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1、UDC 621.56/.59.001.4 Ref. No. : ISO/R 916-1968 (E) IS0 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION IS0 RECOMMENDATION R 916 TESTING OF REFRIGERATING SYSTEMS 1st EDITION December 1968 COPYRIGHT RESERVED The copyright of IS0 Recommendations and IS0 Standards belongs to IS0 Member Bodies. Reproducti
2、on of these documents, in any country, may be authorized therefore only by the national standards organization of that country, being a member of ISO. For each individual country the only valid standard is the national standard of that country. Printed in Switzerland Also issued in French and Russia
3、n. Copies to be obtained through the national standards organizations. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 01:20:59 MDTNo reproduction or networking permitted without
4、 license from IHS -,-,- This page intentionally left blank Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 01:20:59 MDTNo reproduction or networking permitted without license fro
5、m IHS -,-,- -3- BRIEF HISTORY The IS0 Recommendation R 916, Testing of refrigerating systems, was drawn up by Technical Committee ISO/TC 86, Refrigeration, the Secretariat of which is held by the British Standards Institution (BSI). Work on this subject was entrusted to Sub-Committee ISO/TC 86/SC3,
6、the Secretariat of which is held by Belgium. The work began in 1960, and was carried out using as a basis for discussion the “Recommendations for an international code for refrigerating machines”*, published in November 1957 by the International Institute of Refrigeration. The work led to the adopti
7、on of a Draft IS0 Recommendation. In March 1967, this Draft IS0 Recommendation (No. 1153) was circulated to all the IS0 Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by the following Member Bodies : Australia Germany Belgium Greece Canada Hungary
8、Chile Italy Czechoslovakia Netherlands Denmark New Zealand France Poland Sweden Switzerland U.A.R. United Kingdom Yugoslavia No Member Body opposed the approval of the Draft. The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council? which decided, in December 1968, to acc
9、ept it as an IS0 RECOMMENDATION. * Bulletin IIF - 177 Boulevard Malesherbes, Paris 17e - Volume XXXVIII, No. 1. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 01:20:59 MDTNo rep
10、roduction or networking permitted without license from IHS -,-,- -4- HO/R 9164968 (E) CONTENTS Page Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Units . 6 Definitions and test data . 7 Determination of performance . 8 Organization of tes
11、ts 8 Measurement of refrigerating capacity . 9 Measurement of energy consumption . 17 Measuring instruments 17 Tolerances 18 Statement of results . 19 Numerical tables - Diagrams . 19 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Techni
12、cal Standards 1/9972545001 Not for Resale, 04/20/2007 01:20:59 MDTNo reproduction or networking permitted without license from IHS -,-,- .- 5 - ISO/R 916-1968 (E) IS0 Recommendation R 916 December 1968 TESTING OF REFRIGERATING SYSTEMS INTRODUCTION This IS0 Recommendation has for its object the deter
13、mination of the technical performance of a refrigerating system, but not of the functional duty of a complete installation or of the performance of its individual components. The term refrigerating system implies the conventional vapour compression type consisting of compressing, condensing and evap
14、orating apparatus, together with the interconnecting piping, and the accessories necessary to complete the refrigerant circuit. The determination of technical performance for other refrigerating systems such as, for example, absorption machines and ejector type machines is not provided for in this I
15、S0 Recommendation, but may be dealt with in other IS0 Recommendations. The only tests envisaged are those of complete refrigeration systems operating normally and under steady working conditions (frequency, voltage, water supply, etc.), and where the refrigerant is entirely in a liquid state at entr
16、y to the expansion valve. The direction of the tests should be entrusted only to persons possessing the necessary technical knowledge and experience. When none of the combined methods given in this IS0 Recommendation is practicable or acceptable, it may be possible to restrict the test to a determin
17、ation of the performance of the compressor only, in accordance with IS0 Recommendation R 9 17, Testing of refrigerant compressors. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007
18、 01:20:59 MDTNo reproduction or networking permitted without license from IHS -,-,- -6- ISO/R 916-1968 (E) Quantity I Symbol absolute temperature T,O customary temperature t, 0 pressure P density (mass density) I P specific enthalpy h specific entropy S specific heat capacity C specific latent heat
19、of evaporation I thermal conductivity x surface coefficient of heat transfer cy overall coefficient of heat transfer K kinematic viscosity V mass flow rate I qrn heat flow rate refrigerating capacity (overall, net, useful) refrigerating performance (overall, net, useful) efficiency power area of an
20、exchange surface A relative humidity 9, specific humidity (mixture ratio) X . 1. UNITS K K “R - “c “F N/m* I kgf/cm* lbf/in* kg/m3 I kg/m3 - I lb/ft3 J/kg kc+Y refrigerant (no index) saturated S Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=
21、NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 01:20:59 MDTNo reproduction or networking permitted without license from IHS -,-,- - 7 - ISO/R 916-1968 (E) 2. DEFINITIONS AND TEST DATA 2.1 Definitions 2.1.1 Overall refrigerating capacity. The rate at which heat is removed from exter
22、nal media by the refrigerant. The only heat quantities excluded from this refrigerating capacity are those which result from internal heat exchanges within the refrigerating circuit. It should be noted that, in many cases, the overall refrigerating capacity can be obtained from the difference in spe
23、cific enthalpy of the refrigerant entering the compressor and of the refrigerant leaving the condenser or the liquid sub-cooler, if any, multiplied by the mass flow of refrigerant circulated. 2.1.2 Net refrigerating capacity. The rate at which heat is removed by the refrigerant from the cooling medi
24、um which is used to transmit the refrigerating effect. 2.1.3 Useful refbigerating capacity. The rate at which heat is removed by the refrigerant or by the secondary cooling medium between two specific points, taking into account the conditions of utilisation. 2.2 Test data 2.2.1 One of the three ref
25、rigerating capacities defined under clause 2.1 should be stated. 2.2.2 In the case of refrigerating systems having several stages of evaporation and carrying out partial refrigerating duties, the intermediate temperatures should also be given. 2.2.3 In all cases, the following figures of consumption
26、 should be given : (a) the intake of power (in terms of consumption of electricity, coal, steam, fuel oil, etc., together with the requisite data regarding characteristics); (b) water for cooling, if used, together with full details of supply. 2.2.4 It is advised that the following operating details
27、 should be included in the data : (a) the refrigerant used; (b) the speed of rotation of the compressor; (c) if applicable, the pressure of the refrigerant at compressor suction, at the condenser inlet and at the evaporator outlet; (4 when the overall refrigerating capacity is specified (see clause
28、2.1. l), the conditions of the refrigerant at the expansion valve and at the entry of the compressor; 0 e when the net refrigerating capacity is given (see clause 2.1.2), - either the temperature of the heat transfer medium at the entry and exit of the condenser and of the evaporator, - or the tempe
29、rature of the heat transfer medium, either entering or leaving the condenser and the evaporator, together with the corresponding rate of flow. Preference should be given to the following : (1) for an evaporative condenser : the inlet temperature of the water, the temperature of the air and the relat
30、ive humidity of ambient air (generally the temperature at inlet); (2) for an air cooled evaporator : the inlet temperature of the air and, if appropriate, its relative humidity; (3 j jbr a brine circulation evporator : the outlet temperature of the brine. 2.2.5 It is not necessary to assess the flow
31、 of the heat transfer medium in an evaporator when its temperature should be practically uniform around the evaporator, in a space or in a reservoir (e.g. a brine tank). Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards
32、1/9972545001 Not for Resale, 04/20/2007 01:20:59 MDTNo reproduction or networking permitted without license from IHS -,-,- -8- ISO/R 916-1968 (E: 3. DETERMINATION OF PERFORMANCE 3.1 The determination of the technical performance required in the Introduction concerns the following data in particular
33、: 3.1.1 The refrigerating capacity given in clause 2.2.1 above, which should be so chosen that it is capable of practical verification. 3.1.2 The corresponding consumption given in clause 2.2.3. 3.1.3 The conditions of operation given in clause 2.2.4. 3.2 The data should be capable of verification u
34、nder the conditions of operation laid down for the test. 3.2 As the test conditions are subject in practice to temporary unclassifiable variations, it is advised that the data be set out in such a way that they are applicable throughout the specified period of the test. 3.3.1 It is therefore advisab
35、le that the data in clauses 2.2.1 to 2.2.3 should provide for varying conditions in the neighbourhood of the conditions of operation in clause 2.2.4, and especially for different values in the neighbourhood of the temperatures given. For ease of interpolation, and in order to avoid adjustment by cal
36、culation, these values may be presented3raphically, within the limits of fluctuation, for each pair of temperatures specified. Maximum permissible deviations should be laid down. 3.3.2 So far as the influence of temporary variations in other operating conditions is concerned, this should be the subj
37、ect of an agreement between the interested parties. 4. ORGANIZATION OF TESTS 4.1 4.2 4.3 4.4 4.5 Readings showing an excessive variation from the mean should be disregarded. 4.6 The nu .mber of readi .ngs used for a calculation spaced at maximum inte WdS of 20 minutes. should be at least ten. The re
38、adings should be regularly 4.7 All measurements should be made in conformity with international rules which may be in force, or, failing this, in conformity with the national rules accepted by those concerned. All measuring instruments should have been tested and certified for the purpose of the tes
39、t. 4.8 The tests refer Introduction). exclusively to refrigerating plant operating under steady working conditions (see Preliminary tests for adj ustment to specified condi tions should be carried out before the official test is started. After this, only agreed a .djustments should be made du .ring
40、the ac tual test period. The tests should be made under the condi to the working conditions. tions defined in clause 4.4, which should be as close as possible The stability of operation (steady condition) should preferably be checked by plotting successive measure- ments over a sufficiently long tim
41、e interval and until the initial and final states are the same for all quantities essential to the verification of the data. The refrigerating system should be provided with the necessary thermometer and pressure gauge connections. These should be of a type suitable for the purpose for which they ar
42、e to be used, so as to avoid errors in measurement (frosting, longitudinal heat flow along pipes, etc.). Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 01:20:59 MDTNo reproducti
43、on or networking permitted without license from IHS -,-,- 9 - - ISO/R 916-1968 (E) 9 . 4.9 All equipment required exclusively for these tests should in no way interfere with normal operation or accessibility. 4.10 It is advisable that a sightglass should be provided upstream of the expansion valve t
44、o serve as a means of determining the level of the refrigerant. Furthermore, it is necessary to ascertain that the plant has been purged before testing, and that the entrainment of lubricating oils is not excessive. 4.11 It is recommended that, wherever possible, two simultaneous tests should be mad
45、e, with particular reference for the second test to the indirect methods described in clause 5.2. If it is only possible to make use of one test method, two consecutive tests should be made, except in the case of a contrary agreement between the interested parties. 4.12 Attention is drawn to the cau
46、ses of inaccuracy in measurements of liquid or vapour flow by calibrated flow-meters (pulsation in pipelines, oil entrainment, impurities in the circuit). 5. MEASUREMENT OF REFRIGERATING CAPACITY 5.1 Direct methods 5.1.1 Overall rejkigerating capacity. When the refrigerant vapour in circulation is d
47、ry saturated or superheated at the compressor inlet, i.e. without liquid entrained or in suspension, the overall refrigerating effect can be calculated by the equation : cl =qm (h, -k) . . . . . (1) State 1 is the state at the inlet flange of the compressor, and state 5 is the state at the outlet fr
48、om the sub- cooler (to be exact, the inlet flange on the expansion valve or the inlet flange of the internal heat exchanger on the high pressure side, as shown in Fig. 1 or 2). Specific enthalpies for the more common refrigerants are given in the tables and diagrams referred to in clause 10.1. The measurement of the mass flow rate of refrigerant in the low pressure circuit should be made either by heat balance (see clause 5.1.1.1) or by calibrated flow-meter (see clause 5.1-l .2). Copyright International Organization for Standardizatio