ISO 25745 aims to define the energy performance of lifts, escalators and moving walks through three separate documents: - Part 1 (2012): Energy measurement and verification. - Part 2 (2015): Energy calculation and classification for lifts (elevators). - Part 3 (2015): Energy calculation and classification of escalators and moving walks (which we do not cover in this article). PART 1 The aim of the first document is to indicate methods for measuring the actual energy consumption and for carrying out periodic checks to verify the energy consumption of lifts, escalators, and moving walks in operation in a reference travel. Since installations with a speed of less than 0.15 m/s are explicitly excluded from the scope of Part 2, it can be deduced that EN ISO 25745-1 is not applicable to lift platforms. Since the term “lifts” is used, lifts for persons and goods are also to be understood as included. Before ISO 25745-1, the energy consumption of lifts, staircases, and escalators could be measured using VDI 4707-1. According to Koos van Lindenberg (author of the article ‘ISO 25745 Bypasses VDI 4707 as a Standard for EPC Measurements’ that appeared in Elevator World on 1 April 2017), the first part of ISO 25745 was not used for some time, at least until the advent of parts 2 and 3. In Part 1, the standard-setter states that the energy consumed by an electric counterbalanced lift in a complete cycle should be measured, with an empty car running to the bottom landing, a condition that results in the maximum demand of the system; and an empty car running to the top landing, which represents the minimum. For the unbalanced hydraulic lift, on the other hand, only the minimum demand condition needs to be measured. In both cases, this measurement must be carried out for a minimum of 10 travels, and the average value obtained must be taken into account. Then there is the stationary or standby phase. Even during “non-operation”, the lift or escalator absorbs a certain amount of energy. In this case, it is necessary to measure the power consumed in W, for one minute, immediately after the end of the cycle, i.e. after the doors have been closed; at this point, it is necessary to wait 5 minutes (the conventional duration chosen to define the standby state) in order to be able to measure the required power for another minute. The standardiser has therefore assumed that the control system can decide that some equipment can be switched off or paused immediately after the end of the cycle, and others after a time ranging from 1 to 5 minutes at the end of the cycle. Finally, the last chapter is dedicated to the documentation that must be issued at the end of the test. An appendix shows how to interface the instrumentation to the system, so that measurements can be performed correctly and comparably. PART 2 Considering the data obtained by using the first part of the standard as a reference cycle, the second part uses it to make a hypothetical calculation of the lift consumption for a given period of time. With regard to the energy consumed in motion, assumptions must inevitably be made about the intensity and pattern of traffic in the building in which the lift is installed. This is considered by dividing the actual situations into six categories of use, depending on the number of daily trips that are assumed to occur in the building on average. The lifts are then subdivided according to their capacity and to the number of stops they must serve. Using two simple tables for this purpose, the three data relating to use categories, stops and capacity ranges are combined to derive hypothetical average load percentages in relation to maximum load, and average lengths of distances travelled as a percentage of maximum load. From a physical point of view, the energy consumed is related to load and distance, so an estimate is made of the energy consumed in an average cycle from the average load. By multiplying this by the assumed number of daily runs, the energy consumed in motion in a day is obtained. The standard then gives the method for estimating the non-operation time, and the compiler, having indicated the power his lift consumes in sta31 The standards for the measurement and calculation of energy consumption and energy efficiency classification of lifts The UNI EN ISO 25745-1:2013 and UNI EN ISO 25745-2:2015
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