2004 Standard For Performance Rating Of Positive Displacement Refrigerant Compressors And Compressor Units

Transcription

1 2004 Standard For Performance Rating Of Positive Displacement Refrigerant Compressors And Compressor Units ANSI/AHRI Standard 540 (formerly ARI Standard 540)

2 IMPORTANT SAFETY RECOMMENDATIONS ARI 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 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. 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/guidelines will be non-hazardous or free from risk. Note: This standard supersedes ARI Standard Price $10.00 (M) $20.00 (NM) Printed in U.S.A. Copyright 2004, by Air-Conditioning, Heating, and Refrigeration Institute Registered United States Patent and Trademark Office

3 SECTION TABLE OF CONTENTS PAGE Section 1. Purpose... 1 Section 2. Scope... 1 Section 3. Definitions... 1 Section 4. Test Requirements... 3 Section 5. Rating Requirements... 3 Section 6. Minimum Data Requirements for Published Ratings... 3 Section 7. Operating Requirements... 7 Section 8. Marking and Nameplate Data... 7 Section 9. Conformance Conditions... 7 TABLES Table 1. Table 2. Standard Rating Conditions for Compressors and Compressor Units for Commercial Refrigeration Applications... 5 Standard Rating Conditions for Compressors and Compressor Units Used In Air Conditioners and Heat Pumps... 6 APPENDICES Appendix A. References - Normative... 8 Appendix B. References - Informative... 8 Appendix C. Method to Handle Zeotropic Mixtures - Informative... 9 FIGURES Figure C1. Cycle Process for Single Component Refrigerants and Azeotropic Mixtures... 9 Figure C2. Cycle Process for Zeotropic Refrigerant Mixtures Figure C3. Definitions of Subcooling and Superheating... 11

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5 ANSI/AHRI STANDARD PERFORMANCE RATING OF POSITIVE DISPLACEMENT REFRIGERANT COMPRESSORS AND COMPRESSOR UNITS Section 1. Purpose 1.1 Purpose. The purpose of this standard is to establish, for single and variable capacity positive displacement refrigerant compressors and compressor units: definitions; test requirements; rating requirements; minimum data requirements for Published Ratings; operating requirements; marking and nameplate data and conformance conditions Intent. This standard is intended for the guidance of the industry, including manufacturers, engineers, installers, contractors and users Review and Amendment. This standard is subject to review and amendment as technology advances. Section 2. Scope 2.1 Scope. This standard applies to electric motor driven, single and variable capacity positive displacement refrigerant compressors and compressor units. This standard also applies to the presentation of performance data for positive displacement refrigerant compressors and compressor units for air-cooled, evaporatively-cooled or water-cooled air-conditioning, heat pump and refrigeration applications Refrigerant. The rating points in this standard are based on commonly used refrigerants. 2.2 Exclusions This standard does not apply to compressors and compressor units employing ammonia, as covered in ARI Standard This standard does not apply to compressors and compressor units intended for use in: a. Household refrigerators and freezers b. Automotive air-conditioners c. Dehumidifiers Section 3. Definitions All terms in this document will 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 Compressor or Compressor Unit Efficiency. The efficiency is defined by the following equation: = 100 m C (h 2s - h 1 ) / P where: m = mass flow of volatile refrigerant, lb/h [kg/s] h 1 = specific enthalpy of the refrigerant vapor entering the compressor or compressor unit, Btu/lb [kj/kg] h 2s = specific enthalpy of the refrigerant vapor at the discharge pressure and the specific entropy of the refrigerant vapor entering the compressor or compressor unit, Btu/lb [kj/kg] C = W/Btu/h [1.0 kw/kj/s] 1

6 ANSI/AHRI STANDARD P = measured motor input power, W [kw] = compressor or compressor unit efficiency, %. 3.2 Positive Displacement Refrigerant Compressor. A compressor in which an increase in vapor pressure is attained by changing the internal volume of the compression chamber Hermetic Refrigerant Motor-Compressor. A compressor and motor assembly, both of which are enclosed in the same housing, with the motor operating in the refrigerant. 3.3 Positive Displacement Refrigerant Compressor Unit. A Positive Displacement Compressor with accessories, such as strainers, service valves, check valves, suction filters, oil separators, as provided by the manufacturer. This will also include variable capacity controls, electronic or electro-mechanical, as supplied or specified by the manufacturer External-Drive Refrigerant Compressor Unit. An External-Drive Refrigerant Compressor with motor mounted on a structural base and with accessories as provided by the manufacturer Hermetic Refrigerant Motor-Compressor Unit. A Hermetic Refrigerant Motor-Compressor with accessories as provided by the manufacturer. 3.4 Power Input. The power required from the incoming power source for the compressor(s) only, not including the power required for capacity control of the compressor or compressor unit including the oil heaters, motor starters, unloaders, frequency converters and other controls as specified by the manufacturer, expressed in W[kW]. 3.5 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. These values apply to all units of like nominal size and type (identification) produced by the same manufacturer. The term Published Rating includes the rating of all performance characteristics shown on the unit or published in specifications, advertising or other literature controlled by the manufacturer, at stated rating conditions Application Rating. A rating based on tests performed at application Rating Conditions (other than Standard Rating Conditions) Standard Rating. A rating based on tests performed at Standard Rating Conditions. 3.6 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 Standard Rating Conditions. Rating conditions used as the basis of comparison for performance characteristics. 3.7 Refrigerating Capacity. The capacity associated with the increase in total enthalpy between the liquid refrigerant entering the expansion valve and superheated return gas multiplied by the mass flow rate of the refrigerant Maximum Capacity. The highest displacement capacity by the compressor or compressor unit expressed in ft 3 /min [m 3 /sec] Minimum Capacity. The lowest displacement capacity obtainable by the compressor or compressor unit expressed in ft 3 /min [m 3 /sec]. 3.8 "Shall" or "Should," shall be interpreted as follows: Shall. Where "shall" or "shall not" is used for a provision specified, that provision is mandatory if compliance with the standard is claimed Should. "Should" is used to indicate provisions which are not mandatory, but which are desirable as good practice. 2

7 ANSI/AHRI STANDARD Section 4. Test Requirements 4.1 Test Requirements. All Published Ratings shall be verified by tests conducted in accordance with ASHRAE Standard 23. Section 5. Rating Requirements 5.1 Standard Ratings. The Standard Ratings of a compressor or compressor unit shall consist of standard mass flow ratings, lb/h [kg/s] identified at the Standard Rating Conditions, plus its associated Power Input rating W[kW] and efficiency rating, percent, when tested as specified by the manufacturer Standard Rating of a Commercial Refrigerating Compressor or Compressor Unit. The rating when operated under one of the Standard Rating Conditions presented in Table Standard Rating of a Compressor and Compressor Unit Used in an Air-Conditioner or Heat Pump. The ratings when operated under one of the Standard Rating Conditions presented in Table Application Ratings of Compressor and Compressor Units. Application Ratings shall consist of a mass flow rating and associated Power Input rating when tested at stated conditions other than those presented in Table 1 or 2, as specified by the manufacturer. 5.3 Nameplate Voltages for Rating. Rating tests shall be performed at the nameplate rated voltage and frequency. For dual nameplate voltage ratings, rating tests shall be performed at both voltages, or at the higher of the two voltages, if only a single rating is to be published. 5.4 Tolerances. To comply with this standard, measured test results shall not be less than 95% of Published Ratings for capacity and energy efficiency and power input shall be no more than 105% of the rated values. 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 claims to ratings within the scope of this standard shall include the statement Rated in accordance with ARI Standard 540. All claims to ratings outside the scope of this standard shall include the statement Outside the scope of ARI Standard 540. Wherever Application Ratings are published or printed, they shall include a statement of the conditions at which the ratings apply. 6.2 Tabular Data. General performance data, covering the operational spectrum of the equipment, shall be presented in tabular form within defined accuracies and ranges of operation. The tables shall include: a. Suction dew point temperature range, F [ C] b. Discharge dew point temperature range, F [ C] c. Applicable superheat, F [ C] d. Power Input, W [W] e. Compressor or Compressor Unit Efficiency, percent f. Refrigerant mass flow rate, lb/h [kg/s] g. Current, A [A] h. Refrigerant designation per ASHRAE Standard 34 The manufacturer's tabular data shall be based on data obtained from tests performed or calculated by whatever means or methods deemed necessary at conditions within the range of application usage specified in 6.3.1, 6.3.2, or Data to be Reported. The tabular data shall be reported at the following conditions for the compressor or compressor unit application usage intended. The extreme ends of the tabular data may be omitted and not reported due to limits of acceptable 3

8 ANSI/AHRI STANDARD operation of the compressor or compressor unit as determined by the manufacturer Air-Conditioning (including heat pumps): -10 F to 55 F [-23 C to 13 C] suction dew point temperature in 5 F [3 C] increments 80 F to 140 F [27 C to 60 C] discharge dew point temperature in 10 F [5.6 C] increments Return gas temperature per Table High Temperature (water coolers and walk-in coolers, for example): 20 F to 50 F [-7 C to 10 C] suction dew point temperature in 5 F [3 C] increments 80 F to 140 F [27 C to 60 C] discharge dew point temperature in 10 F [5.6 C] increments Return gas temperature per Table Medium Temperature (display cases, for example): -10 F to 32 F [-23 C to 0 C] suction dew point temperature in 5 F [3 C] increments 80 F to 140 F [27 C to 60 C] discharge dew point temperature in 10 F [5.6 C] increments Return gas temperature per Table Low Temperature (freezer cases, for example): -40 F to 10 F [-40 C to -12 C] suction dew point temperature in 5 F [3 C] increments 80 F to 140 F [27 C to 60 C] discharge dew point temperature in 10 F [5.6 C] increments Return gas temperature per Table Polynomial Equation. The polynomial equation that shall be used to represent the tabular data is a third degree equation of ten coefficients in the form of: where: X = C1 +C2 (S) + C3 D +C4 (S 2 ) + C5 (S D) + C6 (D 2 ) + C7 (S 3 ) + C8 (D S 2 ) +C9 (S D 2 ) + C10 (D 3 ) 1 C = Equation coefficient, represents compressor performance S = Suction dew point temperature, F [ C] D = Discharge dew point temperature, F [ C] X can represent any of the following variables: Power Input, W or kw [kw] Mass flow rate, lb/h [kg/s] Current, A [A] Compressor or Compressor Unit Efficiency 4

9 ANSI/AHRI STANDARD Table 1. Standard Rating Conditions for Compressors and Compressor Units for Commercial Refrigeration Applications (Based on 95 F [35 C] Ambient Temperature) Suction Dew Point Temperature Compressor Type Discharge Dew Point Temperature Return Gas Temperature Subcooling F C F C F C F C All All* /65* 4.4/18* Hermetic All* /65* 4.4/18* All* /65* 4.4/18* 0 0 Note: If airflow across the compressor is used to determine ratings, it shall be specified by the compressor manufacturer. * 1) For hermetic type compressors, 40 F [4.4 C] return gas temperature shall be used. 2) For external drive and accessible hermetic type compressors, 65 F [18 C] return gas temperature shall be used. 5

10 ANSI/AHRI STANDARD Table 2. Standard Rating Conditions for Compressors and Compressor Units Used In Air Conditioners and Heat Pumps (Based on 95 F [35 C] Temperature Surrounding Compressor-- See Notes 1 and 3) Rating Test Point Intended Use Suction Dew Point Temperature Discharge Dew Point Temperature Return Gas Temperature Capacity Setting (Note 2) A B C D E F G H Air Source (Cooling) Air Source (Cooling) Air Source (Cooling & Heating) Air Source (Heating) Air Source (Heating) Air Source (Cooling) Air Source (Heating) Water Source (Cooling & Heating) F C F C F C MAX MAX MIN MAX MAX MIN MIN MAX. & MIN. NOTE: 1) If airflow across the compressor is used to determine ratings, it shall be specified by the compressor manufacturer. 2) The maximum and minimum capacity setting is the highest and lowest displacement capacity obtainable by the compressor or compressor unit. 3)15 F [8.3 C] degrees of subcooling To establish the coefficients to be used in the Equation 1, the method of Least Squares shall be used. For those conditions where the tabular data cannot be published due to the operating limits of the compressor, the compressor manufacturer will use test data or extrapolated values for the omitted points inside the range(s) specified in 6.3 so that the calculation may be completed and generate the coefficients to be used in the Equation Equation 1 shall not be used to extrapolate beyond the range of data specified in Superheat Corrections Superheat Range. For superheat, other than that specified, correction values will be provided upon request of the user for the following applications and ranges: Air-Conditioning: 15 F to 30 F [8.3 C to 16.7 C] High Temperature 15 F to 45 F [8.3 C to 25 C].

11 ANSI/AHRI STANDARD Med. Temperature 15 F to 75 F [8.3 C to 41.7 C] Low Temperature 15 F to 105 F [8.3 C to 58.3 C]. 6.6 Values Calculated Using Equation 1. Values of the same performance characteristics calculated from the ten coefficient third order equation and the coefficients provided by the compressor manufacturer shall agree with the tabular values within ± 1%. In the event that the compressor manufacturer determines that the values calculated from the ten coefficient equation may differ by more than 1% from the tabulated values in portions of the operating range, the compressor manufacturer will indicate this by shading, cross-hatching or otherwise identifying those affected data points in the table. Section 7. Operating Requirements 7.1 Loading Requirements. The compressor or compressor unit shall be capable of operating continuously at the maximum loading conditions stated in 7.2 for a minimum period of two hours at minimum and maximum utilization voltage as described in ARI Standard 110, Table Maximum Loading Conditions. The maximum suction dew point temperature limit shall be published. This limit shall be established with the compressor operating at conditions described below: a. Ambient temperature surrounding the compressor of 115 F [46.1 C] dry-bulb for all types. b. 145 F [62.8 C] discharge dew point temperature for compressors or compressor units for air cooled applications; 120 F [48.9 C] discharge dew point temperature for compressors and compressor units for water cooled applications. c. Superheated return gas temperature shall be no lower than 65 F [18 C]. Section 8. Marking and Nameplate Data 8.1 Compressor Electrical Marking. As a minimum, the voltage, phase, frequency, and locked-rotor current of all motors furnished as part of the compressor shall be clearly marked on the nameplate. Nameplate voltages for 60 Hertz systems shall include one or more of the utilization voltages shown in Table 1 of ARI Standard 110. Nameplate voltages for 50 Hertz systems shall include one or more of the equipment nameplate voltages shown in Table 1 of IEC Standard Compressor Unit Nameplate Marking. As a minimum, each compressor unit shall have a nameplate, affixed to its housing or base, on which the following information, in addition to that required under 8.1, shall be marked: a. Manufacturer's name and/or symbol b. Model number c. Refrigerant designation per ASHRAE Standard 34 d. Input voltage and frequency (Hz) e. Rated-load current (where applicable) Section 9. Conformance Conditions 9.1 Conformance. While conformance with this standard is voluntary, conformance shall not be claimed or implied for products or equipment within the standard s Purpose (Section 1) and Scope (Section 2) unless such product claims meet all of the requirements of the standard and 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. 7

12 ANSI/AHRI STANDARD APPENDIX A. REFERENCES - NORMATIVE A.1 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 the standard. A.1.1 ANSI/ASHRAE Standard with Addenda, Number Designation and Safety Classification of Refrigerants, 2001, American National Standards Institute/American Society of Heating, Refrigerating and Air- Conditioning Engineers, 11 West 42 nd Street, New York, NY 10036, U.S.A./1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A. A.1.2 AHRI Standard (formerly ARI Standard ), Air-Conditioning and Refrigerating Equipment Nameplate Voltages, 2002, Air-Conditioning, Heating, and Refrigeration Institute, 2111 Wilson Boulevard, Suite 500, Arlington, VA 22201, U.S.A. A.1.3 AHRI Standard (formerly ARI Standard ), Ammonia Compressor Units, 1993, Air- Conditioning, Heating, and Refrigeration Institute, 2111 Wilson Boulevard, Suite 500, Arlington, VA 22201, U.S.A. A.14 ASHRAE Standard , Methods of Testing for Rating Positive Displacement Refrigerant Compressors and Condensing Units, 1993, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A. A.1.5 ASHRAE Terminology of Heating, Ventilation, Air Conditioning and Refrigeration 1991 Second Edition, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A. A.1.6 IEC Standard Publication 60038, IEC Standard Voltages, 2002, International Electrotechnical Commission, 3, rue de Varembe, P.O. Box 131, 1211 Geneva 20, Switzerland. A1.7 ISO 917: 1989, Testing of Refrigerant Compressors, 1989, International Organization for Standardization, Case Postale 56, CH-1211, Geneva 21 Switzerland. APPENDIX B. REFERENCES INFORMATIVE None. 8

13 ANSI/AHRI STANDARD APPENDIX C.METHOD TO HANDLE ZEOTROPIC MIXTURES INFORMATIVE C1 Cycle Process For reference, Figure C1 shows a typical single stage cycle for single component refrigerants and azeotropic mixtures. The description is consistent with the ISO 917 standard. As shown, the evaporating and condensing processes occur at fixed temperatures t o and t c. Figure C1: Cycle Process for Single Component Refrigerants and Azeotropic Mixtures 9

14 ANSI/AHRI STANDARD Figure C2: Cycle Process for Zeotropic Refrigerant Mixtures Figure C2 shows temperature glide for zeotropic refrigerant mixtures at the evaporation and condensation processes. Standard reference temperatures are the dew-point temperatures t " 0 at the evaporating pressure p g1 and t " c at the condensing pressure p g2. The following equations may be used to calculate the mean evaporating temperature, mean condensing temperature, refrigerant superheating, and refrigerant subcooling: mean evaporating temperature: t 0,m = (t 01 + t " 0 )/ 2 C1 mean condensing temperature: t c,m = (t ' c + t c)/ " 2 C2 refrigerant superheating: t Sg = t g1 - t " 0 ) C3 refrigerant subcooling: t Sf = t ' c - t f2 = t f1 - t f2 C4 Because t 01 = t " 0 and t ' c = t " c for single-component refrigerants and azeotropic multi-component refrigerants, the cycle process model represents a particular kind of model for zeotropic refrigerant mixtures. In all reference systems refrigerating capacity is: Q = m (h g1 h f2 ) C5 and Q 0 = m (h g1 h f1 ) C6 10

15 ANSI/AHRI STANDARD for refrigerating capacity converted to no subcooling. The reference systems described above allow one to calculate and present performance data for all kinds of refrigerants in a similar way. ISO 917 requires zero subcooling for the calculation of refrigerating capacity of the compressor. In this case h f1 and h f2 are equal. Note: In connection with zeotropic mixtures, different definitions of the expressions superheating and subcooling can be found in technical documentation (Figure C3). The Equations C3 and C4 are equivalent to A in Figure C3 and shall be used for the purpose of calculating ratings. For reference only, B in Figure C3 with mean temperatures as reference points, uses the following equations: refrigerant superheating: t Sg = t g1 - t 0,m C7 refrigerant subcooling t Sf = t cm - t f2 t f1 - t f2 C8 Figure C3: Definitions of Subcooling and Superheating 11

16 ANSI/AHRI STANDARD C2 Symbols and Subscripts Symbols: f 1 g 1 g 2 h f1 h f2 h g1 = Bubble point at condensing process. = Point where the refrigerant enters the compression process. = Point where the refrigerant leaves the compression process = Enthalpy of the refrigerant at bubble point of condensing process. = Enthalpy of the subcooled refrigerant liquid entering the expansion process. = Enthalpy of the refrigerant gas entering the compression process. m = Refrigerant mass flow rate. P g1 = Compressor suction dew point pressure. P g2 = Compressor discharge dew point pressure. Q = Refrigerating capacity. Q 0 = Refrigerating capacity assuming no subcooling. t c = Condensing temperature. t c' = Bubble point temperature at condensing process. t c'' = Dew point temperature at condensing process. t c,m = Mean condensing temperature. t f1 = Temperature at which the subcooled liquid exits the expansion process t f2 = Temperature at which the subcooled liquid enters the expansion process. t g1 = Temperature of the refrigerant entering the compression process. t 0 = Evaporating temperature. t 0 '' = Dew point temperature at evaporation process. t 01 = Temperature at the outlet of the expansion process and inlet to the evaporation process. t 0,m = Mean evaporating temperature. tsf = Refrigerant subcooling. tsg = Refrigerant superheat. Subscripts: c = Condensing process c = Bubble point of condensing process c = Dew point of condensing process c,m = Mean condensing process f1 = Bubble point of condensing process f2 = Point at which the subcooled refrigerant liquid enters the expansion process g1 = Dew point at compressor suction g2 = Dew point at compressor discharge 0 = Evaporating process 01 = Outlet of the expansion process and inlet to the evaporation process 0,m = Mean evaporating process tsf = Temperature, saturated fluid tsg = Temperature, saturated gas 12