AHRI 450-2007 Performance Rating of Water-Cooled Refrigerant Condensers Remote Type.pdf

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1、 2007 Standard for Performance Rating of Water-Cooled Refrigerant Condensers, Remote Type AHRI Standard 450-2007 (Formerly ARI Standard 450-2007)Price $10.00 (Members) $20.00 (Non-Members) Copyright 2007, by Air-Conditioning, Heating, and Refrigeration Institute Printed in U.S.A. Registered United S

2、tates Patent and Trademark Office IMPORTANT SAFETY DISCLAIMER AHRI does not set safety standards and does not certify or guarantee the safety of any products, components or systems designed, tested, rated, installed or operated in accordance with this standard/guideline. It is strongly recommended t

3、hat products be designed, constructed, assembled, installed and operated in accordance with nationally recognized safety standards and code requirements appropriate for products covered by this standard/guideline. AHRI uses its best efforts to develop standards/guidelines employing state-of-the-art

4、and accepted industry practices. AHRI does not certify or guarantee that any tests conducted under its standards/guidelines will be non-hazardous or free from risk. Note: This standard supersedes ARI Standard 450-99. TABLE OF CONTENTS SECTION PAGE Section 1. Purpose . 1 Section 2. Scope .1 Section 3

5、. Definitions .1 Section 4. Test Requirements .2 Section 5. Rating Requirements .2 Section 6. Minimum Data Requirements for Published Ratings 5 Section 7. Marking and Nameplate Data 6 Section 8. Conformance Conditions .6 TABLES Table 1. Standard Rating Conditions .3 APPENDICES Appendix A. References

6、 Normative 7 Appendix B. References Informative 7 AHRI STANDARD 450-2007 1 PERFORMANCE RATING OF WATER-COOLED REFRIGERANT CONDENSERS, REMOTE TYPE Section 1. Purpose 1.1 Purpose. The purpose of this standard is to establish for remote type, Water-Cooled Refrigerant Condensers: definitions; test requi

7、rements; rating requirements; minimum data 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 manufacturers, engineers, installers, contractors and users. 1.1.2 Review and Ame

8、ndment. This standard is subject to review and amendment as technology advances. Section 2. Scope 2.1 Scope. This standard applies to water-cooled refrigerant condensers. 2.2 Exclusions. This standard does not apply to condensers supplied as components of factory-assembled refrigeration and air-cond

9、itioning units. Section 3. Definitions All terms in this document follow the standard industry definitions in the current edition of ASHRAE Terminology of Heating, Ventilation, Air Conditioning and Refrigeration, unless otherwise defined in this section. 3.1 Bubble Point. Refrigerant liquid saturati

10、on temperature at a specified pressure. 3.2 Clean Tube Capacity. The Total Heat Rejection Effect of the condenser with clean tubes at Standard Rating Conditions expressed in Btu/h W. 3.3 Dew Point. Refrigerant vapor saturation temperature at a specified pressure. 3.4 Field Fouling Allowance. Provisi

11、on for the anticipated Fouling Factor during use. 3.4.1 Fouling Factor. The thermal resistance due to fouling accumulated on the heat transfer surface. 3.5 Liquid Refrigerant Storage Capacity. The maximum liquid refrigerant storage capacity of a condenser shall be computed as being 80 percent of the

12、 available volume for the refrigerant and shall be expressed in ft3L or in lb kg of a specified refrigerant, assuming saturated liquid refrigerant density at 90.0F 32.2C. 3.6 Nominal Refrigerating System Capacity. The cooling effect determined by the product of the mass flow rate of refrigerant and

13、the difference in enthalpy between the refrigerant entering the evaporator and the refrigerant leaving the evaporator. 3.7 Published Rating. A statement of the assigned values of those performance characteristics, under stated Rating Conditions, by which a unit may be chosen to fit its application.

14、These values apply to all Water-Cooled Refrigerant Condensers of like nominal size and type produced by the same manufacturer. As used herein, the term Published Rating includes the rating of all performance characteristics shown on the unit or published in specifications, advertising or other liter

15、ature controlled by the manufacturer, at stated Rating Conditions. AHRI STANDARD 450-2007 2 3.7.1 Application Rating. A rating based on tests performed at application Rating Conditions (other than Standard Rating Conditions). 3.7.2 Standard Rating. A rating based on tests performed at Standard Ratin

16、g Conditions. 3.8 Rating Conditions. Any set of operating conditions under which a single level of performance results and which causes only that level of performance to occur. 3.8.1 Standard Rating Conditions. Rating Conditions used as the basis of comparison for performance characteristics. 3.9 Sa

17、turated Condensing Temperature. For single component and azeotrope refrigerants, it is the saturated temperature corresponding to the refrigerant pressure at the condenser entrance. For zeotropic refrigerants, it is the arithmetic average of the dew point and bubble point temperatures corresponding

18、to the refrigerant pressure at the condenser entrance. 3.10 “Shall“ or “Should.“ “Shall“ or “should“ shall be interpreted as follows: 3.10.1 Shall. Where “shall“ or “shall not“ is used for a provision specified, that provision is mandatory if compliance with the standard is claimed. 3.10.2 Should. “

19、Should“ is used to indicate provisions which are not mandatory but which are desirable as good practice. 3.11 Total Heat Rejection Effect. The total amount of heat removed from the refrigerant. This value is the product of the mass flow rate of refrigerant and the difference in enthalpy between the

20、entering refrigerant vapor and the leaving refrigerant liquid, expressed in Btu/h W. (The total heat rejection, for all practical purposes, is the total heat transfer in the evaporator of the system plus the heat added to the refrigerant by the refrigeration compressor.) 3.12 Water-Cooled Refrigeran

21、t Condenser. A factory-made assembly in which heat is transferred from the refrigerant vapor to the water such that the refrigerant vapor is condensed into a liquid. Section 4. Test Requirements 4.1 Test Requirements. All Standard Ratings shall be verified by tests conducted in accordance with ASHRA

22、E Standard 22. Section 5. Rating Requirements 5.1 Standard Rating. Published Ratings shall include the Standard Rating, as specified, for at least one of the rating conditions shown in Table 1 and properly identified as the Standard Rating. Standard Ratings shall be based on tests with initially cle

23、an tubes. The water-side and refrigerant-side Fouling Factors shall be assumed to be zero. 5.2 Application Ratings. Application Ratings provide performance data at operating conditions other than those shown in Table 1. Whenever Application Ratings are published or printed, they shall include, or be

24、 accompanied by, the Standard Rating, clearly designated as such, including a statement of the conditions at which the ratings apply. Application Ratings shall contain all information shown in 6.2. When Application Ratings include a water-side Field Fouling Allowance, they shall be calculated by the

25、 method specified in 5.3. Published Ratings shall be subject to the tolerances of this standard. 5.2.1 Either Application Ratings or a method of adjusting the clean tube ratings may be presented to show the effect of various water-side Field Fouling Allowances. These calculation methods or methods o

26、f adjusting these ratings shall be calculated in accordance with 5.3. AHRI STANDARD 450-2007 3 Table 1. Standard Rating Conditions Rating Condition Saturated Condensing Temperature of the Entering Refrigerant Minimum Actual Temperature of the Entering Refrigerant Vapor Temperature of Entering Water

27、Temperature of Leaving Water F C F C F C F C 1 2 3 4 105 105 85.0 100 40.6 40.6 29.4 37.8 125 125 105 120 51.7 51.7 40.6 48.9 75.0 85.0 50.0 70.0 23.9 29.4 10.0 21.1 95.0 95.0 70.0 85.0 35.0 35.0 21.1 29.4 5.2.2 The manufacturer shall publish the maximum and minimum recommended flow rates for clean

28、water. 5.3 Determination of Ratings. Ratings shall be determined in accordance with the following: 5.3.1 Clean Tube Ratings. Clean tube ratings shall be based on tests with initially clean tubes and conducted in accordance with 4.1. The results of these tests shall be accepted as reflecting a Foulin

29、g Factor of zero. 5.3.2 Fouled Ratings. From the results of the clean tube tests, calculate the clean tube overall heat transfer coefficient, Uc. Then, mathematically add the specified Fouling Factor to the reciprocal of the clean tube Ucand calculate the fouled ratings for publication using the fol

30、lowing method (refer to ARI Guideline E for discussion of Fouling Factors). ccqUA(LMTD)(1) where: w1swe sswew1s t(- ) - (- )ttt tLMTD = -ttln -twl weswl wlweswl( - )tt= (- ) + ( - )tt t tln-ttR= LMTDln (1+ R/S)(2) The following equations shall be used to calculate fouled ratings: 5.3.2.1 For fouling

31、 inside tubes (condensing outside): a. Based on outside surface: fcofooiiAA1U = 1+ rU(3a) AHRI STANDARD 450-2007 4 b. Based on inside surface: fificiU1= 1+ rU(3b) 5.3.2.2 For fouling outside tubes (condensing inside): a. Based on outside surface: fofoco1U = 1+ rU(3c) b. Based on inside surface: fiif

32、ocioAA1U 1rU(3d) 5.3.2.3 The following equations shall be used for all configurations to obtain the small temperature difference, Sf, at the fouled conditions: a. Based on outside surface: fxR= S- 1e(4a) Where: ofoU AR x = qb. Based on inside surface: fyR= S- 1e(4b) Where: ifi AURy = q5.3.2.4 The ne

33、w condensing temperature with fouled tubes, tsf, can then be found using the small temperature difference, Sf : sf w1 ftS = + t (5) AHRI STANDARD 450-2007 5 5.3.2.5 Symbols and Subscripts. The symbols and subscripts used in Equations 1 through 5 are as follows: Symbols: A = Total heat transfer surfa

34、ce, ft2m2 Ai /Ao= Ratio of inside to outside surface area Ao /Ai= Ratio of outside to inside surface area e = Base of natural logarithm LMTD = Logarithmic mean temperature difference, F C q = Total heat rejection rate, Btu/h W r = Heat transfer resistance, h ft2 F/Btu m2 C/W R = Water temperature ra

35、nge = twl- twe, F C S = Small temperature difference = ts- twl, F C t = Temperature, F C U = Overall heat transfer coefficient, Btu/h ft2 F W/m2 C Subscripts: c = clean e = entering f = fouled or fouling i = inside l = leaving o = outside s = saturated condensing w = water 5.4 Tolerances. To comply

36、with this standard, measured test results shall not be less than 95% of the Published Rating for Total Heat Rejection Effect and shall not exceed 110 percent of the Published Ratings for pressure drop. Section 6. Minimum Data Requirements for Published Ratings 6.1 Minimum Data Requirements for Publi

37、shed Ratings. As a minimum, Published Ratings shall include all Standard Ratings. All claims to ratings within the scope of this standard shall be accompanied by the statement “Rated in accordance with AHRI Standard 450.” All claims to ratings outside the scope of this standard shall be accompanied

38、by the statement “Outside the scope of ARI Standard 450.” Wherever Application Ratings are published or printed, they shall include a statement of the conditions at which the ratings apply. Application Ratings shall contain all information shown in 6.2. When Application Ratings include a liquid-side

39、 Fouling Factor, they shall be calculated by the method specified in 5.3. 6.2 Published Ratings 6.2.1 Published Ratings shall include the following: a. Refrigerant designation(s) in accordance with ANSI/ASHRAE Standard 34 with Addenda b. Saturated Condensing Temperature, F C c. Leaving liquid refrig

40、erant temperature, F C d. Total Heat Rejection Effect, Btu/h W e. Water flow rate, gpm L/s f. Water pressure drop, psi kPa g. Fouling Factor (waterside) ft2 h F/Btu m2 C/W AHRI STANDARD 450-2007 6 plus at least one of the following: h. Temperature of entering water, F C i. Temperature of leaving wat

41、er, F C 6.2.2 Published Ratings shall be accompanied by the following information: a. Design pressures for water-side and refrigerant-side, psig kPa b. Overall dimensions c. All connection sizes and types d. Maximum refrigerant storage capacity, ft3L or lb kg e. Shipping weight, lb kg f. Operating w

42、eight (including refrigerant and water), lb kg g. If only clean tube ratings are published, a statement shall be included to contact the manufacturer if fouled tube ratings are required Section 7. Marking and Nameplate Data 7.1 Marking and Nameplate Data. As a minimum, each condenser shall have the

43、following information shown in a conspicuous place: a. Name of manufacturer b. Manufacturers model or serial number c. Design pressure for the water-side, psig kPa d. Design pressure for the refrigerant-side, psig kPa e. Refrigerant designation in accordance with ANSI/ASHRAE 34 with Addenda Section

44、8. Conformance Conditions 8.1 Conformance. While conformance with this standard is voluntary, conformance shall not be claimed or implied for products or equipment within the standards Purpose (Section 1) and Scope (Section 2) unless such product claims meet all of the requirements of the standard a

45、nd all of the testing and rating requirements are measured and reported in complete compliance with the standard. Any product that has not met all the requirements of the standard shall not reference, state, or acknowledge the standard in any written, oral, or electronic communication. AHRI STANDARD

46、 450-2007 7 APPENDIX A. REFERENCES NORMATIVE A1 Listed here are all standards, handbooks, and other publications essential to the formation and implementation of the standard. All references in this appendix are considered as part of this standard. A1.1 ANSI/ASHRAE Standard 34-2004 with Addenda, Des

47、ignation and Safety Classification of Refrigerants, 2004, American National Standards Institute/American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc., 11 West 42nd Street, New York, NY 10036 U.S.A./1791 Tullie Circle, N.E., Atlanta, GA 30329, U.S.A. A1.2 ASHRAE Standard 22

48、-2003, Methods of Testing for Rating Water Cooled Refrigerant Condensers, 2003, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle, N.E., Atlanta, GA 30329, U.S.A. A1.3 ASHRAE Terminology of Heating, Ventilation, Air-Conditioning and Refrigeration, 19

49、91, Second Edition, American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc., 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A. APPENDIX B. REFERENCES INFORMATIVE B1 Listed here are standards, handbooks and other publications which may provide useful information and background but are not considered essential. References in this appendix are not considered part of the standard. B1.1 AHRI Guideline E-1997 (formerly ARI Guileline