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1、nHydraulicandMachineRoomLess(MRL) Elevator SystemsOver the last 70 years, most elevator installations have been hydraulic elevator systems. However, there has been a lack of research comparing hydraulic machine room less (MRL) elevators and the nHydraulicandMachineRoomLess(MRL) Elevator SystemsOver

2、the last 70 years, most elevator installations have been hydraulic elevator systems. However, there has been a lack of research comparing hydraulic machine room less (MRL) elevators and the t influence elevator As a result, elevator purchasers lack understanding about elevator resulting in wasted in

3、vestments, inefficient energy use, and sive life-cycle The e of this study was to determine if hydraulic elevators are as efficient MRL elevators and to identify which factors influence three measures of efficiency: performance, energy consumption, and life cycle cost. Multiple was used to evaluate

4、the influence of multiple factors (including type) on each of 3 response variables. Data were obtained from industry-s of elevator performance. The findings t significant exist n hydraulic and MRL elevators. In relation to performance and consumption, for life cycle cost, ysis provided strong result

5、s in favor of MRLelevators, ysis provided strong results in favor of hydraulic In addition, 3 variables (elevator were significant and predictors of all 3 , elevator speed, and floors traveled), while others were significant for all 3 variables. The findings may lead itive l change enablingbuilding

6、operatorsto choose elevator treduceabuildingsthe potential and consumption ted with elevators. Further, this ay assist purchasers making tradeoffs among competing factors to make wise selections and to cope therising cost ofbuildingconstruction andHydraulicElevators The History of Hydraulic Elevator

7、sAccording to Sedrak (2001), the National Elevator Manufacturing (NEMI) t hydraulic elevators in the U.S. market gained popularity in early1870s.Twohydraulicsystemswereavailabletothepublic:thehydraulicandroped ger hydraulic. Both types utilized city re to propel the The roped hydraulic units were ab

8、le iver speeds of up to 1,400 feet per ratioof1:14(p. Sedrak (2001) t soon after, in 1899, electric traction machines roduced. These electric traction machines used both alternating current (AC) direct current (DC)Sedrak (2001) t soon after, in 1899, electric traction machines roduced. These electri

9、c traction machines used both alternating current (AC) direct current (DC) drive operation. Later, in 1903, a new gearless drive machine roduced (p. 1). There is a common t electric traction elevators roduced prior to hydraulic elevators. However, the economic boom opened the market for traction ele

10、vators. This boom was mainly driven by the inherent problem of water hydraulic elevators. In addition, higher building rise required more technologies coupled with the need for improved safety, and these new forced elevator designers roduce the traction elevator, thereby driving over hydraulic eleva

11、tor systems. Hence, traction elevators became more hydraulic heverticalionbusiness(p. In the 1920s, water hydraulic elevator systems were popular until roductionof oil hydraulic systems (Sedrak, 2000, p. 1). Celik and Korbahti evator manufacturers did roduce the oil hydraulic elevator the 1950s.Ther

12、eafter, the oil hydraulic elevator increased in popularity. Oil elevators were used originally for freight pur improved and enhanced the opportunitiespassenger use. Hence, hydraulic sales esonly.Later,however,oilroduce hydraulic elevators to increase because hydraulic were economically favoredovertr

13、actionelevators. Inaddition, thelaborand material, hoist way, and building construction of the oil hydraulic elevator made it less expensive to install for building owners (p. 1).ElevatorMarketSegmentsinSalesAccording to Sedrak (2001), the National Elevator Industry, Incorporated t in 1986, geared a

14、nd evator sales declined by nearly 50% toamarketcontraction. In1996ascomparedto1986, tractionelevatorsalesstartedto increase. In 1998, sales volume nearly doubled over the sales volume of 1994. The chart below does not reflect potential modernization of existing elevators. In nearly 5,000 traction u

15、nits in 1998 and potentially 3,000 hydraulic units were reported. Figure 1 below a tractionelevator units(p.ysis of the sales volume of hydraulic Figure 1. NEII reported annual sales in millions of dollars of hydraulic, geared, and gearless elevators. From “Hydraulic Elevators: A Look at the Past, P

16、resent, and Future,” by D. 2001,ElevatorWorld,Figure 1. NEII reported annual sales in millions of dollars of hydraulic, geared, and gearless elevators. From “Hydraulic Elevators: A Look at the Past, Present, and Future,” by D. 2001,ElevatorWorld,p.Sedrak (2001) t hydraulic elevators sales made up ne

17、arly 133% compared to traction elevator sales; a ratio of almost 2:1 hydraulicto traction sales. In fact, n 1962 and 1998, hydraulic sales increased nearly eightfold.majority of hydraulic installations, 90-95%, were in-ground hydraulic installations (p. HydraulicHydraulic elevators o two categories:

18、 ained re and hydraulic. his , les of the systems will be shared (OtisElevatorCompany,1991,p.ained re hydraulic systems, by todays standards, are his system, liquid was placed re to keep the rized at times. Useof thesesystemswasdiscontinuedmanyyearsagobecausewhenthewater line lost pre re, the elevat

19、or would not function, thus making the system unsafe (p. On the other hand, in the electro-hydraulic elevator system, the liquid (oil) pumped re through the control valve o the cylinder by means of pump and electric motor (Mehta, 2010, p. 73). This combination makes electro-hydraulic elevator the mo

20、st commonly used hydraulic system today. namesforelectro-hydraulicaredirectp p. 6).Additional hydraulic ms exist holed and holeless hydraulic elevators. piston centrally located at the center jack is buried in the ground. Direct-gerorhydro(OtisElevatorCompany,t meet current standards. These systems

21、The holed hydraulic elevator uses a the platform. The ston or ger or ston units are the common installation in the marketplace. While other variations such as combination sible, they areextremelyrare.For the common installation in the marketplace. While other variations such as combination sible, th

22、ey areextremelyrare.For the eofthisresearch, hydraulicelevator willbeevaluatedingreaterdepth(OtisElevatorCompany,1991,p. In holeless hydraulic elevators, the jack is installed above ground within hoistway.Theevator is further classified by the way the car is connected the jack (Otis Elevator Company

23、, 1991, pp. 6-7). In direct connect, the connects directly to the car (Mehta, 2010, p. 77). Roped, or indirect connect, uses rope to connect ston to thecar (Otis Elevator Company, 1991, pp. 6-7). Figureshowsapplicationsof holedand holelesshydraulicFigure 2. Hydraulic applications of holedand holeles

24、s types. From roduction to elevators,” by Otis Elevator Company, 1991, Otis Elevator Library, p. 13.Copyright 1990 by Otis Elevator Company.TheProsandConsof HydraulicDevelopers and building owners throughout the world have widely accepted hydraulic elevators. In most cases, hydraulic elevators repla

25、ced single- double-speed AC traction elevators. Below are reason why developers adopted hydraulic elevators in l andresidentialbuilding 1. Thecost of hydraulic elevator equipment and enance is n the cost equipment and enance for the typical traditional traction elevator. traction elevators cost twic

26、e as much as hydraulic elevators for the same two- three-stop application. For le, if a hydraulic elevator costs $30,000, a elevator of the same speed and capacity would costthree-stop application. For le, if a hydraulic elevator costs $30,000, a elevator of the same speed and capacity would cost $6

27、0,000. In addition, enance cost of hydraulic elevators may be $2,400 per year, while elevator enancecost wouldbe$4,800per 2. Hydraulic elevators provide the building owner with a more efficient use of building space compared to older traction elevators. For instance, a typical elevator requires 12%

28、less hoist way n traditional traction elevators. In words, hydraulic elevators use about 30 square feet less n traction In addition, a cleaner, more refined roofline would appeal to the building Moreover, thebuildingconstruction costisreducedbecausenopenthouseisneededhouse the overhead t is required

29、 for traditional traction However, the hoist way must be equipped with the proper overhead and pit depth to modate the operational requirements of the system. Furthermore, because hydraulic elevators e vertical loads, thevertical energy is focused toward Therefore, the building structure does not ne

30、ed to be over engineered in order support the required by traction elevators. To make these systems even desirable, the hydraulic elevator machine room can be moved or placed near or adjacent to the elevator hoist way. Atypical code-acceptable distance is about 25-40 feet depending on the city, se,

31、or county.3. Hydraulic elevators are also more ecause of their lifting load They are more ntraction elevatorsforlifting loadsof over 10,000 At such loads, these systems are less expensive to operate. Because high speed is not a requirement for lifting loads of over 10,000 pounds, hydraulic elevators

32、 can designedtoliftloadsnearing 125,000pounds(OtisElevator Company, 1991, p. ,1. Hydraulic elevators are not designed to operate at speeds exceeding 150 feet minute (fpm). Exceeding a rise of 40 feet is also mended for elevator use. However, applicationsofspeedsreachingahighof 200fpmandariseof 60 fe

33、et are common.2. The performance of hydraulic elevators can vary as the oil temperature varies. the temperaturechanges, the viscosity oftheoilchanges, causing an erraticoperation. As a result, the ambient temperature must be controlled, particularly when The elevatorindustryhasseen many advantagesof

34、 hydraulic elevators.However in some instan, their applicationand use have been mismanaged. Disadvantages ofhydraulic elevatorsinclude theelevator system is utilizing a sor control. Therefore, an additional cost ted with aining the proper ambient temperature (Celik & Kucur, 2011, 86; Edwards,1989,pp

35、.49-3. Typically, with the hydraulic system, the cylinder is buried in the elevator system is utilizing a sor control. Therefore, an additional cost ted with aining the proper ambient temperature (Celik & Kucur, 2011, 86; Edwards,1989,pp.49-3. Typically, with the hydraulic system, the cylinder is bu

36、ried in the ground. problem prevents an inspection of the underground cylinder. ch leak chemical and electrolytic sible and can potentially cause blowoutunderground, withlittletononotice(Edwards, 1989, pp.49-4. Not all hydraulic elevator systems have descending or ascending safety Therefore, if the

37、hydraulic fluid loses re, the elevator system will not be able ain he elevator hoist way. As a result, a free-fall condition causecatastrophic5. Any potential he cylinder may cause the he cylinder to leak andpollutetheundergroundwater6. The energy efficiency of hydraulic elevators is two to three ti

38、mes ntof a traction elevator. In addition, the er supply required to operate t required by the similar speed hydraulic elevator is considerably ncapacitytractionelevator.Moreover,theer supply must bedesigned at larger capacity to eliminate lights dimming and potential voltage drop within the 7. Hydr

39、aulic e two additional concerns: (a) the cost of aining underground system is typically unknown for the building owner, and (b) the es a problem of unknown soil condition. In some cases, the condition e heavy-duty costs while drilling the hole for the hydraulic and cylinder. Potential ground obstruc

40、tion and soil contamination es may also present. These types of problems are very common when drilling to house hydraulic underground systems. drilling cost All elevator contractors exclude the enance of In areas where replacement of the system is sary, and existing building conditions make it more

41、difficult complete the 8. Carefully considering the installation contractor is a key component of the hydraulic elevator installation. Many exist when the ger and are not installed plumb. A t is not installed plumb will cause operational problemsandmany 9. The design characteristics of hydraulic ele

42、vators inherently produce high heat. heat from these systems is o high temperatures and dissipated in elevator machine room. heat from these systems is o high temperatures and dissipated in elevator machine room. As a result, building owners must provide a method exhausting theheat fromthe machinero

43、omto outside air (pp.49-10. Hydraulic elevators are well known for the noise in comparison t of elevators because a hydraulic system transmits drive noises to the car. For le, belt-coupled motor is inherently n a submerged motor design. For applications, noise is not a major problem. However, noise reduction is an ongoing problem, and improvements will be made as new materials and techniques developed(OtisElevatorCompany,1991,pp.10-