to decrease the power subscription due to lower starting power peaks (- 30%). The higher the building, the more competitive the variable speed regulation is. The other advantages of this technology are:
- lower maintenance costs (no brakes)
- higher comfort (slower start and stop)

If the building is well designed, it should be possible to use the stairs instead of the lift, specially for small distance.