AHRI 750-2007 Thermostatic Refrigerant Expansion Valves.pdf

1、 ANSI/AHRI Standard 750-2007(Formerly ARI Standard 750-2007)2007 Standard for Thermostatic Refrigerant Expansion ValvesIMPORTANT 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

2、 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 safety standards and code requirements appropriate for products covered by this standard/guideline. A

3、HRI uses its best efforts to develop standards/guidelines employing state-of-the-art 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 750-94

4、. Price $10.00 (M) $20.00 (NM) 8Copyright 2007, by Air-Conditioning Heating and Refrigeration Institute Printed in U.S.A. Registered United States Patent and Trademark Office TABLE OF CONTENTS SECTION PAGE Section 1. Purpose .1 Section 2. Scope 1 Section 3. Definitions 1 Section 4. Test Requirements

5、2 Section 5. Rating Requirements 2 Section 6. Minimum Data Requirements for Published Ratings 2 Section 7. Marking and Nameplate Data 3 Section 8. Conformance Conditions .3 TABLES Table 1. Standard Rating Conditions3 APPENDICES Appendix A. References - Normative4 Appendix B. References - Informative

6、 4 Appendix C. Recommended Maximum Operating Pressures for Pressure-Limiting Type Thermostatic Refrigeration Expansion Valves - Informative.5 Appendix D. Recommended Refrigerant Designation(s) and Color Coding for Valve Identification - Informative .6 Appendix E. Recommended Standard Connection Size

7、s - Informative7 ANSI/AHRI STANDARD 750-2007 1THERMOSTATIC REFRIGERANT EXPANSION VALVES Section 1. Purpose 1.1 Purpose. The purpose of this standard is to establish for Thermostatic Refrigerant Expansion Valves: definitions; test requirements; rating requirements; minimum data requirements for Publi

8、shed 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 Amendment. This standard is subject to review and amendment as techn

9、ology advances.Section 2. Scope 2.1 Scope. This standard applies to Thermostatic Refrigerant Expansion Valves for use with refrigerants listed in 2.1.1 at evaporator temperatures between +50F 10C and -40F -40C. 2.1.1 Refrigerants. This standard applies to Thermostatic Expansion Valves for use with R

10、efrigerants 12, 22, 502, 134a, 404A, 407C, 410A and 507.Section 3. Definitions All terms in this document shall 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

11、.1 Capacity of a Thermostatic Refrigerant Expansion Valves. The refrigerating effect produced by the evaporation of refrigerant which will pass through the valve under the following specified conditions: a. Liquid refrigerant temperature at the valve inlet b. Saturated evaporator temperature c. Pres

12、sure difference across the valve d. Static superheat setting e. Superheat change 3.2 Maximum Operating Pressure (MOP). The maximum equalizer (internal or external) pressure permitted by a pressure-limiting type Thermostatic Refrigerant Expansion Valve (see Appendix C). 3.3 Published Rating. A statem

13、ent of the assigned values of those performance characteristics, under stated Rating Conditions, by which a Thermostatic Refrigerant Expansion Valve may be chosen to fit its application. These values apply to all Thermostatic Refrigerant Expansion Valves of like nominal size and type (identification

14、) produced by the same manufacturer. As used herein, the term Published Rating includes the rating of all performance characteristics shown on the Thermostatic Refrigerant Expansion Valve or published in specifications, advertising or other literature controlled by the manufacturer, at stated Rating

15、 Conditions. 3.3.1 Application Rating. A rating based on tests performed at Application Rating conditions (other than Standard Rating Conditions). 3.3.2 Standard Rating. A rating based on tests performed at Standard Rating Conditions. 3.4 Rating Conditions. Any set of operating conditions under whic

16、h a single level of performance results and which cause only that level of performance to occur. 3.4.1 Standard Rating Conditions. Rating conditions used as the basis of comparison for performance characteristics. 3.5 “Shall“ or “Should“. “Shall“ or “should“ shall be interpreted as follows: 3.5.1 Sh

17、all. Where “shall“ or “shall not“ is used for a provision specified, that provision is mandatory if compliance with the standard is claimed. 3.5.2 Should. “Should“ is used to indicate provisions which are not mandatory but which are desirable as good practice.3.6 Thermostatic Refrigeration Expansion

18、 Valve. A controlling device which regulates the flow of volatile refrigerant into an evaporator of a refrigeration system and which is actuated by changes in evaporator pressure and superheat of the refrigerant gas leaving the evaporator. 3.7 Thermostatic Refrigeration Expansion Valve Pressure Drop

19、. The pressure drop across the valve port, which is the net pressure difference between the valve inlet and outlet pressures. 3.8 Thermostatic Refrigeration Expansion Valve Superheat. The difference between the temperature of the thermal bulb and the dew point temperature corresponding to the refrig

20、erant pressure at the valve outlet, or at the equalizer connection, when provided. ANSI/AHRI STANDARD 750-2007 2 3.8.1 Static Superheat. The superheat as defined in 3.9 at which the manufacturer calibrates or “sets“ the thermostatic expansion valve. 3.9 Vapor-Free (Subcooled) Liquid. Refrigerant liq

21、uid which has been cooled below the bubble point temperature for a given pressure.Section 4. Test Requirements 4.1 Testing for Capacity. Thermostatic Refrigerant Expansion Valve ratings shall be based on tests conducted in accordance with the test procedure outlined in ANSI/ASHRAE 17. 4.1.1 Alternat

22、ive flow test methods may be used provided that the results obtained can be confirmed by the test method specified in 4.1 within the tolerance specified in 5.5.Section 5. Rating Requirements 5.1 Published Capacity Ratings. Published capacity ratings shall consist of Standard Ratings and may include

23、Application Ratings. Such ratings shall be based on tests of valves made for use with the refrigerant specified in the ratings. All Published Ratings shall be based on Vapor-Free (Subcooled) Liquid refrigerant entering the Thermostatic Refrigeration Expansion Valve. The tests shall be made in accord

24、ance with the test procedure outlined in Section 4 of this standard. 5.1.1 Standard Ratings. Standard Ratings of capacity shall be shown for all Standard Rating Conditions, shown in Table 1, falling within the intended range of application of the valve. 5.1.2 Nominal Rating. The nominal rating is th

25、e equivalent capacity rating of the valve at the 40F 4.4C evaporator Standard Rating Condition (Standard Rating Condition A in Table 1). 5.1.3 Application Ratings. Application Ratings give capacities under operating conditions which differ from those in Table 1. Wherever Application Ratings are publ

26、ished or printed, they shall include a statement of conditions at which the ratings apply, and be accompanied by the pertinent Standard Rating(s), clearly designated as such. 5.2 Interpolation and Extrapolation of Air Test Data. Published capacity ratings shall be based on air-fixture tests made at

27、two or more evaporator dewpoint temperatures. Air-fixture test data may be extrapolated or interpolated no more than 15F 8.3C from test points and only when the same thermostatic charge is used. In the case of Refrigerants 12 and 134a, data may be extrapolated a maximum of 25F 14C below the lowest t

28、est point in order to obtain a rating at -40F -40C evaporator dewpoint temperature. 5.3 Superheat Change. Every published capacity rating shall be based on the capacity resulting from a superheat change above the static superheat. This superheat change shall not exceed 7F 4C for any Published Rating

29、 unless clearly designated. 5.4 Static Superheat. For purposes of rating, the static superheat shall be no less than 2F 1C.5.5 Tolerance. To comply with this standard, published capacity ratings shall be based on data obtained in accordance with the provisions of this section, and shall be such that

30、 any production Thermostatic Refrigeration Expansion Valve selected at random and tested shall produce not less than 95% of its published rated capacity. Section 6. Minimum Data Requirements for Published Ratings 6.1 Minimum Data Requirements for Published Ratings. As a minimum, Published Ratings sh

31、all include all Standard Ratings. All claims to ratings within the scope of this standard shall include the statement “Rated in accordance with AHRI Standard 750“. All claims to ratings outside the scope of this standard shall include the statement “Outside the scope of AHRI Standard 750”. Wherever

32、Application Ratings are published or printed, they shall include a statement of the conditions at which the ratings apply. 6.2 Published Capacity Ratings. Published capacity ratings shall state the pertinent operating conditions and shall include at least the following:a. Refrigerant designation(s)

33、per ASHRAE Standard 34 with Addenda b. Net refrigerant capacity, Btu/h W or tons of refrigeration kW c. Evaporator dewpoint temperature, F C d. Pressure drop across the valve, psi kPa e. Maximum superheat change at which ratings apply, F C. f. Capacity correction factors for liquid temperatures at t

34、he valve inlet which differ from the standard value of 100F 37.8C. ANSI/AHRI STANDARD 750-2007 3Table 1. Standard Rating Conditions *Pressure Drop Across Valve Liquid Temperature Evaporator Dewpoint Temperature R12, R134a R404A, R407C, R507, R22, R502 R410A StandardRating Condition F C F C psi kPa p

35、si kPa psi kPa A B C D 100 100 100 100 37.8 37.8 37.8 37.8 +40 +20 -10 -40 +4.4 -6.7 -23 -40 60 80 100 120 413 551 689 827 100 125 150 175 689 861 1034 1206 160 200 240 280 1100 1380 1660 1930 *These values assume pressure drops between the outlet of the Thermostatic Refrigeration Expansion Valve an

36、d the evaporator outlet, in addition to the pressure drop through the valve. Where such additional pressure drops do not exist, the manufacturers rating tables shall include the necessary corrections. (These include corrections for liquid density and refrigerating effect and are based on an average

37、evaporator temperature of 0F -18C).Section 7. Marking and Nameplate Data 7.1 Nameplate Data. Each Thermostatic Refrigerant Expansion Valve shall display the manufacturers name or trade name, model number, and refrigerant designation(s). Section 8. Conformance Conditions 8.1 Conformance. While confor

38、mance with this standard is voluntary, conformance shall not be claimed or implied for products or equipment within its Purpose (Section 1) and Scope (Section 2) unless such claims meet all of the requirements of the standard.ANSI/AHRI STANDARD 750-2007_ 4 APPENDIX A. REFERENCES - NORMATIVE A1 Liste

39、d 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 the standard. A1.1 ANSI/ASHRAE Standard 17-1986 (RA 1990), Methods of Testing for Capacity Rating of Thermostatic Refrig

40、erant Expansion Valves, 1990, American National Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 25 West 43 Street, 4 Floor, New York, NY 10036, U.S.A./1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A. rd thA1.2 ASHRAE Standard 34-2001 with Addend

41、a, Designation and Safety Classification of Refrigerants, 2001, 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, Second Edition, 199

42、1, 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 None. ANSI/AHRI STANDARD 750-2007 5APPENDIX C. RECOMMENDED MAXIMUM OPERATING PRESSURES FOR PRESSURE-LIMITING TYPE THERMOSTATIC R

43、EFRIGERATION EXPANSION VALVES - INFORMATIVE Air-Conditioning Commercial Refrigeration Low Temperature Refrigerant psig kPa psig kPa psig kPa R12 R22 R502 R134a R410A R404A R507 R407C 55.0 100 110 55.0 170 120 120 100 380 690 760 380 1170 830 830 690 35.0 65.0 75.0 35.0 115 80.0 80.0 65.0 240 450 520

44、 240 790 550 550 450 10 25.0 30.0 10 50.0 30.0 30.0 25.0 70 170 210 70 350 210 210 170 NOTE: These are approximate system values. They are subject to the valve manufacturers tolerances and to variations in systems. ANSI/AHRI STANDARD 750-2007_ 6 APPENDIX D. RECOMMENDED REFRIGERANT DESIGNATION(S) AND

45、 COLOR CODING FOR VALVE IDENTIFICATION - INFORMATIVE Refrigerant Color *PMS Number R12 R22 R502 R134a R404A R407C R410A R507 Yellow Green Light Purple Light Blue Orange Medium Brown Rose Blue-Green (Teal) 109 352 251 2975 165 469 507 326 *Denotes Pantone Matching System NOTE: Producers and wholesale

46、rs of refrigerants use a color coding system which may differ from that above. Therefore, dependence should not be placed solely on the color code as a means of identifying the refrigerant. ANSI/AHRI STANDARD 750-2007 7APPENDIX E. RECOMMENDED STANDARD CONNECTION SIZES - INFORMATIVE Capacity, tons kW

47、 Connection Size, ODF R404A, R507, R12, R502, R134a R22, R410A, R407C Inlet, in mm Outlet, in mm 0.50 2.0 3.0 7.5 10 1.8 7.0 11 26 35 1.0 3.0 5.0 10 16 4.0 11 18 35 56 0.25 6.4 0.375 9.52 0.50 13 0.625 18.9 0.875 22.2 0.50 13 0.50 13 0.625 18.9 0.875 22.2 1.125 28.58 NOTE: For capacities which fall between those listed, the larger connection size is the recommended standard.