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1、BRITISH STANDARD BS EN 13741:2003 Thermal performance acceptance testing of mechanical draught series wet cooling towers The European Standard EN 13741:2003 has the status of a British Standard ICS 91.060.50 ? Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontroll
2、ed Copy, (c) BSI BS EN 13741:2003 This British Standard, was published under the authority of the Standards Policy and Strategy Committee on 22 December 2003 BSI 22 December 2003 ISBN 0 580 43139 8 National foreword This British Standard is the official English language version of EN 13741:2003. The
3、 UK participation in its preparation was entrusted to Technical Committee RHE/30, Heat exchangers, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international
4、or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to in
5、clude all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enq
6、uiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 33 and a back
7、 cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPE
8、NNE EUROPISCHE NORM EN 13741 December 2003 ICS 91.060.50 English version Thermal performance acceptance testing of mechanical draught series wet cooling towers Essais de rception des performances thermiques des arorfrigrants humides tirage mcanique et fabriqus en srie Wrmetechnische Abnahmeprfung an
9、 zwangsbelfteten standardisierten Nasskhltrmen This European Standard was approved by CEN on 1 October 2003. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any altera
10、tion. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translati
11、on under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Irelan
12、d, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2003 CENAll rights of explo
13、itation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13741:2003 E Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13741:2003 (E) 2 ContentsPage Foreword.4 1Scope5 2Normative references5 3Terms, def
14、initions and symbols5 3.1Terms and definitions.5 3.2Symbols .8 4Performance tests General10 4.1Subject of the thermal performance acceptance.10 4.2Performance curves10 4.2.1Performance curves format .10 4.2.2Performance curve parameters.11 5Measuring procedures and instrumentation11 5.1General.11 5.
15、2Measurements.12 5.2.1Temperatures.12 5.2.2Water flow13 5.2.3Fan power 14 5.2.4Cooling tower pumping head.14 5.2.5Temperature and flow of make up and blow down15 6Acceptance tests.15 6.1General.15 6.1.1Introduction .15 6.1.2Time of the acceptance test.15 6.1.3Management of the acceptance tests .15 6
16、.2Preparation of acceptance tests15 6.2.1Number and arrangement of the measuring points 16 6.2.2Condition of the plant.16 6.3Execution of acceptance tests.17 6.3.1Pre conditions .17 6.3.2Trial measurements 17 6.3.3Acceptable deviations of operating conditions.17 6.3.4Operating conditions during the
17、test18 6.3.5Frequency of readings18 6.3.6Test duration19 6.3.7Validity of test results.19 7Assessment of test results in view of guaranteed performance data.19 7.1Assessment of test results 19 7.2Finding of face values from performance data19 7.3Comparison with the guaranteed performance data.20 8Te
18、st tolerance20 8.1General.20 8.2Error created by measuring tolerances20 8.2.1Influence of wet bulb measurement uncertainties w.21 8.2.2Influence of cooling range measurement uncertainties z21 8.2.3Influence of fan power measurement uncertainties F21 8.2.4Influence of water flow rate measurement unce
19、rtainties m21 8.3Determination of measuring equipment tolerances21 Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13741:2003 (E) 3 8.4Determination of measuring tolerances .22 8.5Determination of random errors22 8.6Determination of the t
20、est tolerance.23 9Test report23 Annex A (informative) Example.24 Annex B (informative) Performance curves.25 Annex C (informative) Position of measuring points for cooling towers .29 Annex D (informative) Test Result analysis .31 Bibliography .33 Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 3
21、0 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13741:2003 (E) 4 Foreword This document (EN 13741:2003) has been prepared by Technical Committee CEN/TC 110 “Heat Exchangers“, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, ei
22、ther by publication of an identical text or by endorsement, at the latest by June 2004, and conflicting national standards shall be withdrawn at the latest by June 2004. Annexes A, B and C are informative. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
23、 following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Licensed C
24、opy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13741:2003 (E) 5 1 Scope This European Standard specifies requirements, test method and acceptance tests for thermal performance of mechanical draught series cooling towers. This European Standard is
25、applicable to series type wet cooling towers as defined in 3.1. The acceptance testing covers the verification of the thermal and hydraulic performance data of the cooling tower selected from the product line (see 3.1) and specified in the contract between the supplier and the purchaser. If these te
26、sts are required then this should be recognized at the time of the contract, as additional fittings, and preparations for the test may be required. A methodology to calculate the test tolerance is included in this standard. The contract should specify whether this methodology shall be used for the a
27、ssessment of the test results or not. Legal and commercial consequences that might result from achieving or not achieving the contractually agreed performance are not part of this European Standard. 2 Normative references This European Standard incorporates by dated or undated reference, provisions
28、from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amen
29、dment or revision. For undated references the latest edition of the publication referred to applies (including amendments). Not applicable. 3 Terms, definitions and symbols 3.1 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 3.1.1 air flow
30、 rate total amount of dry air and associated water vapour moving through the cooling tower 3.1.2 approach difference between cold water temperature and the inlet wet bulb temperature 3.1.3 approach deviation deviation between the design approach and the measured (adjusted) approach 3.1.4 barometric
31、pressure atmospheric pressure at the test site Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13741:2003 (E) 6 3.1.5 basin open structure located beneath the cooling tower for collecting the circulating water and directing it to the sump
32、 or suction line of the circulating pump 3.1.6 basin curb top elevation of the tower basin usually the datum from which the tower elevations are measured. 3.1.7 blow-down water discharged from the system to control the concentration of salts or other impurities in the circulating water 3.1.8 cell sm
33、allest subdivision of the tower, bounded by exterior walls and partition walls , which can function as an independent unit Each cell may have one or more fans or stacks and one or more distribution systems 3.1.9 cold water temperature average temperature of the water entering or leaving the tower ba
34、sin In the case where the measurement is downstream of the basin or the pump, corrections are needed for the effects of the pump, and any other make up water blow down or heat sources entering the basin 3.1.10 cooling range difference between the temperature of the water entering the distribution sy
35、stem and the cold water temperature 3.1.11 cooling tower apparatus in which water is cooled down by heat exchange with ambient air 3.1.12 drift eliminator the assemblies downstream of the heat transfer media, which serve to reduce the drift loss 3.1.13 drift loss portion of the water flow rate lost
36、from the tower in form of fine droplets mechanically entrained in the discharge air stream, commonly expressed as mass per unit time or a percentage of the circulating water flow rate. It is independent by water lost from evaporation 3.1.14 dry bulb temperature temperature of an air-vapour mixture i
37、ndicated by a thermometer with a clean, dry sensing element that is shielded from radiation effects. May be further categorised as either: a) ambient dry bulb temperature: the dry bulb temperature of air measured windward of the tower and free from influence of the tower b) entering dry bulb tempera
38、ture: the dry bulb temperature of the air entering the tower, including the effect of any recirculation and/ or interference Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13741:2003 (E) 7 3.1.15 fan power power consumed by the fan drive
39、r, including the indication whether the efficiency of the driver is included or not 3.1.16 make up water added to the system to replace the water lost by evaporation, drift blowdown and leakage 3.1.17 mechanical draught cooling tower cooling tower where the air circulation is produced by a fan. May
40、further be categorized as either: forced draught: the fan is located in the entering air stream induced draught: the fan is located in the discharge air stream 3.1.18 non series type wet cooling tower wet cooling tower, the design of which is project dependent, and for which the performance data and
41、 test evaluation at specific operating conditions may be subject to agreement 3.1.19 open circuit (wet) cooling tower cooling tower wherein the process fluid is warm water which is cooled by the transfer of mass and heat through direct contact with atmospheric air 3.1.20 pump head sum of static head
42、 and dynamic head from the contractual interface to the discharge of the distribution system to the atmosphere 3.1.21 relative humidity ratio of the mole fraction of water vapour in a given air sample to the mole fraction of water vapour in a sample of saturated air at the same temperature and press
43、ure, usually expressed as percentage 3.1.22 series type wet cooling tower wet cooling tower, the design of which is fixed and described in the manufacturers catalogue and for which the performance data are available, which allows test evaluation over a defined range of operating conditions 3.1.23 te
44、st period time duration where readings or recordings of every measurement have to be averaged, and test period results may be calculated 3.1.24 test readings individual sets of data recorded at regular intervals for each instrument or measurement point required 3.1.25 thermal lag time interval befor
45、e the temperature of the water leaving the influence of the cooling air is detected at the point of cold water temperature measurement Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13741:2003 (E) 8 3.1.26 water flow rate quantity of war
46、m water flowing into the open cooling tower 3.1.27 water loading water quantity expressed as quantity per unit of fill plan area of the tower 3.1.28 wet bulb temperature temperature of air, which when properly measured approximates the temperature of adiabatic saturation. May further be categorised
47、as either: ambient wet bulb temperature: the wet bulb temperature of air measured windward of the tower and free from influence of the tower entering wet bulb temperature: the wet bulb temperature of the air entering the tower, including the effect of any recirculation and/or interference NOTETerms
48、like guarantee values and acceptance used in this standard are understood in a technical but not in a legal or commercial sense. 3.2 Symbols For the purposes of this European Standard, the symbols of Table 1 apply. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 06:59:45 GMT+00:00 2006, Uncon
49、trolled Copy, (c) BSI EN 13741:2003 (E) 9 Table 1 Symbols SymbolsDesignated parametersUnits twWet bulb temperatureC twGGuaranteed wet bulb temperatureC twkWet bulb temperature measured at reading kC thHot water temperatureC thkHot water temperature measured at reading kC tcCold water temperatureC tcgGuaranteed cold water temperatureC tckCold water temperature at reading kC tcfkFace value of cold water temperature at conditions found at reading k from performance
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