1、50.1CHAPTER 50TERMINOLOGY OF REFRIGERATIONHIS chapter seeks to define some of the common terms used inTindustrial refrigeration systems, specifically those using am-monia as the refrigerant. The following glossary was compiled froma variety of sources throughout the industry, including ASHRAE,the In
2、ternational Institute of Ammonia Refrigeration (IIAR), theU.S. Occupational Safety and Health Administration (OSHA), andthe U.S. Environmental Protection Agency (EPA). Specific sourcesfor entries are listed in the endnotes. Minor edits for punctuation,conciseness, and consistency with usage elsewher
3、e in the Handbookhave been made.In many cases, definitions of a single item from various sourcesmay not fully agree. However, multiple definitions are listed hereonly if they differ substantively. This glossary does not seek todefine the correct definition; rather, it leaves it to users to pick thea
4、ppropriate definition for their application.Accidental release. Unanticipated emission of a regulated sub-stance or other extremely hazardous substance into the ambient airfrom a stationary source.5Actuator. (1) Mechanism for transmission of movement orforce.10, 11 (2) Device, either electrically, p
5、neumatically, or hydrau-lically operated, that acts as a motor to change the position of mov-able devices such as valves or dampers.2Adjusted flow capacity. Estimated capacity of a relief valveassembly accommodating the reduction in flow caused by pressuredrop in the three-way valve.15Affected emplo
6、yee. Any employee who works in the vicinity ofan ammonia refrigeration system.5Air-cooled condenser. A refrigerant condenser in which heatremoval is accomplished entirely by heat absorption by air flowingover condensing surfaces. See also Condenser; Desuperheater;Double-pipe (tube-in-tube) condenser
7、; Evaporative condenser;Shell-and-tube condenser.2, 7, 10, 12Air-cooled desuperheater. (1) That part of the system designedto cool ammonia refrigerant vapor after it is discharged from thecompressor and before it enters the condenser. It is provided with ameans of forcing air circulation over the ex
8、ternal surface of thedesuperheater coil for the heat removal necessary to cool the refrig-erant vapor on the inside of the tubes.7,10,12(2) Heat exchanger,preceding the condenser or incorporated in it, for removing all orpart of the superheat.2Air duct. A tube or conduit used for conveying air. The
9、air pas-sages of self-contained systems are not air ducts.10,12Ammonia. Refrigerant-grade anhydrous ammonia.10,12ANSI. American National Standards Institute (www.ansi.org).Approved. Acceptable to the jurisdictional authorities.1,7,10,12ARIP. Accidental Release Information Program, a U.S. Environ-men
10、tal Protection Agency (EPA) database that can be reviewed forpast ammonia refrigeration incidents.ASHRAE. American Society of Heating, Refrigerating and AirConditioning Engineers, Inc. (www.ashrae.org).ASME. American Society of Mechanical Engineers (www.asme.org).Authorized inspection agency. An est
11、ablished and recognizedagency or individual regularly engaged in conducting tests or fur-nishing inspection services, when such agency or individual hasbeen approved by the jurisdiction involved.7,12Automatic expansion valve. A controlling device that regulatesthe flow of volatile liquid refrigerant
12、 into an evaporator of a closed-circuit ammonia refrigerating system, and is actuated by evaporatorpressure.7,10Automatic liquid refrigerant drain valve. See High-side floatvalve.Back pressure. The static pressure existing at the outlet of anoperating pressure relief device caused by pressure in the
13、 dischargeline.1, 13Balanced (safety) relief valve. A pressure relief valve thatincorporates means of minimizing the effect of back pressure on theoperational characteristics of the valve (opening pressure, closingpressure, and relieving capacity).1, 13Blends. Refrigerants consisting of mixtures of
14、two or more dif-ferent chemical compounds, often used individually as refrigerantsfor other applications.1Blocked in. Having a piece of equipment, vessel, or piping iso-lated from the rest of the system by closed valves and/or blindflanges.13Block flow diagram (BFD). A simplified schematic drawingsh
15、owing the ammonia refrigeration system. The primary purpose ofthe BFD is to show the major components of the ammonia refriger-ation system and flow direction. Temperatures and pressures may beshown for clarity.13Blowdown. (1) The difference between actual popping pressureof a pressure relief valve a
16、nd actual reseating pressure, expressed asa percentage of set pressure or in pressure units.2, 13(2) Discharge ofwater from a steam boiler or open recirculating system that containshigh total dissolved solids. The addition of makeup water reducesthe concentration of dissolved solids to minimize thei
17、r precipita-tion.2Blowdown pressure. The value of decreasing inlet static pres-sure at which no further discharge is detected at the outlet of a pres-sure relief valve after the valve has been subjected to a pressureequal to or above the popping pressure.13Booster compressor. (1) A compressor for di
18、scharging to thesuction of a higher-stage compressor. See also Compressor; Posi-tive-displacement compressor.10(2) Compressor for raising thepressure of a gas delivered to a following compressor.2Brazed joint (high-temperature). Gastight joint obtained byjoining metal parts with alloys that melt at
19、temperatures higher than800C, but at less than the melting temperatures of the joined parts.2Brazed joint (low-temperature). Gastight joint obtained byjoining metal parts with metallic mixtures or alloys that melt at tem-peratures below 800C but above 540C.2Brine. (1) Any liquid used for the transmi
20、ssion of heat without achange in its state.7(2) Formerly, any liquid cooled by a refrigerantand used for heat transmission without a change in its state, havingno flash point or a flash point above 66C. Now called a secondarycoolant. (3) A secondary coolant that is a solution of salt in water.2,3Bui
21、lt-up back pressure. Pressure existing at the outlet of a pres-sure relief device caused by flow through that device into a dis-charge system.15CAS. Chemical Abstracts Service.5The preparation of this chapter is assigned to TC 10.1, Custom EngineeredRefrigeration Systems.50.2 2010 ASHRAE HandbookRef
22、rigeration (SI)Catastrophic release. A major uncontrolled emission, fire, or ex-plosion involving ammonia that presents serious danger to employ-ees in the workplace, to public health, or to the environment.4,5,17Certify. To acknowledge in writing that statements are true,accurate, and complete.5CFR
23、. Code of Federal Regulations.Charging. The process of adding liquid ammonia to a system.5Check valve. A valve allowing fluid flow in one directiononly.2,7,10Classified information. As defined in the Classified Informa-tion Procedures Act, 18 U.S. Code (USC), App. 3, section 1(a), “anyinformation or
24、 material that has been determined by the UnitedStates Government pursuant to an executive order, statute, or regu-lation, to require protection against unauthorized disclosure for rea-sons of national security.”4,5,17Closed-circuit ammonia refrigerating system. A refrigeratingsystem using mechanica
25、l compression to remove the refrigerantfrom the low-pressure side and to deliver it to the high-pressure sideof the system.10Code authority. Any group or body recognized by the jurisdic-tion involved, and which has authority over the rules and regulationsgoverning design, fabrication, testing, and a
26、ssembly of refrigerationand related equipment.12Codes. Standard practices, typically issued by national organiza-tions. A code becomes a legal document, which can be enforced bya regulatory authority, when it is adopted by an authority such as astate legislature.5Commissioning. (1) Completion of the
27、 start-up process, whichdemonstrates the performance of the system.12(2) Process forachieving, verifying, and documenting the performance of a build-ing to meet the buildings operational needs within the capabilitiesof the design and to meet the design documentation and the ownersfunctional criteria
28、, including preparation of operator personnel.2Companion (block) valve. Pairs of mating stop valves thatallow sections of a system to be joined before opening these valvesor separated after closing them.1,2,7Compressor. (1) Device for mechanically increasing the pres-sure of a gas.2(2) A machine use
29、d to compress refrigerant vapor.1,5(3) A specific machine, with or without accessories, for compress-ing ammonia refrigerant vapor. See also Booster compressor; Pos-itive-displacement compressor.7,10,12Compressor unit. (1) A condensing unit less the condenser andliquid receiver.7(2) A compressor wit
30、h its prime mover and acces-sories.1Computerized maintenance management system (CMMS).A computerized database for planning, scheduling, tracking, andrecording the completion of quality assurance, testing, inspection,and other preventative maintenance tasks. A CMMS can also per-form other tasks relat
31、ed to preventative maintenance such as plan-ning and issuing work orders, maintenance of equipment historydata, material and spare parts inventory and ordering, issuing pur-chase orders, and maintenance of work instructions and procedures.Condenser. (1) The part of the refrigerating system where ref
32、rig-erant is liquefied by removal of heat.1,7,10,12(2) Heat exchanger inwhich vapor is liquefied by rejection of heat into a heat sink.2Condenser coil. (1) That part of a condenser constructed of pipeor tubing not enclosed in a pressure vessel.7,10,12(2) Condenserconstructed of pipe or tubing, not e
33、nclosed in a pressure vessel.1,2Condensing unit. A specific refrigeration machine combinationconsisting of one or more power-driven compressors, condensers,liquid receivers (when required), and the regularly furnishedaccessories.1,7Container. A cylinder used for the transportation of refriger-ant.1,
34、 7Contractor. (1) In construction terminology, the person or entityresponsible for performing the work and identified as such in anowner-contractor agreement.2(2) A company or individual whowill provide services, labor, materials, and tools to perform specificwork under contract or purchase order fr
35、om the employer.5(3) Theorganization or corporation that assumes contractual responsibilityfor installation, setting, and tying together of the various compo-nents of the refrigerating system in its final operating form.7Control valve. All valves except shutoff valves. Examplesinclude solenoid valve
36、s, check valves, and regulating valves.10,11Controlled-pressure receiver. An intermediate pressurereceiver used to flash cool refrigerant and to control the feed pres-sure. See also Pressure vessel.2,10Conventional safety relief valve. A pressure relief valve with itsspring housing vented to the dis
37、charge side of the valve. Operationalcharacteristics (opening pressure, closing pressure, and relievingcapacity) are directly affected by changes of pressure at the outlet ofthe valve.15Corrective action. An action taken to eliminate the causes of adeficiency in a product, procedure, process, or sys
38、tem.5Corridor. An enclosed passageway that limits travel to a singlepath.1Corrosion. (1) Dissolving or wearing away of a material; oftenrefers to chemical attack on a metal.5(2) Rusting or deterioration ofa substance (usually a metal) or its properties because of a reactionwith its environment.2Cove
39、red process. A process that has a regulated substance pres-ent in more than a threshold quantity as determined under RMP 1910.119 or 68.115.4,5Critical pressure. A point on the saturation curve where refrig-erant liquid and vapor have identical volume, density, and enthalpy,and there is no latent he
40、at.1,2Crossover valve. A valve that allows interconnection of two dif-ferent portions of a refrigeration system that normally operate at dif-ferent pressures.10Cutter/welder. An individual performing hot work operations.5Cylinder. A container used for the transportation of ammoniarefrigerant.12Desig
41、nated agency. The state, local, or federal agency desig-nated by the state under the provisions of 40CFR68.215(d) (defini-tion from EPAs RM Program regulations).5Design pressure. (1) The maximum pressure for which a spe-cific part of a refrigeration system is designed.1,5,7,10,12Design working press
42、ure. (1) In the United States, the maxi-mum working pressure for which an apparatus has been designed.(2) In some countries, the design pressure is greater than the maxi-mum working pressure.2Desuperheater. A device that provides sensible cooling to therefrigerant vapor prior to condensing.10, 12Des
43、uperheating coil. Heat exchanger, preceding the condenseror incorporated in it, for removing all or part of the superheat.2Device. (1) Term for shutoff valves, control valves, and strain-ers.10(2) Piece of equipment or a mechanism designed to serve aspecial purpose or to perform a special function;
44、refer to specificdevice of interest.2Direct expansion (DX). Evaporator arrangement whereby liq-uid refrigerant is fed through an expansion valve or device and evap-orates completely before leaving as vapor.10Direct-expansion (DX) coil. Coil used in direct refrigerationmethod.2DOT. U.S. Department of
45、 Transportation (www.dot.gov).Double-pipe (tube-in-tube) condenser. Condenser constructedof concentric tubes in which refrigerant circulates through the annu-lar space and the cooling medium through the inner tube.2Double-pipe (tube-in-tube) condenser/desuperheater. A typeof condenser/desuperheater
46、constructed of one or more assembliesof two tubes, one within the other, in which refrigerant vapor iscondensed/desuperheated either in the annular space or the innertube. See also Air-cooled condenser; Condenser; Desuperheater;Evaporative condenser; Shell-and-tube condenser.10,12Terminology of Refr
47、igeration 50.3Downstream. A direction, given relative to a piece of equip-ment, that is the same as the main system flow (e.g., a compressorsdischarge piping is downstream from its suction piping).5Downstream power regulator. (1) A control valve that regu-lates flow of oil or refrigerant gas or liqu
48、id through the device,which is actuated toward open by pressure falling below regulatorset point downstream of the valve.11(2) A controlling device thatregulates flow of refrigerant gas or liquid or oil through the devicefrom a section of the system to a lower-pressure section of the sys-tem, and th
49、at is actuated toward open by pressure falling below reg-ulator set point downstream of the regulator orifice.7Dual pressure relief device. (1) Two pressure relief devices(valves or rupture members) mounted on a three-way valve thatallows one device to remain active while the other is isolated. Seealso Pressure relief device; Pressure relief valve.1,10Duct. (1) A tube or conduit used to convey or encase. For exam-ple, an air duct is a tube or conduit used to convey air (air passagesin self-contained systems are not air ducts); a pipe duct is a tube orconduit used to encase pipe or
