The emission of man-made gases into the atmosphere has been associated with potential future adverse affects on the global climate. The industries involved in Mobile Air Conditioners are trying to reduce the over all emission of the frequently used coolant R134a or to introduce alternatives such as R152a or CO2. New methodologies for determining emission values of R134a, R152a or CO2 based upon gas analysis using Photoacoustic Spectroscopy (PAS) are being developed and tested by the industry. The Gas Monitoring Need In order to evaluate refrigerant emission from mobile A/C systems or its components such as hoses, seals, O-rings or joints, the change in concentration of refrigerant versus time is measured in a closed test chamber of known volume. Such measurements have been done by Delphi Thermal & Interior Technical Center, Lockport, NY using the Photoacoustic Multi-gas Monitor 1314 in their laboratory for measurements of R134a, R152a and Carbon Dioxide. The PAS technique provides an accurate and rapid result with a high rate of repeatability, even at very low emission rates, such as those that occur at low to moderate temperatures. Unlike the traditional gravimetric method, gas analysis using PAS technology also allows separate measurements of hose permeation and coupling emission. To Delphi, the use of Photoacoustic Spectroscopy is a valuable and timesaving alternative.
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