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ASHRAE Standard 84 2020

ASHRAE Standard 84 2020

$29.58

ASHRAE Standard 84-2020 — Method of Testing Air-to-Air Heat/Energy Exchangers (ANSI Approved)

Published By Publication Date Number of Pages
ASHRAE 2020 48
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ASHRAE Standard 84 provides rules for the measurement and expression of values characterizing the energy-related performance of air-to-air heat/energy exchangers. The revised 2020 edition of the standard includes the following changes: * Rules are provided for measurement of fixed-bed regenerator performance. * The metric ā€œenergy recovery ratio,ā€ first introduced in ASHRAE Standard 90.1-2016, is defined. This metric differs from the fundamental effectiveness equations in that it characterizes only an exchanger’s ability to reduce the load associated with the supply air at a specified condition. * The standard was revised to comply with ASHRAEā€™s mandatory language policy.

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PDF Pages PDF Title
1 ANSI/ASHRAE Standard 84-2020
3 CONTENTS
4 FOREWORD
1. PURPOSE
2. SCOPE
2.1 This standard prescribes the laboratory methods for testing the performance of air-to-air heat and energy exchangers. In this standard, an air-to-air heat/energy exchanger is a device to transfer heat, or heat and water vapor, from one airstream …
5 3. DEFINITIONS
7 4. REQUIREMENTS FOR PERFORMANCE TESTING
4.1 Performance Determinations. The performance of an air-to-air heat/energy exchanger is primarily characterized by the following set of metrics: (a) effectiveness and net effectiveness, (b) recovery efficiency ratio and net recovery efficiency rati…
9 4.2 Pretest Uncertainty Analysis. A pretest uncertainty analysis, defined in ASME PTC 19.1 1, shall be performed prior to any testing on all the parameters outlined in Section 4.2. Test points, procedures, and equipment shall be analyzed to confirm t…
10 4.3 Apparatus. The test apparatus shall consist of four measurement stations. Three measurements shall be taken at each measurement station as follows:
4.4 Instrument Calibration. All measurement instruments shall be calibrated using sensors, transfer standards, and primary instruments that are traceable to NIST standards. Instrument uncertainty levels shall be shown by the pretest uncertainty analy…
5. TEST PARAMETERS
5.1 Thermal Performance. Performance tests are subject to the following provisions.
5.2 Leakage
11 5.3 Pressure Drop. Air friction pressure drop across the heat/energy exchanger from Stations 1 to 2 and Stations 3 to 4 shall be determined at the tested airflows.
6. OPERATING CONDITIONS, INEQUALITY CHECKS, AND CONDITIONS FOR REJECTION OF TEST DATA
6.1 The inlet air property variations during thermal performance testing shall satisfy the following inequalities:
6.2 During thermal performance testing, the dry airflow mass measured flow rates shall satisfy the following inequality equation:
6.3 For all thermal performance tests where no condensate or frosting occurs, the dry airflow mass measured flow rates and the water vapor mass measured flow rates shall satisfy the following inequality equations:
12 6.4 For the case of thermal performance tests of sensible-only devices where no phase change, condensate, or frosting occurs, the measured sensible energy flow rates shall satisfy the inequality of Equation 23 rather than that of Equation 22:
6.5 During testing to determine OACF and EATR, the readings shall satisfy the airflow mass inequality:
7. PRE- AND POST-TEST UNCERTAINTY ANALYSIS
13 8. INSTRUMENTS AND METHODS OF MEASUREMENT
8.1 Systematic and Random Uncertainty. The systematic uncertainty and random uncertainty for each measurement shall be such that the total uncertainty for the heat/energy exchanger effectiveness satisfy the limits in Section 7. When testing fixed-bed…
8.2 Instrumentation. Instrument specification and application shall be in accordance with ANSI/ASHRAE Standards 41.1 3, 41.2 4, 41.3 5, and 41.6 6, respectively, unless otherwise specified in this document.
8.3 Temperature
8.4 Humidity
14 8.5 Pressure
8.6 Static Pressure
8.7 Barometric Pressure
8.8 Airflow Measurement. Any flow measurement method (pressure differential device) used shall not exceed the uncertainty introduced by an appropriate flow nozzle or velocity sensor traverse method, as described by ASHRAE Standard 41.2-1987 (RA1992) …
8.9 Tracer Gas Measurement. To measure air transfer from the exhaust to the supply side of an exchanger, an inert tracer gas is injected into a turbulent region of the exhaust inlet. Air samples are then drawn from each of Stations 1 to 4. The sampli…
15 8.10 Fixed-Bed Regenerator Performance Testing
19 8.11 Adjustable Purge Setting. When a rotary regenerator with adjustable purge section is tested, purge angle or area setting shall be recorded for all tests.
9. CALCULATIONS
9.1 Airflow Rate. The airflow rate calculations shall be based on the measurements obtained in Section 8.8.
9.2 Total Enthalpy. The total enthalpy shall be calculated from the following equations:
20 9.3 The Standardized Air Friction Pressure Drop
9.4 Outdoor Air Correction Factor
9.5 Exhaust Air Transfer
21 10. REPORTING RESULTS
10.1 Reporting Requirements. Test results shall not be reported as meeting the requirements of this standard unless
10.2 Results of Test. Test results shall be reported at no less than two selected mass flow rates and no less than two ratios of mass flow rates for the following:
10.3 Test Conditions. Reports of performance test results of air-to-air exchangers in a laboratory shall include the following data:
10.4 Uncertainties of Results. The uncertainties of each result in Section 10.2 shall be reported. Uncertainties shall be reported for all performance factors at the 95% data coverage level as described in ASME PTC 19.1 1.
11. NOMENCLATURE
11.1 Symbols (SI [I-P])
22 11.2 Subscripts
23 12. NORMATIVE REFERENCES
24 INFORMATIVE APPENDIX A: LABORATORY TEST CONFIGURATIONS
29 INFORMATIVE APPENDIX B: TRANSIENT TESTING OF ENERGY EXCHANGERS USING A BAG SAMPLING METHOD
B1. Bag Sampling Method
B2. Transient Testing of Energy Exchangers
30 INFORMATIVE APPENDIX C: AN EXPLANATION FOR THE USE OF EFFECTIVENESSES TO CHARACTERIZE AIR-TO-AIR HEAT/ENERGY EXCHANGERS
C1. Development of Effectiveness Definitions
34 C2. Research Findings
35 C3. EXHAUST AIR TRANSFER RATIO AND OUTDOOR AIR CORRECTION FACTOR
36 C4. RECOVERY EFFICIENCY RATIO
37 INFORMATIVE APPENDIX D: SELECTION OF TEST CONDITIONS
D1. Testing Conditions
D2. Selection of Operating Conditions
D2.1 The Graphical Selection Method. The psychrometric chart in Figure D-1 allows a pretest estimation of the uncertainty levels associated with any combination of supply condition with an exhaust condition of 24Ā°C and 50% rh. Figure D-2 presents si…
D2.2 The Calculation Method. It is convenient to define an operating condition uncertainty (U*[ei(OC)]) using only the denominator from the definition of the effectiveness:
40 INFORMATIVE APPENDIX E: FIELD TESTING
E1. MASS FLOW MEASUREMENT
42 E2. TEMPERATURE AND HUMIDITY DETERMINATIONS
E3. QUASI-STEADY FIELD TEST CRITERIA
43 E4. Rejection of Test Data
44 INFORMATIVE APPENDIX F: EXTRAPOLATION OF TEST PERFORMANCE DATA
45 INFORMATIVE APPENDIX G: INFORMATIVE REFERENCES AND BIBLIOGRAPHY
G1. INFORMATIVE REFERENCES
46 G2. BIBLIOGRAPHY

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ASHRAE Standard 84 2020
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