BS 5141-1-1975 Specification for air heating and cooling coils - Method of testing for rating of cooling coils《空气加热和冷却蛇管规范 第1部分 冷却蛇管评定试验方法》.pdf

1、BRITISH STANDARD CONFIRMED JULY 1983 BS 5141-1: 1975 Specification for Air heating and cooling coils Part 1: Method of testing for rating of cooling coils UDC 697.97 + 697.971.001.4BS5141-1:1975 This British Standard, having been approved by the Refrigeration, Heating and Air Conditioning Industry S

2、tandardsCommittee, was published under the authority ofthe Executive Board on 30 June 1975 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference RHE/6 Draft for comment 72/38381 DC ISBN 0 580 08198 2 Co-operating organizations The Refrigeration, Heating an

3、d Air Conditioning Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Consulting Engineers* Association of Manufacturers of Domesti

4、c Electrical Appliances Boiler and Radiator Manufacturers Association* British Gas Corporation British Mechanical Engineering Confederation British Oil and Gas Firing Equipment Manufacturers Association British Refrigeration and Air Conditioning Association* Department of the Environment Department

5、of Health and Social Security* Electricity Council, The Central Electricity Generating Board and the Area Boards in England and Wales Engineering Equipment Users Association Heating and Ventilating Contractors Association* Heating and Ventilating Research Association* HEVAC Association* Institute of

6、 Fuel Institute of Refrigeration* Institution of Electrical Engineers Institution of Gas Engineers Institution of Heating and Ventilating Engineers Lloyds Register of Shipping Ministry of Defence (Navy)* National Coal Board Royal Institute of British Architects Society of British Gas Industries Wate

7、r-tube Boilermakers Association The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard. Department of the Environ

8、ment, Building Research Establishment Greater London Council Manufacturers Association of Radiators and Convectors Oil Appliance Manufacturers Association Unit Heater Manufacturers Association Amendments issued since publication Amd. No. Date of issue CommentsBS5141-1:1975 BSI 11-1999 i Contents Pag

9、e Co-operating organizations Inside front cover Foreword ii 0 Introduction 1 1 Scope 1 2 References 1 3 Definitions 1 4 Nomenclature 2 5 Instrumentation 6 6 Air flow leakage test 6 7 Test apparatus 7 8 General test instructions 7 9 Calculations 8 10 Requirements for rating tests 11 11 Test required

10、for establishing a rating 11 12 Heat transfer calculations 11 13 Pressure drop calculations 16 14 Accuracy and calculations 17 Appendix A Examples of heat transfer test data calculations 18 Appendix B Examples of cooling duty calculations 20 Appendix C Calculation of sensible cooling load from inlet

11、 conditions 24 Appendix D Typical values of thermal conductivity 25 Figure 1 Typical arrangements of passes 26 Figure 2 Typical arrangements of rows 27 Figure 3 Types of fins 28 Figure 4 Thermometer pockets 29 Figure 5 Multi-junction differential thermocouple 30 Figure 6 Air sampling tubes 31 Figure

12、 7 Apparatus for air flow leakage test (showing alternative air supply systems) 32 Figure 8 Water supply system 33 Figure 9 Alternative water supply system 34 Figure 10 Inverted U-tube manometer and piezometer ring 35 Figure 11 Typical test duct arrangements 36 Figure 12 Air flow mixers 37 Figure 13

13、 Condensate drain 38 Figure 14 Efficiency of fins of constant thickness 39 Figure 15 Efficiency of fins of constant area for heat flow and of spiral fins 40 Figure 16 Graph of R aversus (R a+ R m ) 41 Figure 17 Graph of R mversus f a 42 Figure 18 Water film heat transfer coefficient for tube with tu

14、rbulators 43 Figure 19 Graph of F, factor for corrected logarithmic mean temperature 43 Figure 20 Graph of R adas a function of velocity ( r ) 44 Figure 21 Surface temperature chart 45 Figure 22 Surface temperature chart; determination of C scale 46 Figure 23 Use of surface temperature chart 47BS514

15、1-1:1975 ii BSI 11-1999 Page Figure 24 Graph for determination of Z in relation to coil surface temperature 48 Figure 25 Graph of R awas a function of velocity ( r ) 49 Figure 26 Hydraulic pressure drop correction factor 50 Figure 27 Graph of A ocversus R aw 50 Publications referred to Inside back c

16、overBS5141-1:1975 BSI 11-1999 iii Foreword This Part of this British Standard has been prepared under the authority of the Refrigeration, Heating and Air Conditioning Industry Standards Committee in response to requests from industry. The Committee acknowledge their debt to the Heating and Ventilati

17、ng Research Association for the Associations work in formulating the methods of testing that appear in this standard. This Part is the first of a series concerned with air heating and cooling coils. It is intended to issue further Parts which will deal with methods of testing for rating of heating c

18、oils, with air cooling coils for chilled water and for direct expansion, and with construction and safety aspects of heating and cooling coils. Where reference is made to British Standards for which no metric version is available then the appropriate British Standard in imperial units shall be used

19、in conjunction with BS350 “Conversion factors and tables”; attention is also drawn to BS3763 “The International System of units (SI)”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application.

20、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 to iv, pages 1 to 50, an inside back cover and a back cover. This standard has been updated (see copyright date) and ma

21、y have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS5141-1:1975 BSI 11-1999 1 0 Introduction The principal complexities in testing cooling coils arise from a) small water temperature differences; b) the accuracy of measurement of air

22、wet-bulb temperature near saturation; c) the non-uniform air temperature and non-uniform humidity profiles off the coil. a) andb) can be overcome either by specifying sophisticated instrumentation or by the careful use of simple instruments, e.g. thermocouple and mercury in glass thermometer; the la

23、tter alternative has been adopted in this standard, errors being assessed by an overall heat balance. The non-uniform off-coil conditions can only be overcome by adequate air mixing and suitable mixers have therefore been specified. In this standard fairly tight tolerances have been applied to the d

24、efinition of steady state conditions. The tight tolerances are to allow for the probability of small water temperature differences and for the large effect of a small air wet bulb temperature change on the air total heat and dew point. The duration of the test period has been chosen to ensure an acc

25、urate average heat transfer figure. The wide range of cooling coils produced by any one manufacturer makes it desirable that testing is carried out only on a relatively small number of representative coils. Such a technique is already in existence for hot water air heater batteries (see BS3208) wher

26、e a representative coil is defined as one having the same water tube arrangement, number of circuits, fin type and spacing as the coils in the production range. It is logical to apply the same principle to cooling coils. However, the effect of dehumidification cannot be ignored and consequently the

27、method of analysis employed for cooling coils is considerably more complex than that given for heating coils in BS 3208. The method of analysis used in this standard is based upon that given in ARI 1)Standard 410-64, “Standard for forced-circulation air-cooling and air-heating coils”, as this is con

28、sidered to be the most satisfactory method available at present. Tests have to be carried out on coils with both dry and fully wet surfaces in order to obtain the air-side thermal resistances. This data is then used to obtain the heat transfer, both latent and sensible, for a wide range of entering

29、air conditions. 1 Scope This standard gives a method of testing for rating of duct-mounted air cooling coils, with chilled water as the cooling medium, within the following range of variables: Inlet air temperature: below 40 C Inlet water temperature: 2 C to 20 C Inlet air wet bulb depression: great

30、er than 4 C Sensible heat ratio (Q s /Q T ): less than 0.8 (for dehumidifying coils) Water flow: Reynolds number above 3100 Air velocity at coil face: 1m/s to 4m/s 2 References The titles of the British Standards referred to in this standard are listed on the inside back cover. 3 Definitions For the

31、 purpose of this standard, the following definitions apply: 3.1 cooling coil a water-to-air heat exchanger of the tubular type through which air is passed by mechanical means over the external surface; such as is normally connected into a system of ventilation ductwork in this British Standard, the

32、heat exchanger surface considered is of the extended surface, externally finned type 1) Air Conditioning and Refrigeration Institution, Arlington, Virginia, USA.BS5141-1:1975 2 BSI 11-1999 3.2 reference air conditions temperature: 20 C, absolute pressure: 1.013 bar 2) , relative humidity: 43%, densi

33、ty: 1.200 kg/m 3 3.3 rows the number of banks of tubes in the direction of the air flow (seeFigure 1) 3.4 passes the number of times the water in any one circuit crosses the air flow (seeFigure 2) 3.5 similar coils a range of similar coils is defined as coils having the same: a) water tube size, spa

34、cing, arrangement (in-line or staggered, seeFigure 2) and internal construction; b) fin type, construction and spacing (seeFigure 3); c) water flow geometry, i.e. the general method of combining rows and circuits shall be the same for all coils in the range. 3.6 turbulator a device inside a tube for

35、 increasing the turbulence and heat transfer 4 Nomenclature 2) 1 bar = 10 5N/m 2= 100 kPa. Symbol Description Units A dc Calculated dry coil external surface area m 2 A De Surface area of ductwork between inlet sampling tube and centre of coil m 2 A Do Surface area of ductwork between outlet samplin

36、g tube and centre of coil m 2 A F Coil face area m 2 A i Coil internal surface area (N t d i l t 10 3 ) m 2 A o Coil external surface area (A p+ A s ) m 2 A oc Calculated coil external surface area m 2 A p Area of exposed tubes m 2 A s Total surface area of coil fins (both sides) a m 2 A t Cross-sec

37、tional area of coil tube m 2 A wc Calculated wet coil external surface area m 2 B Coil surface area ratio (A o /A i ) C Thermal resistance ratio kg K/kJ c pa Specific heat capacity of moist air kJ/(kg K) c pw Specific heat capacity of water kJ/(kg K) c pam Specific heat capacity of air at mean air t

38、emperature kJ/(kg K) c pwm Specific heat capacity of water at mean water temperature kJ/(kg K) C o Heat transfer exponent d i Tube internal diameter mm a For A s , total surface area of coil fins, where fin collars are employed, the collar is taken as part of the exposed tube area.BS5141-1:1975 BSI

39、11-1999 3 d o Tube external diameter mm E Effectiveness F Factor for corrected logarithmic mean temperature f a Air side heat transfer coefficient W/(m 2K) f w Water side heat transfer coefficient W/(m 2K) f ws Water side heat transfer coefficient for smooth bore tubes W/(m 2K) f wt Water side heat

40、transfer coefficient for tubes fitted with turbulators W/(m 2K) g Acceleration due to gravity m/s 2 h ai Enthalpy of inlet air kJ/kg dry air h aic Corrected enthalpy of inlet air kJ/kg dry air h ao Enthalpy of outlet air kJ/kg dry air h aoc Corrected enthalpy of outlet air kJ/kg dry air h si Enthalp

41、y of saturated air at coil surface temperature at air inlet kJ/kg dry air h so Enthalpy of saturated air at coil surface temperature at air outlet kJ/kg dry air h am Mean air enthalpy (h aic+ h aoc )/2 kJ/kg dry air h sm Enthalpy of saturated air at mean coil surface temperature kJ/kg dry air h sD E

42、nthalpy of saturated air at inlet air dew point kJ/kg dry air h B Enthalpy of air at wet/dry boundary kJ/kg dry air h s Enthalpy of saturated air at apparatus dew point kJ/kg dry air %h m Log mean enthalpy difference kJ/kg dry air k Thermal conductivity of insulating material W/(m k) K i Air inlet s

43、ection heat leakage coefficient kW/K K o Air outlet section heat leakage coefficient kW/K K w Hydraulic pressure drop correction factor k t Thermal conductivity of tube wall material W/(m K) k f Thermal conductivity of fin material W/(m K) l e Length of one complete water circuit (l i= N t l t /N c

44、) m l t Length of each water tube (one pass) m M Air-to-water side heat capacity ratio m a Air mass flow rate kg/s m w Water mass flow rate kg/s N Number of rows in coil N c Number of circuits N m Number of rows in test coil N n Number of rows in n row coil N t Number of tubes in coil P b Barometric

45、 pressure bar a P F Static pressure upstream of flow meter Pa %P sn Static pressure drop for n row coil Pa a 1 bar = 10 5N/m 2= 100 kPa. Symbol Description UnitsBS5141-1:1975 4 BSI 11-1999 %p c Coil air side pressure drop Pa %p cr Coil air side pressure drop corrected to reference density Pa %p F Ai

46、r flow meter pressure drop Pa %p w Hydraulic pressure drop (measured) Pa %p wc Hydraulic pressure drop corrected for head differences between coil inlet and outlet Pa %p wct Hydraulic pressure drop at reference temperature Pa Q Heat transferred kW Q s Mean sensible heat transferred kW Q as Sensible

47、heat transferred on air side kW Q aT Total heat transferred on air side kW Q T Mean total heat transferred kW Q w Heat transferred on water side kW R Overall thermal resistance m 2K/W R ad Air film thermal resistance for a dry surface m 2K/W R aw Air film thermal resistance for a moist surface m 2K/

48、W R f Fin thermal resistance m 2K/W R md Dry metal thermal resistance m 2K/W R t Tube wall thermal resistance m 2K/W R w Water film thermal resistance (based on A o ) m 2K/W t a Ambient temperature, (dry bulb) C t ad Apparatus dew point C t ai Inlet air temperature, (dry bulb) C t ao Outlet air temp

49、erature, (dry bulb) C t aic , t aoc t aiand t aocorrected for heat losses C Inlet air temperature, (wet bulb) C Outlet air temperature, (wet bulb) C t D Inlet air dew point C t F Flow meter temperature, (dry bulb) C Flow meter temperature, (wet bulb) C t si Coil surface temperature at inlet C t so Coil surface temperature at outlet C t sm Mean coil surface temperature C t wi Inlet water temperature C t wo Outlet water temperature C t wm Mean water tem