ARI 470-2001 Desuperheater Water Heaters《减温器或热水器》.pdf

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1、2001 STANDARD for AIR-CONDITIONING test requirements; rating requirements mniimimi daia requirements for Published Ratings; marking and nameplate data; and conformance conditions. 1.1.1 Intent. This standard is intended for the guidance of the industry, including manucturers, engheers, installers, c

2、ontractors and users. 1.1.2 Review and Amendment. This standard is subject to review and amendment as technology advances. Section 2. Scope 2.1 Scope. Thk standard applies to DesuperhaterNater Heaters supplied as separate components, as defined in Section 3 and using single component and azeotropic

3、reigerants oniy. 2.2 Exclusions. This standard does not apply to DesuperheaterNater Heaters supplied as components of ctory-assembled reiigeration or air conditioning units. This standard does not apply to systems using zeotropic refiigerants. Section 3. Definitions All terms this document shall fol

4、low the standard industry definitions in the current edition ofASHRAE Terminology of Heating, Ventilation, Air Conditioning, and Refrigeration unless otherwise defned in this section. 3.1 Desuperheutermater Heater. A ctory-made assembly of elements by which refngerant vapor flow and water flow are m

5、aintained in such heat transfer relationship that the refngerant vapor is desuperhated and the water is heated. 3.2 Fouling Factor during use. Field Fouling Allowance. Provisions for anticipated 3.2.1 to fouling accumulated on the heat transfer surfce. Fouling Factor. The thermai resistance due 3.3

6、Net Heating Capacity. The useful heat exchanged between the reigerant vapor and the water being heated. This value is the product ofhe mass flow rate of water, the specific heat of water and the water temperature rise, BtUm Wl. 3.3.1 Clean Tube CapaciQ. This is the Net Heating Capacity of the heat e

7、xchanger, Btulh Wl, with clean tubes at the Rating Conditions chosen per Table 1. 3.4 Published Rating. A statement of assigned values of those performance characteristics, under stated rating conditions, by which a unit may be chosen to fit its application. These values apply to ali DesuperheaterlW

8、ater Heaters of like nominal size and type (identifidon) produced by the same manucturer. As used herein, the team hbliched Rating includes all performance charactexkcs shown on the unit or published in specifications, advertking or other literature controlled by the manufcurer, at stated Rathg Cond

9、itions. 3.4.1 perfnned at Application Rating Conditions. Application Rating. Arahg based on tests 3.4.2 Standard Rating. A rating based on tests perbnned at Standard Rating Conditions. 3.5 Rating Conditions Any set of operating conditions under which a single level of performance results and which c

10、auses oniy that level of performance to occur. 3.5.1 Application Rating Conditions, Rating Conditions other than Standard Rating Conditions. 3.5.2 Standard Rating Conditions. Rating Conditions used as the bask of comparison fix performance characteristics. 3.6 “Shall“ or “Should.“ “Shall“ or “should

11、“ shali be interpreted as follows: 3.6.1 Shall. Where “shall“ or “shall not“ is used fir a provision specified, that provision k mandatory if compliance With the standard is claimed. 3.6.2 Should. “Should“ is used to indicate provisions which are not mandatory but which are desirable as good practic

12、e. Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AR1 STANDARD 470-2001 Table 1. Standard Rating Conditions I I Note: Ratings are for single component and azeotropic refii

13、gerants only. Excluded are zeotropic reftigerants. Section 4. Test Requirements 4.1 Test Requirements. The tests shall be conducted in accordance with the test procedure contained in Appenix C. Section 5. Rating Requirements 5.1 Published Ratings. Published Ratings consist of Standard Ratings and Ap

14、plication Ratings. Such ratings shall be based on tests of DesuperheaterAVater Heaters with the reigerant specified in the ratings. 5.2 Standard Ratings. Published Ratings shall include the Standard Rating, given for one of the Standard Rating Conditions shown in Table 1 and properly identified as t

15、he Standard Rating. Standard Ratings shall be based on tests with initially clean tubes. 5.3 Application Ratings. Application Ratings give perfrmance data under operating conditions other than those shown in Table 1. Application Ratings shall contain all infrmation shown in 6.2. When Application Rat

16、ings include water-side Field Fouling Ailowance(s) they shall be calculated by the method specified in 5.4. Published Ratings shaii be subject to the tolerances of this standard. 5.3.1 Either Application Ratings or a method of adjusting the clean tube ratings may be presented to show the effect of v

17、arious waterside Field Fouhg Aliowances. These calculation methods or method of adjusting these ratings shall be caicuiated in accordance with 5.4. 5.4 in accordance with the following: *Detemination of Ratings. Ratings shall be determined 5.4.1 Clean Tube Ratings. Published Rathgs sha be determined

18、 by test with initially clean tubes at conditions specified for the selected system in Table 1 and conducted in accordance with Appendix C. The results of these tests shall be accepted as including a Fouling Factor of zero. 5.4.2 Fouled Tube Ratings. From the results of the clean tube tests, calcula

19、te the clean tube overall heat transfer coefficient, U,. Then, mathematically add the specified Fouling Factor to the recipmcal of the clean tube U, and calculate the fouled ratings for publication, using the foliowing methods, as applicable. a. Tube-in-tube (counter flow arrangement shown - paralle

20、l flow also covered). ingle tube pass shell-in-tube (counter flow arrangement shown - parallel flow also covered). t Y8 *Note: Where steady state operation is in a condensing mode, this analysis will be in error. Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license wi

21、th ARINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AR1 STANDARD 470-2001 c. Coil-in-sheil, single pass (counter flow arrangement shown - parallel flow also The next step in determination of fouled ratings is the calcuiation of the total thermal resistance includ

22、ing covered). Obtain U, from the foilowing equation: 4 A -(LMTD), U, = where (LMTD), is defined by: Parallelel Plow Flow Le for counterflow: Fbw Length 1 2a 2b The total thermal resistance is equal to the reciprocal of the overall coefficient of heat transfer: fouling. This is found by addbig the sp

23、ecified Fouling Factor to the clean-tube overall resistance, as illustrated below. 1. Refrigerant outside tubes (fouling inside): A. Basing calcuaons on outside surface area: ,. B. Basing calculations on inside 4b 2. Refrigerant inside tubes (fouling outside): A. Basing calcuations on outside surfce

24、 area: R fo Rc0 i- rfo 5a B. Basing calculations on inside surce ara: Now calculate the following: Ch& = ( ri c& = Hot fluid (refrigerant) capacity rate at Rating Conditions, Btu/(h - OF) W/OC Cco1d = (ri *c&, = Cold fluid (water) capacity rate at Rating Conditions, Btu/ (h * OF) W/OC C- = The small

25、er of Chd or Ccold C, = The larger of Got or Coo1d 9nax = Gnin (t, - 447 Btum wl , dimension1 ess 6 A Rf * Cmin NTU = where Rf is based on area A. 3 3 Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARINot for ResaleNo reproduction or networking permitted wi

26、thout license from IHS-,-,-AR1 STANDARD 470-2001 The actual heat transfer under fouled conditions, qfi is calculated iTom 4f EQ- 7 where E is determined for either counterflow or parallel flow arrangements of the exchanger types shown in 4.4.2, items a, b and c. Counterflow, where Cmin f Cmm: 1 -NW

27、I-Cd IC- ( 1 - EXP -NTu I CmICmrU) 1-(C- ICmm)EXP - where Cmin = Cmm: NTU E= (l+NTU) 8b Parailel flow: I - Exp -m(1 + Cmin 1 Cma) I + (Cmin 1 Cma) E= 8c Now having the actual heat transfer under fouled conditions, the leaving water and reigaant temperatures can be caiculated fiom: cold 4.f t, =t, -

28、ChOt 9a 9b The combination of qfi twe and tre define the fouled ratings at the given operating conditions. 5.5 used in Equations 1 through 9 are as foliows: Symbols and Subscripts. The symbols and subscripts Symbols: A = Total heat transfer area, It2 m C = Flow-stream capacity rate (ri? . $), c, = S

29、pecific heat at constant pressure, Btu E = Exchanger heat transfer effectiveness Btd (h . OF) W/“C (lb*“F) kJ/ (kgoc) EXP = Baseofnaturallogarithm,e LMT = ri?= Log mean temperature difference, OF Fluid mass flow rate, Iblh kg/s “CI NTU = Number of exchanger heat transfer units q = Total heat transfe

30、r rate, Btu/h WJ R = otal thermal resistance, hIt2.0 r = Individuai thermal resistance term, t = Temperature, “F “CI U = Overail heat transfer coefficient, m2-oCIw h.ft“F/Btu m.“C/w t/(h It2.“q W/(-C) Subscripts: c= e= i= I= r= f= o= w= Clean Entering Fouled or fouling Inside Outside ReXgerant Water

31、 Leawig 5.6 Tolerances. To comply with this siandard, published Net Hating Capacity shall be based on data obtained in accordance with the provisions of this siandard, and shall be such that any production unit selected at random and tested in accordance With this standard shaii have a Net Heating C

32、apacity not less than 95% of the Published Rating, a water pressure drop not more than 110% of the published water pressure drop and a refigerant pressure drop not more than 110% ofthe published refigerant pressure drop. Section 6. Minimum Data Requirements for Published Ratings 6.1 Minimum Data Req

33、uirements for Published Ratings. As a minimum, Published Ratings shall include ail Standard Ratings. Ail ch to ratings within the scope of this standard shaii include the statement “Rated in accordance with ART Standard 470.“ All claims to ratings outside the scope of this siandard shall include the

34、 statement “Outside the scope of ARI Standard 470.“ Wherever Application Ratings are published or printed, they shall include a statement of the conditions at which the ratings apply. 6.2 Published Ratings. Published Ratings shall state allhe pertinent operating conditions and shall include the foll

35、owing: a. Reigerant designation(s) per ANSVASHRAE Standard 34 with Addenda b. Entering refrigerant temperature, “F “CI c. Entering reiigerant pressure, psig Pa gage d. Net Heating Capacity, Btu/h Wl e. Water flow rate, gpm Us E Water pressure drop, psi or fi H20 Ha g. Reigerant side pressure drop, p

36、si Wal h. Reiigerant mass flow rate, lbh pgk 4 Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STANDARD 470-2001 i. Fouling Factor (water-side), ft2h.“F/BtU m2.“CMr Section

37、 7. Marking and Nameplate Data Plus at least one of the following: j. k. Entering Water Temperature, OF “CI Leaving Water Temperature, OF “CI 6.3 hiblished Ratings shall be accompanied by the foliowing information: a. b. c. d. Design pressures for water-side and refngerant- side, psig kPa gage Minim

38、um water flow rate, gpm Us, at minimum entering water temperature, OF “CI Maximum recommended flow rate, gpm Us Ifonly clean tube ratings are published, a statement shall be included to contact the manucturer if fouied tube ratings are required 7.1 Marking and Nameplate Data. As a minimum, each Desu

39、perheaterwater Heater shall have the following inforpation shown in a conspicuous place: a. Name of manucturer b. Ivanucturers model number c. d. Design working pressure for the water side Design working pressure fr the reiigerant side Section 8. Conformance Conditions 8.1 Conformance. While conform

40、ance with this standad is voluntary, conformance shall not be claimed or irnpfied iDr products or equipment within its Purpose (Section 1) and Scope (Section 2) unless such claims meet all of the requirements of the standard. 5 Copyright Air-Conditioning and Refrigeration Institute Provided by IHS u

41、nder license with ARINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AR1 STANDARD 470-2001 APPENDIX A. REFERENCES - NORMATIVE Al Listed here are aii sandards, handbooks and other A1.3 ASHRAE Handbook- Fundamentals, 2001, publications essential to the rmation and im

42、plementation of American Society of Heating, Rekigerating and Air- the standard. AU references in this appendix are considered as Conditioning Engineers, Inc., 1791 Tullie CircleN.E., part of the Standard. Atlanta, GA 30329, U.S.A. Al.l ANSVASHRAE Standard 34-1997 with A1.4 ASHRAE Terminology of Hea

43、ting, Addenda, Designation and Safety Classification of Ventilation, Air Conditioning and Refrigeration, Refrigerants, 1997, American Society of Heating, Second Edition, 1991, American Society of Heating, Rekigerating and Air-conditioning Engineers, Jnc., Reigerating and Air-conditioning Engineers,

44、Inc., 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A. 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A. A1.2 ANSVASHRAE Standard 41.1-1986 (RA A1.5 ASME Standard PTC 19.5-1972,Application 9 i), Standard Method for TernperarureMeasurement, Part II of Fluid Meters, 1972, American Society of 199 1,

45、 American Society of Heating, Rekigerating and Mechanical Engineers, 345 East 47th Street, New Air-Conditioning Engineers, Inc., 1791 Tullie Circle York, NY 10017, U.S.A. N.E., Atlanta, GA 30329, U.S.A. APPENDIX B. REFERENCES = INFORMATIVE B1 Listed here are standards, handbooks and other B1.l ANSVA

46、SHRAE Standard 41.2-1987 (RA publications which may provide usefid inknation and background but are not considered essentiai. References in this appendix are not considered part of the standard. 92), Standard Methods for Laboratory Air Flow Measurement, 1987, American Society of Heating, Reigerating

47、 and Air-conditioning Engineers, Inc., 1791 Tuiiie Circle N.E., Ahta, GA 30329, U.S.A. 6 Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AR1 STANDARD 470-2001 APPENDIX C. M

48、ETHOD OF TESTING DESUPERHEATEWATER HEATERS - NORMATIV C1 for rating DesuperheaterWater Heaters. C2 Heaters supplied as a separate component. C3 Definitions. C3.1 identicai with those in Section 3 of this standard. Pulpose. This appendix prescribes methods of testing Scope. This appendix applies to D

49、esuperheatermater Definitions. Definitions of this appendix are C4 Test Results. C4.1 Test results shall be expressed in the fllowhg c5 tenns: a. b. d. e. g- h. C. 1. j. Net Heating Capacity, Btu/h WJ Entering water temperature, OF “CI Leaving water temperature, OF “CI Entering refrigerant temperature, OF “CI Water flow rate, gpm Us Ref