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Cooling R&D at RWTH Aachen. Lutz Feld, Michael Wlochal (RWTH Aachen University) CEC Meeting, CERN 21. 4. 2009. Outline of R&D Program. thermal design of SLHC tracker module and super-module thermal design design and optimization of thermal interfaces
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Cooling R&DatRWTH Aachen Lutz Feld, Michael Wlochal (RWTH Aachen University) CEC Meeting, CERN 21. 4. 2009
Outline of R&D Program • thermal design of SLHC tracker • module and super-module thermal design • design and optimization of thermal interfaces • precise measurements of thermal gradients • evaluation of new materials • specification of the lowest possible operating temperature • properties and performance of a CO2 cooling system • design, construction and commissioning of a re-circulating CO2 cooling test system • accordingto Bart Verlaat (NIKHEF), whogave a lotofadvice, a recirculatingsystemisneeded in order toachivestableoperatingconditions • investigation of operating conditions and performance as a function of temperature, load, time-dependent variations etc. • gain confidence in CO2 cooling Lutz Feld (RWTH Aachen University)
Open CO2Cooling System: „Blow System“ RoomTemperature Vent 7 Valvetokeeppressureatpoints (3)-(6) atsaturationvapourpressureatcoolingtemperature 6 pre-cooling Rupture Disk 20 bar Heating 2 1 T = -40°C T = -40°C Rupture Disk 80 bar 4 HeatExchanger 5 3 cooling pre-cooling heating 3 4 5 6 R R R 1 2 Bypass insp. glass Valvetocontrol CO2flow rate CO2 Rupture Disk 20 bar Power Supply CO2-Sensor 50…200 W Balance 7 Lutz Feld (RWTH Aachen University)
CO2EnthalpyPressureDiagram: „Blow System“ CO2EnthalpyPressureDiagram liquid pre-cooling 2 1 liquid + gas gas cooling pre-cooling heating 3 4 5 6 dry ice 7 Lutz Feld (RWTH Aachen University)
CO2EnthalpyPressureDiagram: Re-Circulating System CO2EnthalpyPressureDiagram liquid DQ 2 3 liquid + gas gas DQ 4 -> 5: detectorload 1 4 6 5 dry ice Lutz Feld (RWTH Aachen University)
Re-Circulating CO2Cooling Test System design considerations • load: 500 W maximum • CO2temperatureatdetector:-45°C … +20°C • precisetemperaturecontrol • preciseflowmeasurement • continuousoperation • safeoperation (100 bar max.) chillertemperature vapourpressure evaporationtemperature Chiller 2 heatremoval 6 5 Chiller 1 DQ 3 4 2 3 1 Pressure DQ flowmeter pump sub-cooled liquid 4 -> 5: detectorload 1 4 6 5 2 Enthalpy Lutz Feld (RWTH Aachen University)
Implementationof Re-Circulating CO2Cooling Test System Components Chiller 1: Huber Unistat 815 (1.2 kW@-60C) Chiller 2: Huber CC-505 Expansion Vessel: Swagelok304LHDF4-1Gal Levelmeter: Rechner SensorsKFS-1-500-365-PEEK-VA-3/4“ HeatExchangers: SWEP B16DWx8/1P-SC-U Pump: GATHER 1MX-X/12-11/X-SS/S/Q/K200/HDT/DS2D50 Flow Meter: RheonikRHM015-T2-P1-SM0-M0-G1-N Piping, fittings etc.: Swagelok Frame: ITEM TemperatureProbes: various Lutz Feld (RWTH Aachen University)
Status & Plans • mostcomponentsforre-circulating CO2 cooling test system havebeendelivered • systemshouldbe operational by June • connecttopipewithdummyloadsandtemperatureprobes • thenperformtestsofthecoolingsystem • testthesystemundervariationofloadandtemperature • testreliabilityandfailiuremodes • thenperform thermal andhydraulicmeasurementsof • pipes • interfaces • detectormodules • super-modules Lutz Feld (RWTH Aachen University)
Questionstobeanswered Aboutthecoolingsystem: • Doesthesystemoperatereliably • overthefulldetectortemperaturerange -45°C … +20°C ? • overthefulldetectorloadrange 0 W … 500 W? • Whatarethe time constants • atstart-up? • whentemperatureischanged? • whentheloadischanged? Aboutthedetectorsystem: • Whatarethe thermal / pressuregradientsalongstraightandbentpipesofvariousdiameters? • Doesgravityhave a negative impact on thecoolingsystemperformance? • Whatisthe optimal (i.e. low thermal resistanceandlowmass) interfacebetween a 1-2 mm diametercoolingpipeand a detectormodule? • Whatisthe optimal contactareafor a givenheatload? requiresratheracuratetemperaturemeasurementsandstablesystembehaviour Lutz Feld (RWTH Aachen University)