1、ANSI/ASHRAE Standard 20-1997 (RA 2016)(Reaffirmation of ANSI/ASHRAE Standard 20-1997)Method of Testing forRating RemoteMechanical-DraftAir-CooledRefrigerant CondensersApproved by ASHRAE on May 31, 2016, and by the American National Standards Institute on June 1, 2016.ASHRAE Standards are scheduled t
2、o be updated on a five-year cycle; the date following the Standard number is the year ofASHRAE approval. The latest edition of an ASHRAE Standard may be purchased on the ASHRAE website (www.ashrae.org)or from ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: ordersashr
3、ae.org. Fax: 678-539-2129. Telephone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US and Canada). For reprintpermission, go to www.ashrae.org/permissions. 2016 ASHRAE ISSN 1041-2336SPECIAL NOTEThis American National Standard (ANS) is a national voluntary consensus Standard de
4、veloped under the auspices of ASHRAE. Consensus is definedby the American National Standards Institute (ANSI), of which ASHRAE is a member and which has approved this Standard as an ANS, as“substantial agreement reached by directly and materially affected interest categories. This signifies the conc
5、urrence of more than a simple majority,but not necessarily unanimity. Consensus requires that all views and objections be considered, and that an effort be made toward their resolution.”Compliance with this Standard is voluntary until and unless a legal jurisdiction makes compliance mandatory throug
6、h legislation. ASHRAE obtains consensus through participation of its national and international members, associated societies, and public review.ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing the Standard. The ProjectCommittee Chair and Vice-Ch
7、air must be members of ASHRAE; while other committee members may or may not be ASHRAE members, allmust be technically qualified in the subject area of the Standard. Every effort is made to balance the concerned interests on all Project Committees. The Senior Manager of Standards of ASHRAE should be
8、contacted fora. interpretation of the contents of this Standard,b. participation in the next review of the Standard,c. offering constructive criticism for improving the Standard, ord. permission to reprint portions of the Standard.DISCLAIMERASHRAE uses its best efforts to promulgate Standards and Gu
9、idelines for the benefit of the public in light of available information and acceptedindustry practices. However, ASHRAE does not guarantee, certify, or assure the safety or performance of any products, components, or systemstested, installed, or operated in accordance with ASHRAEs Standards or Guid
10、elines or that any tests conducted under its Standards or Guidelineswill be nonhazardous or free from risk.ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDSASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method of testing for rating purposes, b
11、ysuggesting safe practices in designing and installing equipment, by providing proper definitions of this equipment, and by providing other informationthat may serve to guide the industry. The creation of ASHRAE Standards and Guidelines is determined by the need for them, and conformanceto them is c
12、ompletely voluntary.In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall be made, either stated or implied,that the product has been approved by ASHRAE.ASHRAE STANDARDS COMMITTEE 20152016Douglass T. Reindl, Chair Steven J. Emmerich Heather L. Plat
13、tRita M. Harrold, Vice-Chair Julie M. Ferguson David RobinJames D. Aswegan Walter T. Grondzik Peter SimmondsNiels Bidstrup Roger L. Hedrick Dennis A. StankeDonald M. Brundage Srinivas Katipamula Wayne H. Stoppelmoor, Jr.John A. Clark Rick A. Larson Jack H. ZarourWaller S. Clements Lawrence C. Markel
14、 Julia A. Keen, BOD ExOJohn F. Dunlap Arsen K. Melikov James K. Vallort, COJames W. Earley, Jr. Mark P. ModeraKeith I. Emerson Cyrus H. NasseriStephanie C. Reiniche, Senior Manager of StandardsASHRAE Standing Standard Project Committee 20-1997Cognizant TC: TC 8.4, Air-to-Refrigerant Heat Transfer Eq
15、uipmentSPLS Liaison: Gordon F. ClydeRoland A. Ares, Chair* Todd Amsey Michael* Paul F. Lammert*Daniel E. Kramer* Richard S. Oas*Denotes members of voting status when the document was approved for publicationCONTENTSANSI/ASHRAE Standard 20-1997 (RA 2016)Method of Testing for Rating RemoteMechanical-D
16、raft Air-Cooled Refrigerant CondensersSECTION PAGEForeword. 21 Purpose 22 Scope . 23 Definitions. 24 Test Methods 25 Test Instruments. 36 Test Apparatus . 67 Test Procedure. 88 Data to be Recorded 99 Source of Physical Properties. 1010 Symbols 1011 Computations 1112 References . 12Appendix A .13Appe
17、ndix B .15NOTEApproved addenda, errata, or interpretations for this standard can be downloaded free of charge from the ASHRAEWeb site at www.ashrae.org/technology. 2006 ASHRAE1791 Tullie Circle NE Atlanta, GA 30329 www.ashrae.org All rights reserved.ASHRAE is a registered trademark of the American S
18、ociety of Heating, Refrigerating and Air-Conditioning Engineers, Inc.ANSI is a registered trademark of the American National Standards Institute.2 ANSI/ASHRAE Standard 20-1997 (RA 2016)(This foreword is not a part of this standard. It is merelyinformative and does not contain requirements necessaryf
19、or conformance to the standard. It has not beenprocessed according to the ANSI requirements for astandard and may contain material that has not beensubject to public review or a consensus process.)FOREWORDThis is a reaffirmation of Standard 20-1997 (RA2007).This standard was prepared under the auspi
20、ces of ASHRAE. Itmay be used, in whole or in part, by an association or govern-ment agency with due credit to ASHRAE. Adherence is strictlyon a voluntary basis and merely in the interests of obtaininguniform guidelines throughout the industry. This version of thereaffirmation has no changes. 1. PURP
21、OSEThis standard prescribes methods of laboratory testing tomeasure the heat rejection capabilities of remote mechanicaldraft, air-cooled refrigerant condensers for refrigerating andair conditioning. The objective is to ensure uniform perfor-mance information for establishing ratings.2. SCOPE2.1 Thi
22、s standard provides a. uniform methods of testing for obtaining performance data,b. definition of terms,c. specification of data to be recorded and calculationformulas, andd. test limits and tolerances.2.2 This standard does not covera. methods of test for production or field use,b. liquid-cooled co
23、ndensers, norc. heat reclaim condensers using less than full refrigerantliquid condensing.3. DEFINITIONS3.1 Generalcalorimeter: a device for accurately determining refrigerantflow rate by the principle of known heat input or output,known physical characteristics of the transfer media, andobserved th
24、ermal differences.condenser subcooling: number of degrees that a pressur-ized liquid is cooled lower than its saturated temperature atthat pressure.condensing temperature: the saturation temperature, indegrees, corresponding to the measured refrigerant pressure atthe condenser inlet.remote mechanica
25、l-draft air-cooled refrigerant condenser:a self-contained, waterless refrigerating system componentthat fully condenses refrigerant vapor by rejecting heat to air,mechanically circulated by integral fans and fan drives over itsfinned-tube heat transfer surface, causing a temperature rise inthe air.
26、Refrigerant gas desuperheating and liquid subcoolingare expected to occur.shall (“it is required”): term used in standards and regula-tions (as “shall” or “shall not”) to indicate a provision that ismandatory.should (“it is recommended”): term used in standards andregulations to indicate a provision
27、 that is not mandatory butthat is recommended as good practice.temperature difference (TD): the difference in degreesbetween the condensing temperature and the entering air dry-bulb temperature.3.2 Coil Dimensionscoil depth: the dimension of the finned surface as measuredfrom the entering air face t
28、o the leaving air face in the directionof airflow.coil face area: the product of the coil length and coil width.coil length: the dimension of the face of the coil in the direc-tion of the finned tubes exposed to the flow of air.coil width: the dimension of the face of the coil perpendicularto the di
29、rection of the tubes and includes only the width overthe tube and fins exposed to the airflow. Note: Height may besubstituted for width if the condenser has a vertical coil orien-tation.3.3 Testing Termsequilibrium: the steady-state condition during which the fluc-tuations of variables being measure
30、d remain within statedlimits.test: the recorded group of readings of test variables takenwhile equilibrium is maintained and used in the computationof results.test run: the complete group of readings of test variables,which includesa. those observed or recorded during a sufficient periodto indicate
31、that equilibrium was obtained prior to thetest andb. those recorded during the period of the test.4. TEST METHODS4.1 General4.1.1 To fulfill the requirements of this standard, twosimultaneous methods of determining condenser capacityshall be usedone primary method and one confirmingmethod. The prima
32、ry method utilizes the refrigerant massflow rate and enthalpy differences of the refrigerant enteringand leaving the condenser. This is determined from the accu-rate measurement of the pressure-temperature state of boththe refrigerant gas entering and liquid leaving the condenser.Condenser heat of r
33、ejection shall then be calculated as a prod-uct of refrigerant flow rate measured (see Section 4.1.2) andthe enthalpy difference.ANSI/ASHRAE Standard 20-1997 (RA 2016) 34.1.2 Primary Methods4.1.2.1 Liquid-Line Flow Method. Refrigerant massflow rate is determined by direct meter reading. This is thep
34、referred primary method.4.1.2.2 Low-Side Electric Calorimeter Method.Refrigerant mass flow rate is determined from the measuredelectrical heat input to a calorimeter divided by the enthalpychange of the refrigerant passing through it.4.1.2.3 Low-Side Water Chiller Method. Refrigerantflow rate is det
35、ermined from the measured water-side heatinput to the chiller divided by the enthalpy change of therefrigerant passing through it.4.1.3 Confirming Methods4.1.3.1 Low-Side Electric Calorimeter Method. Con-denser heat rejection rate is determined by arriving at the sumof the electrical heat input to t
36、he calorimeter and the electricalpower input utilized for the mechanical compression of therefrigerant circulated through the condenser (as corrected forany non-insulated refrigerant line losses).4.1.3.2 Low-Side Water Chiller Method. Condenserheat rejection rate is determined by measuring the sum o
37、f thewater-side heat input to the chiller and the electrical powerinput utilized for the mechanical compression of the refriger-ant circulated through the condenser.4.1.3.3 High-Side Air Calorimeter Method. Measure-ments of the airflow rate shall be made by the use of precisionairflow nozzle(s) (see
38、 Section 6.2.9). The condenser heattransfer rate shall then be calculated as the product of the airmass flow rate, specific heat, and temperature rise of the air.4.1.3.4 Calibrated Compressor Method. Condensercapacity shall be determined from lab test data utilizing a cal-ibrated compressor. The cal
39、ibrated compressor shall beemployed within the range of test conditions of its calibration.The condenser heat rejection rate is taken from the compres-sor calibration curve at the test operating points of refrigerantpressure and temperature and power (kW) of the compressor.4.1.3.5 Suction Line Orifi
40、ce Method. Refrigerantmass flow as determined by the orifice method set forth inANSI/ASHRAE Standard 41.7-1984 (RA 2006),StandardMethod for Measurement of Flow of Gas.104.2 Energy Balance. For a test run to be valid, the heatrejection capacity of the condenser, as measured by the pri-mary and the co
41、nfirming methods, shall agree within 5% (seeSection 7.7). Note: A confirming method may be another ofthe primary methods not therein used for that test run.5. TEST INSTRUMENTS5.1 General. Calibration of all instrumentation, includingpressure transducers and temperature diodes and their cir-cuits, ut
42、ilized for test measurements for Sections 8.3, 8.4, and8.5, shall be performed before and after each run or series oftest runs extending over not more than seven elapsed days.Calibration shall be traceable to primary or secondary stan-dards calibrated by the National Institute of Standards andTechno
43、logy (NIST). Standard test instruments that have beencalibrated in accordance with such standards, having the sameor greater accuracy than required by this standard, which areused solely for test laboratory standardizing purposes, complywith the intent of this paragraph.Each instrument calibration s
44、hall be recorded and a copythereof made part of the test record of the condenser. Beforeand after test calibration shall be within the accuracy limitsstated as follows for each instrument type. Where calibrationof an instrument after a test series exceeds the applicable limit,analysis may be conduct
45、ed to determine whether the possibleerror induced by the uncertainty is significant, that is, wouldcause the primary and confirming heat rejections to differ bymore than 5%. If not, the result may be retained. This appliesexcept where the out-of-calibration instrument is employed inboth the primary
46、and confirming method, the run or series ofruns shall be discarded.5.2 Temperature-Measuring Instruments5.2.1 Temperature measurements shall be made with aninstrument or instrument system meeting the accuracy andprecision requirements in Section 5.2.2. The following are incommon use for this purpose
47、: a. mercury-in-glass thermometersb. thermocouples with potentiometerc. electric resistance thermometers, including thermistorsand other semiconductor-type devices5.2.2 The accuracy of the temperature-measuring instru-ments shall be within limits as follows:a. dry-bulb air and water temperatures: 1%
48、 of the smallestrequired test temperature difference (TD) computed inaccordance with Section l1.5, i.e., 0.1F (0.06 K) for a10F (6 K) minimum test TDb. refrigerant vapor temperatures: 1.0F (0.6C)c. all other temperatures: 0.5F (0.3C)5.2.3 In no case shall the smallest decimal scale divisionof the in
49、strument exceed twice the specified accuracy; forexample, if the specified accuracy is to be 0.5F (0.3C), thesmallest scale division shall not exceed 1.0F (0.6C).5.2.4 Wherever possible, arrange temperature-measuringinstruments used to measure the change in temperature of a liq-uid or gas so that they readily can be interchanged between inletand outlet positions after every reading, to improve accuracy.5.2.5 The use of two complete sets of temperature-mea-suring instruments, or one air-sampling tube arrangement,meeting the requirements for measuring condenser e
