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ASHRAE Standard 133-2024 -- Method of Testing Direct Evaporative Air Coolers (ANSI Approved), 2024
- ASHRAE Online Bookstore
- Addenda
- Errata
- ANSI/ASHRAE Standard 133-2024 [Go to Page]
- Foreword
- Contents
- 1. Purpose
- 2. Scope [Go to Page]
- 2.1 The scope of this standard covers a method of testing for rating saturation effectiveness, airflow rate, and total power of packaged and component direct evaporative air coolers.
- 2.2 Covered tests include the methods for measuring the static pressure differential of the direct evaporative air cooler, density of the air, and speed of rotation of the fan.
- 2.3 This standard requires that packaged and component direct evaporative air coolers be simultaneously tested for airflow, total power, and saturation effectiveness.
- 2.4 The ratings resulting from application of this standard are intended for use by manufacturers, specifiers, installers, and users of evaporative air-cooling apparatus for residential, commercial, agricultural, and industrial ventilation; air cooli...
- 3. Definitions and Acronyms
- 4. Symbols and Subscripts [Go to Page]
- 4.1 Symbols
- 4.2 Subscripts
- 5. Requirements [Go to Page]
- 5.1 Determinations. The number of determinations required to establish the performance of a direct evaporative air cooler (DEC) over the range from shutoff to free delivery shall be established depending on the shapes of the various characteristic cu...
- 5.2 Test Data Processing. Data point measurements collected during the duration of the testing period shall be processed to calculate sample mean and sample standard deviation.
- 5.3 Temperature and Humidity at Test Conditions. Inlet plenum air dry-bulb temperature shall be 46°C (115°F) maximum, the wet-bulb temperature shall be 5°C (41°F) minimum, and the wet-bulb depression shall be 11°C (20°F) minimum during the test...
- 5.4 Water Conductivity. Conductivity of the water shall be measured using a conductivity meter compensated for temperature. The conductivity of the water supplied to the distribution header shall be between 350 and 3500 microsiemens (µS).
- 5.5 Entrainment Verification. Water entrainment shall not occur in equipment being tested for rating. Water entrainment will affect temperature measurements; consequently, any water entrainment shall invalidate test results. A sensitive paper that ch...
- 5.6 Thermodynamic Properties of Air. Dry and moist air properties shall be obtained from or agree with ASHRAE RP-1485 1.
- 5.7 Airflow Leakage Requirement: Measured airflow leakage into or out of the test apparatus shall not be greater than 0.25% of the airflow at the leak test pressure that is equal to the maximum operating pressure.
- 6. Instruments and Measurement Methods [Go to Page]
- 6.1 Instrument Calibrations. Measurements from the instruments shall be traceable to primary or secondary standards calibrated by the National Institute of Standards and Technology (NIST) or to the Bureau International des Poids et Mesures (BIPM) if ...
- 6.2 Instrument Accuracy Requirements and Measurement Methods. Measuring instruments shall be selected to meet or exceed the instrument accuracy listed in Table 6-1 for each type of measurement. Instruments and measurement methods shall comply with th...
- 6.3 Airflow Measurement. Apply ANSI/ASHRAE Standard 41.2 2 to measure volumetric airflow and standard volumetric airflow using a single- or multiple-nozzle test chamber.
- 6.4 Static Pressure Measurement in Ducts or Chambers. Static pressure in ducts or chambers shall be measured in accordance with the static pressure tap geometry and the piezometer ring specifications in ANSI/ASHRAE Standard 41.2 2, Section 8.
- 6.5 Air Inlet Temperature Sampling Apparatus. Use an air-sampling apparatus and a wet-bulb psychrometer that is constructed as illustrated in Figure 6-1 to obtain the air inlet dry-bulb and wet-bulb temperatures. The sample tree shall sample at least...
- 7. Test Setup and Equipment [Go to Page]
- 7.1 Type A Packaged DEC Test Setup and Equipment
- 7.2 Type B Packaged DEC Test Setup and Equipment
- 8. Test Data to Be Recorded [Go to Page]
- 8.1 Test DEC. The description of the test direct evaporative air cooler (DEC) shall be recorded. The nameplate data shall be copied. Dimensions shall be checked against a drawing and a copy of the drawing attached to the data.
- 8.2 Test Setup. The description of the test setup, including specific dimensions, shall be recorded. The instruments and apparatus used in the test shall be listed. Names, model numbers, serial numbers, scale ranges, and proof of calibration shall be...
- 8.3 Test Data. Test data for each determination shall be recorded at each point of operation that satisfies the stability criteria. Readings shall be made simultaneously.
- 9. Calculations [Go to Page]
- 9.1 DEC Standard Airflow Rate. Apply ANSI/ASHRAE Standard 41.2 2 to calculate the direct evaporative air cooler (DEC) standard volumetric airflow rate, Qstd, m3/s (cfm).
- 9.2 DEC Applicability. The calculations in this section apply to (a) a Type A packaged DEC, (b) a Type B packaged DEC, and (c) a component DEC, noting that
- 9.3 DEC Electric Input Power at Test Conditions. The total electric input power to the test unit is the sum of fan and pump or rotary device electric input power and appurtenance device electric input power.
- 9.4 DEC Media Saturation Effectiveness. Apply Equation 9-2 to determine the DEC media saturation effectiveness at each point of operation that satisfies the stability criteria.
- 9.5 DEC Static Pressure Differential. The DEC static pressure differential, the static pressure differential between plane 0 and plane 1, is obtained using Equation 9-13.
- 9.6 DEC Standard Sensible Cooling Capacity
- 9.7 DEC Coefficient of Performance (COP) and Energy Efficiency Ratio (EER)
- 9.8 DEC Standard Airflow. The ratio of the input volumetric airflow to the standard airflow shall be obtained from the ANSI/ASHRAE Standard 41.2 2 test results as shown in Equation 9-22.
- 9.9 Fan Speed at Standard Conditions. Fan speed at standard conditions shall be calculated from the fan laws using Equation 9-23.
- 9.10 DEC Standard Static Pressure Differential. From the fan laws and Equation 9-23, the standard static pressure differential of the DEC shall be calculated using Equation 9-24.
- 9.11 Fan Electric Input Power at Standard Conditions. Calculate the fan electric input power at standard conditions using Equation 9-25.
- 9.12 Total Fan Electric Input Power at Standard Conditions. Use Equation 9-26 to calculate the total fan electric input power at standard conditions.
- 9.13 Correction to Nominal Fan Speed at Standard Density. Apply Equations 9-27, 9-28, and 9-29 to convert test data to test data at nominal fan speed.
- 10. Test Report [Go to Page]
- 10.1 Performance data shall be provided in a spreadsheet. If the DEC is not supplied with a pump or rotary device, a description of the method of supplying the water and the flow rate of water delivered to the DEC shall be included.
- 10.2 Performance Curves. The following DEC test results shall be presented as performance curves:
- 11. References
- Informative Appendix A: Bibliography
- Informative Appendix B: Additional Figures [Go to Page]
