ASHRAE Standard 41.9 2018
$33.58
ASHRAE Standard 41.9-2018 – Standard Methods for Refrigerant Mass Flow Measurements Using Calorimeters (ANSI Approved)
| Published By | Publication Date | Number of Pages |
| ASHRAE | 2018 | 30 |
N/A
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | ANSI/ASHRAE Standard 41.9-2018 |
| 3 | CONTENTS |
| 4 | FOREWORD 1. PURPOSE 2. SCOPE 2.1 This standard applies to measuring mass flow rates for refrigerants and refrigerant/lubricant mixtures using calorimeters in laboratories. 2.2 This standard applies where the entire flow stream of the refrigerant or the refrigerant/lubricant mixture enters the calorimeter as a subcooled liquid and leaves as a superheated vapor (evaporator type). 2.3 This standard applies where the entire flow stream of the refrigerant or the refrigerant/lubricant mixture enters the calorimeter as a superheated vapor and leaves as a subcooled liquid (condenser type). 3. DEFINITIONS 4. CLASSIFICATIONS 4.1 Calorimeter Types. Calorimeters that are within the scope of this standard are classified as one of the two types listed in Sections 4.1.1 and 4.1.2. 5. REQUIREMENTS 5.1 Test Plan. A test plan shall specify the test points to be performed. The test plan shall be one of the following: 5.2 Values to be Determined and Reported. The test values to be determined and reported shall be as shown in Table 5-1. Use the unit of measure in Table 5-1 unless otherwise specified in the test plan in Section 5.1. 5.3 Refrigerant Mass Flow Rate. Determine the refrigerant mass flow rate, kg/s (lbm/h), through the unit under test using one of the test methods described in Sections 7 through 10 unless otherwise specified in the test plan in Section 5.1. |
| 5 | 5.4 Measurement Uncertainty. The uncertainty in each refrigerant mass flow rate measurement, kg/s (lbm/h), shall be estimated using the methods described in Section 12 for each test point unless otherwise specified in the test plan in Section 5.1. Al… 5.5 Lubricant Circulation Rate 5.6 Lubricant Sampling Port. A sampling port shall be provided for extracting samples of liquid refrigerant and circulating lubricant for use in determining lubricant circulation rates if required by Section 5.5. 5.7 Steady-State Criteria for Refrigerant Mass Flow Rate Measurements. Refrigerant mass flow rate test data shall be recorded at steady-state test conditions unless otherwise stated in the test plan in Section 5.1. Section 5.8 describes nonsteady ref… Table 5-1 Measurement Values and Units of Measure |
| 6 | 5.8 Transient Refrigerant Mass Flow Rate Measurements. If required by the test plan in Section 5.1, refrigerant mass flow rate test data shall be recorded 5.9 Refrigerant Properties. Refrigerant properties shall be obtained from NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP) 1 or from the refrigerant supplier if a constituent of the refrigerant being tested is not includ… 5.10 Input Power. Compressor input power shall be measured in accordance with ASHRAE Standard 41.11 2 if required by the test plan in Section 5.1. 5.11 Safety Requirements. Test apparatus shall be designed in accordance with ASHRAE Standard 15 3. Materials of construction shall be selected based on refrigerant flammability, toxicity, structural strength, rigidity, corrosion resistance, chemical… Figure 5-1 Theoretical cycle of refrigerant flow rate for a pulse-width modulated compressor that delivers 50% load. 6. INSTRUMENTS 6.1 Instrumentation Requirements for All Measurements 6.2 Temperature Measurements. If temperature measurements are required by the test plan in Section 5.1, the temperature measurement system accuracy shall be within the following limits unless otherwise specified in the test plan. |
| 7 | 6.3 Pressure Measurements 6.4 Coolant Liquid Flow Rate Measurements. If the unit under test (UUT) or the selected calorimeter method includes coolant liquid flow rate measurement, the measurement system errors shall be measured within ±1.0% of reading in laboratory applicati… 6.5 Time Measurements. Time measurement system accuracy shall be within ±0.5% of the elapsed time measured, including any uncertainty associated with starting and stopping the time measurement, unless (a) otherwise specified in the test plan in Sect… 6.6 Mass Measurements. If mass measurements are required by the test plan in Section 5.1, the measurement system errors shall be within ±0.2% of the reading unless otherwise specified in the test plan. 7. SECONDARY REFRIGERANT CALORIMETER METHOD 7.1 Equipment Description. A secondary refrigerant calorimeter (Figure 7-1) shall consist of two independent fluid circuits located in heat exchange relationship to each other. The primary refrigerant evaporator coil is suspended in the upper portion… 7.2 Calorimeter Safety Features. The calorimeter shall be equipped with (a) a safety switch that will stop the flow of heat into the secondary refrigerant and (b) a spring-actuated or rupture-disk-type pressure relief valve. The pressure settings for… 7.3 Test Data. Test data to be recorded at each steady-state test condition in accordance with Section 5.7 are as follows: Figure 7-1 Secondary refrigerant calorimeter. |
| 8 | 7.4 Heat Leakage. The heat leakage to the surroundings for each calorimeter shall be measured once, and the results shall be applied to all subsequent refrigerant mass flow rate measurements. The heat leakage shall be less than 5% of the heat input t… 7.5 Preparations 7.6 Operating Procedures 7.7 Test Condition Tolerances During Data Recording |
| 9 | 7.8 Refrigerant Mass Flow Rate Calculations. Refrigerant mass flow rates measured using the secondary refrigerant calorimeter method shall be calculated using Equation 7-3: 7.9 Measurement Uncertainty. Measurement uncertainty in the refrigerant mass flow rate measurement shall be estimated using the procedures prescribed in Section 12 as required by Section 5.4. 8. SECONDARY FLUID CALORIMETER METHODS 8.1 Equipment Description. A secondary fluid calorimeter shall consist of two independent fluid circuits located in heat exchange relationship to each other. The refrigerant enters the calorimeter as a subcooled liquid and leaves the calorimeter as a… 8.2 Calorimeter Safety Features. The calorimeter shall be equipped with a safety switch that will stop the flow of heat into the secondary fluid, and a spring-actuated or rupture-disk type pressure relief valve. The pressure settings for the safety s… 8.3 Test Data Figure 8-1 Secondary fluid calorimeter that uses a single-phase liquid. (Informative Note: Water and brine are examples of single-phase liquids that are used in secondary fluid calorimeters.) |
| 10 | 8.4 Heat Leakage. The heat leakage to the surroundings for each calorimeter shall be measured once, and the results shall be applied to all subsequent refrigerant flow rate measurements. The heat leakage shall be less than 5% of the heat input to the… Figure 8-2 Secondary fluid calorimeter that uses a two-phase fluid. (Informative Note: Steam is an example of a two-phase fluid that is used in secondary fluid calorimeters.) |
| 11 | 8.5 Preparations 8.6 Operating Procedures 8.7 Test Condition Tolerances During Data Recording 8.8 Calculations. Refrigerant mass flow rates measured using the secondary fluid method shall be calculated using Equation 8-3a for a single-phase liquid and using Equation 8- 3b for a two-phase fluid: 8.9 Measurement Uncertainty. Measurement uncertainty in the refrigerant mass flow rate measurement shall be estimated using the procedures prescribed in Section 12 as required by Section 5.4. 9. PRIMARY REFRIGERANT CALORIMETER METHOD |
| 12 | 9.1 Equipment Description. The primary refrigerant calorimeter (Figure 9-1) consists of an arrangement of refrigerant tubes or tubular vessels designed to evaporate the refrigerant flow. Heat input shall be provided by an electric heating device appr… 9.2 Calorimeter Safety Features. The calorimeter shall be equipped with a safety switch that will stop the flow of heat input, and a spring-actuated or rupture-disk type pressure relief valve. The pressure settings for the safety switch and the press… 9.3 Test Data. Test data to be recorded at each steady-state test condition in accordance with Section 5.7 are as follows: 9.4 Heat Leakage. The heat leakage to the surroundings for each calorimeter shall be measured once, and the results shall be applied to all subsequent refrigerant flow rate measurements. The heat leakage shall be less than 5% of the heat input to the… Figure 9-1 Primary refrigerant calorimeter method. |
| 13 | 9.5 Preparations 9.6 Operating Procedures 9.7 Test Condition Tolerances During Data Recording 9.8 Calculations. Refrigerant mass flow rates measured using the primary refrigerant calorimeter method shall be calculated using Equation 9-3: 9.9 Measurement Uncertainty. Measurement uncertainty in the refrigerant mass flow rate measurement shall be estimated using the procedures prescribed in Section 12 as required by Section 5.4. 10. CONDENSER CALORIMETER METHOD 10.1 Equipment Description. The condenser calorimeter (Figure 10-1) consists of a heat exchanger that is cooled by a single-phase liquid with known transport properties and capable of condensing superheated refrigerant vapor and producing subcooled r… 10.2 Calorimeter Safety Features. The calorimeter shall be equipped with a safety switch that will stop the flow of heat into the refrigerant, and a spring-actuated or rupture-disk type pressure relief valve. The pressure settings for the safety swit… 10.3 Test Data. Test data to be recorded at each steady-state test condition in accordance with Section 5.6 are as follows: 10.4 Heat Leakage. The heat leakage to the surroundings for each calorimeter shall be measured once, and the results shall be applied to all subsequent refrigerant flow rate measurements. The heat leakage shall be less than 5% of the heat input to th… |
| 14 | 10.5 Preparations 10.6 Operating Procedures 10.7 Test Condition Tolerances During Data Recording 10.8 Refrigerant Mass Flow Rate Calculations. The refrigerant mass flow rate measured using the condenser calorimeter method shall be calculated using Equation 10-2: Figure 10-1 Condenser calorimeter. |
| 15 | 10.9 Measurement Uncertainty. Measurement uncertainty in the refrigerant mass flow rate measurement shall be estimated using the procedures prescribed in Section 12 as required by Section 5.4. 11. LUBRICANT CIRCULATION RATE MEASUREMENTS 11.1 Symbols. Table 11-1 defines the symbols used in Section 11. 11.2 Lubricant Circulation Rate Measurement without an Auxiliary Lubricant Separator 11.3 Lubricant Circulation Rate Measurement with an Auxiliary Lubricant Separator Table 11-1 Symbols Used in Section 11 |
| 16 | Figure 11-1 Auxiliary lubricant separator schematic. 12. UNCERTAINTY REQUIREMENTS 12.1 Uncertainty Estimate. An estimate of the measurement uncertainty, performed in accordance with ASME PTC 19.1 8, shall accompany each refrigerant mass flow measurement. 12.2 Method to Express Uncertainty. All assumptions, parameters, and calculations used in estimating uncertainty shall be clearly documented prior to expressing any uncertainty values. Uncertainty shall be expressed as follows: 13. TEST REPORT 13.1 Test Identification 13.2 Unit under Test Description 13.3 Calorimeter Description |
| 17 | 13.4 Ambient Conditions 13.5 Test Conditions 13.6 Test Results 14. REFERENCES |
| 18 | INFORMATIVE APPENDIX A—FRAMEWORK FOR UNCERTAINTY ANALYSIS FOR A PRIMARY REFRIGERANT CALORIMETER AND A SECONDARY FLUID REFRIGERANT CALORIMETER |
| 19 | Table A-1 Parameter Description for Informative Appendix A Example Table A-2 Uncertainty Parameter Description for Informative Appendix A Example |
| 20 | Figure A-1 Refrigerant pressure-enthalpy diagram. |
| 21 | INFORMATIVE APPENDIX B—EXAMPLE OF UNCERTAINTY ESTIMATE FOR A SECONDARY REFRIGERANT CALORIMETER |
| 22 | Table B-1 Test Data for Informative Appendix B Example Table B-2 Enthalpy Data for Informative Appendix B Example |
| 23 | INFORMATIVE APPENDIX C—EXAMPLE OF UNCERTAINTY ESTIMATE FOR A CONDENSER CALORIMETER C1. Baseline Case |
| 24 | C2. Second Case C3. Third Case |
| 25 | Table C-1 Uncertainty Contribution of Each Term in the Equation for the Baseline Case Table C-2 Test Data for Informative Appendix C Example |
| 26 | Table C-3 Uncertainty Contribution of Each Term in the Equation for the Second Case Table C-4 Uncertainty Contribution of Each Term in The Equation for the Third Case |
| 27 | INFORMATIVE APPENDIX D—SOURCES OF TEMPERATURE MEASUREMENT ERROR |
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