ANNEX IISupplementary provisions
ANNEX II TECHNICAL PROVISIONS FOR THE DETERMINATION OF LEAKAGES FROM AIR-CONDITIONING SYSTEMS 1. INTRODUCTION This annex applies to vehicles with an air-conditioning system (AC) designed to contain fluorinated greenhouse gases with a global warming potential higher than 150, in order to evaluate the release to the atmosphere of refrigerant fluid. Topics addressed in this Annex include: 1. Equipment requirements 2. Test conditions 3. Test procedure and data requirements 2. DESCRIPTION OF TEST 2.1. The air-conditioning leakage test is designed to determine the amount of hydro-fluoro-carbons (HFC-134a) released to the atmosphere from vehicles fitted with an air-conditioning system, as a consequence of the normal operation of such a system. 2.2. The test can be undertaken on the whole vehicle, on the air-conditioning system or on individual leak components. 2.3. Leak components need to be tested without additional oil involved. Residual oil from the manufacturing process can stay in. Compressors use standard charge of oil. 2.4. The individual components boundaries have to be within a metal tube area. The boundary sections have to be sealed tightly by welding or brazing. One of the components boundaries may, if appropriate, be connected to a suitable volume metal container holding the two-phase refrigerant. 2.5. The HFC-134a container and leak component has to be filled with two-phase (liquid and vapour) refrigerant HFC-134a to maintain constant pressure at the required temperature level by heating means. The leak component under pre-conditioning or under test is installed in the sealed enclosure. The temperature of the component is maintained at the requested preconditioning or testing temperature in order to have only the vapour phase of HFC-134a inside the component. For complete air-conditioning systems the actual nominal charge has to be used. The manufacturer recommended oil concentration and type should be used. 2.6. Every leak component of the air-conditioning system shall be submitted to a test except those considered as leak free. 2.6.1. The following components are considered leak free: — Evaporator without connections — Metallic tubes without connections — Condenser without serviceable integrated dryer without connections — Receiver/dryer without connections — Accumulator without connections. 2.7. The worst case sample of a leak component or an air-conditioning system shall be chosen for testing. 2.8. Mass leakage of refrigerant fluid from any leak component is added up to provide an overall result for the test. 3. TEST EQUIPMENT The test has to be undertaken in a sealed enclosure including an equipment to ensure a homogeneous concentration of gas and the use of a gas analysis method. All the equipment used during the test shall be calibrated with relation to reference equipment. 3.1. Measurement enclosure 3.1.1. For the pre-conditioning phase, the temperature conditioning system must be capable of controlling the internal air temperature throughout the duration of this phase, with a tolerance of ± 3 K. 3.1.2. For the measurement phase, the leakage measurement enclosure must be a sealed gas-tight measurement enclosure able to contain the system, component under test. The enclosure when sealed must be gas tight in accordance with the Appendix. The inner surface of the enclosure must be impermeable and non-reactive to the air-conditioning refrigerant fluid. The temperature conditioning system must be capable of controlling the internal enclosure air temperature throughout the test, with an average tolerance of ± 1 K over the duration of the test. 3.1.3. The measurement enclosure must be constructed with rigid panels that maintain a fixed enclosure volume. 3.1.4. The inner size of the measurement enclosure shall be appropriate to contain the components or systems to be tested with the required accuracy. 3.1.5. Gas and temperature homogeneity inside the measurement enclosure shall be ensured by mean of at least one recirculation fan or an alternative method that can be demonstrated to provide homogeneous temperature and gas concentration. 3.2. Measuring equipment 3.2.1. The amount of HFC-134a released shall be measured by means of gas chromatography, infrared spectro-photometry, mass spectrometry, infrared photo-acoustic spectroscopy (see the Appendix). 3.2.2. If the used technique is not one of the mentioned before, equivalency shall have to be demonstrated and the equipment has to be calibrated with a procedure similar as described in the Appendix. 3.2.3. The target accuracy of the measuring equipment for the total air-conditioning system is established in ± 2 g/year. 3.2.4. Equipment for gas analysis, combined with any other equipment, which allows an accuracy down to 0,2 grams/year shall be used for any component test. 3.2.5. For components where it is very difficult to achieve the above mentioned accuracy the number of samples in each test can be increased. 3.2.6. The repeatability of the analyser expressed as one standard deviation must be better than 1 % of full scale deflection at zero and at 80 % ± 20 % of full scale on all ranges used. 3.2.7. The zero and span of the gas analyser must be calibrated before any test according to manufacturer instructions. 3.2.8. The operational ranges of the analyser must be chosen to give best resolution over the measurement, calibration and leak checking procedures. 3.3. Gas analyser data recording system 3.3.1. The gas analyser must be fitted with a device to record electrical signal output either by strip chart recorder or other data processing system at a frequency of at least once per 60 minutes. The recording system must have operating characteristics at least equivalent to the signal being recorded and must provide a permanent record of results. The record must show a positive indication of the beginning and end of the test (including beginning and end of sampling periods along with the time elapsed between start and completion of each test). 3.4. Additional equipment 3.4.1. Temperature recording 3.4.1.1. The temperature in the measurement enclosure is recorded at one or two points by temperature sensors which are connected so as to show a mean value. The measuring points shall be representative of the temperature inside the measurement enclosure. 3.4.1.2. Temperatures must, throughout the HFC-134a leakage measurements, be recorded or entered into a data processing system having a frequency of at least once per minute. 3.4.1.3. The accuracy of the temperature recording system must be within ± 1,0 K. 3.4.2. Pressure measuring device 3.4.2.1. The accuracy of the pressure recording system for P shed must be within ± 2 hPa and the pressure must be capable of being resolved to ± 0,2 hPa. 3.4.3. Fans 3.4.3.1. By the use of one or more fans, blowers or other appropriate method, like N 2 flush, it must be possible to reduce the HFC-134a concentration in the measurement enclosure to the ambient level. 3.4.3.2. The leak component or system to be tested in the enclosure must not be subjected to a direct stream of air from the fans or blowers when used. 3.4.4. Gases 3.4.4.1. Where specified by the supplier of the gas analyser, the following gases must be available for calibration and operation: — purified synthetic air with an oxygen content between 18 % and 21 % by volume, — HFC-134a, 99,5 % minimum purity, 3.4.4.2. Calibration and span gases must be available containing mixtures of HFC-134a and purified synthetic air or any other suitable inert gas. The true concentrations of a calibration gas must be within ± 2 % of stated figures. 4. PRECONDITIONING 4.1. General requirement 4.1.1. Before preconditioning and leakage measurement is performed, the air-conditioning system is to be evacuated and charged with the specified nominal charge of HFC-134a. 4.1.2. In order to ensure saturated conditions during the whole duration of the test, including preconditioning phase, each ‘leak’ component, with or without additional container, is to be evacuated and charged with sufficient amount of HFC-134a but not exceeding 0,65 g/cm 3 of the total inner volume of the leak component or container. 4.2. Preconditioning conditions 4.2.1. The applicant for approval may choose to conduct preconditioning either in a single step at 40 °C or in a two step approach of shorter total duration. The two step approach shall involve two sequential stages, the first at 50 °C immediately followed by the second at 40 °C. The duration of preconditioning shall be as shown below. Option 1 Option 2 System part 40 °C Time [h] Step 1 — 50 °C Time [h] Step 2 — 40 °C Time [h] Complete system 480 240 24 Compressor 144 72 24 Hose assemblies 480 240 24 All other leak parts 96 48 24 Shorter preconditioning times can be used if it can be demonstrated the steady state (constant loss rate) regarding permeation losses has been reached. 4.2.2. After preconditioning, the leak components or system have to be placed in the measurement enclosure for the leak test within four hours. 4.3. Compressor 4.3.1. When necessary for lubrication and seal running-in, compressor may be run in between preconditioning and test during a minimum period of 1 min at minimum speed of 200 rpm. 4.3.2. The HFC-134a charge in the leak component or air-conditioning system has to be kept intact between preconditioning and measurement in order not to loose the preconditioning effect. This means that the same configuration has to be submitted to both preconditioning and measurement without disassembling and re-assembling in between. 5. TEST SEQUENCE 5.1. General requirements The test sequence, in figure I , shows the steps to be followed during the development of the test. 5.2. Leakage test 5.2.1. The test is to be undertaken at static and steady state conditions at the temperature of 313 K (40 °C). Differences in HFC-134a concentration over the test time is used to calculate annual losses. 5.2.2. The measurement enclosure must be purged for several minutes until a stable background is obtained. 5.2.3. Prior to the test the background level in the measurement enclosure must be measured and the gas analyzer zeroed and spanned. 5.2.4. In case the configuration is moved from the preconditioning to a different measurement chamber, the start of the measuring period shall be not earlier than four hours after the measurement enclosure is closed, sealed and test temperature set. 5.2.5. The leak component or system is then introduced in the measurement enclosure. 5.2.6. The measurement enclosure is closed and sealed gas-tight. The test chamber has to be completely filled at atmospheric pressure with a reference gas (e.g. clean air). Figure I Configuration of the leak components or system Evacuate and charge with the specified amount of HFC-134a Preconditioning phase Close and seal the chamber, if appropriate, clean the measurement enclosure with purge gas and fill it with reference gas (clean air or suitable inert gas). Set test temperature at 40 °C 4 hours Initial measurement of HFC-134a in the measurement enclosure 24 hours Final measurement of HFC-134a in the measurement enclosure Calculation of leakage (L) 5.2.7. The test period begins when the measurement enclosure is sealed and the temperature in the measurement enclosure reaches 313 K (40 °C). The temperature is maintained at that value until the end of the testing period. The HFC-134a concentration, temperature and barometric pressure are measured to give the initial readings C HFC-134ai ; P shed and T shed for the testing period but not earlier than four hours after closing the measurement enclosure and setting the test temperature as specified in section 5.2.4. These values are used in the leakage calculation according to section 5.3. 5.2.8. The nominal measurement period shall be 24 hours. A shorter period is allowed provided that sufficient accuracy can be demonstrated. 5.2.9. The gas analyser must be zeroed and spanned immediately after the end of the testing period. 5.2.10. At the end of the testing period the HFC-134a concentration, temperature and barometric pressure in the measurement enclosure must be measured. These are the final readings C HFC-134af , P shed and T shed for the leakage calculation according to section 5.3. 5.3. Calculation 5.3.1. The test described in section 5.2 allows the HFC-134a emissions to be calculated. Leakage is calculated using the initial and final HFC-134a concentrations, temperatures and pressures in the enclosure, together with the net measurement enclosure volume. The total Leakage-Mass HFC-134a is calculated by means of the following formula: where: HFC-134a = Leak flow rate of HFC-134a [kg/s] n HFC-134a = Number of moles of HFC-134a [mol] V shed = SHED-chamber net volume [m 3 ] V AC = Gross volume of the air-conditioning system or component [m 3 ] T shed = Temperature in the SHED [K] P shed = Pressure in the SHED [kPa] C HFC-134ae = HFC-134a final concentration [ppm v ] C HFC-134ai = HFC-134a initial concentration [ppm v ] t e = Final time [s] t i = Initial time [s] M HFC-134a = Molar mass of HFC-134a(=102 kg/kmol) [kg/kmol] R = Gas constant(= 8,314 kJ/(kmol*K)) [kJ/(kmol*K)] NB: C HFC-134a is defined as the number of moles of HFC-134a (n HFC-134a ) per mole of air (n air+HFC-134a ) ppm v : parts per million volume/volume equivalent to mol/mol. 5.3.2. The mass in grams, obtained as a function of the time, shall be transformed to grams/year (g/y). 5.4. Overall results of test The total leakage for the complete air-conditioning system is calculated by adding the partial values for any of the leak component tested. 1. System testing AC Leakage, L(g/y) = CF * HFC-134a (g/y) 2. Component testing AC Leakage, L(g/y) = CF * Σ HFC-134a (g/y) where CF (Correlation Factor) = 0,277. 6. APPROVAL 1. The tested air-conditioning system shall be approved if the value L (g/y) is lower than the values expressed in the next table, according to Directive 2006/40/EC: L (g/y) AC Refrigerant 40/60 ( *1 ) HFC-134a 2. The leak component shall be approved if it has been tested in accordance with the requirements of Sections 2 to 5.3. ( *1 ) In case of dual evaporation system.