AHRI 1250 I-P-2014 Performance Rating of Walk-in Coolers and Freezers.pdf

1、 2014 Standard for Performance Rating of Walk-in Coolers and Freezers -AHRI Standard 1250 (I-P) Price $10.00 (Members) $20.00 (Non-Members) Printed in U. S.A. Copyright 2014, by Air-Conditioning, Heating, and Refrigeration Institute Registered United States Patent and Trademark Office IMPORTANT SAFE

2、TY 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 that products be designed, constructed, assembled

3、, installed and operated in accordance with nationally recognized safety standards and code requirements appropriate for products covered by this stand-ard/guideline. AHRI uses its best efforts to develop standards/guidelines employing state-of-the-art and accepted industry practices. AHRI does not

4、certify or guarantee that any tests conducted under its standards/guidelines will be non-hazardous or free from risk. Note: This standard supersedes AHRI Standard 1250 (I-P)-2009 For SI ratings, Refer to AHRI Standard 1251 (SI) 2014 i TABLE OF CONTENTS PAGE Section 1 Purpose 1 Section 2 Scope . 1 Se

5、ction 3 Definitions . 1 Section 4 Test Requirements . 3 Section 5 Rating Requirements . 5 Section 6 Calculation for Walk-in Box Load 18 Section 7 Calculation for Annual Walk-in Energy Factor . 20 Section 8 Symbols and Subscripts 40 Section 9 Minimum Data Requirements for Published Ratings 43 Section

6、 10 Marking and Nameplate Data . 43 Section 11. Conformance Conditions. 43 TABLES Table 1 Instrumentation Accuracy . 3 Table 2 Test Operating and Test Condition Tolerances for Steady-state Test . 4 Table 3 Fixed Capacity Matched Refrigerator System, Condensing Unit Located Indoor 5 Table 4 Fixed Cap

7、acity Matched Refrigerator System, Condensing Unit Located Outdoor . 6 Table 5 Two Capacity Matched Refrigerator System, Condensing Unit Located Outdoor . 6 Table 6 Variable Capacity Matched Refrigerator System, Condensing Unit Located Outdoor . 8 Table 7 Fixed Capacity Matched Freezer System, Conde

8、nsing Unit Located Indoor 10 Table 8 Fixed Capacity Matched Freezer System, Condensing Unit Located Outdoor . 10 Table 9 Two Capacity Matched Freezer System, Condensing Unit Located Outdoor . 11 Table 10 Variable Capacity Matched Freezer System, Condensing Unit Located Outdoor . 13 Table 11 Fixed Ca

9、pacity Refrigerator Condensing Unit, Condensing Unit Located Indoor 15 Table 12 Fixed Capacity Refrigerator Condensing Unit, Condensing Unit Located Outdoor 16 Table 13 Fixed Capacity Freezer Condensing Unit, Condensing Unit Located Indoor 16 Table 14 Fixed Capacity Freezer Condensing Unit, Condensi

10、ng Unit Located Outdoor 17 ii TABLES (continued) PAGE Table 15 Refrigerator Unit Cooler . 17 Table 16 Freezer Unit Cooler . 18 Table 17 EER for Remote Commercial Refrigerated Display Merchandisers and Storage Cabinets 30 Table 18 Unit Cooler Nominal Values for Condensing Unit Energy Calculations 33

11、FIGURES Figure 1 Schematic of the Operation for Units with Single Capacity Compressor . 21 Figure 2 Schematic of the Various Modes of Operation for Units with Two Capacity Compressors . 23 Figure 3 Schematic of the Various Modes of Operation for Units with Variable Capacity Compressors . 26 APPENDIC

12、ES Appendix A. References Normative 44 Appendix B. References Informative 46 Appendix C. Methods of Testing Walk-in Cooler and Freezer Systems Normative . 47 Appendix D. Weather Data in Region IV Normative 60 TABLES FOR APPENDICES Table C1 Unit Cooler Fan Power Measurements . 49 Table C2 Test Readin

13、gs 49 Table C3 Data to be Recorded 51 Table C4 Unit Cooler Nominal Values for Condensing Unit Energy Calculations 58 Table D1 Bin Temperatures and Corresponding Bin Hours for AWEF Calculation 60 FIGURES FOR APPENDICES Figure C1 Method 1: DX-Dual Instrumentation 52 Figure C2 Method 2: DX- Calibrated

14、Box 53 AHRI STANDARD 1250 (I-P)-2014 1 PERFORMANCE RATING OF WALK-IN COOLERS AND FREEZERS Section 1. Purpose 1.1 Purpose. The purpose of this standard is to establish, for walk-in coolers and freezers: definitions; test requirements; rating requirements; minimum data requirements for Published Ratin

15、gs; operating requirements; marking and nameplate data and conformance conditions. 1.1.1 Intent. This standard is intended for the guidance of the industry, including manufacturers, designers, installers, contractors and users. 1.1.2 Review and Amendment. This standard is subject to review and amend

16、ment as technology advances. Section 2. Scope 2.1 Scope. This standard applies to mechanical refrigeration equipment consisting of an integrated single package refrig-eration unit, or separate Unit Cooler and condensing unit sections, where the condensing section can be located either outdoor or ind

17、oor. Controls may be integral, or can be provided by a separate party as long as performance is tested and certified with the listed mechanical equipment accordingly. 2.2 Exclusions. This standard does not apply to: 2.2.1 Enclosures used for telecommunications switch gear or other equipment requirin

18、g cooling 2.2.2 Enclosures designed for medical, scientific or research purposes 2.2.3 Performance testing and efficiency characterization of large parallel rack refrigeration systems (condensing unit) Section 3. Definitions All terms in this document will follow the standard industry definitions in

19、 the ASHRAE Wikipedia website (https:/www.ashrae.org/resources-publications/free-resources/ashrae-terminology) unless otherwise defined in this section. 3.1 Annual Walk-in Energy Factor (AWEF). A ratio of the total heat, not including the heat generated by the operation of refrigeration systems, rem

20、oved, in Btu, from a walk-in box during one year period of usage for refrigeration to the to-tal energy input of refrigeration systems, in watt-hours, during the same period. 3.2 Energy Efficiency Ratio, (EER). A ratio of the Refrigeration Capacity in Btu/h to the power input values in watts at any

21、given set of Rating Conditions expressed in Btu/Wh. 3.3 Forced-circulation Free-delivery Unit Coolers (Unit Coolers). A factory-made assembly, including means for forced air circulation and elements by which heat is transferred from air to refrigerant without any element external to the cooler impos

22、ing air resistance. These may also be referred to as Air Coolers, Cooling Units, Air Units or Evaporators. 3.4 Gross Refrigeration Capacity. The heat absorbed by the refrigerant, Btu/h. This is the sum of the Net Refrigeration Capacity and the heat equivalent of the energy required to operate the Un

23、it Cooler. This includes both sensible and la-tent cooling. 3.5 Load Factor. A ratio of the Total Walk-in System Heat Load to the steady-state Net Refrigeration Capacity. 3.6 Load Period. A twenty-four hour day. 3.6.1 High Load Period. The period of the day corresponding to frequent door openings, p

24、roduct loading events, and other design Load Factors. For the purposes of this standard, this period shall be 8 continuous hours. AHRI STANDARD 1250 (I-P)-2014 2 3.6.2 Low Load Period. The period of the day other than the High Load Period. For the purposes of this standard, this period shall be the

25、remaining 16 continuous hours of the total Load Period. 3.7 Net Refrigeration Capacity. The refrigeration capacity available for space and product cooling, Btu/h. It is equal to the Gross Refrigeration Capacity less the heat equivalent of energy required to operate the Unit Cooler (e.g.: evaporator

26、fans, defrost) 3.8 Positive Displacement Condensing Unit. A specific combination of refrigeration system components for a given re-frigerant, consisting of one or more electric motor driven positive displacement compressors, condensers, and accesso-ries as provided by the manufacturer. 3.9 Published

27、 Rating. A statement of the assigned values of those performance characteristics, under stated rating condi-tions, 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 Publishe

28、d Rating includes the rating of all performance characteristics shown on the unit or published in specifications, advertising or other literature controlled by the manu-facturer, at stated Rating Conditions. 3.9.1 Application Rating. A rating based on tests performed at application Rating Conditions

29、, (other than Standard Rating Conditions). 3.9.2 Standard Rating. A rating based on tests performed at Standard Rating Conditions. 3.10 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. 3.10.

30、1 Standard Ratings Conditions. Rating conditions used as the basis of comparison for performance character-istics. 3.11 Refrigeration Capacity. The capacity associated with the increase in total enthalpy between the liquid refrigerant en-tering the expansion valve and superheated return gas multipli

31、ed by the mass flow rate of the refrigerant. 3.12 Saturation Temperature. Refrigerant temperature at the Unit Cooler inlet or outlet determined either by measuring the temperature at the outlet of the two-phase refrigerant flow, for a Liquid Overfeed Unit Cooler, or by measuring refrigerant pressure

32、 and determining the corresponding temperature from reference thermodynamic tables or equations for the refriger-ant, F. For zeotropic refrigerants, the corresponding temperature to a measured pressure is the refrigerant Dew Point. 3.13 “Shall“ or “Should“. “Shall” or “should” shall be interpreted a

33、s follows: 3.13.1 Shall. Where “shall“ or “shall not“ is used for a provision specified, that provision is mandatory if compliance with the standard is claimed. 3.13.2 Should. “Should,“ is used to indicate provisions which are not mandatory, but which are desirable as good practice. 3.14 Steady-stat

34、e. An operating state of a system, including its surroundings, in which the extent of change with time is within the required limits within this standard. 3.15 Test Reading. The recording of one full set of the test measurements required to assess the performance of the test unit. The reading of a s

35、pecific test instrument at a specific point in time. The test measurement may be averaged with other meas-urements of the same parameter at the same time to determine a Test Reading or averaged over the duration of the test to de-termine the value for the test run. Refer to Table C1 for Test Reading

36、 minimum time rate, number of Test Readings and min-imum test duration. 3.16 Total Walk-in System Heat Load. Total heat load to the walk-in system including Walk-in Box Load and the heat load to the box contributed by the operation of the refrigeration system. 3.16.1 Walk-in System High Load (). Tot

37、al Walk-in System Heat Load during a High Load Period. 3.16.2 Walk-in System Low Load ()Total Walk-in System Heat Load during a Low Load Period. AHRI STANDARD 1250 (I-P)-2014 3 3.17 Volatile Refrigerant. A refrigerant which changes from liquid to vapor in the process of absorbing heat. 3.18 Walk-in

38、Box Load. Heat load to the walk-in box resulting from conduction, infiltration and internal heat gains from equipment that is not related to the refrigeration system, such as lights and anti-sweat heaters, etc. 3.18.1 High Box Load (). Walk-in Box Load during a High Load Period. 3.18.2 Low Box Load

39、(). Walk-in Box Load during a Low Load Period. Section 4. Test Requirements 4.1 Instruments. All measuring instruments shall be selected to meet or exceed the accuracy criteria listed in Table 1 for each type of measurement. All temperature measurement shall be made in accordance with Table 2, Test

40、Tolerance. Precision instruments and automated electronic data acquisition equipment shall be used to measure and record temperature, pressure and refrigerant flow rate test parameters. All measuring instruments and instrument systems (e.g. data acquisition coupled to temperature, pressure, or flow

41、sensors) shall be calibrated by comparison to primary or secondary standards with calibrations traceable to National Institute of Standards and Technology (NIST) measurements, other recognized national laboratories, or derived from accepted values of natural physical constants. All test instruments

42、shall be calibrated annually, whenever dam-aged, or when the accuracy is called into question. Table 1. Instrumentation Accuracy Measurement Medium Minimum Accuracy Temperature, F Air dry-bulb 0.5 Air wet-bulb Refrigerant liquid Refrigerant vapor 0.5 0.5 1.0 Air Dew Point Others Relative humidity, %

43、1Air 3 Pressure Refrigerant, psi Pressure corresponding to 0.2 F of saturation tem-perature Air, in Hg 0.05 Flow Refrigerant 1 % of reading Liquids 1 % of reading Electrical Motor kilo-watts/amperes/voltage 1 % of reading Auxiliary kilowatt input (e.g. heater) AHRI STANDARD 1250 (I-P)-2014 4 Table 1

44、. Instrumentation Accuracy (cont.) Measurement Medium Minimum Accuracy Speed Motor / fan shaft 1 % of reading Specific Gravity Brine 1 % of reading Time Hours / minutes / seconds 0.5 % of time interval Note: 1. Relative humidity and air dew point measurements are intended to confirm the dry coil con

45、dition. Table 2. Test Operating and Test Condition Tolerances for Steady-state Test Test Operating Toleran-ce1Test Condition Toleran-ce2Indoor dry-bulb, F Entering temperature . Indoor wet-bulb, F Entering temperature . Outdoor dry-bulb, F Entering temperature . Outdoor wet-bulb, F Entering temperat

46、ure . Electrical voltage, % of reading. Electrical Frequency, % of reading 4.0 4.0 4.0 2.0 1.0 0.5 0.5 1.0 1.0 Notes: 1. Test Operating Tolerance is the maximum permissible range of any measurement. When expressed as a percentage, the maximum allowable variation is the specified percentage of the av

47、erage value. 2. Test Condition Tolerance is the maximum permissible variation of the average value of the measure-ment from the specified test condition. AHRI STANDARD 1250 (I-P)-2014 5 4.2 Method of Test. The method of test for walk-in cooler and freezer systems that have matched Unit Coolers and c

48、on-densing units, and the procedures of testing condensing units and Unit Coolers individually are described in Appendix C of this standard. 4.3 Test Conditions. Walk-in systems, condensing units and Unit Coolers shall be tested under the standard rating condi-tions defined in Section 5. Section 5.

49、Rating Requirements 5.1 Standard Ratings. Standard Ratings shall be established at the Standard Rating Conditions in the following listed ta-bles and shall include its associated power input and Energy Efficiency Ratio (EER). When tested with a specified motor, the associated compressor speed (external drive compressors only) shall also be included as part of the rating. The power re-quired to operate all included accessories such as condenser fans, water pumps, controls, and similar accessories shall be ac-counte