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ASHRAE 84 08 2008

ASHRAE 84 08 2008

$21.13

ASHRAE Standard 84-2008 Method of Testing Air-to-Air Heat Exchangers

Published By Publication Date Number of Pages
ASHRAE 2008 26
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PDF Pages PDF Title
4 FOREWORD
FOREWORD
1. PURPOSE
1. PURPOSE
2. scope
2. scope
2.1 This standard prescribes the methods for testing the performance of air-to-air heat/energy exchangers.
2.1 This standard prescribes the methods for testing the performance of air-to-air heat/energy exchangers.
2.2 In this standard, an air-to-air heat/energy exchanger is a device to transfer heat and/or water vapor from one airstream to another. The types of air-to-air heat/energy exchangers covered by this standard are:
2.2 In this standard, an air-to-air heat/energy exchanger is a device to transfer heat and/or water vapor from one airstream to another. The types of air-to-air heat/energy exchangers covered by this standard are:
2.3 The scope of this standard also includes both laboratory and field tests, provided that appropriate levels of uncertainty can be achieved when testing.
2.3 The scope of this standard also includes both laboratory and field tests, provided that appropriate levels of uncertainty can be achieved when testing.
2.4 A test is deemed to be within the scope of this standard if both a pre-test uncertainty analysis and a post-test uncertainty analysis yield satisfactory uncertainty limits.
2.4 A test is deemed to be within the scope of this standard if both a pre-test uncertainty analysis and a post-test uncertainty analysis yield satisfactory uncertainty limits.
3. definitions
3. definitions
5 4. Guidelines for performance testing
4. Guidelines for performance testing
4.1 General. The performance of air-to-air heat/energy exchangers depends upon many factors but especially upon operating conditions. It must be understood that changes in operating conditions will affect the apparent heat/energy exchanger performance.
4.1 General. The performance of air-to-air heat/energy exchangers depends upon many factors but especially upon operating conditions. It must be understood that changes in operating conditions will affect the apparent heat/energy exchanger performance.
4.2 Performance Determinations. The performance of an air-to-air heat/energy exchanger is primarily determined by (a) its effectiveness and recovery efficiency ratio, (b) its pressure drop and mass flow characteristics, (c) the outside air correction…
4.2 Performance Determinations. The performance of an air-to-air heat/energy exchanger is primarily determined by (a) its effectiveness and recovery efficiency ratio, (b) its pressure drop and mass flow characteristics, (c) the outside air correction…
6 Figure 1 Scheme of airflow for air-to-air heat/energy exchangers.
Figure 1 Scheme of airflow for air-to-air heat/energy exchangers.
4.3 Pre-Test Uncertainty Analysis. A pre-test uncertainty analysis, defined in ANSI/ASME PTC 30,2 shall be performed prior to any testing on all the parameters outlined in Section 4.2. Test points, procedures and equipment should be analyzed to ensur…
4.3 Pre-Test Uncertainty Analysis. A pre-test uncertainty analysis, defined in ANSI/ASME PTC 30,2 shall be performed prior to any testing on all the parameters outlined in Section 4.2. Test points, procedures and equipment should be analyzed to ensur…
4.4 Apparatus. The test apparatus shall consist of four measurement stations. Three measurements shall be taken at each measurement station as follows:
4.4 Apparatus. The test apparatus shall consist of four measurement stations. Three measurements shall be taken at each measurement station as follows:
4.5 Instrument Calibration. All measurement instruments shall be calibrated using sensors, transfer standards and primary instruments that are traceable to NIST standards. Uncertainty levels shall be acceptable by the pre-test uncertainty analysis. C…
4.5 Instrument Calibration. All measurement instruments shall be calibrated using sensors, transfer standards and primary instruments that are traceable to NIST standards. Uncertainty levels shall be acceptable by the pre-test uncertainty analysis. C…
7 5. Test parameters
5. Test parameters
5.1 Laboratory Test Configurations. Laboratory test facilities can be of two types: closed-loop systems or open- loop systems.
5.1 Laboratory Test Configurations. Laboratory test facilities can be of two types: closed-loop systems or open- loop systems.
5.2 Thermal Performance. Performance tests are subject to the following provisions.
5.2 Thermal Performance. Performance tests are subject to the following provisions.
5.3 Leakage (Plus Purge Flow When Applicable)
5.3 Leakage (Plus Purge Flow When Applicable)
5.4 Pressure Drop
5.4 Pressure Drop
6. OPERATING CONDITIONS AND Balance Checks and Rejection of Test Data
6. OPERATING CONDITIONS AND Balance Checks and Rejection of Test Data
6.1 Laboratory Testing. During thermal performance testing, when a set of property data is measured and stored, the inlet air property variations shall satisfy the following inequalities:
6.1 Laboratory Testing. During thermal performance testing, when a set of property data is measured and stored, the inlet air property variations shall satisfy the following inequalities:
8 Figure 2 Closed-loop test configuration.
Figure 2 Closed-loop test configuration.
9 Figure 3 Open-loop test configuration.
Figure 3 Open-loop test configuration.
10 6.2 Field Testing. For field testing, which is presented in informative Appendix C, the upper limits on inequalities of Equations 7–19 shall be increased by a factor of 2.0.
6.2 Field Testing. For field testing, which is presented in informative Appendix C, the upper limits on inequalities of Equations 7–19 shall be increased by a factor of 2.0.
7. Post-Test Uncertainty Analysis
7. Post-Test Uncertainty Analysis
7.1 Laboratory Testing. For testing of effectiveness, pre- test and post-test uncertainties shall satisfy the following equations:
7.1 Laboratory Testing. For testing of effectiveness, pre- test and post-test uncertainties shall satisfy the following equations:
11 7.2 Field Testing. For field testing, which is presented in Appendix C, the uncertainty limits in inequalities in Equations 20–23 and Equations 25–29 shall be increased by a factor of 1.5.
7.2 Field Testing. For field testing, which is presented in Appendix C, the uncertainty limits in inequalities in Equations 20–23 and Equations 25–29 shall be increased by a factor of 1.5.
8. iNSTRUMENTS AND METHODS OF MEASUREMENT
8. iNSTRUMENTS AND METHODS OF MEASUREMENT
8.1 Bias and Precision Uncertainty. The bias and precision limits for each measurement shall be such that the total uncertainty for the heat/energy exchanger effectiveness satisfy the limits in Section 7.
8.1 Bias and Precision Uncertainty. The bias and precision limits for each measurement shall be such that the total uncertainty for the heat/energy exchanger effectiveness satisfy the limits in Section 7.
8.2 Instrumentation. Temperature and humidity measurement instruments, unless otherwise specified below, shall be in accordance with ANSI/ASHRAE Standard 41.13 and ANSI/ASHRAE Standard 41.6,4 respectively.
8.2 Instrumentation. Temperature and humidity measurement instruments, unless otherwise specified below, shall be in accordance with ANSI/ASHRAE Standard 41.13 and ANSI/ASHRAE Standard 41.6,4 respectively.
8.3 Airflow Measurement
8.3 Airflow Measurement
12 8.4 Tracer Gas Measurement
8.4 Tracer Gas Measurement
9. Calculations
9. Calculations
9.1 Airflow Rate
9.1 Airflow Rate
9.2 Effectiveness
9.2 Effectiveness
9.3 Total Enthalpy. The total enthalpy shall be calculated from the following equation:
9.3 Total Enthalpy. The total enthalpy shall be calculated from the following equation:
9.4 The Air Friction Pressure Drop
9.4 The Air Friction Pressure Drop
13 9.5 Exhaust Air Transfer
9.5 Exhaust Air Transfer
10. reporting results
10. reporting results
10.1 Laboratory Testing
10.1 Laboratory Testing
14 10.2 Field Testing
10.2 Field Testing
11. Nomenclature
11. Nomenclature
12. references
12. references
15 INFORMATIVE APPENDIX A— AN EXPLANATION FOR THE USE OF EFFECTIVENESSES TO CHARACTERIZE AIR-TO-AIR HEAT/ENERGY EXCHANGERS
INFORMATIVE APPENDIX A— AN EXPLANATION FOR THE USE OF EFFECTIVENESSES TO CHARACTERIZE AIR-TO-AIR HEAT/ENERGY EXCHANGERS
A1. Development of Effectiveness Definitions
A1. Development of Effectiveness Definitions
17 A2. Research Findings
A2. Research Findings
18 INFORMATIVE APPENDIX B— SELECTION OF Test CONDITIONS
INFORMATIVE APPENDIX B— SELECTION OF Test CONDITIONS
B1. Testing Conditions
B1. Testing Conditions
B2. Selection of Operating Conditions
B2. Selection of Operating Conditions
B2.1 The Graphical Selection Method. The psychrometric chart in Figure B-1 allows a pre-test estimation of the uncertainty levels associated with any combination of supply condition with an exhaust condition of 24°C and 50% relative humidity. Figure…
B2.1 The Graphical Selection Method. The psychrometric chart in Figure B-1 allows a pre-test estimation of the uncertainty levels associated with any combination of supply condition with an exhaust condition of 24°C and 50% relative humidity. Figure…
B2.2 The Calculation Method. It is convenient to define an operating condition uncertainty, , using only the denominator from the definition of the effectiveness:
B2.2 The Calculation Method. It is convenient to define an operating condition uncertainty, , using only the denominator from the definition of the effectiveness:
INFORMATIVE APPENDIX C— Field Testing
INFORMATIVE APPENDIX C— Field Testing
19 Figure B-1 Lines of constant uncertainty in measured effectiveness values for different supply inlet conditions. The assumed bias and precision in mass flow rate, temperature, and humidity are ±4% and ±1%, ±0.2K and ±0.1K, and ±2%RH and ±1% RH,…
Figure B-1 Lines of constant uncertainty in measured effectiveness values for different supply inlet conditions. The assumed bias and precision in mass flow rate, temperature, and humidity are ±4% and ±1%, ±0.2K and ±0.1K, and ±2%RH and ±1% RH,…
20 Figure B-2 Lines of constant uncertainty in measured effectiveness values for different supply inlet conditions. The assumed bias and precision in mass flow rate, temperature, and humidity are ±5% and ±3%, ±0.5K and ±0.1K, and ±3%RH and ±1% RH,…
Figure B-2 Lines of constant uncertainty in measured effectiveness values for different supply inlet conditions. The assumed bias and precision in mass flow rate, temperature, and humidity are ±5% and ±3%, ±0.5K and ±0.1K, and ±3%RH and ±1% RH,…
21 C1. Mass Flow Measurement
C1. Mass Flow Measurement
22 C2. Temperature and Humidity Determinations
C2. Temperature and Humidity Determinations
C3. QuasI-Steady Field Test Criteria
C3. QuasI-Steady Field Test Criteria
23 C4. Rejection of Test Data
C4. Rejection of Test Data
INFORMATIVE APPENDIX D— extrapolation of test performance data
INFORMATIVE APPENDIX D— extrapolation of test performance data
INFORMATIVE APPENDIX E— BIBLIOGRAPHY
INFORMATIVE APPENDIX E— BIBLIOGRAPHY

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ASHRAE 84 08 2008
$21.13