A study for improving the energy efficiency of lifts with adjustable counterweighting

Abstract

This article presents a study of the potential energy efficiency improvement by means of adjusting the lift counterweight. The lift energy consumption in different counterweight setups is studied by employing measured lift traffic and energy consumption data from an office building in Finland. Overall, dimensioning the counterweight based on traffic analysis is one of the fastest and most cost-effective means of improving the energy efficiency of lifts. The results from the building imply, however, that with a relatively constant loading throughout the day, the continuous adjusting of the counterweight provides limited energy savings compared to systems where the counterweight is sized according to the average load. Nevertheless, active adjustment of the counterweight size may provide considerable savings in lift systems if there is a wide variation in the car loading between the hours of the day. Furthermore, reducing the counterweight potentially improves the ISO 25745-2 energy efficiency classification of the lift, thus increasing the product attractiveness in the market. Practical Application This article presents practical approaches to analysing the energy consumption of counterbalanced lifts. The modelled results can be used to optimise the mass of the counterweight in order to achieve considerable energy savings in the actual or expected traffic profile.

High-resolution modeling of elevator power consumption

“…In these types of elevators, the energy recovered during a start is fed back to the electric grid of the building. As a rule of thumb, it can be presumed that 70 -75% of energy required to lift the same load can be recovered as electricity [11,18]. This means that the hoisting efficiency is around 85 percent in modern installations.…”

“…Secondary targets for the model to fulfill are the duration of the start and the resulting instantaneous power profile within the start. For this test, we utilized previous measurements [11] as the reference, and employed the known values for car mass, system efficiency, and counterbalance ratio as well as an estimate for door motor power. Fig.…”

“…Recently, the adaptation of energy efficiency classification in elevators has followed the trend of classifying household appliances according to their energy performance. The two most known approaches are the VDI 4707-1 guideline [7] and the ISO 25745-2 standard [8] , which are discussed, e.g., in [9,10,11].…”

Evaluating the Applicability of Elevators in Frequency Containment Reserves

“…In addition, the hoisting efficiency was set at 0.77. The selected values are assumed to correspond to typical values in the installed stock of elevators, while modern installations typically have less standby demand and higher efficiency [11], [12], [13].…”

Vertical Transportation System Power Usage: Behavioural Case Study of Regulated Buildings in Bangkok

“…The standby energy can be reduced by 80% if drive technology is implemented [26]. Building energy saving through elevators by adaptive counterweight sizing has been proposed, involving the measurement of daily elevator traffic and load behaviour, through which significant savings can be achieved [27]. Due to the problems of the traction wheel and the wire rope slippage causing excessive wear and tear, the image processing technique has been adapted to detect wire rope slippage, which can enhance safety usage and reduce energy consumption [28].…”