ashrae standard method of testing direct evaporative...

ASHRAE STANDARDASHRAE STANDARD

ANSI/ASHRAE Standard 133-2008(Supersedes ANSI/ASHRAE Standard 133-2001)

Method of Testing Direct EvaporativeAir Coolers

Approved by the ASHRAE Standards Committee on June 21, 2008; by the ASHRAE Board of Directors onJune 25, 2008; and by the American National Standards Institute on June 26, 2008.

ASHRAE Standards are scheduled to be updated on a five-year cycle; the date following the standard numberis the year of ASHRAE Board of Directors approval. The latest copies may be purchased from ASHRAE Cus-tomer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: [email protected]. Fax: 404-321-5478. Telephone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US and Canada).

© Copyright 2008 ASHRAEISSN 1041-2336

American Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.

1791 Tullie Circle NE, Atlanta, GA 30329www.ashrae.org

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SPECIAL NOTEThis American National Standard (ANS) is a national voluntary consensus standard developed under the auspices of the American

Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Consensus is defined by the American National StandardsInstitute (ANSI), of which ASHRAE is a member and which has approved this standard as an ANS, as “substantial agreement reachedby directly and materially affected interest categories. This signifies the concurrence of more than a simple majority, but not necessarilyunanimity. Consensus requires that all views and objections be considered, and that an effort be made toward their resolution.”Compliance with this standard is voluntary until and unless a legal jurisdiction makes compliance mandatory through legislation.

ASHRAE obtains consensus through participation of its national and international members, associated societies, and publicreview.

ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing the Standard. TheProject Committee Chair and Vice-Chair must be members of ASHRAE; while other committee members may or may not be ASHRAEmembers, all must be technically qualified in the subject area of the Standard. Every effort is made to balance the concerned interestson all Project Committees.

The Manager of Standards of ASHRAE should be contacted for:a. interpretation of the contents of this Standard,b. participation in the next review of the Standard,c. offering constructive criticism for improving the Standard,d. permission to reprint portions of the Standard.

ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDSASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method

of testing for rating purposes, by suggesting safe practices in designing and installing equipment, by providing proper definitions of this equipment, and by providing other information that may serve to guide the industry. The creation of ASHRAE Standards and Guidelines is determined by the need for them, and conformance to them is completely voluntary.

In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall bemade, either stated or implied, that the product has been approved by ASHRAE.

DISCLAIMERASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of the public in light of availableinformation and accepted industry practices. However, ASHRAE does not guarantee, certify, or assure the safety orperformance of any products, components, or systems tested, installed, or operated in accordance with ASHRAE’s Standardsor Guidelines or that any tests conducted under its Standards or Guidelines will be nonhazardous or free from risk.

ASHRAE STANDARDS COMMITTEE 2007–2008

Stephen D. Kennedy, ChairHugh F. Crowther, Vice-ChairRobert G. BakerMichael F. BedaDonald L. BrandtSteven T. BushbyPaul W. CabotKenneth W. CooperSamuel D. Cummings, Jr.K. William DeanRobert G. DoerrRoger L. HedrickEli P. Howard, IIIFrank E. Jakob

Nadar R. JayaramanByron W. Jones

Jay A. KohlerJames D. Lutz

Carol E. MarriottR. Michael MartinMerle F. McBride

Frank MyersH. Michael NewmanLawrence J. SchoenBodh R. SubherwalJerry W. White, Jr.

Bjarne W. Olesen, BOD ExOLynn G. Bellenger, CO

Claire B. Ramspeck, Assistant Director of Technology for Standards and Special Projects

ASHRAE Standard Project Committee 133 Cognizant TC: TC 5.7, Evaporative Cooling

SPLS Liaison: Byron W. Jones

Patricia Thomas Graef, Chair * Branislav Korenic*

Gursaran D. Mathur* Roy T. Otterbein*

Leon Shapiro* Michael S. Sherber*

*Denotes members of voting status when the document was approved for publication

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CONTENTS

ANSI/ASHRAE Standard 133-2008Method of Testing Direct Evaporative Air Coolers

SECTION PAGE

Foreword ................................................................................................................................................................... 2

1 Purpose .......................................................................................................................................................... 2

2 Scope ............................................................................................................................................................. 2

3 Definitions and Acronyms............................................................................................................................... 2

4 Symbols and Subscripts ................................................................................................................................. 3

5 Requirements ................................................................................................................................................. 4

6 Instruments and Methods of Measurement .................................................................................................... 4

7 Equipment and Setup ..................................................................................................................................... 5

8 Data to be Recorded ...................................................................................................................................... 6

9 Calculations .................................................................................................................................................... 6

10 Performance Corrections to Nominal or Standard Airflow Rate and Speed ................................................... 8

11 Report and Results of Test ............................................................................................................................. 8

12 Figures............................................................................................................................................................ 9

13 References ................................................................................................................................................... 11

Informative Appendix A: Bibliography............................................................................................................... 11

Informative Appendix B: Additional Figures...................................................................................................... 12

NOTE

When addenda, interpretations, or errata to this standard have been approved, they can be downloaded free of charge from the ASHRAE Web site at www.ashrae.org.

© Copyright 2008 American Society of Heating,Refrigerating and Air-Conditioning Engineers, Inc.

1791 Tullie Circle NEAtlanta, GA 30329www.ashrae.org

All rights reserved.

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(This foreword is not part of this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the standard. It has not beenprocessed according to the ANSI requirements for astandard and may contain material that has not beensubject to public review or a consensus process.Unresolved objectors on informative material are notoffered the right to appeal at ASHRAE or ANSI.)

FOREWORD

First published in 2001, Standard 133 provides proce-dures for testing direct evaporative cooling devices under lab-oratory conditions to obtain rating information. As anASHRAE method-of-testing standard, it is intended to offerrecommended practices and accurate measurement proce-dures. In addition, the committee incorporates the effects ofambient conditions, testing error, instrument accuracy, and theneed to make certain that no other sources of heat transfer aretaking place during the testing.

This revision makes two key changes to Standard 133-2001. First, the difference between the dry-bulb and wet-bulbtemperatures has been decreased from 25°F to 20°F (14°C to11°C). The committee agreed that this would increase thetimes when testing could be accomplished using uncondi-tioned air and still not reduce the accuracy of the test.

Second, to provide better flexibility, temperature measure-ment in Section 6.1.1 is no longer limited to specific types ofinstruments as long as they meet the requirements of ANSI/ASHRAE Standard 41.1, Standard Method for TemperatureMeasurement.

Various other improvements were made as well. All refer-ences were updated to the latest editions. Mandatory languagewas clarified by changing “will” to “shall.”

1. PURPOSE

This standard establishes a uniform method of laboratorytesting for rating packaged and component direct evaporativeair coolers.

2. SCOPE

2.1 The scope of this standard covers a method of testing forrating the saturation effectiveness, airflow rate, and totalpower of packaged and component direct evaporative aircoolers.

2.2 Covered tests also include the methods for measuringthe static pressure differential of the direct evaporative aircooler, density of the air, and speed of rotation of the fan.

2.3 This standard requires that packaged and componentdirect evaporative air coolers be simultaneously tested for air-flow, total power, and saturation effectiveness.

2.4 The ratings resulting from application of this standardare intended for use by manufacturers, specifiers, installers,and users of evaporative air cooling apparatus for residential,commercial, agricultural, and industrial ventilation; for air

cooling applications; and for commercial, industrial, and agri-cultural processing applications.

3. DEFINITIONS AND ACRONYMS

adiabatic saturation: evaporating water into air without exter-nal gain or loss of heat. Sensible heat in both air and waterbecomes latent heat in evaporated vapor. The air is cooled andhumidified.

appurtenance device power: the electric power to drive acces-sories, not including fans, pumps, or rotary devices, suppliedas a standard component of the production model of the evap-orative cooling unit (ECU) and the appurtenances that arenecessary for, contribute to, or enhance the cooling capacity ofthe ECU. Appurtenance device power includes, but is notlimited to, water metering devices, conductivity controllers,timers, dump cycle pumps, and solenoids. Devices such asthermostats, transformers providing low voltage to controlmechanisms, and freeze protection devices shall not beincluded.

boundaries: evaporative cooling unit inlet and outlet bound-aries are defined as the interface between the cooling unit andthe remainder of the system, and these boundaries are at aplane perpendicular to the airstream where it enters or leavesthe ECU. Various appurtenances, such as filter media assem-blies, inlet boxes, inlet vanes, inlet cones, silencers, screens,rain hoods, dampers, discharge cones, eaves, that are suppliedas standard components to the unit shall be included as a partof the cooling unit between the inlet and outlet boundaries.

component direct evaporative cooler: a self-contained cabi-net without a fan whose primary functions are (1) the conver-sion of the sensible heat of unsaturated air passing through thecabinet to latent heat by the process of evaporating recirculat-ing or non-recirculating water directly exposed to this air, and(2) the movement of this air through the cabinet that allows aportion of this water to evaporate. An example of a componentdirect evaporative cooler is shown in Appendix B, Figure B-7.

determination: a complete set of measurements for a partic-ular point of operation of an ECU. The measurements shall besufficient to determine all ECU performance variables asdefined in this standard.

ECU: an acronym created for use in this document that standsfor evaporative cooling unit. The term cooling unit is also usedinterchangeably throughout this document for evaporativecooling unit, evaporative air cooler, and evaporative cooler.

ECU airflow rate: the volumetric airflow rate based uponentering air density.

ECU outlet area: the gross inside area measured in theplane(s) of the outlet opening(s).

ECU static pressure differential: the static pressure differen-tial measured across the ECU and its appurtenances at eachpoint of operation.

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ANSI/ASHRAE Standard 133-2008

ECU total power: the sum of the power in watts supplied to theelectrical components of the evaporative cooler tested. Thisincludes fan motors, pump motors, and other devices neededto produce the cooling effect. The power to control devicessuch as thermostats, transformers providing low voltage tocontrol mechanisms, and freeze protection devices shall not beincluded in total power.

ECU water flow rate: the water supplied to the ECU header.

evaporative air cooling: two methods using evaporating waterto cool air: (1) direct, which is adiabatic and humidifies the air,and (2) indirect, which is not adiabatic and cools the air beingtreated without adding moisture.

fan power: the power required to drive the fan and anyelements in the drive train that are considered a part of the fan.

fan speed: the rotational speed of the impeller. If a fan hasmore than one impeller, fan speeds are the rotational speeds ofeach impeller.

free delivery: the point of operation where the external staticpressure is zero.

gas constant: the gas constant (R) for air is 287.1 J/kg⋅K(53.35 ft⋅lbf/lbm⋅°R).

packaged direct evaporative cooler: a self-contained unitincluding a fan and fan motor whose primary functions are (1)the conversion of the sensible heat of unsaturated air passingthrough the cabinet to latent heat by the process of evaporatingrecirculating or nonrecirculating water directly exposed to thisair and (2) the movement of this air through the unit. An exam-ple of a direct evaporative air cooler is shown in Appendix B,Figure B-6.

point of operation: the relative position on the cooling unitcharacteristic curve corresponding to a particular airflow rate.It is controlled during a test by adjusting the position of thethrottling device, by changing flow nozzles or auxiliary fancharacteristics, or by any combination of these.

pressure, barometric: the absolute pressure exerted by theatmosphere.

pump or rotary device power: the electric power to drive thepump or rotary device used to distribute water in the ECU.

saturation effectiveness: the dry-bulb temperature reductionachieved by the ECU divided by the entering wet-bulb depres-sion.

shutoff: the point of operation where the airflow rate is zero.

standard air: dry air with a density of 1.204 kg/m3 (0.075 lbm/ft3),a specific heat of 1.006 kJ/kg⋅K (0.24 Btu/lbm⋅°F), and a viscosityof 1.82 × 10-5 N⋅s/m2 (1.22 × 10-5 lbm/ft⋅s). Air at 20°C (68°F),0% relative humidity, and 101.325 kPa (29.92 in. Hg) has theseproperties, approximately.

test: a series of determinations for various points of operation.

wet-bulb depression: the difference between the dry-bulb andwet-bulb temperatures of an airstream.

4. SYMBOLS AND SUBSCRIPTS

4.1 SymbolsSYMBOL DESCRIPTION SI UNITS I-P UNITS

A Area of cross section m2 ft2

C Nozzle discharge coefficient dimensionless dimensionless

D Diameter and equivalent diameter m ft

D Pressure tap diameter mm in.

E Energy factor dimensionless dimensionless

L Nozzle throat dimension m ft

M Chamber diameter or equivalent diameter m ft

Nn Nominal or corrected fan speed rpm rpm

N ECU fan speed as measured rpm rpm

n Number of readings dimensionless dimensionless

Pn Static pressure at nominal air density Pa in. w.g.

Psx Static pressure at plane X Pa in. w.g.

Pstd Static pressure at standard air density Pa in. w.g.

pb Ambient barometric pressure Pa in. Hg

pe Saturated vapor pressure at twx Pa in. Hg

pp Partial vapor pressure Pa in. Hg

QECU ECU airflow rate m3/s cfm

Qn Nominal airflow rate m3/s cfm

Qw ECU water flow rate L/s gpm

R Gas constant J/kg⋅K ft⋅lbf/lbm⋅°R

Re Reynolds number dimensionless dimensionless

tdx Dry-bulb temperature at plane X °C °F

twx Wet-bulb temperature at plane X °C °F

Vx Velocity at plane x m/s fpm

W Total power W W

Wf Power input to ECU fan W W

Wfn Nominal power input to ECU fan W W

Wp Power input to pump or rotary device W W

Wa Power input to appurtenances W W

Wstd Total ECU power at standard air density W W

Wfstd ECU fan power at standard air density W W

Y Nozzle expansion factor dimensionless dimensionless

α Static pressure ratio for nozzles dimensionless dimensionless

β Diameter ratio for nozzles dimensionless dimensionless

ε Saturation effectiveness dimensionless dimensionless

γ Ratio of specific heats of air dimensionless dimensionless

ΔP Pressure differential Pa in. wg

ΔPECU Pressure differential across ECU Pa in. wg

ΔPelbow Pressure differential of elbow Pa in. wg

ΔPnozzle Pressure differential of nozzle Pa in. wg

ΔPstd Pressure differential corrected

to standard air Pa in. wg

μ Air viscosity Pa⋅s lbm/ft⋅s

ρ Air density kg/m3 lbm/ft3

ρx Air density at plane X kg/m3 lbm/ft3

ρstd Density of air at standard air condition kg/m3 lbm/ft3

Σ Summation sign --- ---

4.2 SubscriptsSUBSCRIPT DESCRIPTION

x Plane or station x, where x = 0, 1, 2, etc., as appropriate

0 Plane 0 (ECU inlet)

1 Plane 1 (pressure tap station)

2 Plane 2 (temperature measurement station)

3 Plane 3 (nozzle inlet station)

4 Plane 4 (nozzle discharge station)

n Nominal

std Standard

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5. REQUIREMENTS

5.1 Determinations. The number of determinationsrequired to establish the performance of an evaporative cool-ing unit over the range from shutoff to free delivery shall beestablished depending on the shapes of the various character-istic curves. Plans shall be made to vary the opening of thethrottling device in to evenly space the test points. For smoothcharacteristics, at least eight determinations shall be requiredto define curves that are not smooth. When performance atonly one point of operation is required, at least three determi-nations shall be made to define a short curve that includes thatpoint.

5.2 Equilibrium. Equilibrium conditions shall be estab-lished before each determination. To test for equilibrium, trialobservations shall be made until steady readings are obtained.Ranges of air delivery over which equilibrium cannot beestablished shall be recorded.

5.3 Stability. Any bi-stable performance points (airflowrates at which two different ECU static pressure differentialsare be measured) shall be so reported. When they are a resultof hysteresis, the points shall be identified as that for increas-ing and decreasing airflow rate.

5.4 Acceptable Temperature and Humidity Test Condi-tions. Inlet plenum air dry-bulb temperature (td0) shall be46°C (115°F) maximum, the wet-bulb temperature (twb) shallbe 5°C (41°F) minimum, and the wet-bulb depression shall be11°C (20°F) minimum during the testing period.

The upstream wet-bulb temperature (tw0) shall differ fromthe downstream wet-bulb temperature (tw2) by no more than1°C (2°F) during the test for the test results to be consideredvalid.

5.5 Acceptable Water Quality. Conductivity of the watershall be measured using a conductivity meter. The conductiv-ity of the water supplied to the distribution header shall bebetween 350 and 3500 µS. (microsiemens).

5.6 Entrainment Verification. Precautions shall be takento ensure water entrainment is not occurring in equipmentbeing tested for rating. Water entrainment will obviouslyaffect temperature measurements; therefore, any waterentrainment shall invalidate test results. A means to check theplenum air flow measuring station for “wetness” shall beincorporated in the test apparatus, such as a “sensitive” paperthat changes color when water touches it.

6. INSTRUMENTS AND METHODS OF MEASUREMENT

6.1 Temperature-Measurement. Temperature measurementand temperature-measuring instruments, unless noted below,shall conform to the requirements of ANSI/ASHRAE Standard41.1, Standard Method for Temperature Measurement.1

The apparatus shall be the aspirated psychrometer with asample tree shown in Figure 4. The sample tree shall sampleat least nine equal areas of the chamber. Both dry- and wet-bulb temperatures shall be measured in this air-samplingdevice. Care shall be taken to ensure that there is no loss of heat

or moisture from this device. To prevent erroneous airflowreadings, the discharge of the psychrometer shall be recon-nected to the duct or chamber.

6.1.1 Type. Temperature measurement shall be made withinstruments that demonstrate the accuracy required by Sec-tion 6.1.2.

6.1.2 Accuracy. The accuracy shall be within the follow-ing limits:

a. air wet-and dry-bulb temperatures, ±0.2°C (0.40°F), and b. other dry-bulb temperatures, ±0.30°C (0.50°F).

6.1.3 Scale. In no case shall the smallest scale division ofthe temperature-measuring instrument exceed twice the spec-ified accuracy. For example, for the specified accuracy of±0.20°C (0.40°F), the smallest scale division shall not exceed0.4°C (0.80°F).

6.1.4 Calibration. Where an accuracy closer than±0.30°C (0.50°F) is specified, the instruments shall be cali-brated by comparison with a thermometer that has a NationalInstitute of Standards and Technology (NIST) certification inthe range of use or a thermometer with a NIST certificationshall be used.

6.1.5 Practice

6.1.5.1 Wet-Bulb Temperature. Wet-bulb tempera-tures shall be read only under conditions that ensure an airvelocity of 3.5 to 10 m/s (700 to 2,000 ft/min) over the wetbulb, and only after sufficient time has been allowed for evap-orative equilibrium to be attained.

6.1.5.2 Measurement Stations. The same measuringmethods and equipment shall be used at all measurement sta-tions.

6.2 Pressure-Measurement. Other than barometric pres-sure, static pressure in ducts or chambers shall be measuredwith special taps designed to eliminate velocity effects. Eachlocation requiring a static pressure measurement shall use aminimum of four taps equidistant around the perimeter of theduct or chamber. These taps shall be joined in a piezometerring and the ring used for measurement. Static pressure tapsare required on both sides of the flow nozzles and downstreamof the ECU.

6.2.1 Type. Pressure measurement shall be made inaccordance with ASHRAE Standard 41.3, Standard Methodfor Pressure Measurement.2

6.2.2 Accuracy. The accuracy of pressure-measuringinstruments shall permit measurements with ±1% of the read-ing. Barometric pressure shall have accuracy of ±34 Pa(0.01 in. Hg).

6.2.3 Scale. In no case shall the smallest scale division ofthe pressure-measuring instrument exceed two times the spec-ified accuracy.

6.3 Airflow Measurement. The airflow rate shall be deter-mined by measuring the pressure differential across ellipticalflow nozzles in chambers as shown in Figure 1. Determina-tions shall be in accordance with ASHRAE Standard 41.2,Standard Methods for Laboratory Air-Flow Measurement.3


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6.3.1 Nozzle Apparatus. This airflow-measuring appara-tus is shown schematically in Figures 1 and B-1. Each nozzlestation consists of a receiving chamber and a discharge cham-ber separated by a partition in which one or more nozzles, ofequal or unequal size, are located. A detailed description ofthe nozzle apparatus is given in ASHRAE 41.2.3

6.3.2 Calibration. The standard nozzle is considered aprimary instrument and need not be calibrated if maintainedin the specified condition. Reliable coefficients have beenestablished for throat dimension L = 0.6D. Throat dimensionL = 0.6D is recommended for testing airflow of direct evapo-rative cooling equipment.

6.3.3 Practice. The throat velocity of any nozzle in useshall not be less than 15 m/s (3000 ft/min) nor greater than 35m/s (7000 ft/min). For detailed instructions on nozzle con-struction and use with the airflow-measuring apparatus, seeASHRAE 41.2.3

6.4 Power. Power shall be measured using a wattmeter con-nected to the ECU. Wattmeters shall have an accuracy of±1.0% of observed reading.

6.5 Water Flow. Water flow shall be measured using atotalizing water meter connected to the ECU and a timingdevice to determine the rate of water flow. Water meters shallhave an accuracy of ±5.0% of observed reading.

6.6 Speed. Speed shall be measured with a revolution coun-ter and chronometer, a stroboscope counter and chronometer,a precision instantaneous tachometer, an electronic counter-timer, or any other device that has a demonstrated accuracy of±0.5% of the value being measured.

6.6.1 Strobe. A stroboscopic device triggered by the linefrequency of a public utility is considered a primary instru-ment and need not be calibrated if it is maintained in goodcondition.

6.6.2 Chronometer. The chronometer used for all timemeasurements shall have a display in seconds and keep timeaccurately to within ±2 minutes per day.

6.6.3 Other Devices. The combination of a line frequencystrobe and chronometer shall be used to calibrate all otherspeed-measuring devices. Friction-driven counters shall notbe used when they influence the speed due to drag.

6.7 Water Conductivity. Water conductivity shall be mea-sured using a conductivity meter having an accuracy ±10% ofobserved reading. The meter shall have a means for tempera-ture compensation.

6.7.1 Calibration. Conductivity meters shall be cali-brated using a certified calibration solution according to themanufacturer’s instructions.

7. EQUIPMENT AND SETUP

7.1 Setup. The suggested setup is shown in Figure B-1.

7.1.1 Down Discharge Coolers. Down discharge coolersshall be tested with a uniform elbow of an area with ±0.5% ofthe ECU outlet area and a shape to fit the ECU outlet. Theelbow shall connect the discharge of the ECU to the chamber.See Figure 2.

7.1.2 The elbow system effect factor (SEF) shall be con-sidered. To minimize system effect factor for down draftECU’s having centrifugal blowers, the blower shall be ori-ented such that the turn of the elbow follows the rotation of theshaft (see Figure 2).

7.1.3 Component Direct Evaporative Cooler Testing.Component ECU testing shall be performed using the sametechniques as packaged ECU testing.

7.1.4 Mixers. Mixing or other types of devices shall beused to ensure uniform temperature profiles to the ECU andmeasurement devices in accordance with ANSI/ASHRAEStandard 41.1.1

7.2 Ducts. Short ducts that are used to simulate outlet ductwork, shall be between 2 and 3 equivalent diameters in lengthand have an area ± 0.5% of the outlet area and a uniform shapeto fit the outlet.

If the ECU is tested without outlet ductwork, it shall bemounted on the end of the chamber.

7.2.1 Leakage. The ducts, chambers, and other equip-ment utilized shall be designed to withstand the pressure andother forces to be encountered. All joints between the ECUand the measuring station shall be sufficiently tight so thatmeasurements are not affected by more than one-half theallowable instrument error.

7.3 Chambers. A chamber shall be incorporated in a labo-ratory setup to provide a measuring station or to simulate theconditions the ECU is expected to encounter in service orboth. Such a chamber shall have a circular or rectangularcross-sectional shape. The dimension M in the test setup dia-gram is the inside diameter of a circular chamber or the equiv-alent diameter of a rectangular chamber with inside transversedimensions a and b where

. (1)

7.3.1 Airflow Settling Means. Airflow settling meansshall be installed in the chamber(s) where indicated on the testsetup as shown in Figures 1 and B-1. Settling means providea proper airflow pattern. Where a measuring plane is locateddownstream of the settling means, the settling means is pro-vided to ensure a substantially uniform airflow ahead of themeasuring plane. In this case, the maximum velocity at a dis-tance 0.1 M downstream of the screen shall not exceed theaverage velocity by more than 25% unless the maximumvelocity is less than 2 m/s (400 fpm).

Where measuring planes are located on both sides of thesettling means within the chamber, the requirements for eachside as outlined above shall be met.

A performance check shall be performed to verify that theairflow settling means are providing proper airflow patterns.

7.3.2 Multiple Nozzles. Multiple nozzles shall be locatedas symmetrically as possible. The centerline of each nozzleshall be at least 1.5 nozzle throat diameters from the chamberwall. The minimum distance between centers of any two noz-zles in simultaneous use shall be three times the throat diam-eter of the larger nozzle.

M 4ab π⁄( )1 2⁄=

5

-

7.4 Point of Operation. A means of varying the point ofoperation shall be provided in the laboratory setup.

If auxiliary fans are used to control the point of operationof the ECU, they shall be designed to produce sufficient pres-sure at the desired airflow rate to overcome losses through thetest setup, including any necessary transitional ductwork orelbows located between the ECU and test chamber. Auxiliaryfans shall not surge or pulsate during tests.

8. DATA TO BE RECORDED

8.1 Test ECU. The description of the test ECU shall berecorded. The nameplate data shall be copied. Dimensionsshall be checked against a drawing and a copy of the drawingattached to the data.

8.2 Test Setup. The description of the test setup, includingspecific dimensions, shall be recorded. The instruments andapparatus used in the test shall be listed. Names, model num-bers, serial numbers, scale ranges, and calibration informationshall be recorded.

8.3 Test Data. Test data for each determination shall berecorded. Readings shall be made simultaneously wheneverpossible.

For all tests, three readings of the following shall berecorded and averaged for each determination:

a. ECU inlet dry-bulb temperature (td0), b. ECU inlet wet-bulb temperature (tw0), c. ambient barometric pressure (pb), d. ECU downstream dry-bulb temperature (td2), e. ECU downstream wet-bulb temperature (tw2),f. fan speed (N), g. power input to fan (Wf), h. power input to pump or rotary device (Wp), i. power input to appurtenances (Wa), j. ECU static pressure differential (ΔPECU), k. nozzle pressure differential (ΔPNozzle), andl. water conductivity.

When the ECU is not supplied with a pump or rotarydevice, water flow to the ECU (QW) shall be recorded.

8.4 Personnel. The names of test personnel shall be listedwith the data for which they are responsible.

9. CALCULATIONS

9.1 Calibration Correction. Calibration corrections, whenrequired, shall be applied to individual readings before aver-aging or other calculations. Calibration corrections need notbe made if the correction is smaller than one-half the maxi-mum allowable error as specified in Section 6.

9.2 Density and Viscosity of Air

9.2.1 Air Density

9.2.1.1 Atmospheric Air Density. The atmospheric airdensity (ρ0) shall be determined from measurements of dry-bulb temperature (td0), wet-bulb temperature (tw0), and baro-metric pressure at plane 0 (pb) using the following equations:

(2 SI)

(2 I-P)

(3 SI)

(3 I-P)

(4 SI)

(4 I-P)

Equation 2 is approximately correct for saturated vaporpressure (pe) for a range of tw0 between 4°C (40°F) and 32°C(90°F). More precise values of pe can be obtained fromASHRAE Handbook—Fundamentals.4 The gas constant (R)for air is 287.1 J/kg⋅K (53.35 ft⋅lbf/lbm⋅°R).

9.2.1.2 Chamber Air Density. The density of air in aduct or chamber at plane x (ρx) may be calculated by correct-ing the density of atmospheric air (ρ0) for pressure (Psx) andtemperature (tdx) at plane x using:

(5 SI)

(5 I-P)

If Psx is numerically less than 1 kPa (4 in. wg), ρx may beconsidered equal to ρ0.

9.2.2 Air Viscosity. The viscosity (μ) shall be calculatedfrom:

(6 SI)

(6 I-P)

The viscosity value for air at 20°C (68°F), which is 1.819× 10–5 Pa⋅s (1.222 × 10–5 lbm /ft⋅s), is sufficiently accurate tobe used for temperatures ranging between 4°C (40°F) and32°C (100°F).

9.3 ECU Airflow Rate at Test Conditions9.3.1 Nozzle. The airflow rate may be calculated from the

pressure differential (ΔPNozzle) measured across a single noz-zle or a bank of multiple nozzles.

9.3.1.1 Alpha Ratio. The ratio (α) of absolute nozzleexit pressure to absolute approach pressure shall be calculatedfrom:

(7 SI)

(7 I-P)

9.3.1.2 Beta Ratio. Beta ratio is the ratio (β) of nozzleexit diameter (D4) to approach duct diameter (D3):

(8)

For the chamber approach, it is sufficiently accurate for βto be taken as zero.

pe 3.25E-03 tw02 1.86E-02 tw0 0.692+ +=

pe 2.96E-04 tw02 1.59E-02 tw0– 0.41+=

pp pe pb td0 tw0–( )– 1500⁄=

pp pe pb td0 tw0–( )– 2700⁄=

ρ0 pb 0.378pp–( ) R td0 273.15+( )⁄=

ρ0 70.73 pb 0.378pp–( ) R td0 459.67+( )⁄=

ρxtd0 273.15+( )tdx 273.15+( )

----------------------------------Psx pb+( )

pb------------------------ ρ0( )×=

ρxtd0 459.67+( )tdx 459.67+( )

----------------------------------Psx 13.63pb+( )

13.63pb( )-------------------------------------- ρ0( )×=

μ2 1.723 0.0048td2+( ) 10× 5–=

μ2 1.100 0.0018td2+( ) 10 5–×=

α 1 PNozzleΔ PS3 pb+( )⁄{ }–=

α 1 5.187 PNozzleΔ ρ2R td2 459.67+( )( )⁄{ }–=

β D4 D3⁄=

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9.3.1.3 Expansion Factor. The expansion factor (Y)shall be calculated as follows:

(9)

The ratio of specific heats (γ) shall be taken as 1.4 for airor, alternatively, the expansion factor for air may be approxi-mated with sufficient accuracy under this standard using thefollowing equation:

. (10)

9.3.1.4 Reynolds Number. The Reynolds number (Re)based on air properties measured at plane 2 and nozzle exitdiameter (D4) in m (ft), shall be calculated from

(11 SI)

(11 I-P)

using properties of air as determined in Section 9.2 and theappropriate velocity (V4) in m/s (fpm). Since the velocitydetermination depends on Reynolds number, an approxima-tion shall be employed:

(12 SI)

(12 I-P)

A simplified approximation suitable for the range oftemperatures from 4°C (40°F) to 38°C (100°F) is:

(13 SI)

(13 I-P)

This is based on the chamber approach where C = 0.95, Y= 0.96, E = 1.0, (1 - Eβ4)1/2 = 1, and μ2 = 1.819 × 10–5 Pa⋅s (1.222 × 10–5 lbm /ft⋅s).

9.3.1.5 Discharge Coefficient. For Re of 12,000 andabove, the nozzle discharge coefficient (C), shall be deter-mined from:

(14)

(15)

9.3.1.6 Airflow Rate for Chamber Nozzles. The volu-metric airflow rate (Q3) at the entrance to a nozzle or multiplenozzles with the chamber approach shall be calculated fromair density determined at plane 2. For (Q3 = Q2):

(16 SI)

(16 I-P)

The coefficient (C) and area (A4) shall be determined foreach nozzle and their products summed as indicated. The area(A4) is measured at the plane of the throat taps or the nozzleexit for nozzles without throat taps.

9.3.1.7 ECU Airflow Rate. The ECU airflow rate(QECU) at test conditions shall be obtained from the equationof continuity:

(17)

9.4 ECU Power Input at Test Conditions. The total powerinput to the test unit is the sum of fan and pump or rotarydevice power and appurtenance device power:

(18)

9.4.1 Fan power. The electric power input to the fan(expressed in watts) shall be included in the total power input.

9.4.2 Pump or Rotary Device Power. The electric powerinput to the pump or rotary device (expressed in watts) shallbe included in the total power input.

9.4.3 Appurtenance Power. The electric power input toappurtenances supplied with the ECU (expressed in watts)shall be included in the total power input when

a. the appurtenance is a standard component of the produc-tion unit, and

b. the appurtenance is necessary for, contributes to, orenhances the cooling capacity of the ECU.

9.5 Saturation Effectiveness. The saturation effectivenessshall be calculated as follows:

(19)

9.6 ECU Static Pressure Differential. The ECU staticpressure differential (ΔPECU) shall be the static pressure dif-ferential between plane 0 and plane 1:

(20)

For a down draft ECU utilizing an elbow as shown inFigure B-1, the elbow static pressure (ΔPelbow) shall be deter-mined in accordance with system effect factor (SEF) calcula-tions such as those found in the ASHRAE Handbook—Fundamentals.4 Static pressure differential (ΔPECU) of adown draft ECU utilizing an elbow shall be as follows:

(21)

The ΔPelbow and system effect factor shall be based onstandard air. The density correction then corrects ΔPelbow +SEF to test conditions such that ΔPECU represents the ECUstatic pressure differential at test density.

Y γγ 1–----------- α2 γ⁄( )1 α–

1 α–------------

γ 1–( ) γ⁄ 1 2⁄ 1 β4–

1 β4α2 γ⁄–--------------------------

1 2⁄

=

Y 1 0.548 0.71β4+( ) 1 α–( )–=

Re D4V4ρ2 μ2⁄=

Re D4V4ρ2 60μ2⁄=

Re 2μ2-------CD4Y ΔPNozzleρ2 1 Eβ4–( )⁄[ ]

12---

=

Re 109760μ2------------CD4Y PNozzleΔ ρ2 1 Eβ4–( )⁄[ ]

12---

=

Re 7.09 104× D4 PNozzleΔ ρ2[ ]=

Re 1.36 106× D4 PNozzleΔ ρ2[ ]=

C 0.9986 7.006 Re⁄( )– 134.6 Re⁄( )+= for L D⁄ 0.6=

C 0.9986 6.688 Re⁄( )– 131.5 Re⁄( )+= for L D⁄ 0.5=

Q2 Y4 2 PNozzleΔ ρ2⁄( )1 2⁄ ΣCA4( )×=

Q2 1097Y4 2 PNozzle ρ2⁄Δ( )1 2⁄ ΣCA4( )×=

QECU Q2 ρ2 ρ0⁄( )=

W Wf Wp Wa+ +=

ε 100 td0 td2–( ) td0 tw0–( )⁄=

PECUΔ Ps1 PS0–=

PECUΔ PS1 PS0– PelbowΔ SEF+( ) ρstd ρ0⁄( )+=

7

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10. PERFORMANCE CORRECTIONS TO NOMINAL OR STANDARD AIRFLOW RATE AND SPEED

10.1 Standard Saturation Effectiveness. Standard satura-tion effectiveness, based on constant volumetric airflow, shallbe calculated from the test data as follows:

(22)

10.2 ECU Standard Static Pressure Differential. Thestandard static pressure differential of the ECU shall be cal-culated as follows:

(23)

10.3 Fan Standard Power

(24)

10.4 ECU Standard Power Input

(25)

10.5 Correction to Nominal Fan Speed at Standard Den-sity. During a laboratory test, speed of rotation may varyslightly from one determination to another. Equations 26, 27,and 28 shall be used to convert the results calculated for testconditions to those that would prevail at nominal constantspeed, using the following:

(26)

(27)

(28)

11. REPORT AND RESULTS OF TEST

11.1 Report. The report of a laboratory evaporative coolertest shall include object, results, test data, and descriptions ofthe evaporative cooler, including appurtenances, test setup,and test instruments as outlined in Section 8. The test baro-metric pressure shall be clearly identified. The laboratoryshall be identified by name and location. Performance data fora packaged ECU shall be summarized in a table similar to Fig-ure B-4. Performance data for a component ECU shall besummarized in a table similar to Figure B-5. If the ECU is notsupplied with a pump or rotary device, a description of the

method of supplying the water as well as the flow rate of waterdelivered to the ECU shall be included.

11.1.1 Identification. Performance sheets shall list thetest evaporative cooling unit and test setup. Sufficient detailsshall be listed to identify clearly the cooling unit and setup.

11.1.2 Appurtenances. Various appurtenances, such asfilter media assemblies, inlet boxes, inlet vanes, inlet cones,silencers, screens, rain hoods, dampers, discharge cones,eaves, shall be included as a part of the cooling unit betweenthe inlet and outlet boundaries. The test reports shall clearlystate the inlet and outlet boundaries of the cooling unit and listincluded appurtenances.

11.2 Performance Curves. The results of an ECU test shallbe presented as performance curves. All information, exceptairflow and water flow, shall be published at standard air den-sity and be clearly identified as such.

11.2.1 Test Points. The results for each determinationshall be shown on the performance curve as a series of circledpoints, one for each variable plotted as ordinate.

11.2.2 Curve-Fitting. Curves for each variable shall beobtained by drawing a curve or curves using the test points forreference. The curves shall not depart from the test points bymore than 0.5% of any test value and the sum of the deviationsshall approximate zero.

11.2.3 Discontinuities. When discontinuities exist, theyshall be identified with a broken line. If equilibrium cannot beestablished for any determination, the curves joining thepoints for that determination with adjacent points shall bedrawn as broken lines.

11.2.4 Coordinates for Package ECU PerformanceCurves. Performance curves shall be drawn with ECU flowrate as abscissa. ECU standard static pressure differential,ECU standard power input, and ECU standard saturationeffectiveness shall be plotted as ordinates. If all results wereconverted to a nominal speed, such speed shall be listed; oth-erwise a curve with fan speed as ordinate shall be drawn. Typ-ical packaged ECU performance curve format is shown inFigures B-2a and B-2b.

11.2.5 Coordinates for Component ECU PerformanceCurves. Performance curves shall be drawn with airflow rateas abscissa. ECU standard static pressure differential, ECUstandard power input, and ECU standard saturation effective-ness shall be plotted as ordinates. Typical component ECUperformance curve format is shown in Figure B-3.

εstd 1 1 ε–( ) ρ0 ρstd⁄( )–=

PstdΔ PECUΔ ρstd ρ0⁄( )=

Wfstd Wf ρstd ρ0⁄( )=

Wstd Wfstd Wp Wa+ +=

Qn QECU Nn N⁄( )=

PnΔ PstdΔ Nn N⁄( )2=

Wfn Wfstd Nn N⁄( )3=

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---


12. FIGURES

Note: Dimension J shall be at least 1.0 times the fan equivalent discharge diameter for ECU’s having fans with axis of rotationperpendicular to the discharge airflow and at least 2.0 times the fan equivalent discharge diameter for ECU’s having fans withaxis of rotation parallel to the discharge airflow.

Figure 1 Airflow-measuring apparatus from setup in Figure B-1 (shown without throat taps or air-sampling device).

Figure 2 Details of orientation of elbows for down draft ECUs from Figure 1.

Proper orientation of elbow with respect to rotation of fan.

Incorrect orientation of elbow with respect to rotation of fan.

Incorrect orientation of elbow with respect to rotation of fan.

Note: The distance from the exit face of the largest nozzle to the downstream settling means shall be a minimum of 2.5 × D4,the throat diameter of the largest nozzle.

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9

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---

Surface shall be smooth and free from irregularities within 20 D of holes. Edge of hole shall be square and free from burrs.

Note: A 2 mm (0.07 in.) hole is the maximum size that will allow space for a smooth surface 20 D from the hole when installed38 mm (1.5 in.) from a partition, as in Figures 1 and B-1.

Figure 3 Static pressure tap.

Figure 4 Air-sampling device.


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13. REFERENCES

1. ANSI/ASHRAE Standard 41.1-1986 (RA 2006), StandardMethod for Temperature Measurement.

2. ASHRAE Standard 41.3-1989, Standard Method for Pres-sure Measurement.

3. ASHRAE Standard 41.2-1987 (RA 92), Standard Methodsfor Laboratory Air-Flow Measurement.

4. 2005 ASHRAE Handbook—Fundamentals.

(This appendix is not part of this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the standard. It has not been pro-cessed according to the ANSI requirements for a stan-dard and may contain material that has not been subjectto public review or a consensus process. Unresolvedobjectors on informative material are not offered theright to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX A—BIBLIOGRAPHY

ANSI/ASHRAE Standard 51-2007 (AMCA Standard 210-2007), Laboratory Methods of Testing Fans for Aerody-namic Performance Rating, American Society of Heat-ing, Refrigerating and Air-Conditioning Engineers, Inc.,1999.

ASME Steam Properties. American Society of MechanicalEngineers, 1967.

2004 ASHRAE Handbook—HVAC Systems and Equipment,Chapter 19, American Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc., 2004.

ASHRAE Guideline 2-2005, Engineering Analysis of Experi-mental Data, American Society of Heating, Refrigerat-ing and Air-Conditioning-Engineers, Inc., 2005.

ANSI/ASHRAE Standard 41.1-1986 (RA 2006), StandardMethod for Temperature Measurement, American Soci-

ety of Heating, Refrigerating and Air ConditioningEngineers, Inc., 2006.

2005 ASHRAE Handbook—Fundamentals, Chapter 6,American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 2005.

ASHRAE Standard 41.2-1987 (RA 92), Standard Methodsfor Laboratory Airflow Measurement, American Societyof Heating, Refrigerating and Air-Conditioning Engi-neers, Inc., 1992.

ASHRAE Standard 41.3-1989, Standard Method for PressureMeasurement, American Society of Heating, Refrigerat-ing and Air-Conditioning Engineers, Inc., 1989.

ASHRAE Standard 41.6-1994 (RA 2006), Standard Methodfor Measurement of Moist Air Properties, AmericanSociety of Heating, Refrigerating and Air-ConditioningEngineers, Inc., 2006.

Australian Standard AS 2913-2000, Evaporative Air-Condi-tioning Equipment. The Standards Association of Aus-tralia, North Sydney, NSW, 2000.

ISO 5167-1:1991E, Measurement of Fluid Flow by Means ofPressure Differential Devices—Part 1: Orifice Plates,Nozzles and Venturi Tubes in Circular Cross-sectionConduits Running Full, International Organization forStandardization (c/o American National Standards Insti-tute), 1991.

Koca, R., and W. C. Hughes, Evaporative Cooling Pads: TestProcedure and Evaluation, University of Illinois atUrbana-Champaign, written for ASHRAE, May 9,1989.

MacLaine-Cross, I. L., and P.J. Banks, A General Theory ofWet Surface Exchanger and Its Application to Regener-ative Evaporative Cooling, Journal of Heat Transfer,Vol. 103, August 1991.

Zaleski, R. H., and J.M. Murr, A Study of Evaporative Cool-ing Pad Media, ACME Engineering & ManufacturingCorp., Muskogee, OK, 1982.

11

(This appendix is not part of this standard. It is merely informative and does not contain requirements necessary forconformance to the standard. It has not been processed according to the ANSI requirements for a standard and maycontain material that has not been subject to public review or a consensus process. Unresolved objectors on informativematerial are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX B—ADDITIONAL FIGURES

Figure B-1 Suggested setup for testing direct evaporative coolers.

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---


Figure B-2a Typical performance curve format for packaged ECU reported at constant speed.

Date of Test: _____________ Test #: _____________________ Project #: ___________________________________Manufacturer: ________________________________________ Model #: _______________ Fan Speed: __________Appurtenances: _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Name of Testing Laboratory: ____________________________ Curve By:___________________________________Address of Testing Laboratory: __________________________ Signature:______________________________________________________________________________________ Date: ______________________________________

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`

13

,,`,`,,`---

Figure B-2b Typical performance curve format for packaged ECU reported with varying speed.

Date of Test: _____________ Test #: _____________________ Project #: ___________________________________Manufacturer: ________________________________________ Model #:____________________________________Appurtenances: ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Name of Testing Laboratory: ____________________________ Curve By:___________________________________Address of Testing Laboratory: __________________________ Signature:___________________________________ ___________________________________________________ Date: ______________________________________

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---


Figure B-3 Typical performance curve format for component ECU.

Date of Test: _____________ Test #: _____________________ Project #: ___________________________________Manufacturer: ________________________________________ Model #: ___________________________________ECU Inlet area of Media or Wet Section: ___________________ m2(ft2) Media or Wet Section Type:____________Appurtenances: _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Name of Testing Laboratory: ____________________________ Curve By:___________________________________Address of Testing Laboratory: __________________________ Signature:______________________________________________________________________________________ Date: ______________________________________

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---

15

Figure B-4 Typical report format for packaged ECU.

Date of Test: ______________ Test #: ______________ Project #: __________________________________________Test Unit Description (photo or drawing attached):__________________________ H: _______ W: _______L:_______

ECU Manufacturer:________________________________ Model #:___________________________________________Nameplate Power:__________Volts: ___________ Hz: _________ Amperes: ___________ Phase: __________

Fan Mfr.:________________________Model # _______________ OD:__________ Width:_________Pitch: _________Motor: Mfr.:_____________________________________ Model #: ___________________________________Nameplate Power:_______ Volts: ______ Hz: _________ Amperes: _____ RPM: _________Phase: ________Drive: ________________ Sheave Mfr.:______________ Pulley Size: _________ Belt Length:____________

Description of Pump, Rotary Device or Other Method to Circulate ECU Water: _________________________________Manufacturer: _____________________________ Model #: _________________________________________Nameplate Power: ____________Volts: ________ Hz: ______ Amperes: ______ RPM: _______ Phase: _____

Test Duct Description, (Photo or sketch attached): __________________________ H: _______ W: ______ L: _______Appurtenances:____________________________________________________________________________________________________________________________________________________________________________________

INPUT DATA ___________ 1 ________ 2_______ 3 _______ 4 _______ 5_______ 6_______7 _______8 _______

1. ECU Outlet Area: _____________________________________________________________________________________2. Nozzles Used (_a, _b, _c):_______________________________________________________________________________3. Nozzle ΔP: __________________________________________________________________________________________4. Static Pressure Differential of ECU: _______________________________________________________________________

ΔPECU = ΔPs + (Δ Pelbow + SEF)(ρstd / ρ0) ______________________________________________________________a) ΔPs = Ps1 – Ps0__________________________________________________________________________________b) ΔPelbow: _______________________________________________________________________________________c) SEF___________________________________________________________________________________________

5. Dry Bulb Temp. in, td0: _________________________________________________________________________________6. Dry Bulb Temp. out, td2: ________________________________________________________________________________7. Wet Bulb Temp. in, tw0:_________________________________________________________________________________8. Wet Bulb Temp. out, tw2:________________________________________________________________________________9. Saturation Effectiveness: ________________________________________________________________________________

ε = (td0 – td2) / (td0 – tw0): ___________________________________________________________________________

10. Barometric Pressure, Pb: ________________________________________________________________________________11. Air Density: _________________________________________________________________________________________

a) ρ0:____________________________________________________________________________________________b) ρ2: ___________________________________________________________________________________________

12. ECU W = Wf +Wp + Wa: ________________________________________________________________________________a) Fan Power, Wf: __________________________________________________________________________________b) Pump Power, Wp:________________________________________________________________________________c) Appurtenance Power, Wa: _________________________________________________________________________

13. Fan Rotation, N: _____________________________________________________________________________________14. Sheave Setting: _______________________________________________________________________________________15. Nozzle Coefficients, C: _________________________________________________________________________________

a) C, Nozzle ‘a’ ___________________________________________________________________________________b) C, Nozzle ‘b’ ___________________________________________________________________________________c) C, Nozzle ‘c’ ___________________________________________________________________________________

16. Nozzle Area, Aa + Ab + Ac ______________________________________________________________________________a) Nozzle Area, Aa: ________________________________________________________________________________b) Nozzle Area, Ab: ________________________________________________________________________________c) Nozzle Area, Ac: ________________________________________________________________________________

17. QECU = (Qa + Qb + Qc)(ρ2 / ρ0) _________________________________________________________________________a) Airflow, Nozzle ‘a’, Qa:___________________________________________________________________________b) Airflow, Nozzle ‘b’, Qb ___________________________________________________________________________c) Airflow, Nozzle ‘c’, Qc ___________________________________________________________________________

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---


Figure B-4 Typical report format for packaged ECU (continued).

18. Entrainment? (Y, N): ___________________________________________________________________________________19. ECU Water Flow Rate, Qw ______________________________________________________________________________20. Water Conductivity ____________________________________________________________________________________STANDARD DENSITY CORRECTIONS __1 ______ 2 ______ 3 ______ 4______ 5 ______ 6 ______ 7 _____ 8 _____

21. εstd = 1– (1 – ε)(ρ0/ρstd):________________________________________________________________________________22. ΔPstd = ΔPECU (ρstd / ρ0): ______________________________________________________________________________23. Wfstd = Wf (ρstd / ρ0):__________________________________________________________________________________24. Wstd = Wfstd + Wp + Wa: _______________________________________________________________________________SPEED CORRECTIONS _______________1 ______2 ______ 3 ______ 4 ______5 ______ 6 ______7 _____ 8 _____

25. Corrected to Constant Fan Speed, Nn:26. Qstd = Q3(Nn / N): _____________________________________________________________________________________27. ΔPn = ΔPstd(Nn / N)2 ___________________________________________________________________________________28. Wfn = Wfstd(Nn / N)3____________________________________________________________________________________29. Wn = Wfn + Wp + Wa ___________________________________________________________________________________LIST OF INSTRUMENTS _____________________________________________________________________________Name __________ Make _______Model # ______ Serial# ______ Scale Range ______Accuracy ______ Date Calibrated _

1. ____________________________________________________________________________________________________2. ____________________________________________________________________________________________________3. ____________________________________________________________________________________________________4. ____________________________________________________________________________________________________5. ________________________________________________________________________________________________________________________________________________________________________________________________________

Name of Testing Laboratory: ____________________________________ Tested By: ________________________Address of Testing Laboratory: ____________________________________ Signature: _________________________

__________________________________________________________________Date: _________________________________________________________________________________________________________________________________

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---

17

Figure B-5 Typical report format for component ECU.Date of Test: ______________ Test #: ______________ Project #: __________________________________________Test Unit Description (photo or drawing attached):__________________________ H: _______ W: _______L:_______Manufacturer:__________________________________ Model #:___________________________________________________

Nameplate Power:__________Volts: ___________ Hz: _________ Amperes: ___________ Phase: __________Description of Pump, Rotary Device or Other Method to Circulate ECU Water: _________________________________

Manufacturer: _____________________________ Model #: _________________________________________Nameplate Power: ____________Volts: ________ Hz: ______ Amperes: ______ RPM: _______ Phase: _____

Test Duct Description, (Photo or sketch attached): __________________________ H: _______ W: ______ L: _______Appurtenances:____________________________________________________________________________________________________________________________________________________________________________________

INPUT DATA ___________ 1 ________ 2_______ 3 _______ 4 _______ 5_______ 6_______7 _______8 _______

1. ECU Outlet Area: _____________________________________________________________________________________2. Nozzles Used (_a, _b, _c):_______________________________________________________________________________3. Nozzle ΔPNozzle: ______________________________________________________________________________________4. Static Pressure Differential of ECU: _______________________________________________________________________

ΔPECU = ΔPs + (Δ Pelbow + SEF)(ρstd / ρ0) ______________________________________________________________a) ΔPs = Ps1 – Ps0__________________________________________________________________________________b) ΔPelbow: _______________________________________________________________________________________c) SEF___________________________________________________________________________________________

5. Dry Bulb Temp. in, td0: _________________________________________________________________________________6. Dry Bulb Temp. out, td2: ________________________________________________________________________________7. Wet Bulb Temp. in, tw0:_________________________________________________________________________________8. Wet Bulb Temp. out, tw2:________________________________________________________________________________9. Saturation Effectiveness: ________________________________________________________________________________

ε = (td0 – td2) / (td0 – tw0): ___________________________________________________________________________

10. Barometric Pressure, Pb: ________________________________________________________________________________11. Air Density, ρ: _______________________________________________________________________________________

a) ρ0:____________________________________________________________________________________________b) ρ2: ___________________________________________________________________________________________

12. ECU W = Wf + Wp + Wa:________________________________________________________________________________a) Pump Power, Wp: ________________________________________________________________________________b) Appurtenance Power, Wa: _________________________________________________________________________

13. Nozzle Coefficients, C: _________________________________________________________________________________a) C, Nozzle ‘a’ ___________________________________________________________________________________b) C, Nozzle ‘b’ ___________________________________________________________________________________c) C, Nozzle ‘c’ ___________________________________________________________________________________

14. Nozzle Area, Aa + Ab + Ac ______________________________________________________________________________a) Nozzle Area, Aa: ________________________________________________________________________________b) Nozzle Area, Ab: ________________________________________________________________________________c) Nozzle Area, Ac: ________________________________________________________________________________

15. Entrainment? (Y, N): ___________________________________________________________________________________16. ECU Water Flow Rate, Qw ______________________________________________________________________________17. Water Conductivity ____________________________________________________________________________________DENSITY CORRECTIONS _____________1 ______ 2 ______ 3 ______ 4______ 5 ______ 6 ______ 7 _____ 8 _____

18. QECU = (Qa + Qb + Qc) (ρ2 / ρ0) _________________________________________________________________________a) Airflow, Nozzle ‘a’, Qa:___________________________________________________________________________b) Airflow, Nozzle ‘b’, Qb ___________________________________________________________________________c) Airflow, Nozzle ‘c’, Qc

19. εstd = 1 – (1 – ε)(ρ0/ρstd): _______________________________________________________________________________20. ΔPstd = ΔPECU (ρstd / ρ0): ______________________________________________________________________________21. Wstd = Wp + Wa:______________________________________________________________________________________


Figure B-5 Typical report format for component ECU (continued).LIST OF INSTRUMENTS _____________________________________________________________________________Name ________ Make______ Model # ______ Serial# _____ Scale Range_____ Accuracy ______Date Calibrated ______

1. __________2. ____________________________________________________________________________________________________3. ____________________________________________________________________________________________________4. ________________________________________________________________________________________________________________________________________________________________________________________________________

Name of Testing Laboratory: ____________________________________ Tested By: ________________________Address of Testing Laboratory: ____________________________________ Signature: _________________________

__________________________________________________________________Date: _____________________________

Figure B-6 Illustration of a packaged direct-evaporative air cooler (ECU).

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---

19

Figure B-7 Illustration of a component direct-evaporative air cooler (ECU).

--`,,`,,,,````,,,,`,,`,,,,``,``-`-`,,`,,`,`,,`---


POLICY STATEMENT DEFINING ASHRAE’S CONCERNFOR THE ENVIRONMENTAL IMPACT OF ITS ACTIVITIES

ASHRAE is concerned with the impact of its members’ activities on both the indoor and outdoor environment. ASHRAE’smembers will strive to minimize any possible deleterious effect on the indoor and outdoor environment of the systems andcomponents in their responsibility while maximizing the beneficial effects these systems provide, consistent with acceptedstandards and the practical state of the art.

ASHRAE’s short-range goal is to ensure that the systems and components within its scope do not impact the indoor andoutdoor environment to a greater extent than specified by the standards and guidelines as established by itself and otherresponsible bodies.

As an ongoing goal, ASHRAE will, through its Standards Committee and extensive technical committee structure,continue to generate up-to-date standards and guidelines where appropriate and adopt, recommend, and promote those newand revised standards developed by other responsible organizations.

Through its Handbook, appropriate chapters will contain up-to-date standards and design considerations as the material issystematically revised.

ASHRAE will take the lead with respect to dissemination of environmental information of its primary interest and will seekout and disseminate information from other responsible organizations that is pertinent, as guides to updating standards andguidelines.

The effects of the design and selection of equipment and systems will be considered within the scope of the system’sintended use and expected misuse. The disposal of hazardous materials, if any, will also be considered.

ASHRAE’s primary concern for environmental impact will be at the site where equipment within ASHRAE’s scopeoperates. However, energy source selection and the possible environmental impact due to the energy source and energytransportation will be considered where possible. Recommendations concerning energy source selection should be made byits members.

86433PC 9/08

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ashrae standard method of testing direct evaporative...

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