Guidelines onEnergy Efficiency ofLift & EscalatorInstallations2007 ED I TI O NtheSupplementto theCodedocumentpage 1 of 27

Guidelines on Energy Efficiency of Lift & Escalator Installations, 2007PrefaceThe Code of Practice for Energy Efficiency of Lift & Escalator Installations (Lift & Escalator Code)developed by the Electrical & Mechanical Services Department (EMSD) aims to set out the minimumdesign requirements on energy efficiency of lift & escalator installations. It forms a part of a set ofcomprehensive Building Energy Codes (BEC) that addresses energy efficiency requirements in buildingservices installations. The set of comprehensive BEC covers the Lift & Escalator Code, the Codes ofPractice for Energy Efficiency of Lighting Installations, Air Conditioning Installations and ElectricalInstallations, and the Performance-based Building Energy Code.As a supplement to the Lift & Escalator Code, the EMSD has developed this handbook of Guidelineson Energy Efficiency of Lift & Escalator Installations (Guidelines). The intention of the Guidelines is toprovide guidance notes to compliance with the Lift & Escalator Code and draw attention of lift &escalator designers & operators to general recommended practices for energy efficiency andconservation on the design, operation & maintenance of lift & escalator installations. The Guidelinesseek to explain the requirements of the Lift & Escalator Code in general terms and should be read inconjunction with the Lift & Escalator Code. It is hoped that designers will not only design installationsthat would satisfy the minimum requirements stated in the Lift & Escalator Code, but also pursueabove the minimum requirements.The Guidelines were first published in 2000. With the Lift & Escalator Code upgraded to its 2005edition, an addendum for the Guidelines was issued in 2005. The Guidelines are amended in 2007 tosuit the 2007 edition of the Lift & Escalator Code.To promote the adoption of the BEC, the Hong Kong Energy Efficiency Registration Scheme forBuildings was also launched. The Registration Scheme provides the certification to a buildingcomplying with one or more of the BEC.This book of Guidelines is copyrighted and all rights (including subsequent amendments) are reserved.AcknowledgementIn the preparation of the Guidelines, reference has been made to the following publications:a) CIBSE Guide D – Transportation Systems in Buildings, CIBSEb) Barney, G.C., and Dos Santos, S.M., Elevator Traffic Analysis Design and Control, Peter Peregrinus,1995 [Relevant contents quoted are: 2.8.2 (p57, 58), 3.1 (p85), 3.3.3 (p95), Table 2.3 (p51), andExamples 2.11 & 2.12 (p65 to 67)c) Stawinoga, Roland, “Designing for Reduced Elevator Energy Cost”, ELEVATOR WORLD magazine,Jan 1994d) Al-Sharif, Lutfi, Bunching in Lifts, ELEVATOR WORLD magazine, Jan 1996e) Malinowski, John, Elevator Drive Technologies, ELEVATOR WORLD magazine, Mar 1998f) Guide Notes on Elevators (Lifts) Planning, Selection and Design, 1997, Department of Public Works& Services, Australia [Relevant contents quoted are: 7. Electrohydraulic Lifts]The Building Energy Codes, corresponding Guidelines and Registration Scheme documentsare available for download at uiry: [email protected] CK W E B - S IT E F OR L AT E S T INF OR M AT IONi

Guidelines on Energy Efficiency of Lift & Escalator Installations, 2007CONTENTS1. INTRODUCTION .12. CODE COMPLIANCE . 12.1 Maximum Allowable Electrical Power of Lifts, Escalators and Passenger Conveyors2.2 Energy Management of Lifts, Escalators & Passenger Conveyors 2.3 Power Quality Requirements 1223. CONSIDERATIONS IN DESIGN OF LIFTS & ESCALATORS . 33.1 Factors That Affect Energy Consumption of Lift and Escalator System .3.2 General Principles to Achieve Energy Efficiency .334. ENERGY EFFICIENCY FOR LIFT AND ESCALATOR EQUIPMENT 44.1 General 4.2 Traction Lift Equipment .4.2.1Motor Drive Control System .4.2.2Motor Drive Gears .4.2.3Motor .4.2.4Other Means to Reduce Running Friction . 4.3 Hydraulic Lift Equipment 4.3.1Main Components .4.3.2Basic Arrangements 4.3.3Valve Unit .4.3.4Energy Efficiency for Hydraulic Lift Equipment . .4.4 Escalator and Passenger Conveyor Equipment 4.4.1Motor Drive Control System .4.4.2Motor Drive Gears and Power Transmission .4.5 Power Quality of Equipment .4.6 VVVF Motor Drive, Energy optimizer, Service-on-demand Escalator4446778889911111212145. ENERGY EFFICIENCY FOR DESIGN OF LIFT AND ESCALATOR SYSTEM 145.1 Appropriate Sizing of Vertical Transportation System .5.2 Appropriate Zoning of Lift Installations 5.3 Energy Management of Lift System .5.3.1Provisions of Metering Devices .5.3.2Control Algorithm of Lift 5.3.3Standby Mode of Lift Equipment .5.4 Energy Management of Escalator and Conveyor System .5.4.1Provision of Metering Devices 5.4.2Standby Mode of Escalators and Conveyors 5.5 Internal Decoration of Lift Cars .5.6 Lift Traffic Design 5.7 Handling Capacity of Lift System .1416171717181919191919216. HOUSEKEEPING MEASURES TO ENHANCE ENERGY EFFICIENCY .227. MODERNISATION OF OLD EQUIPMENT . .23APPENDIX I – SAMPLE CALCULATION FOR LIFT TRAFFIC ANALYSIS .25page iiii of 27

Guidelines on Energy Efficiency of Lift & Escalator Installations, 20071.INTRODUCTIONThe primary objective of the Code of Practice for Energy Efficiency of Lift & Escalator Installations(Lift & Escalator Code), published by the Electrical and Mechanical Services Department (EMSD), isto set out the minimum energy-efficient design standards for lift & escalator installations withoutimposing any adverse constraint on building functions, nor hindrance to comfort or productivityof the building occupants. The Guidelines on Energy Efficiency of Lift & Escalator Installations(Guidelines) is a supplement to the Lift & Escalator Code. The intention of the Guidelines is toexplain the principles behind relevant requirements in the Lift & Escalator Code and provideguidance on Code compliance. The Guidelines also provide the recommended general practicesfor energy efficiency and conservation on the design, operation & maintenance of lift & escalatorinstallations. Whilst focusing on energy efficiency aspects, the Guidelines are not to provide acomprehensive set of guidance notes in lift & escalator design.2. CODE COMPLIANCEThe Lift & Escalator Code mainly controls the following areas:zzzThe maximum allowable electrical power of lifts, escalators & passenger conveyors.Energy management of lifts, escalators & passenger conveyorsTotal Harmonic Distortion and Total Power Factor for motor drive system.2.1 Maximum Allowable Electrical Power of Lifts, Escalators & Passenger ConveyorsThe requirement of the maximum allowable electric power indicates ultimately the energyperformance of the equipment. The power for lift equipment is to be measured when thelift is carrying its rated load and moving upward at its contract speed. For escalators andpassenger conveyors, since the rated load is usually defined as number of person (not in kgweight), there is no theoretical rated load in kg for the equipment. Thus the electric power isto be measured when the escalator/conveyor is carrying no load and moving at its ratedspeed either in the upward or downward direction. Control figures are given in the Lift &Escalator Code.For lift equipment, the power is measured at full load contract speed. A number of factorswill affect this power consumption. In the case of suspension lift, the weight of the lift carwill usually be balanced by the counterweight. Thus if power is measured at the contractspeed, the factors that affect the power consumption will be primarily the proportion of thefull load that is balanced by the counterweight. In usual lift machine design, thecounterweight is usually sized to balance the weight of the lift car plus 45%-50% of thecontract load. If the counterweight is designed to balance 45% of the contract load, thepower consumption at the full load contract speed up condition will be higher. Other factorthat has significant effects on this power consumption is the efficiency of the motor, friction,the controller and the gear box. For hydraulic lifts, the dead weight of the lift car is thepredominating factor on this maximum running power as there is no counterweight tobalance its dead weight.In escalator and passenger conveyor equipment, the dominating factor is similar to thetraction lift equipment. That is, the efficiency of the motor, friction, the controller and thedriving gear box. The proportion of frictional loss of the machine can also becomesignificant in the power consumption in no load condition, as it is the fix overhead to keepthe equipment running.For lift and escalator system designers, it is difficult to obtain this power figure during thedesign stage because most of the lift manufacturers can only provide the motor’s powerrating figure of their equipment which is much larger than the running power. This runningpower can only be measured during the testing and commissioning process, thus it ispage 1 of 27

Guidelines on Energy Efficiency of Lift & Escalator Installations, 2007difficult to tell exactly during the design stage whether a certain piece of equipment complywith the Code. It is therefore, advisable to look at testing and commissioning records ofsimilar installations when rated power is obtained from lift manufacturers.In order to meet the allowable electrical power, some good engineering practices fortraction lift are:zzzzLift machine to locate directly above the lift shaft to avoid losses through additionalpulley mechanism;Maximum rise (m) to limit to 50 (s) x Speed (m/s) to minimize the travel distance andthus the energy consumption;Maximum rise (m) to limit to 40m for under slung type roping arrangement withbasement/side type traction, so as to minimize the travel distance and thus the energyconsumption; andAvoid blind hoist way above the top most landing to minimize the dead weight ofropes.2.2 Energy Management of Lifts, Escalators & Passenger ConveyorsFor the purpose of energy management, the Code requires that metering devices orprovision for meter connection be provided for taking readings concerning energyperformance. The readings taken can help to compile a better picture of building energyconsumption during energy audit and let building owners know the running costs that theyare paying for their vertical transportation system.The Code has allowed flexibility for equipment installations. The provision of only aconnection point with reasonable accessibility and spacing is acceptable to the Code whilethe ideal provision is to provide the metering equipment together with the lift/escalatorequipment. It should be noted that the word “provision” should refer to permanentprovisions. Metering devices or measuring provisions are not required for individualequipment. Instead only one set of metering device or provision is required for each groupof escalators/conveyors or each bank of lift. The readings that are required include voltage,current (both line and neutral current), total power factor, energy consumption, power andmaximum demand. Multi-function meter that can measure multiple figures is acceptableand recommended. In fact using multi-function meter can simplify the installation work.Besides the metering requirement, the Code requires that for lift banks with two or more liftcars, at least one lift car should be operated under a “standby” mode during off-peakperiod. It is also required that during the standby mode, the lift should not response topassenger calls until it is returned to normal operation mode. It merely means to shut downone of the lifts in the lift bank during off peak hours. Additionally, if the lift car’s motordrive is DC-MG type motor drive, it is required that the generator driving motor of the liftcar should be shut down during the standby mode. As most of newly installed liftequipment in Hong Kong are VVVF equipment, this requirement is expected to have verylittle impact to the lift industry.Another requirement is to shut off the ventilation fan while a lift car has been idled for morethan 2 minutes. The reason for not shutting down also the lift car lighting is merely due tosafety considerations.2.3 Power Quality RequirementsThe power quality requirements in the Code mainly set out in form of Total HarmonicDistortion requirement and Total Power Factor requirement. Relevant reference materialsconcerning power quality requirement can be obtained from the Guidelines for EnergyEfficiency of Electrical Installations published by the Electrical and Mechanical Servicespage 2 of 27

Guidelines on Energy Efficiency of Lift & Escalator Installations, 2007Department. Designers should note the measuring conditions and locations of the powerquality requirements. For escalators installations, since the requirement of Total PowerFactor is to be measured under the motor brake load condition, which is difficult to simulateon site, thus, manufacturer’s calculations or proof of compliance will be consideredacceptable.3. CONSIDERATIONS IN DESIGN OF LIFTS & ESCALATORSThe lift and escalator industry is a very unique trade among other building services equipmentindustries. The equipment suppliers usually have lines of basic products. However, eachinstallation is site specific. That is, the final installation is tailor-made to suit individual site’sconstraints and requirements. This makes the establishment of generic energy efficiencystandard a difficult task, as there are large diversities among different installations.3.1 Factors That Affect Energy Consumption in Lift and Escalator SystemEnergy is consumed by lift and escalator equipment mainly on the following categories:z Friction losses incurred while travelling.z Dynamic losses while starting and stopping.z Lifting (or lowering) work done, potential energy transfer.z Regeneration into the supply system.The general approach to energy efficiency in lift and escalator equipment is merely tominimize the friction losses and the dynamic losses of the system. There are many factorsthat will affect these losses for a lift and escalator system:(A) Characteristic of the equipment The type of motor drive control system of the machine. The internal decoration of the lift car. Means to reduce friction in moving parts (e.g. guide shoes). The type of lifts and escalators. The speed of the lift/escalator system. The pulley system of the equipment.(B)Characteristic of the premises The population distribution of the premises. The type of the premises. The height of the premises. The house keeping of the premises.(C) The configuration of the lift/escalator system The zoning of the lift system. The combination of lift and escalator equipment. The strategies for vertical transportation. The required grade of service of the system.3.2 General Principles to Achieve Energy EfficiencyIn general the principles for achieving energy efficiency for lift/escalator installations are:z Specify energy efficiency equipment for the system.z Do not over design the system.z Suitable zoning arrangement.z Suitable control and energy management of lift equipmentz Use light weight materials for lift car decoration.z Good house 3 of 27

Guidelines on Energy Efficiency of Lift & Escalator Installations, 20074.ENERGY EFFICIENCY FOR LIFT AND ESCALATOR EQUIPMENT4.1 GeneralThe mode of vertical transport in buildings can be mainly classified into three modes:z by stair trafficz by lift trafficz by escalator trafficEach of these modes of vertical transport has their own characteristics and limitations.Despite the vast diversified usage of the lift equipment, there are basically two maincategories of lift equipment, namely traction lift and hydraulic lift. From energy performancepoint of view, traction lift is more energy efficient than hydraulic lift system. In hydraulic liftinstallation, a considerable amount of energy is wasted in heating up the hydraulic fluidwhen building up the hydraulic pressure. Some installations may even need separate coolersto cool down the fluid to avoid overheating. Furthermore, hydraulic lifts are usually notprovided with a counterweight. Thus the lift motor has to be large enough to raise the ratedload plus the dead weight of the car cage. In traction lift, the maximum weight to be raisedunder normal operation is only about half of its rated load. Therefore, designers shouldavoid using hydraulic lifts if there is no constraint on the installation of traction liftequipment.4.2 Traction Lift Equipment4.2.1Motor Drive Control SystemElectricity is directly consumed by the motor drive system of the lift machine. Thushow effective the motor drive can convert the electrical energy into the requiredkinetic energy have a remarkable effect on the energy performance of theequipment. In the history of lift equipment development, different types of motordrive system were developed. Some of these motor drive systems include: DC motor drive with generator set (DC M-G).DC motor drive with solid state controller (DC SS).AC 2 speed motor drive.AC motor drive with variable voltage controller (ACVV).AC motor drive with variable voltage and variablecontroller(ACVVVF).frequencyAmong the above drive systems, DC M-G has the lowest efficiency because of largeenergy loss in the motor and generator arrangement, which converts electricalenergy into mechanical energy and finally back to electrical energy again. Anotherreason for the low efficiency of the DC M-G motor drive is that the motor has to bekept running when the lift is idle.Similarly, the AC 2 speed motor drive is also considered a less energy efficient drivesystem. These two speed motors are usually started up with resistance in the highspeed winding, whilst smooth deceleration is obtained by inserting a bufferresistance, either in the low- or high-speed winding during transition to low speed.Sometimes, a choke is used instead of a buffer resistance, which results in asmoother and less peaked curve of braking torque. The insertion of buffer resistanceand choke wastes much energy during the start up and deceleration. Furthermore,two-speed system is installed with a large flywheel to smooth the sudden change intorque. The flywheel stores energy, which is dissipated later, contributing to the lowsystem 4 of 27

Guidelines on Energy Efficiency of Lift & Escalator Installations, 2007A general guideline on the motor drive system for traction lift equipment is shown inthe following table:Contract Speed V Suggested Order of Preference(m/s)Motor Drive Control Systems for Passenger Traction LiftsV 1.0AC VVVF / AC VV / DC SS / AC 2-speed1.0 V 3.0AC VVVF / AC VV / DC SS3.0 V 5.0V 5.0AC VVVF / AC VVAC VVVFDC M-G set is not in the guideline throughout the range as the energy performanceis extremely poor. The AC-2 speed motor drive system is not recommended for liftswith contract speed higher than 1 m/s due to their inferior energy performance. It ishighly recommended that even for lift with speed under 1 m/s, building designersshould always consider to use AC VVVF whenever feasible. As an illustration on theenergy saving potential for utilizing VVVF drive, let’s take the energy of a lift with apole-changing motor as 100%. Then the ACVV system requires approx