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ASHRAE Standard 20-2019 - Methods of Laboratory Testing Remote Mechanical-Draft Air-Cooled Refrigerant Condensers, 2019
- ANSI/ASHRAE Standard 20-2019 [Go to Page]
- CONTENTS
- FOREWORD
- 1. PURPOSE
- 2. SCOPE [Go to Page]
- 2.1 This standard provides
- 2.2 This standard does not cover
- 3. DEFINITIONS
- 4. REQUIREMENTS [Go to Page]
- 4.1 Test Setup. Informative Appendix A describes known workable systems. This standard does not specify an exclusive list of required components.
- 4.2 Duration of Test. After establishment of steady-state test conditions, all required readings, a test set, as detailed in Section 7.3, shall be recorded at a maximum of 30-second intervals. The test period, a test run, shall be defined as a minimu...
- 4.3 Safety Requirements. All components in the test apparatus and the condenser shall meet the design requirements for safety as outlined in ANSI/ASHRAE Standard 15, Safety Standard for Refrigeration Systems 2.
- 5. INSTRUMENTS [Go to Page]
- 5.1 Instruments (or instrument systems) shall be selected to meet the minimum accuracies shown in Table 1.
- Table 1 Instrumentation Accuracy
- 5.2 Measurements from the instruments shall be traceable to primary or secondary standards calibrated by National Institute of Standards and Technology (NIST) or to the Bureau International des Poids et Mesures (BIPM) if a National Metrology Institut...
- 5.3 Instruments shall be applied and used in accordance with the following documents:
- 5.4 The current version of NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties (REFPROP)7 shall be the source for thermodynamic properties, or a reference that provides compliant properties per ISO 17584:2005 8...
- 6. METHOD OF TESTING [Go to Page]
- 6.1 Heat Rejection Measurements. Refrigerant flow through the condenser shall be measured. Entering and leaving refrigerant enthalpies shall be determined from the corresponding pressure and temperature measurements.
- Table 2 Test Condition Stability Requirement
- 6.2 Air Temperature Measurement. The air temperatures entering the condenser coil(s) shall be the arithmetic average of the individual recorded station readings at a specific time during a test run.
- 6.3 Test runs conducted with the condenser positioned outdoors shall be invalid when average wind velocity exceeds 4.5 mps (10 mph) or when wind velocity exceeds 7 mps (15 mph) over a 1-minute duration.
- 6.4 See Table 2 for stability criteria for test conditions.
- 6.5 Piping and charging with refrigerant shall be in accordance with the manufacturer’s specification. All components in the test apparatus and test condenser shall conform to the design requirements for safety as outlined in ANSI/ASHRAE Standard 1...
- 6.6 Condenser Operation
- 7. DATA TO BE RECORDED [Go to Page]
- 7.1 Test System Description. The system type used with applicable schematic. See Informative Appendix A for examples of system type and applicable schematics.
- 7.2 Manufacturer’s Condenser Data
- 7.3 Test Data (Taken at Each Reading Interval)
- 8. NOMENCLATURE AND COMPUTATIONS [Go to Page]
- 8.1 Nomenclature
- 8.2 Computations
- 9. NORMATIVE REFERENCES
- 10. INFORMATIVE REFERENCES
- INFORMATIVE APPENDIX A: TEST APPARATUS [Go to Page]
- A1. Receiver Location and Sizing [Go to Page]
- A1.1 The liquid head in the receiver, as indicated in Figures A-1, A-2, and A-3, shall be maintained such that there is a visible level in the receiver as confirmed with sight glasses.
- A1.2 The condenser exit pipe line shall be sized for a maximum liquid refrigerant velocity of 0.5 m/s (100 ft/min). The line shall be sloped at least 10 mm/m (0.125 in./ft) of pipe length.
- A2. Systems [Go to Page]
- A2.1 High-Side Gravity Recirculation Systems. The system in Figure A-1 is a gravity recirculating system where the entire system is at the high side or condensing pressure level. The liquid head from the liquid level of the receiver to the flow regul...
- A2.2 High-Side Pump Recirculation System. The entire system in Figure A-2 is at the high side or condensing pressure level. This system eliminates the need for a high static head between the receiver and the boiler/evaporator, as in Figure A-1, by us...
- A2.3 Compressor-Driven Recirculation Systems. In the system in Figure A-3, the oil separator shall meet the specifications of the compressor manufacturer and shall reduce the oil content of the refrigerant to a maximum of 0.5% by weight. Testing lubr...
- A3. Heat Input: Electrical, Steam, or Hot Water
- A4. Noncondensables [Go to Page]
- Figure A-1 High-side gravity recirculation system.
- Figure A-2 High-side pump recirculation system.
- Figure A-3 Compressor-driven recirculation system.
- INFORMATIVE APPENDIX B: METHOD FOR REMOVING NONCONDENSABLES IN REMOTE MECHANICAL-DRAFT REFRIGERANT CONDENSERS [Go to Page]