1、Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c) BSIPUBLICLY AVAILABLE SPECIFICATION PAS 62:2003 Refrigerated transport Procedure for determining performance and calculating energy efficiency ICS 27.220; 43.040.60; 43.080.20 Licensed C
2、opy: Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c) BSIPAS 62:2003 This Publicly Available Specification comes into effect on 30 July 2003 BSI 30 July 2003 ISBN 0 580 42214 3 Amendments issued since publication Amd. No. Date Comments Licensed Copy:
3、 Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c) BSIPAS 62:2003 BSI 30 July 2003 i Contents Page Committees responsible Inside front cover Foreword ii Introduction 1 1S c o p e 1 2T e r m s a n d d e f i n i t i o n s 1 3S y m b o l s 2 4 Principle
4、2 5 Measurement criteria and equations 3 6 Temperature measurements 4 7 Procedures for measuring K coefficient and overall heat leakage (U) of an insulated body 4 8 Procedure for measuring the effective refrigerating capacity of a refrigeration unit 5 9 Determining the coefficient of performance (CO
5、P) for mechanical refrigeration units at ATP and typical operating conditions 7 10 Test report 8 Bibliography 9 Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c) BSIPAS 62:2003 ii BSI 30 July 2003 Foreword This Publicly Available Specif
6、ication, PAS 62, was sponsored by the Department for Transport through its Transport Energy Best Practice programme and DEFRAs Market Transformation Programme, and developed through the British Standards Institution. Acknowledgement is given to the following organizations that were consulted in the
7、development of this Publicly Available Specification. AEA Technology Environment Cambridge Refrigeration Technology Carrier Transicold Cold Storage and Distribution Federation Frigoblock UK GAH Transport Refrigeration Gray and b) refrigeration units which are driven by independent engines or motors,
8、 or those driven by the vehicle itself by electrical, mechanical or hydraulic means. This PAS is aimed at suitably qualified and experienced personnel in the refrigerated transport industry. 2 Terms and definitions For the purposes of this Publicly Available Specification, the following terms and de
9、finitions apply. 2.1 calorimeter box calibrated insulated chamber fitted with electric resistance heaters for adding a measured quantity of heat 2.2 class chilled carriage at 0 C and frozen carriage at 20 C 2.3 coefficient of performance (COP) ratio of refrigerating capacity to power input 2.4 compr
10、essor mechanically operated component for compressing a refrigerant vapour 2.5 fan heater unit any combination of fan(s) and heater(s) used to maintain internal temperature during testing 2.6 insulated body thermally insulated vehicle body designed for the transport of thermally sensitive goods by r
11、oad 2.7 K coefficient overall coefficient of heat transfer which represents the insulating capacity of the equipment 2.8 mechanical refrigeration unit refrigeration unit that is mechanically driven and uses a vapour compression refrigeration system 2.9 refrigerant working fluid in a refrigerating sy
12、stem absorbing heat at low pressure/temperature by evaporation and rejecting it at a higher pressure/temperature by condensation Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c) BSIPAS 62:2003 2 BSI 30 July 2003 2.10 refrigerating capa
13、city refrigeration power available to extract heat from the cargo space of the insulated body under specified internal and external conditions 2.11 refrigeration unit equipment designed to be fitted to an insulated body in order to maintain cargo temperature by cooling NOTE The equipment might also
14、include a means of heating. 2.12 test chamber insulated chamber with the means to maintain an even and controlled constant temperature 2.13 testing station facility with the appropriate equipment and personnel to conduct testing of refrigerated transport equipment 3 Symbols For the purposes of this
15、PAS the following apply. 4 Principle The energy efficiency of refrigerated transport equipment is evaluated by measuring the K coefficient for insulated bodies and the coefficient of performance for refrigeration units at specified conditions. Refrigerating capacity may be determined with the refrig
16、eration unit attached to an insulated body or to a calorimeter box. It is necessary to measure the overall heat leakage of the insulated body or calorimeter box before the refrigeration capacity can be determined. Refrigerating capacity shall be determined both at ATP (agreement on the international
17、 carriage of perishable foodstuffs) test conditions and at typical operating conditions. KK coefficient, the overall coefficient of heat transfer which represents the insulating capacity of the equipment W/m 2 C W Thermal capacity required to maintain a constant absolute temperature difference W S T
18、he mean surface area of the insulated body is the geometric mean of the inside and outside surface areas m 2 DT m Difference between the mean internal and mean external temperatures C T i Mean internal temperature C T e Mean external temperature C U Overall heat leakage is the heat flow per degree o
19、f difference between the air temperature inside and outside the calorimeter box or the insulated body W/ C W o Effective refrigerating capacity of a unit W W j Heat dissipated by the fan heater unit to maintain the temperature difference in equilibrium W E e Enthalpy of the refrigerant vapour leavin
20、g the evaporator kJ/kg E i Enthalpy of the liquid at the inlet to the evaporator kJ/kg m Mass flow of the refrigerant liquid kg/s S i Internal surface area m 2 S e External surface area m 2 W f Heat generated by the evaporator fans W Licensed Copy: Wang Bin, ISO/Exchange China Standards Information
21、Centre, 10 October 2003, Uncontrolled Copy, (c) BSIPAS 62:2003 BSI 30 July 2003 3 5 Measurement criteria and equations 5.1 Absolute temperature difference between the inside and outside walls of the insulated body (DT m ) The absolute temperature difference DT mbetween the inside and outside walls o
22、f the insulated body is the difference between the mean internal temperature T iand the mean external temperature T eand shall be calculated using the equation given below. 5.2 K coefficient is the overall coefficient of heat transfer which represents the insulating capacity of the insulated body Th
23、e K coefficient is defined by the following equation: 5.3 Mean surface area (S) When determining S, the two surface areas, structural peculiarities and surface irregularities of the insulated body, e.g. chamfers, wheel-arches and similar features, shall be taken into account. If the insulated body i
24、s covered with corrugated sheet metal, the area considered shall be that of the plane surface occupied, not that of the developed corrugated surface. 5.4 Overall heat leakage (U) The mean temperature (DT m ) and thermal capacity (W) measured over the last 6 h of the steady state period shall be used
25、 to calculate the overall heat leakage. The overall heat leakage (U) shall be determined using the following equation: 5.5 Refrigerating capacity of a refrigeration unit (W o ) When attached to either a calorimeter box or the insulated body, and operating continuously, the refrigerating capacity of
26、a refrigeration unit W ois defined as: where If the enthalpy method is used, the following equation shall be used to determine the refrigerating capacity of the unit: 5.6 Coefficient of performance (COP) DT m T i = T e K W SD T m - = SS i S e () = U W DT m - = W o W j UD T m () + = U W DT m - and DT
27、 m T i T e = = W o E e E i () m 10 3 W f = COP refrigeration unit cooling capacity W o W () refrigeration unit energy consumption W W () - = Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c) BSIPAS 62:2003 4 BSI 30 July 2003 6 Temperatu
28、re measurements 6.1 Equipment The instrumentation for measuring temperature shall be protected against radiation. 6.2 Temperature measuring points 6.2.1 Parallelepipedic bodies Measure the internal temperature of the insulated body 10 cm from the body walls at the following 12 points: the eight insi
29、de corners of the body; the centres of the four inside faces having the largest area. Calculate the mean temperature (T i ) from these measurements. Measure the external temperature of the insulated body 10 cm from the body walls at the following 12 points: the eight outside corners of the body; the
30、 centres of the four outside faces having the largest area. Calculate the mean temperature (T e ) from these measurements. 6.2.2 Non-parallelepipedic bodies Measure the inside and outside temperature of the body at suitably distributed points, having regard for the shape of the body. Calculate the m
31、ean temperatures T iand T efrom these measurements. 7 Procedures for measuring K coefficient and overall heat leakage (U) of an insulated body 7.1 General The overall heat leakage (U) shall be determined in continuous operation using the internal heating method and calculated using the equation give
32、n in 5.4. NOTE The overall heat leakage can also be derived from the test to determine the K coefficient. For the K coefficient an area calculation is required, whereas this is unnecessary for determining the overall heat leakage. 7.2 Test equipment Electrical heating appliances (e.g. resistors) sha
33、ll be used, and shall be fitted with fans having a delivery rate sufficient to obtain 4070 air changes per hour related to the empty volume of the insulated body under test. The air distribution around all inside surfaces of the insulated body shall be sufficient to ensure that the maximum differenc
34、e between the temperatures of any two of the 12 points specified in 6.2 does not exceed 2 C when continuous operation has been established. The heat dissipated by the heating appliances shall not exceed a flow of 1 W/cm 2and a low emissivity casing shall protect the heating units. Testing stations s
35、hall be provided with the equipment and instruments necessary to ensure that the K coefficient or overall heat leakage (U) is determined with a maximum margin of error of 5 %. 7.3 Test conditions The empty insulated body shall be placed in a test chamber at the following conditions: a) the temperatu
36、re difference between the inside of the insulated body and the chamber shall be 25 C2 C; b) the average temperature of the walls of the insulated body shall be maintained at 20 C0. 5 C. Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c)
37、BSIPAS 62:2003 BSI 30 July 2003 5 The mean internal T iand external T etemperatures shall: 1) be measured over a steady state period of not less than 12 h, with a calculation period of at least 6 h for each; 2) not vary by more than 1.0 C during the 6 h preceding the steady state period; 3) during t
38、he steady state period, not vary by more than 0.3 C; 4) not differ by more than 0.2 C as measured at the beginning and end of the calculation period. The mean temperature values and thermal capacity measured over at least the last 6 h of the steady state period shall be used in the overall heat leak
39、age (U) calculation. 7.4 Test procedure Switch on the appliances for generating and distributing heat and for measuring the quantity of heat exchanged, and the heat equivalent of the air-circulating fans. Circulate the mass of air in the chamber such that its speed of movement 10 cm from the body wa
40、lls is maintained between 1 m/s and 2 m/s as measured using an anemometer. Measure and/or calculate the heat losses in the electrical cable between the heat input measuring instrumentation and the insulated body under test, and subtract this amount from the total heat input measured. Measure the hea
41、ting power (W) over two periods of not less than 3 h at the beginning and end of the steady state period, with these periods being separated by at least 6 h. The difference between the two measurements shall be less than 3 %. Measure the mean inside and mean outside temperatures of the body and reco
42、rd the results not less than four times per hour. 8 Procedure for measuring the effective refrigerating capacity of a refrigeration unit 8.1 General The refrigeration unit shall either be fitted to a calorimeter box or an insulated refrigerated transport body. In either case the heat leakage is meas
43、ured at a single mean wall temperature prior to the capacity test. An arithmetical correction factor, based upon the experience of the testing station, shall be made to take into account the average temperature of the walls at each thermal equilibrium during the determination of the effective refrig
44、erating capacity. It is preferable to use a calibrated calorimeter box or room to obtain maximum accuracy. It is sufficient to calculate the overall heat leakage (U) only, where U is the heat flow per degree of difference between the air temperatures inside and outside the calorimeter box or insulat
45、ed body measured with the refrigeration unit fitted. The refrigeration capacity for ATP purposes is that relating to the mean temperature at the air inlet(s) of the evaporator. 8.2 Test equipment Test equipment shall consist of a calorimeter box, calibrated calorimeter box or insulated body. NOTE 1
46、A calibrated calorimeter box should be used to obtain maximum accuracy. If a calorimeter box is used, U DT mshall not be more than 35 % of the total effective refrigeration capacity. NOTE 2 This applies only to those tests under ATP test conditions, and not to those under typical operating conditions. The calorimeter box or the insulated body shall be heavily insulated. Test stations shall be equipped with instrumentation to measure U to an accuracy of 5 %. Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 10 October 2003, Uncontrolled Copy, (c) BSI
