ASHRAE 181-2014 Methods of Testing for Rating Liquid-to-Liquid Heat Exchangers.pdf

1、ANSI/ASHRAE Standard 181-2014Methods of Testing forRating Liquid-to-LiquidHeat ExchangersApproved by the ASHRAE Standards Committee on June 28, 2014; by the ASHRAE Board of Directors on July 2, 2014; and by theAmerican National Standards Institute on July 3, 2014.ASHRAE Standards are scheduled to be

2、 updated on a five-year cycle; the date following the standard number is the year ofASHRAE Board of Directors 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-m

3、ail:ordersashrae.org. Fax: 678-539-2129. Telephone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US andCanada). For reprint permission, go to www.ashrae.org/permissions. 2014 ASHRAE ISSN 1041-2336Includes Uncertainty Analysis Methodology workbook (See Appendix A).(Requires Mic

4、rosoft Excel)SPECIAL NOTEThis American National Standard (ANS) is a national voluntary consensus standard developed under the auspices of ASHRAE.Consensus is defined by the American National Standards Institute (ANSI), of which ASHRAE is a member and which has approved thisstandard as an ANS, as “su

5、bstantial agreement reached by directly and materially affected interest categories. This signifies the concurrenceof more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that aneffort be made toward their resolution.” Compli

6、ance with this standard is voluntary until and unless a legal jurisdiction makes compliancemandatory through legislation.ASHRAE obtains consensus through participation of its national and international members, associated societies, and public review.ASHRAE Standards are prepared by a Project Commit

7、tee appointed specifically for the purpose of writing the Standard. The ProjectCommittee Chair and Vice-Chair 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 balan

8、ce the concerned interests on all ProjectCommittees.The Manager of Standards of ASHRAE should be contacted for:a. 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 repr

9、int portions of the Standard.DISCLAIMERASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of the public in light of available information andaccepted industry practices. However, ASHRAE does not guarantee, certify, or assure the safety or performance of any products,

10、 components,or systems tested, installed, or operated in accordance with ASHRAEs Standards or Guidelines or that any tests conducted under itsStandards or Guidelines will be nonhazardous or free from risk.ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDSASHRAE Standards and Guidelines are establishe

11、d to assist industry and the public by offering a uniform method of testing for ratingpurposes,bysuggestingsafepracticesindesigningandinstallingequipment,byprovidingproperdefinitionsofthisequipment,andbyprovidingother information that may serve to guide the industry.The creation of ASHRAE Standards

12、and Guidelines is determined by the need for them,and conformance to them is completely 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 Standard P

13、roject Committee 181CognizantTC:TC 8.5, Liquid-to-Refrigerant Heat ExchangersSPLS Liaison: Adam W. HingeJoseph B. Huber, Chair* Justin P. KauffmanThomas P. Carter* James T. Schaefer, Jr. *Lorenzo Cremaschi* Kenneth J. Shultz*Steven J. Eckels* Umair Surani*Denotes members of voting status when the do

14、cument was approved for publicationASHRAE STANDARDS COMMITTEE 20132014William F. Walter, Chair David R. Conover Malcolm D. KnightRichard L. Hall, Vice-Chair John F. Dunlap Rick A. LarsonKarim Amrane James W. Earley, Jr. Mark P. ModeraJoseph R. Anderson Steven J. Emmerich Cyrus H. NasseriJames Dale A

15、swegan Julie M. Ferguson Janice C. PetersonCharles S. Barnaby Krishnan Gowri Heather L. PlattSteven F. Bruning Cecily M. Grzywacz Douglas T. ReindlJohn A. Clark Rita M. Harrold Julia A. Keen, BOD ExOWaller S. Clements Adam W. Hinge Thomas E. Werkema, Jr., CODebra H. KennoyStephanie C. Reiniche, Mana

16、ger of StandardsCONTENTSANSI/ASHRAE Standard 181-2014,Methods of Testing for Rating Liquid-to-Liquid Heat ExchangersSECTION PAGEForeword .21 Purpose.22 Scope23 Definitions .24 Required Test Results.25 Test Methods 26 Instruments and Test Apparatus.37 Test Procedure38 References4Informative Appendix

17、A: Uncertainty Analysis.5Informative Appendix B: Method to Compute the Enthalpy Difference of a Liquid Stream when anEoS-Based Function Is not Available 8NOTEApproved addenda, errata, or interpretations for this standard can be downloaded free of charge from the ASHRAEWeb site at www.ashrae.org/tech

18、nology. 2014 ASHRAE1791 Tullie Circle NE Atlanta, GA 30329 www.ashrae.org All rights reserved.ASHRAE is a registered trademark of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.ANSI is a registered trademark of the American National Standards Institute.2 ANSI/ASHR

19、AE Standard 181-2014(This foreword is not part of this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the standard. It has not been pro-cessed according to the ANSI requirements for a standardand may contain material that has not been subject topublic

20、 review or a consensus process. Unresolved objec-tors on informative material are not offered the right toappeal at ASHRAE or ANSI.)FOREWORDThis standard prescribes methods for testing liquid-to-liquid heat exchangers. To meet this objective, the standardlists and defines the terms for rating liquid

21、-to-liquid heatexchangers and establishes testing methods that are to beused as a basis for obtaining ratings of liquid-to-liquid heatexchangers.The uncertainty analysis methodology discussed in Infor-mative Appendix A has been incorporated into a MicrosoftExcelworkbook which can be located online a

22、twww.ashrae.org/181_2014_UAM.1. PURPOSEThis standard prescribes methods of testing the thermalperformance and pressure drop of liquid-to-liquid heatexchangers.2. SCOPEThis standarda. lists and defines the terms for rating the thermal perfor-mance of liquid-to-liquid heat exchangers;b. establishes th

23、e methods of test to be used as a basis forobtaining the thermal performance and pressure drop ofliquid-to-liquid heat exchangers using water or other sin-gle-phase liquids; andc. applies to laboratory testing for purposes of rating heatexchangers within its scope. This standard is not intendedfor f

24、ield testing of heat exchangers of any type.3. DEFINITION OFTERMSclean: heat exchanger performance without a fouling layer orfactor.cold stream: of the two liquid streams entering the heatexchanger, the stream with the lower entering fluid tempera-ture. Energy will be transferred to this stream.hot

25、stream: of the two liquid streams entering the heatexchanger, the stream with the higher entering fluid tempera-ture. Energy will be transferred from this stream.liquid-to-liquid heat exchanger: a factory-made assembly ofelements in which energy is transferred from one liquid toanother liquid, causi

26、ng one liquid to be cooled and the otherto be heated.log-mean temperature difference (LMTD): logarithmicmean of the temperature difference between the hot and coldstreams at each end of the heat exchanger.temperature of flowing fluids: the mixed mean stream tem-perature at a station perpendicular to

27、 the flow direction.thermal capacity (of the heat exchanger): the quantity ofenergy transferred between the two liquids. This quantity isthe product of mass flow rate for the liquid stream and the dif-ference in enthalpy of the liquid stream as it flows through theheat exchanger, expressed in energy

28、 units per unit of time.4. REQUIREDTEST RESULTS4.1 In expressing test results, the following parameters shallbe stated:a. Net thermal capacity, kW (Btu/h)b. Temperature of entering liquid for both streams, C (F)c. Temperature of leaving liquid for both streams, C (F)d. Liquid mass flow rate of both

29、streams, kg/s (lb/h)e. Description of liquids sufficient to obtain necessary physi-cal propertiesf. Pressure of both fluid streams as they enter the heatexchanger, kPa (psia)g. Pressure drop of both fluid streams, kPa (psi)h. Log mean temperature difference (LMTD), C (F)4.2 For all parameters listed

30、 in Section 4.1, uncertainty shallbe calculated as described in Section 7.4.5. TEST METHODS5.1 Standard Test Methods5.1.1 The thermal capacity of both the hot stream and coldstream shall be determined at the conditions specified.5.1.2 The specified conditions shall include the following:a. Temperatu

31、re of both entering liquid streams, C (F)b. Liquid flow rate of both liquid streams, kg/s (lb/h)c. Pressure of both liquid streams as they enter the heatexchanger, kPa (psi)d. Hot and cold liquids usede. Maximum allowable uncertainty for the reported net ther-mal capacityf. Maximum allowable uncerta

32、inty for the reported logmean temperature differenceg. Maximum allowable uncertainty for the reported pressuredropsh. Arrangement of liquid connections to the heat exchanger5.1.3 The calculated hot stream thermal capacity shall bewithin 3.0% of the calculated cold stream thermal capacityas calculate

33、d by|qh qc|/(qh+ qc)/2 3.0% (5-1)whereqh= thermal capacity of the hot stream, kW (Btu/h)qc= thermal capacity of the cold stream, kW (Btu/h)5.1.4 The stated thermal capacity of the heat exchangershall be the arithmetic average of the hot-stream thermalcapacity and the cold-stream thermal capacity.5.2

34、 Calculation of Thermal Capacity (see Figure 5-1)5.2.1 Determine the thermal capacity for a particularstream by determining the product of the mass flow rate of theANSI/ASHRAE Standard 181-2014 3stream and the difference between the entering and leavingenthalpy of the stream.5.2.2 Determine mass flo

35、w rates of liquid by direct mass orvolume measurement or liquid flowmeter.5.2.3 Determine the entering enthalpy of the liquid by mea-suring the inlet pressure and inlet temperature of the streamand using physical properties of the liquid.5.2.4 Determine the leaving enthalpy of the liquid by mea-suri

36、ng the outlet pressure and outlet temperature of the streamand using physical properties of the liquid.5.2.5 Determine the LMTD using the measured inlet andoutlet liquid temperatures.6. INSTRUMENTS ANDTEST APPARATUS6.1 General6.1.1 Instruments and data acquisition systems shall beselected to satisfy

37、 both of the following requirements:a. Uncertainty requirements listed in Section 5.1.2b. Error limits specified in the sections belowNote: Error limits more stringent than those listed in thesections below may be required to meet the condition of Sec-tion 6.1.1(a).6.1.2 Instrument calibration shall

38、 be traceable to primary orsecondary standards calibrated by the National Institute ofStandards and Technology (NIST) or similar organization.The indicated corrections shall be applied to meet therequired error limits given in subsequent sections. Instru-ments shall be recalibrated on a regular sche

39、dule that isappropriate for each instrument, and calibration records shallbe maintained. All instruments shall be applied in a mannerthat ensures compliance with the specified error limits.6.1.3 The source from which liquid thermodynamic prop-erties are obtained shall be stated in the test report.6.

40、2 Temperature-Measuring Instruments6.2.1 Accuracy shall be that required to meet the uncer-tainty specified in Section 5.1.2.6.2.2 Instruments shall be applied and used in accordancewith ASHRAE Standard 41.1.16.3 Pressure-Measuring Instruments6.3.1 Accuracy shall be that required to meet the uncer-t

41、ainty specified in Section 5.1.2.6.3.2 Instruments shall be applied and used in accordancewith ASHRAE Standard 41.326.4 Liquid Flow-Measuring Instruments6.4.1 Flow measurements shall be made with one or moreof the following instruments or apparatuses:a. Liquid quantity meter, measuring either weight

42、 or volumeb. Liquid flowmeterc. Weight tank, scale, and timer6.4.2 Accuracy shall be that required to meet the uncer-tainty specified in Section 5.1.2.6.4.3 Instruments shall be applied and used in accordancewith ASME PTC 19.5.36.5 Time Measurements. Time measurements shall be madewith an apparatus

43、whose accuracy shall be that required tomeet the uncertainty specified in Section 5.1.2.6.6 Weight Measurements. Weight measurements shall bemade with an apparatus whose accuracy shall be that requiredto meet the uncertainty specified in Section 5.1.2.7. TEST PROCEDURE7.1 Apparatus Assembly7.1.1 The

44、 heat exchanger, selected instruments, and the testapparatus shall be assembled, connected, functionally tested,leak tested, and both hot and cold streams charged with theappropriate amount of liquid.7.1.2 Gases shall be purged from the system. Open fluidloops shall be designed to prevent air entrai

45、nment in the liq-uids.7.1.3 The test fluids must be kept in the liquid state as theypass through the heat exchanger at all times during the test.7.1.4 The results of this test shall be considered as a cleantest.7.2 Operation and LimitsFIGURE 5-1 Depiction of relevant test parameters.TihPihhihmh TohP

46、ohhohTicPichicmcTocPochoc4 ANSI/ASHRAE Standard 181-20147.2.1 Start the system and obtain and maintain the specifiedconditions. After establishment of steady-state conditions, thefollowing conditions must be met:a. The test shall be conducted for a minimum of 30 minutes.b. A minimum of 30 data point

47、s shall be taken.c. The stability of all readings must be sufficient to satisfythe uncertainty requirements listed in Section 5.1.2.7.2.2 The test record shall include the date, names of theobservers, essential identifying physical data of the heatexchanger tested, liquids used, all test readings, r

48、eference toinstrument calibrations and computations, and the determinedresults.7.3 Computation of Results7.3.1 Calculate the hot- and cold-stream thermal capacitiesas follows.qh= mh(hi,hho,h) (7-1)whereqh= thermal capacity of the hot stream, kW (Btu/h)mh= mass flow rate of the hot stream, kg/s (lb/h

49、)hi,h= enthalpy of the hot stream liquid entering the heatexchanger, kJ/kg (Btu/lb)ho,h= enthalpy of the hot stream liquid leaving the heatexchanger, kJ/kg (Btu/lb)andqc= mc(ho,chi,c) (7-2)whereqc= thermal capacity of the cold stream, kW (Btu/h)mc= mass flow rate of the cold stream, kg/s (lb/h)hi,c= enthalpy of the cold stream liquid entering the heatexchanger, kJ/kg (Btu/lb)ho,c= enthalpy of the cold stream liquid leaving the heatexchanger, kJ/kg (Btu/lb)7.3.2 Calculate the net thermal capacity of the heatexchanger as follows:qhx=(qh