建筑环境与能源应用工程专业英语课件

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1、Unit FifteenCommissioning of Variable Air Volume SystemsWhat is Commissioning(Cx)?Definition:“A quality-focused process for enhancing the delivery of a project.The process focuses on verifying and documenting that the facility and all of its systems and assemblies are planned,designed,installed,test

2、ed,operated,and maintained to meet the Owners Project Requirements.”ASHRAE Guideline 0-2005,The Commissioning ProcessASHRAE Guideline 0-2005,The Commissioning Process Commissioning is often performed by an independent third-party engineering company.Operates as an owners representative to insure the

3、 installed systems meet the owners requirements and the plans and specifications Usually hired by the owner,sometimes by the architect,or general contractor.Commissioning PersonAll participants in the construction project have a commissioning responsibility.Participants include the commissioning aut

4、hority,owner,design professionals,construction manager,general contractor,subcontractors,operation and maintenance manager,suppliers,and equipment manufacturers.Benefits of Commissioning Reduced change orders Less warranty and callbacks for contractor Smoother turnover to maintenance Improved equipm

5、ent reliability Reduced IEQ problems Reduced occupant complaints Improved productivity Correct system operation and installation Facility meets Owners expectation and operational needs Reduced utility consumption and operational costsCommissioning Objectives Ensure the facility meets the owners perf

6、ormance requirements Provide a safe and healthy environment Provide optimum energy performance Provide a facility that can be efficiently operated and maintained Provide complete orientation and training to facility staff and occupants Provide improved documentation of system characteristicsCommissi

7、oning -What did we use to do and why do we need it?CX of mechanical and electrical systems was done by the installing contractors No standardization,or clear approach Most of the real CX occurred during the warranty period as warranty calls Buildings operated less efficiently First year of occupancy

8、 was frustrating for the owner Contractors spent more money during the warranty periods Contractors can be rushed without enough time to double-check their work Design Engineers do not have enough budget to oversee the construction in detail Owners have had bad experiences with prolonged project clo

9、seout,and see CX as a solution Hold contractors accountable for the specificationsCommissioning Scope Mechanical Systems All HVAC equipment Building automation system and hardwired controls Electrical Systems Switchgear,major disconnects,backup generators and UPS(Uninterrupted Power Supply)Fire Safe

10、ty Systems Security Systems Kitchen equipment Irrigation system Laboratory Fume hoods,gas controlCommissioning and Construction PhasesPrepare,Design Intent,CX Plan,and SpecificationsReviewSubmittals,Prepare Checklists and Testing PlansVerifyComponents,Witness Start-Upand ComponentTestingPerformFunct

11、ionalTesting,ResolveDeficiencies,ReviewO&MPrepareCX Report,Staff Training,DefineSeasonalTestingPlanningDesignConstructionOccupancyAcceptanceOther Types of Commissioning Retro-commissioning Performed to existing buildings that have not previously been commissioned,after they have been occupied Usuall

12、y instigated as a result of high energy bills or poor occupant comfort Recommissioning Performed 5 to 10 years after a building was previously commissioned Sometime used as a form of deferred maintenanceVariable Air Volume(VAV)use of varying airflow to control the condition of air,in contrast to the

13、 use of constant flow(often)with varying temperature.VAV system controls temperature in a space by varying the quantity of supply air rather than varying the supply air temperature.A VAV terminal unit at the zone varies the quantity of supply air to the space.The supply air temperature is held relat

14、ively constant:while supply air temperature can be moderately reset depending on the season,it must always be low enough to meet the cooling load in the most demanding zone,and to maintain appropriate humidity.Why use VAV?Provides multiple zones of comfort Life cycle cost will be less than other HVA

15、C Systems trying to accomplish similar comfort levels Load diversity Smaller equipment (lower AC unit first cost compared to Constant Volume)Less supply air(less energy consumption)Able to adapt to changes in building useWhy Not?Higher first cost than comparable single zone Controls,equipment,commis

16、sioningIncreased maintenance cost More pieces to look afterConstant volume-variable temperature system have been dominating the HVAC applications in the past for obvious reasons.The implementation of variable volume control has been done with dampers or other mechanical control methods.The advantage

17、s of variable air volume system implemented with variable speed control are:l Fast control to keep the comfort zone limits l Low consumption of electrical energy l Lower consumption of heating and cooling energy than in constant air volume systems l Simpler to keep noise level down 1.Introduction2.C

18、ommissioning method statement3.System components 4.Preliminary checks5.Commissioning sequence 6.Setting to work 7.Terminal units 8.Secondary air distribution9.Return air spigots 10.System diversity 11.Fan design performance check 12.System performance checks Frequently used words and phrases:Variabl

19、e air volume(VAV)system 变风量系统变风量系统commissioning 试运行试运行 调试调试 air volume flow rate 空气体积流量空气体积流量terminal unit 终端设备终端设备 flexible duct 柔性风管柔性风管Pitot tube 毕托管毕托管 thermal anemometer 热线风速仪热线风速仪supply fan 送风风机送风风机 extract fan 排风机排风机over-pressurization 压力过高压力过高 spigot 套管、栓、龙头套管、栓、龙头1.Variable air volume(VAV)s

20、ystems are dynamic air distribution systems and,as their name implies,the air volume flow rate is varied according to various parameters to achieve the required design conditions.2.The fact that VAV systems are designed to vary system performance imposes a number of specific tasks on the commissioni

21、ng specialist,which must be carried out in order to achieve satisfactory overall performance.3.Proprietary units may employ a variety of means of regulating air volume flow rate including motorized dampers,inflating bellows,restricting flexible duct sections or a combination of such devices.Variable

22、 air volume(VAV)systems:变风量系统变风量系统 dynamic:动态的动态的air volume flow rate:空气体积流率空气体积流率 design conditions:设计条件设计条件impose:施加施加 带来带来 commissioning specialist:调试人员调试人员proprietary:私人拥有的私人拥有的 inflating bellows:静压箱静压箱 常用常用plenum chamberflexible duct section:柔性风管部件柔性风管部件plenum chamber静压箱静压箱acoustic plenum chamb

23、er 消声静压箱消声静压箱静压箱是送风系统减少动压、增加静压、稳定气流和减少气流静压箱是送风系统减少动压、增加静压、稳定气流和减少气流振动的一种必要的配件，它可使送风效果更加理想。振动的一种必要的配件，它可使送风效果更加理想。静压箱的作用静压箱的作用 l 可以把部分动压变为静压使风吹得更远；可以把部分动压变为静压使风吹得更远；l 可以降低噪音可以降低噪音 l 风量均匀分配风量均匀分配 l 静压箱可用来减少噪声，又可获得均匀的静压出风，减少静压箱可用来减少噪声，又可获得均匀的静压出风，减少动压损失。而且还有万能接头的作用。把静压箱很好地应动压损失。而且还有万能接头的作用。把静压箱很好地应用到通风

24、系统中，可提高通风系统的综合性能。用到通风系统中，可提高通风系统的综合性能。4.Control sensors may measure air flow by means of pressure differential,Pitot tube,flow grid or thermal anemometer using spot or averaging sensors.5.The guidance is not system-specific,because the detailed tasks associated with one system type may not be the sa

25、me for another type.6.VAV system technology offers such a wide range of design options and proprietary components that the resulting installations are likely to require different commissioning techniques.pitot tube:毕托管毕托管 flow grid:流动网格流动网格thermal anemometer:热线风速仪热线风速仪option:选择选择 选项选项system-specific

26、:根据系统而特殊或不同的根据系统而特殊或不同的7.To ensure that the appropriate commissioning procedures are employed,the commissioning specialist should carefully review the recommendations of the equipment suppliers.8.VAV systems typically comprise the following components,some of which may require specialist commissioni

27、ng by the manufacturer in addition to general commissioning as part of a complete air distribution system9.A particular check should be made to ensure that distribution ductwork internals are clean throughout.If there is any doubt regarding the state of system cleanliness,the commissioning specialis

28、t should formally draw attention to this.review:查阅查阅 复习复习 equipment suppliers:设备提供商设备提供商how to translate?internal:内部内部 draw attention to:对对注意注意10.With the supply and extract fans operating simultaneously,the running speed should be increased gradually.Motor running current checks should be made at v

29、arious increments,and the results recorded for each fan,to assess performance and prevent overloading of the motor.11.The fans should then be stopped and made safe so that the cause of the static pressure irregularity can be investigated and rectified by the appropriate personnel before proceeding f

30、urther.12.during the commissioning of the individual VAV terminals,it may be necessary to further fine-tune the fan speed to compensate for any system pressure variations.current:电流电流 increment:增量增量 overloading:过载过载irregularity:无规律无规律(的变化的变化)rectify:修正修正 调整调整personnel:人员人员 proceed:继续进行继续进行terminal:终

31、端终端 终点终点 terminal station fine-tune:微调微调13.All procedures and techniques to be applied in checking terminal unit volume flow rates should be in accordance with the manufacturers instructions and should be incorporated into the commissioning method statement.14.Verification of these arrangements is n

32、ecessary,and the number of VAV terminal units to be checked should be defined within the project commissioning specification.15.at the outset of the VAV terminal checks,the commissioning specialist should select a number of units with inlet duct configurations suitable for in-duct flow measurements

33、to be taken.instruction:指示指示 说明说明 instruction book specificationincorporate:合并合并 结合结合 incorporated:组成公司的组成公司的 Inc.DELL Inc.statement:说明说明 陈述陈述verification:确认确认 查证查证 define:详细说明详细说明 outset:开始开始 inlet duct configuration:风管入口结构风管入口结构in-duct flow:风管入口流动风管入口流动16.Volume flow rate checks by pitot-static du

34、ct traverse should be conducted on these terminals to validate the method of flow rate measurement adopted within the commissioning method statement,17.With such an arrangement,the commissioning specialist must balance proportionally each of the secondary terminals by the methods detailed in section

35、 A3.2 so that they discharge the specified proportion of the volume of air delivered by the VAV terminal,within the specified(or appropriate)tolerances.18.For all the above arrangements,regulation of the return air inlets must be carried out to achieve a proportional balance within the specified tol

36、erance limits.pitot-static duct traverse:风管横截面布置毕托管风管横截面布置毕托管conduct:进行进行carry out:执行执行secondary terminal:二次终端设备二次终端设备 tolerance:公差公差 允许的误差允许的误差specified:指定的指定的19.It may be necessary to impose a reduced air flow condition on a number of terminals to achieve the required design diversity.20.Where nec

37、essary,guidance should be obtained from the unit supplier or manufacturer and close liaison with the designer is recommended to take account of any particular arrangements that may be required.21.With the required design system diversity applied,total flow rates should be measured and recorded by pi

38、tot traverse.diversity:差异差异 多样性多样性How to translate?guidance:指导指导 liaison:联络联络 联系联系22.In conjunction with this,the static pressure at the least favored unit should be monitored and the system operating pressure set to its optimum point,i.e.the lowest system operating pressure that still satisfies the

39、 least favored unit.23.With the system in this mode,the pressure drop across each component of the air handling unit should be measured and recorded.24.Indicative positioning should be specified by the designer,based on the distribution ductwork system layout and the calculated system resistance cha

40、racteristics.the least favored unit:处于最不利条件下的设备处于最不利条件下的设备indicative:指示性的指示性的 指导性的指导性的 layout:规划规划 布局布局resistance characteristic:阻力特性阻力特性pressure drop:压力降压力降25.It is,therefore,necessary to set up the fan performance controls for checking both maximum and minimum volumes,in addition to checking the e

41、quivalent performance at other intermediate points.26.The setting of the automatic control system should be finalized by the controls specialist in liaison with the commissioning specialist.27.With the supply and extract fans delivering their design maximum air volumes,adjust the outside air damper

42、until the required design volume flow rate is achieved.With the system in its fully turned down condition,the minimum outside air quantity should be checked to ensure that the correct ratio has been maintained.equivalent performance：类似的性能类似的性能 intermediate:中间的中间的turned down:关小，减弱，降低关小，减弱，降低finalize:最终确定最终确定