1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 308 : 1997 ICS 27.0
2、60.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Heat exchangers Test procedures for establishing the performance of air to air and flue gases heat recovery devicesBS EN 308 : 1997 This British Standard, having been prepared under the direction of the Engineering Sector B
3、oard, was published under the authority of the Standards Board and comes into effect on 15 July 1997 BSI 1997 The following BSI reference relates to the work on this standard: Committee reference RHE/30 DD ENV 308 ISBN 0 580 27663 5 Amendments issued since publication Amd. No. Date Text affected Com
4、mittees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee RHE/30, Heat exchangers, upon which the following bodies were represented: British Refrigeration Association Building Services Research and Information Association Federation o
5、f Environmental Trade Associations HEVAC Association Water Heater Manufacturers AssociationBS EN 308 : 1997 BSI 1997 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 308 3ii BSI 1997 BS EN 308 : 1997 National foreword This British Standard has been
6、 prepared by Technical Committee RHE/30 and is the English language version of EN 308 : 1997, Heat exchangers Test procedures for establishing performance of air to air and flue gases heat recovery devices, published by the European Committee for Standardization (CEN). DD ENV 308 is withdrawn. EN 30
7、8 : 1997 was produced as a result of international discussions in which the UK took an active part. Cross-references Publication referred to Corresponding British Standard EN 305 : 1997 BS EN 305 : 1997 Heat exchangers Definitions of performance of heat exchangers and the general test procedure for
8、establishing performance of all heat exchangers Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 12, an inside back cover and a ba
9、ck cover.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1997 Copyright reserved to CEN members Ref. No. 308 : 1997 E EUROPEAN STANDARD EN 308 NORME EUROPENNE EUROPA ISCHE NORM Ja
10、nuary 1997 ICS 27.060.30 Supersedes ENV 308 : 1990 Descriptors: Heat transfer, heat exchangers, regenerative heaters, definitions, tests, measurement, thermodynamic properties English version Heat exchangers Test procedures for establishing performance of air to air and flue gases heat recovery devi
11、ces Echangeurs thermiques Proce dures dessai pour la de termination de la performance des re cupe rateurs de chaleur air/air et air/gaz Wa rmeaustauscher Pru fverfahren zur Bestimmung der Leistungskriterien von Luft/Luft- und Luft/Abgas2 Wa rmeru ckgewinnungsanlagen This European Standard was approv
12、ed by CEN on 1996-12-27. 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 alteration. Up-to-date lists and bibliographical references concerning such national stand
13、ards may be obtained on application to the Central Secretariat or to any CEN member. The European Standards exist in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to t
14、he CEN Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Pag
15、e 2 EN 308 : 1997 BSI 1997 Foreword This European Standard has been prepared by Technical Committee CEN/TC 110, Heat exchangers, the secretariat of which is held by BSI. This European Standard supersedes ENV 308 : 1990. This European Standard shall be given the status of a national standard, either
16、by publication of an identical text or by endorsement, at the latest by July 1997, and conflicting national standards shall be withdrawn at the latest by July 1997. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to impleme
17、nt this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Introduction 3 1 Scope 3 2 Normative references 3 3 Symbols and subscripts 3 4
18、Definitions 4 4.1 Heat recovery device 4 4.2 Mass flows 4 4.3 Ratios 4 4.4 External leakage 4 4.5 Internal leakage 4 4.6 Internal exhaust air leakage 4 4.7 Carry-over air flow 4 4.8 Reference conditions 4 4.9 Pressure 4 5 General requirements 4 5.1 Heat recovery device 4 5.2 External leakage 4 5.3 I
19、nternal exhaust air leakage 5 5.4 Carry-over 5 5.5 Temperature and humidity ratios 5 5.6 Pressure drop 6 6 Test procedures and accuracy requirements 7 6.1 External leakage test 7 6.2 Internal exhaust leakage test (categories I and IIa) 7 6.3 Carry-over test (category III) 7 6.4 Ratio tests (see figu
20、re 3) 7 6.5 Pressure drop tests (see figure 3) 8 6.6 Heat balance 8 7 Test report 8 7.1 Heat recovery device 8 7.2 External leakage 8 7.3 Internal exhaust air leakage 8 7.4 Carry-over 8 7.5 Temperature and humidity ratios 8 7.6 Pressure drop: for standard air 9 7.7 Other indications 9Page 3 EN 308 :
21、 1997 BSI 1997 Introduction This European Standard is one of a series of European Standards dedicated to heat exchangers. 1 Scope This European Standard specifies methods to be used for laboratory testing of air-to-air heat recovery devices or those recovering heat from flue gases of heating applian
22、ces in buildings (except processprocess applications) to obtain rating data. It gives test requirements and procedures for performing such tests and specifies input criteria required for tests to verify performance data given by the manufacturer. For the purposes of this standard, the term exhaust a
23、ir may also be taken to mean the products of combustion. This European Standard is intended to be used as a basis for testing heat recovery devices for HVAC systems, which as specified in prEN 247 consist of the heat exchanger itself installed in a casing having the necessary air duct connecting ele
24、ments and in some cases the fans and pumps, but without any additional components of the HVAC system. This European Standard is applicable to the following categories of heat exchangers: Category I Recuperators Category II With intermediary heat transfer medium Category IIa: without phase-change Cat
25、egory IIb: with phase-change (heat pipe,) Category III Regenerators (containing accumulating mass) Category II1a: non hygroscopic Category II1b: hygroscopic Heat recovery devices with exchangers and intermediary heat transfer medium without phase-change (category IIa) are to be tested as one unit in
26、cluding pump and pipe system between the coils. This European Standard prescribes test methods for determining: a) the external leakage; b) the internal leakage of exhaust air to the supply air within the device at a given pressure difference between air ducts, for recovery devices of categories I a
27、nd II; c) the carry-over of exhaust air to the supply air in recovery devices of category III; d) the temperature and humidity ratios; e) the pressure drop of exhaust air and supply air sides. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from o
28、ther 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 amendment
29、or revision. For undated references the latest edition of the publication referred to applies. prEN 247 Heat exchangers Terminology EN 305 Heat exchangers Definitions of performance of heat exchangers and the general test procedure for establishing performance of all heat exchangers prEN 306 Heat ex
30、changers Methods of measuring parameters necessary for establishing the performance prEN 307 Heat exchangers Guidelines to prepare installation, operating and maintenance instructions required to maintain the performance of each type of heat exchanger 3 Symbols and subscripts a concentration (in 10
31、26 ) n rotating speed (in min 21 ) x moisture contents in kg water/kg dry air d n diameter of a circular duct in which the pressure drop is equal to that of the actual duct at the same air velocity (in mm) m dynamic viscosity (in kgm 21 s 21 ) q mn nominal air mass flow rate of the recovery device,
32、indicated by the manufacturer q m1 exhaust-air mass flow rate (in kgs 21 ) q m2 supply-air mass flow rate (in kgs 21 ) q men external leakage mass flow rates at negative pressures (in kgs 21 ) q mep external leakage mass flow rates at positive pressures (in kgs 21 ) q mco carry-over mass flow rate (
33、in kgs 21 ) q mil internal leakage mass flow rate (in kgs 21 ) Dp 1 pressure drop on exhaust-air side (in Pa) Dp 2 pressure drop on supply-air side (in Pa) h t temperature ratio h x humidity ratio t w wet bulb temperature (in C) 21 supply air inlet (see figure 3) 22 supply air outlet (see figure 3)
34、11 exhaust air inlet (see figure 3) 12 exhaust air outlet (see figure 3)Page 4 EN 308 : 1997 BSI 1997 Subscripts n nominal en external air leakage, negative pressure ep external air leakage, positive pressure il internal air leakage co carry-over air leakage w wet bulb meas measure 4 Definitions For
35、 the purposes of this European Standard, the definitions of prEN 247 and the following definitions apply. 4.1 heat recovery device Heat recovery devices are heat exchangers or combinations of these which transfer heat and, in some cases, moisture between exhaust and supply air flows depending on the
36、 differential of temperature and humidity levels. Heat recovery devices are generally installed in casings with suitable air-duct connections. The heat recovery devices are divided into three categories, as defined in clause 1. 4.2 mass flows The mass-flow rate q m22 , supply air outlet, and q m11 ,
37、 exhaust air inlet, are used as reference values. These are the mass flows that enter or leave on the application side. 4.3 ratios The temperature and humidity ratios of the device are defined on the supply-air side according to: h t = t 22 2 t 21 t 11 2 t 21 h x = x 22 2 x 21 x 11 2 x 21 NOTE. To a
38、void confusion, no definitions of ratio on the exhaust air side are included. The ratio defined on the supply air side has been chosen, because the temperature and humidity of the supply air are the main criteria in sizing recovery devices. If data on the exhaust air side is required conditions can
39、be calculated by heat and mass balances. 4.4 external leakage External leakage is the leakage to or from air flowing through the heat recovery device to or from the environment. 4.5 internal leakage Internal leakage is the air leakage between the primary and secondary air flows in a heat recovery de
40、vice. 4.6 internal exhaust air leakage The internal exhaust air leakage is the internal air leakage from the exhaust air side to the supply air side of a recovery device 4.7 carry-over air flow Carry-over air flow is the transfer of exhaust air into the supply air side in a heat recovery device of c
41、ategory III at over pressure on the supply air side. 4.8 reference conditions The reference condition for air is air with a density of 1,20 kgm -3 , a dynamic viscosity of 18,2 10 -6 kgm -1 s -1 and an absolute pressure of 101,3 kPa (1 013 Bar). Air at 20,0 C, 50 % relative humidity and 101,3 kPa ha
42、s approximately these properties. 4.9 pressure Relative pressures are measured as difference to the atmospheric pressure. Unless otherwise specified the term pressure is used for relative pressure. NOTE 1. Absolute pressure is used for air and fluids properties calculation. NOTE 2. Pressure drop is
43、the pressure difference along a circuit. 5 General requirements The European Standards EN 305, prEN 306, prEN 307 shall apply where appropriate and not otherwise stated in the following clauses. 5.1 Heat recovery device The heat recovery device to be tested shall be installed in a test rig in accord
44、ance with the manufacturers published instructions. 5.2 External leakage The air tightness is established by the external leakage at positive and negative pressures of 400 Pa. The external leakage shall be determined using the test arrangement as described in 6.1, with mean positive and negative pre
45、ssures of 400 Pa relative to ambient condition on supply and exhaust air sides respectively. The measured mass flow rates q mep and q men , the external leakage flow rates, shall be recorded in the test report as a percentage of the nominal air flow (q me /q mn )100 %. Air density during measurement
46、s shall be between 1,16 kgm -3 and 1,24 kgm -3 outside this range the measurements taken shall be corrected to reference conditions. If the recovery device is constructed without any common wall between the supply and exhaust air sides, the external leakage can be determined for the supply and exhau
47、st air exchangers separately at 400 Pa positive and/or negative pressure and summated to indicate the external leakage for the whole recovery device. For those recovery devices which are intended for use in systems with static pressures of 250 Pa or below, the external leakage may be determined at 2
48、50 Pa instead of 400 Pa. This fact shall clearly be stated in the test report.Page 5 EN 308 : 1997 BSI 1997 5.3 Internal exhaust air leakage The air leakage between the two sides in a recovery device is represented by the exhaust air leakage, mass flow rate q mil into the supply air side with a pres
49、sure of 250 Pa in the exhaust side and 0 Pa in the supply-air side, using the test arrangement described in 6.2. Air density during the measurements shall be between 1,16 kgm -3 and 1,24 kgm -3 , outside this range the measurements taken shall be corrected to reference conditions. NOTE 1. Measurements taken with 0 Pa pressure on the supply air side give the internal exhaust air leakage only, excluding any casing leakage. The internal leakage shall be determined for recovery devices belonging to categories I and I
