Warm Helium Screw Compressor Skid Assembly Redesign Venkatarao

Warm Helium Screw Compressor Skid Assembly Redesign Venkatarao Ganni Dana Arenius Kelly Dixon Thomas Jefferson National Accelerator Faciltiy Newport News, VA, USA Work Supported by DOE contract No. DE-AC 05 -06 R 23177 Cryogenics Operations 2008, CERN, Geneva, Switzerland 1 K. Dixon, 22 th-26 th September 2008

Helium Compressor Inefficiency • Cycle inefficiency » Typically 2/3 rd due to warm compressors » Inefficiency % increasing w/other refrig developments • R&D limited » Compressor manufacturers » Refrigerator manufacturers and system integrators • Skid Design » Lack of consistency » Operating experience not incorporated Cryogenics Operations 2008, CERN, Geneva, Switzerland 2 Kelly Dixon, 22 th-26 th September 2008

Energy and Material Cost Impacts • Rapidly increasing energy and material costs » JLab electrical 40% rate increase in July 08 » 75% carbon steel cost increase since January 08 » Increasing transportation, exchange rates • Skid components » » Motors Compressor housing Vessels, heat exchangers Base frame Cryogenics Operations 2008, CERN, Geneva, Switzerland 3 Kelly Dixon, 22 th-26 th September 2008

Improvement of Cost & Performance Goals • Two key base compressor manufacturers changes to take advantage of…. » Reduce external pumping • cooling and sealing with discharge pressure • Pumping only for bearings and slide valve control » Adjustable internal built-in volume ratios • Skid Design Improvement » Bulk oil separator (BOS) • Large flange and oil coalescer elimination • Size reduced with increased oil removal efficiency • Location to reduce alignment and vibration problems » Incorporate “lessons learned” for maintenance, repair, operation Cryogenics Operations 2008, CERN, Geneva, Switzerland 4 Kelly Dixon, 22 th-26 th September 2008

Improvement of Cost & Performance (cont) • Imposed Process Conditions » Ganni Cycle • Reduction in size or number of compressors needed in larger systems, smaller foot print • With higher compressor efficiency… All improvements result in increased overall system efficiency and reliability! Cryogenics Operations 2008, CERN, Geneva, Switzerland 5 Author, 22 th-26 th September 2008

NASA and JLab 12 Ge. V • Next generation compressor skid assembly design » » Jlab/NASA collaborative funding Initially supports NASA James Webb Telescope Testing JLab 12 Ge. V warm helium compressors “Best value” approach from industrial review Cryogenics Operations 2008, CERN, Geneva, Switzerland 6 Philippe Gayet, 22 th-26 th September 2008

Notable Design Features So Far • Fewer compressors required • Reduced HX size requirements • BOS design improvements » diameter reduced 50% » vertical to horizontal design with specialized internal flow distributor, 3 X’s more effective » Oil coalescer removal » Large flanges removed • Gas aftercooler oil removal(~0. 1%) Cryogenics Operations 2008, CERN, Geneva, Switzerland 7 Kelly Dixon, 22 th-26 th September 2008

Notable Design Features So Far • Coalescers moved downstream of aftercooler • Cooling oil flow adjusted with temperature • 75% reduction in pumped flow capacity requirement • Coolers, instrumentation and controls are decoupled from the skid • Easy access to all the components require maintenance Cryogenics Operations 2008, CERN, Geneva, Switzerland 8 Kelly Dixon, 22 th-26 th September 2008

Visual Comparison Existing JLab CHL Compressors Cryogenics Operations 2008, CERN, Geneva, Switzerland 9 New Compressor Assembly Philippe Gayet, 22 th-26 th September 2008

Summary • Through collaboration with NASA and industrial review, JLab is developing a new compressor skid • Short term applications will support the NASA James Webb Telescope Test Facility and the JLab 12 Ge. V upgrade • New design features from the manufacturer, the process cycle requirements, and improved oil removal design should contribute to improved performance while curbing rapidly increasing compressor skid costs Cryogenics Operations 2008, CERN, Geneva, Switzerland 10 Philippe Gayet, 22 th-26 th September 2008