Along with the VDI 4707-1 guideline, there is now ISO 25745 that describes the norms for energy measurements of lifts, escalators and moving walks. In part 2 of the ‘ISO 25745 under the microscope’ series, we shall examine: How does Liftinstituut apply this norm to energy measurements? And why does the first measurement not always produce the desired result?
As an independent party, Liftinstituut has carried out energy measurement of lifts, escalators and moving walks since 2009 and issued EPC certificates. Willem Kasteleijn, Lift Product Manager, notes that the measurement of the energy use of escalators and moving walks is becoming more common. ‘We have a lot of experience with measuring the energy use and producing energy labels, in conformance with EN-ISO 25745.’ Examples of measurements of escalators include the energy measurements of the escalators on the North-South metro line in Amsterdam.
What is measured in an energy measurement?
- Energy measurements for lifts
- For lifts, we measure the energy use after standing still for 5 minutes and then during an upwards ride, the opening and closing of doors, and a downwards ride.
- For EN-ISO 25745-2, we additionally measure the stand-by capacity after 30 minutes of a lift standing still. With these additional measurements, we gain a better insight into the effect of long-term standing still on the energy use. We give the system 30 minutes to switch into the most energy-saving stand-by status.
- The EN-ISO 25745-2 also describes a 24-hour measurement method that gives a realistic image specifically for lifts with an energy storage system (battery).
- Energy measurements for escalators and moving walks
- For existing escalators and moving walks, the measurement assumes a situation without a load: the system is then ‘empty’ and not being used. There is the condition that the system must have been working for at least half an hour (‘warmed up’) before the measurement.
- For new escalators, there is the additional minimum use duration of a thousand hours before measurement.
- We link the measurement values of escalators and moving walks to their system’s properties, like the slope angle, width of the steps and the lifting height. Then we compare these reference values to the measured use, which determines the final energy label.
Optimisation is often necessary after the first measurement
Kasteleijn: ‘In many cases the first measurement does not produce the desired result. This often has to do with the specific installation settings which are not yet optimal. Because we measure in real time, the technician can immediately optimise the settings and realise the optimal energy use and a better energy label.’