CONTACT:   Michael Rubin
GIBBS & SOELL, INC.
(212) 697-2600
or
CARRIER CORPORATION
(315) 432-3147
Speaking here at the International Conference on Climate Change, Jim Parsnow, Carrier director of environmental systems marketing, said, "While direct emissions of all refrigerants account for less than one percent of direct global warming potential, they are nonetheless a factor in GWP measurement. Improved containment can eliminate refrigerants as a GWP factor in direct emissions."
Carrier's approach, called Containment Plus, incorporates many design revisions in its positive pressure chillers -- including its Evergreen centrifugal models, which use chlorine-free HFC-134a refrigerant -- in order to attain virtual total containment at all times.
"Carrier eliminated gaskets and pipe joints where possible in favor of O-rings and O-ring type fittings," said Parsnow. He listed other refrigerant containment features, including: reseatable ASME-certified relief valves, isolation valves rather than plugs on the drain connections, and the elimination of the need for a purge system.
Carrier positive pressure chillers also feature oil heater and recovery systems to manage the oil/refrigerant mixture, and isolation valves on the oil filter to facilitate separation of the oil circuit from the refrigerant during filter changes.
"By making these design revisions," Parsnow said, "Carrier is able to reduce and quantify leak rates. For example, our Evergreen centrifugal chiller, up through 1,500 tons, has an allowable design leak rate for each joint no greater than 0.5 oz. per joint per year."
The Evergreen chiller has 62 external refrigerant joints, so the emission rate is as follows:
62 joints x 0.5 oz./joint/yr = 31 oz. (1.94 lb)/yr
1.94 lb divided by total refrigerant charge of 1,850 lbs = 0.1 percent
Parsnow noted that Carrier's large open drive Model 19EX, with a capacity up to 2,200 tons, has an even lower design emissions rate: 0.05 percent.
Chiller construction and service are also important aspects of Carrier's approach to chiller refrigerant containment. Carrier maintains the integrity of its chiller designs by constructing the chillers to ASME pressure vessel certification. All metal, fittings and components comply with the stringent requirements of the ASME Unfired Pressure Vessels Section VIII construction code.
Carrier leak-checks the entire unit, not just the pressure vessels but also with compressor components mounted, at levels ranging from 225 psig to 300 psig depending on the model (HFC-134a designs). An independent inspector verifies all welding procedures and each weld joint through final testing. In addition, Carrier's Syracuse, N.Y., manufacturing operation, where centrifugal and screw chillers are made, complies with ISO 9001.
Emphasizing the importance of service practice to Carrier's Containment Plus approach, Parsnow said, "refrigerant lost during service has been significantly reduced to less than 0.5 percent per full maintenance operation, which is typically performed every three years."
During maintenance, he said, "oil and refrigerant mixtures are handled using improved oil management features and isolation valves. Carrier's chiller product line up through 2,200 tons features built-in storage capability and isolation valves so the refrigerant never leaves the chiller during service."
Carrier Corporation is the world's largest manufacturer of heating and air conditioning systems and equipment. It is a subsidiary of United Technologies Corporation, provider of a broad range of high-technology products and support services to the aerospace, building systems and automotive industries.
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