1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication ma
3、y be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA)
4、Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgJ2765 OCT2008 SURFACEVEHICLESTANDARDIssued 2008-10Procedure for Measuring System COP Coefficient of Performance of aMobile Air Conditioning System on a Test Bench RATIONALEThe impact of mobile air conditioning systems
5、on the environment is becoming more important. Fuel used to power the system impacts both fuel economy of the vehicle and tail pipe emissions of carbon dioxide. 1. SCOPE 1.1 This Standard applies to motor driven mobile air conditioning systems consisting of one in-car air coil (evaporator), a compre
6、ssor, an expansion device, and one under-hood air coil (condenser).1.1.1 This standard can also be used for measuring systems that use electrically driven compressor if measurement of input power to compressor is carefully considered. 1.1.2 This standard can also be used for measuring systems that i
7、nclude the entire air handling system if air side pressure drop for the entire vehicle system is carefully considered. 1.1.3 This standard can also be used for measuring systems that include the entire front end cooling module if air side pressure drop for the entire vehicle system is carefully cons
8、idered. 1.1.4 This standard can also be used for measuring systems that include a secondary cooling loop if the power to drive the pumps in this system is carefully considered. 1.2 This Standard specifies procedures, apparatus, and instrumentation that will produce accurate steady state capacity and
9、 efficiency data for refrigerant components. 1.3 This Standard does not: 1.3.1 Specify tests for dual evaporator systems, 1.3.2 Specify transient test methods, 1.3.3 Make recommendations for safety 1.3.4 Specify tests for production, specification compliance, or field testing of mobile air condition
10、ing systems.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2765 Issued OCT2008 - 2 -1.4 Purpose 1.4.1 This Standard provides a method of testing the capacity (performance) and efficiency (COP)
11、of mobile air conditioning refrigerant systems under steady state conditions. 1.4.2 The procedure proposed is designed to give maximum repeatability and minimum error in determining cooling capacity (Q) and efficiency (COP Coefficient of Performance) of the refrigeration system of the mobile air con
12、ditioner. For that reason a “breadboard” type facility is proposed in which components are assembled into a system and exposed to operating conditions in individual, separately controlled chambers. The facility should allow for three methods to determine system performance: refrigerant side, airside
13、, and calorimetric chambers. Each side yields its own energy balance calculation to find the capacity of the system. With the three methods used, instead of two as typically required, redundancy will be maintained even when the evaporator refrigerant exit is two phase. In this case only the airside
14、and chamber balances are available. The design should be made so that two independent methods could provide agreement of less than 4.0% between two independent balances.2. REFERENCES 2.1 Applicable Publications The following publications form a part of this specification to the extent specified here
15、in. Unless otherwise indicated, the latest version of publications shall apply. 2.1.1 ASHRAE Publications Available from American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle, N.E., Atlanta, GA 30329-2305, Tel: 404-636-8400, www.ashrae.org.1ANSI/ASHRAE S
16、tandard 41.1-1986 (RA 2001) Standard Method for Temperature Measurement 2ANSI/ASHRAE Standard 41.6-1994 (RA 2001) Standard Method for Measurement of Moist Air Properties 3ASHRAE Standard 41.3-1989 Standard Method for Pressure Measurement 6ASHRAE Standard 41.2-1987 (RA 92) Standard Methods for Labora
17、tory Airflow Measurement 7ANSI/ASHRAE Standard 51-1999 Laboratory Methods of Testing Fans for Aerodynamic Performance Rating (AMCA Standard 210-99) 8ANSI/ASHRAE Standard 37-2005 Methods of Testing for Rating Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment 9ANSI/ASHRAE Standard 4
18、1.4-1996 Standard Method for Measurement of Proportion of Lubricant in Liquid Refrigerant 2.1.2 ASME Publication Available from American Society of Mechanical Engineers, 22 Law Drive, P.O. Box 2900, Fairfield, NJ 07007-2900, Tel: 973-882-1170, www.asme.org.4Fluid MetersTheir Theory and Application,
19、Sixth Edition, 1971 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2765 Issued OCT2008 - 3 -2.1.3 ARI Publication Available from Air-Conditioning and Refrigeration Institute, 4100 North Fairfax
20、 Drive, Suite 200, Arlington, VA 22203, Tel: 703-524-8800, www.ari.org.5ARI Standard 700-2004 Specifications for Fluorocarbon Refrigerants 2.1.4 NIST Publication Available from National Institute of Standards and Technology, 100 Bureau Drive, Stop 1070, Gaithersburg, MD 20899-1070, Tel: 301-975-6478
21、, www.nist.gov.10NIST Standard Reference Database 23 NIST Thermodynamic and Transport Properties of Refrigerants and Refrigerants and Refrigerant MixturesREFPROP 6 3. DEFINITIONS 3.1 Air, Standard Dry air having a mass density of 1.204 kg/m3(0.075 lb/ft3).3.2 Apparatus As used in this standard, this
22、 term refers exclusively to test room facilities and instrumentation. 3.3 Capacity, Total Cooling The rate, expressed in watts (Btu/hr), at which the equipment removes heat from the air passing through it under specified conditions of operation. 3.4 COP, Coefficient of Performance A measure of the e
23、fficiency of an air conditioning system is defined as the average heat removed through the evaporator divided by the average work input to the compressor. Averaging is done using the balances available and/or as described in 7.4.1. This COP is the highest possible because it does not account for air
24、 movement, heat transmission or other losses of similar nature. 3.4.1 Adjustments to this calculation may be necessary for electrically driven compressors, in case the air handling system is used, in the case of front end cooling module is used, and for secondary cooling loop systems. 3.5 Equipment
25、As used in this standard, this term refers exclusively to the mobile air conditioning equipment to be tested. 3.6 Pressure, Standard Barometric 101.325 kPa (14.696 psi). 3.7 Refrigerant A refrigerant that changes from the liquid to the vapor state in the process of absorbing heat. 3.8 Shall or Shall
26、 Not Is used to indicate a provision that is mandatory if compliance with the standard is claimed. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2765 Issued OCT2008 - 4 -3.9 Should, Recommende
27、d or It Is Recommended Is used to indicate provisions which are not mandatory but which are desirable as good practice. 4. INSTRUMENTATION 4.1 Temperature Measuring Instruments 4.1.1 All temperature measurements (with the exception of dew point temperature) shall be made in accordance with ANSI/ASHR
28、AE Standard 41.1-1986 (RA 2001).14.1.2 If used in determining the water vapor content of the air, dew point hygrometers shall be applied as specified in ANSI/ASHRAE Standard 41.6-1994 (RA 2001)2and shall be accurate to within 0.2 C (0.4 F).4.1.3 Inlet air temperature measurements are to be taken ups
29、tream of static pressure taps on the inlet duct (if installed). Outlet air temperature measurements shall be taken downstream of the static pressure taps on the outlet. Very often the best practice is to take temperature immediately downstream of the nozzle throat. 4.2 Pressure Measuring Instruments
30、 4.2.1 Pressure measurements shall be made with any device meeting the requirements of ASHRAE 41.3-1989.34.2.2 The accuracy of pressure measuring instruments shall permit measurement to within 2.5% of the reading.4.3 Air Differential Pressure and Airflow Measurements44.3.1 The static pressure differ
31、ence across nozzles and velocity pressures at nozzle throats shall be measured with manometers or electronic pressure transducers that have been calibrated against a pressure standard to within 1.0% of the reading. The resolution of the device shall be equal to or less than 2.0% of the reading.4.3.2
32、 Areas of nozzles shall be determined by measuring their diameters to within 0.20% in four places approximately equally spaced around the nozzle in each of two planes through the nozzle throat, one at the outlet and the other in the straight section near the radius. 4.4 Electrical Instruments 4.4.1
33、Electrical measurements shall be made with indicating or integrating instruments.4.4.2 Instruments used for measuring the electrical power input to fan motors or other equipment accessories shall be accurate to within 2.0% of the reading.4.4.3 Voltages shall be measured at the equipment terminals. I
34、nstruments used for measuring voltage shall be accurate to within 1.0% of the reading.4.5 Refrigerant Flow Measurement 4.5.1 Refrigerant flow shall be measured with an integrating flow measuring system that is accurate to within 1.0% of the reading 4.6 Condensate Quantity Measurement 4.6.1 Condensat
35、e collection rates shall be determined using a liquid quantity meter that is accurate to within 1.0% of the reading or other method that provides the same accuracy. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license
36、 from IHS-,-,-SAE J2765 Issued OCT2008 - 5 -4.7 Speed Measuring Instruments 4.7.1 Speed measurements shall be made with a revolution counter, tachometer, stroboscope, or oscilloscope that is accurate to within 1.0% of the reading.4.8 Time and Mass Measurements 4.8.1 Time interval measurements shall
37、be made with an instrument that is accurate to within 0.2% of reading. 4.8.2 Mass Measurement shall be made with an apparatus that is accurate to within 1.0% of reading.4.9 Torque Measurements 4.9.1 Torque measurements shall be made with an instrument that is accurate to within 2.0% of reading.4.10
38、Refrigerant mass composition measurements for refrigerant mixtures shall be made using an instrument that is in accordance with ARI Standard 700-2004.55. TEST FACILITY AND MEASURING APPARATUS 5.1 Test Facility (Figure 1) Recommended configurations for the test facility are provided below. In all cas
39、es, suitable means for determining the dry-bulb temperature and water vapor content of the air entering and leaving the heat exchangers shall be provided.FIGURE 1 - SAMPLE TEST FACILITY Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking perm
40、itted without license from IHS-,-,-SAE J2765 Issued OCT2008 - 6 -5.2 Test Room Requirements 5.2.1 Typically, two test rooms are required; an in car room and an under-hood room. If desired, a third room may be used for the compressor to simulate under-hood conditions. That room can be located either
41、outside or in the under-hood room.5.2.2 An in car condition test room is required. This may be any room or space in which the desired test conditions can be maintained within the tolerances given in Table 1.5.2.3 An under-hood test room is required. This may be any room or space in which the desired
42、 test conditions can be maintained within the tolerances given in Table 1. A condenser wind tunnel may be substituted for the under-hood test room provided it is capable of maintaining the conditions given in Table 1.TABLE 1 - PERMISSIBLE VARIATIONS IN TEST CONDITIONS Controlled Test Parameter Opera
43、ting Tolerance(1) Condition Tolerance(2) Evaporator inlet air dry-bulb temperature (C) 0.5 0.3Evaporator inlet air humidity (%) 3 1Evaporator air flow rate (kg/min) 0.3 0.1Targeted air temp. downstream of evaporator (C) 0.5 0.3Condenser inlet air dry-bulb temperature (C) 0.5 0.3Condenser face air ve
44、locity (m/s) 0.18 0.06Compressor speed (rpm) 2 11. Operating Tolerance is the maximum permissible range of any measurement. 2. Condition Tolerance is the maximum permissible variation of the average value of the measurement from the specified test condition.5.3 Wind Tunnels for Heat Exchangers 5.3.1
45、 To produce repeatable and comparable results, it is recommended to control the inlet air temperature and velocity profile across the face of the test heat exchangers. 5.3.2 Below is an example of one setup that has been used to accomplish this end. 5.3.2.1 Each test heat exchanger shall be mounted
46、in a wind tunnel inside their respective test room. The wind tunnel may be constructed from any suitable duct material. The illustration of a duct sections for the test heat exchanger in a wind tunnel are shown in Figure 2. 5.3.2.2 Air enters over the flow straightener (1) and inlet thermocouple gri
47、d (2) to the test heat exchanger (evaporator, condenser, or gas cooler). At the exit of the test heat exchanger is the outlet thermocouple grid (3) before the flow measuring devices nozzles (4). After the nozzles, average air stream temperature is measured by a thermocouple or other appropriate ther
48、mometer (5). Reconditioning of the air (cooling or heating) is done in the conditioning test facility heat exchanger (6). For control purposes, an electrical heater is recommended. The test facility Blower (7) provides air circulation for the test heat exchanger. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2765 Issued OCT2008 - 7 -FIGURE 2 - POSSIBLE AIR LOOP 5.4 Airflow Measuring Apparatus 5.4.1 A suitable means of measuring heat ex
