1、 4100 N. FAIRFAX DR., SUITE 200 ARLINGTON, VIRGINIA 22203 2007 STANDARD for PERFORMANCE RATING OF WATER-COOLED REFRIGERANT CONDENSERS, REMOTE TYPE Standard 450 Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or networking pe
2、rmitted without license from IHS-,-,-Price $10.00 (Members) $20.00 (Non-Members) Copyright 2007, by Air-Conditioning and Refrigeration Institute Printed in U.S.A. Registered United States Patent and Trademark Office IMPORTANT SAFETY DISCLAIMER ARI does not set safety standards and does not certify o
3、r 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 that products be designed, constructed, assembled, installed and operated in accordance with nationally recognized safet
4、y standards and code requirements appropriate for products covered by this standard/guideline. ARI uses its best efforts to develop standards/guidelines employing state-of-the-art and accepted industry practices. ARI does not certify or guarantee that any tests conducted under its standards/guidelin
5、es will be non-hazardous or free from risk. Note: This standard supersedes ARI Standard 450-99. Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE OF CONTENTS SECTION P
6、AGE Section 1. Purpose . 1 Section 2. Scope .1 Section 3. Definitions .1 Section 4. Test Requirements.2 Section 5. Rating Requirements .2 Section 6. Minimum Data Requirements for Published Ratings5 Section 7. Marking and Nameplate Data6 Section 8. Conformance Conditions.6 TABLES Table 1. Standard Ra
7、ting Conditions.3 APPENDICES Appendix A. References Normative 7 Appendix B. References Informative 7 Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright Air-Conditio
8、ning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ARI STANDARD 450-2007 1 PERFORMANCE RATING OF WATER-COOLED REFRIGERANT CONDENSERS, REMOTE TYPE Section 1. Purpose 1.1 Purpose. The purpose of thi
9、s standard is to establish for remote type, Water-Cooled Refrigerant Condensers: definitions; test requirements; 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 t
10、he industry, including manufacturers, engineers, installers, contractors 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. This standard applies to water-cooled refrigerant condensers. 2.2 Exclusions. This stan
11、dard does not apply to condensers supplied as components of factory-assembled refrigeration and air-conditioning 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 an
12、d Refrigeration, unless otherwise defined in this section. 3.1 Bubble Point. Refrigerant liquid saturation 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
13、. Refrigerant vapor saturation temperature at a specified pressure. 3.4 Field Fouling Allowance. Provision 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
14、 maximum liquid refrigerant storage capacity of a condenser shall be computed as being 80 percent of the 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
15、 System Capacity. The cooling effect determined by the product of the mass flow rate of refrigerant and 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
16、 characteristics, under stated Rating Conditions, by which a unit may be chosen to fit its application. 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
17、performance characteristics shown on the unit or published in specifications, advertising or other literature controlled by the manufacturer, at stated Rating Conditions. Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or ne
18、tworking permitted without license from IHS-,-,-ARI 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 Rating Conditions. 3.8 Ra
19、ting 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 Saturated Condensing T
20、emperature. 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 to the refrigerant p
21、ressure 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. “Should“ is used to i
22、ndicate 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 entering refrigerant
23、 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 Refrigerant Condenser. A facto
24、ry-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 ASHRAE Standard 22. Secti
25、on 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 clean tubes. The water-
26、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 accompanied by, the
27、 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 method specified in
28、 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 of adjusting these ra
29、tings shall be calculated in accordance with 5.3. Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ARI STANDARD 450-2007 3 Table 1. Standard Rating Conditions Rating Condit
30、ion Saturated Condensing Temperature of the Entering Refrigerant Minimum Actual Temperature of the Entering Refrigerant Vapor Temperature of Entering Water 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.
31、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 water. 5.3 Determination of Ratings. Ratings shall be determined in accordance with the following: 5.3.1 Clean Tube Ratings. Clean tube ratings
32、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 Fouling 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
33、. Then, mathematically add the specified Fouling Factor to the reciprocal of the clean tube Ucand calculate the fouled ratings for publication using the following method (refer to ARI Guideline E for discussion of Fouling Factors). ccqUA(LMTD)=(1) where: w1swe sswew1s t(- ) - (- )ttt tLMTD = -ttln -
34、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 inside tubes (condensing outside): a. Based on outside surface: fcofooiiAA1U = 1+ rU(3a) Copyright Air-Conditioning and Refrigeration Institut
35、e Provided by IHS under license with ARI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ARI 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)
36、 b. Based on inside surface: fiifocioAA1U 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
37、) Where: ifi AURy = q5.3.2.4 The new condensing temperature with fouled tubes, tsf, can then be found using the small temperature difference, Sf : sf w1 ftS = + t (5) Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or networ
38、king permitted without license from IHS-,-,-ARI 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 surface, ft2m2 Ai /Ao= Ratio of inside to outside surface area Ao /Ai= Ratio of outside to ins
39、ide 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 range = twl- twe, F C S = Small temperature difference = ts- twl, F C t = Temperature, F C
40、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 with this standard, measured test results shall not be less than 95% of the Published Rat
41、ing 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 Published Ratings. As a minimum, Published Ratings shall include all Standard Ratings. All cla
42、ims to ratings within the scope of this standard shall be accompanied by the statement “Rated in accordance with ARI Standard 450.” All claims to ratings outside the scope of this standard shall be accompanied by the statement “Outside the scope of ARI Standard 450.” Wherever Application Ratings are
43、 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 Fouling Factor, they shall be calculated by the method specified in 5.3. 6.2 Published Ra
44、tings 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 refrigerant temperature, F C d. Total Heat Rejection Effect, Btu/h W e. Water flow rate, gpm L/s
45、 f. Water pressure drop, psi kPa g. Fouling Factor (waterside) ft2 h F/Btu m2 C/W Copyright Air-Conditioning and Refrigeration Institute Provided by IHS under license with ARI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ARI STANDARD 450-2007 6 plus at least one
46、 of the following: h. Temperature of entering water, F C i. Temperature of leaving water, 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. Maximu
47、m refrigerant storage capacity, ft3L or lb kg e. Shipping weight, lb kg f. Operating weight (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 Namep
48、late Data 7.1 Marking and Nameplate Data. As a minimum, each condenser shall have the 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 8. Conformance Conditions 8.1 Conformance. While conformance with this standard is voluntary, conformance shall
