BS 5141-2-1977 Specification for air heating and cooling coils - Method of testing for rating of heating coils《空气加热和冷却蛇管规范 第2部分 加热蛇管评定试验方法》.pdf

《BS 5141-2-1977 Specification for air heating and cooling coils - Method of testing for rating of heating coils《空气加热和冷却蛇管规范 第2部分 加热蛇管评定试验方法》.pdf》由会员分享，可在线阅读，更多相关《BS 5141-2-1977 Specification for air heating and cooling coils - Method of testing for rating of heating coils《空气加热和冷却蛇管规范 第2部分 加热蛇管评定试验方法》.pdf（44页珍藏版）》请在麦多课文档分享上搜索。

1、BRITISH STANDARD BS 5141-2: 1977 Specification for Air heating and cooling coils Part 2: Method of testing for rating of heating coils UDC 697.97:697.978.001.4BS5141-2:1977 This British Standard, having been prepared under the directionof the Refrigeration, Heating and Air Conditioning Standards Com

2、mittee, was published under the authority ofthe Executive Board on 31March 1977 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference RHE/6 Draft for comment 76/71779 DC ISBN 0 580 09691 2 Cooperating organizations The Refrigeration, Heating and Air Condit

3、ioning 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 Domestic Electrical Applianc

4、es Boiler and Radiator Manufacturers Association Ltd* British Combustion Equipment Manufacturers Association British Gas Corporation British Mechanical Engineering Confederation British Refrigeration and Air Conditioning Association* Building Services Research and Information Association* Chartered

5、Institution of Building Services* Department of Health and Social Security* Department of the Environment Electricity Supply Industry in England and Wales Engineering Equipment Users Association Heating and Ventilating Contractors Association* HEVAC Association* Institute of Fuel Institute of Refrig

6、eration* Institution of Gas Engineers Lloyds Register of Shipping Manufacturers Association of Radiators and Convectors* Ministry of Defence* National Coal Board Society of British Gas Industries Water-tube Boilermakers Association The Government departments and scientific and industrial organizatio

7、ns 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 Environment Building Research Establishment Institute of Domestic Heating Engineers Unit Heater Manufacture

8、rs Association Amendments issued since publication Amd. No. Date of issue CommentsBS5141-2:1977 BSI 11-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Object of the test 1 4 Definitions 1 5 Nomenclature 2 6 Instrumentation 4 7 Air flow leakage

9、 test 5 8 Test apparatus 5 9 Requirements for rating tests 6 10 Tests required for establishing a rating 6 11 General test procedures 7 12 Test results 7 13 Basic calculations 8 14 Heat transfer calculations 10 15 Pressure drop calculations 15 16 Accuracy and extrapolation 16 Appendix A Procedure fo

10、r heat transfer calculations 17 Appendix B Examples of heat transfer test data calculations 17 Appendix C Examples of heating duty calculations 19 Appendix D Typical values of thermal conductivity 21 Figure 1 Typical arrangement of passes 22 Figure 2 Typical arrangement of rows 23 Figure 3 Types of

11、fins 24 Figure 4 Thermometer pockets 25 Figure 5 Multijunction differential thermocouple 26 Figure 6 Air sampling tubes 26 Figure 7 Inverted tube pattern manometer and piezometer ring 27 Figure 8 Apparatus for air flow leakage test 28 Figure 9 Typical test duct arrangements 29 Figure 10 Air flow mix

12、ers 30 Figure 11 Open-circuit water system 31 Figure 12 Closed-circuit water system 31 Figure 13 Steam system 32 Figure 14 Efficiency of fins of constant thickness 33 Figure 15 Efficiency of fins of constant area for heat flow and of spiral fins 34 Figure 16 Example of graph of R aversus (R a+ R m )

13、 prepared from test data 35 Figure 17 Example of graph of R mversus f a 35 Figure 18 Example of water-film heat transfer coefficient for tube with turbulators for inlet water temperatures between 40 C and 120 C 36 Figure 19 Graph of factor F for corrected logarithmic mean temperature for cross-flow

14、single-pass coils 37 Figure 20 Example of graph of R aas a function of velocity v r 37 Figure 21 Correction factor K wfor hydraulic pressure drop 38 Table 1 Heat transfer variables for test purposes 7 Table 2 Allowed variation from mean value of data 7 Publications referred to Inside back coverBS514

15、1-2:1977 ii BSI 11-1999 Foreword This Part of this British Standard has been prepared under the authority of the Refrigeration, Heating and Air Conditioning Standards Committee in response to requests from industry. It constitutes a revision of BS 2619 “Method of test and rating for steam-heated air

16、-heater batteries” and BS 3208 “Methods of test and rating for hot-water air-heater batteries”, which will both be withdrawn. This Part is the second of a series concerned with air heating and cooling coils. Where reference is made to British Standards for which no metric version is available, the a

17、ppropriate British Standard in imperial units shall be used in conjunction with BS 350. Attention is also drawn to BS 3763. 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. Compliance

18、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, pagesi andii, pages1 to38, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had ame

19、ndments incorporated. This will be indicated in the amendment table on the inside front cover.BS5141-2:1977 BSI 11-1999 1 1 Scope This Part of BS 5141 gives a method of testing for rating of duct-mounted air heating coils with hot water or dry saturated steam as the heating medium within the range o

20、f variables given in Table 1. 2 References The titles of the publications referred to in this standard are listed on the inside back cover. 3 Object of the tests The object of the tests is to provide a fundamental means of establishing the rating of coils operating in other than test conditions by a

21、pplying test data obtained from a prototype coil (or coils). 4 Definitions For the purposes of this British Standard the following definitions apply. 4.1 heating coil a water-to-air or steam-to-air heat exchanger of the tubular type, through which air is passed by mechanical means over the external

22、surface, such as is normally connected into a system of ventilation ductwork. The heat exchanger surface considered is of the extended surface, externally finned type 4.2 reference conditions temperature 20 C, absolute pressure 1.013 bar 1) , relative humidity 43%, density 1.200 kg/m 3 4.3 rows the

23、number of banks of tubes in the direction of air flow (see Figure 1) 4.4 passes the number of times the water or steam in any one circuit crosses the air flow (see Figure 2) 4.5 similar coils a range of coils having the same a) water/steam tube size, spacing, arrangement (in-line or staggered, see F

24、igure 1) and internal construction; b) water or steam flow geometry, the general method of combining rows and circuits (see Figure 2); c) fin type, construction and spacing (see Figure 3). 4.6 turbulator a device inside a tube to increase heat transfer 1) 1 bar = 10 5N/m 2= 100 kPaBS5141-2:1977 2 BS

25、I 11-1999 5 Nomenclature Symbol Description Units A Di Surface area of ductwork between inlet samples and centre of coil m 2 A Do Surface area of ductwork between outlet sampler and centre of coil m 2 A F Coil face area m 2 A i Coil internal surface area (n t ; d il t10 3 ) m 2 A o Coil external sur

26、face area (A P+ A s ) m 2 A P Area of exposed tubes m 2 A s Total surface area of coil fins (both sides); where fin collars are employed, thecollar is taken as part of the exposed tube area m 2 A t Cross-sectional area of coil tube (bore area) m 2 B Coil surface area ratio (A o /A i ) c pa Specific

27、heat capacity of air kJ/(kg K) c pw Specific heat capacity of water kJ/(kg K) c pam Specific heat capacity of air at mean air temperature kJ/(kg K) c pwm Specific heat capacity of water at mean water temperature kJ/(kg K) d i Tube internal diameter mm d o Tube external diameter mm F Factor for corre

28、cted logarithmic mean temperature f a Air-side film transfer coefficient W/(m 2K) f v Steam-side film transfer coefficient W/(m 2K) f w Water-side film transfer coefficient W/(m 2K) f ws Water-side film transfer coefficient for smooth bore tubes W/(m 2K) f wt Water-side film transfer coefficient for

29、 tubes fitted with turbulators W/(m 2K) g Acceleration due to gravity m/s 2 K i Heat leakage coefficient for air inlet section kW/K K o Heat leakage coefficient for air outlet section kW/K K w Correction factor for hydraulic pressure drop k Thermal conductivity of insulating material W/(m K) k t The

30、rmal conductivity of tube wall material W/(m K) k f Thermal conductivity of fin material W/(m K) l c Length of one complete water circuit m l t Length of each coil water tube m L Latent heat of evaporation of steam at the test steam pressure kJ/kg m a Air mass flow rate kg/s m v Condensate mass flow

31、 rate kg/s m w Water mass flow rate kg/s n c Number of circuits n t Number of tubes in coil n Number of rows in test coil n Number of rows in coil under consideration P b Barometric pressure barBS5141-2:1977 BSI 11-1999 3 Symbol Description Units P vi Steam inlet pressure (gauge) bar %p c Coil air p

32、ressure drop Pa %p r Coil air pressure drop corrected to reference density Pa %p rn Coil air pressure drop corrected to reference density for coil of n rows Pa %p w Hydraulic pressure drop (measured) Pa %p wc Hydraulic pressure drop corrected for heat differences between coil inlet and outlet Pa %p

33、wct Hydraulic pressure drop at reference temperature Pa Q Mean heat transferred kW Q a Heat transferred on air side kW Q v Heat transferred on steam side kW Q w Heat transferred on water side kW R Overall thermal resistance m 2K/W R a Thermal resistance of air film m 2K/W R f Fin thermal resistance

34、m 2K/W R m Metal thermal resistance m 2K/W R t Tube wall thermal resistance m 2K/W R v Thermal resistance of steam film (based on A o ) m 2K/W R w Thermal resistance of water film (based on A o ) m 2K/W t a Ambient temperature (dry bulb) C t ai Inlet air temperature (dry bulb) C t ao Outlet air temp

35、erature (dry bulb) C t aic , t aoc t aiand t aocorrected for heat losses or gains C t ai Inlet air temperature (wet bulb) C t ao Outlet air temperature (wet bulb) C t vi Inlet steam temperature C t vs Dry saturated steam temperature corresponding to steam inlet pressure P vi(from steam tables) C t w

36、i Inlet water temperature C t wo Outlet water temperature C t wm Mean water temperature; (t wi+ t wo )/2 C %t m Corrected logarithmic mean temperature difference between air and water C v r Air velocity at coil face at reference condition m/s v w Mean water velocity m/w X b Inner radius of fin mm X

37、e Outer radius or equivalent radius of fin mm Y f Fin thickness mm Y i Thickness of insulating material mmBS5141-2:1977 4 BSI 11-1999 6 Instrumentation 6.1 Temperature measurement 6.1.1 The measurement of temperature shall comply with the requirements of BS 1041. If liquid-in-glass thermometers are

38、used, they shall be graduated in intervals not exceeding 0.1 C, and shall comply with the requirements of BS 593, partial immersion ranges. All temperature-measuring instruments shall be calibrated against an NPL calibrated thermometer to a precision of 0.1 C. 6.1.2 Water and steam temperatures shal

39、l be measured by means of instruments inserted into oil-filled pockets similar to those in Figure 4. 6.1.3 For water temperature differences below 5 C, it is necessary to take special care and the differential thermocouple system shown in Figure 5 is recommended, together with a separate measurement

40、 of inlet water temperature. 6.1.4 The inlet and outlet air temperatures shall be measured by means of the system given in BS 4194 (Appendix D). The measurement system shall be connected to sampling tubes similar to those shown in Figure 6. 6.2 Flow measurement 6.2.1 The measurement of water flow at

41、 temperatures up to 95 C shall preferably be by means of direct weighing (although one of the methods described in BS 1042 may be used). The measurement of water flow at temperatures over 95 C shall be made by one of the methods described in BS 1042. Greek symbols Description Units , Parameters defi

42、ned in 14.1.1.2 Surface effectiveness Fin efficiency Density kg/m 3 r Reference air density (1.2 kg/m 3 ) kg/m 3 Suffices a air b barometric; inner radius of fin c calculated; circuits; corrected D duct e outer radius of fin F face f fin i inlet; insulating; internal m mean; metal o external; outlet

43、 p exposed tubes; pressure r reference condition(s) s smooth; surface t reference temperature; tube(s); turbulator T total v steam w waterBS5141-2:1977 BSI 11-1999 5 When direct weighing is used, the water leaving the test rig shall be collected in vessels of known weight and weighed to an accuracy

44、of0.1% over the range of weights used in the test. The weight of each vessel used shall not exceed 50% of its normal contents. The net weight of each charge shall be recorded by weighing the vessel both after emptying the previous charge and after filling. The vessels shall be covered to prevent los

45、s by evaporation. 6.2.2 The measurement of steam flow shall bebe weighing the condensate. The weighing apparatus shall be as described in 6.2.1. 6.2.3 The measurement of air flow shall be as specified in BS 1042-1 or, alternatively, a flow meter shall be used calibrated in situ by the methods given

46、in BS 1042-2. 6.3 Pressure measurement 6.3.1 Side wall tappings for measurement of hydraulic pressure drop shall be fitted adjacent to the coil. The tappings shall be as specified in Figure 7 and shall be connected to form a piezometric ring. An inverted U-tube manometer, similar to that shown in Fi

47、gure 7, shall be employed for the measurement of hydraulic pressure drop. 6.3.2 Steam pressure gauges shall comply with the requirements of clause 30a) of BS 1780:1960. They shall be at least 150 mm in diameter and shall have a total scale range not more than three times the measured pressure. For p

48、ressures below 0.3 bar (gauge), a liquid manometer is desirable. 6.3.3 Wall static air pressures shall be measured with static taps conforming to the specifications given in BS 1042-2. A minimum of four taps shall be symmetrically disposed about the duct walls and connected to form a piezometric rin

49、g. 6.3.4 Manometers shall have a total scale range of not more than three times the maximum measured pressure. Manometers shall have scale intervals not greater than 2% of the total scale range, with the exception of pressures below 50 Pa, in which case the maximum intervals shall be 1 Pa. The minimum differential pressures for flow measurement shall be 25 Pa for inclined U-tube manometers and micro-manometers and 500 Pa for vertical U-tube ma