Cooling R&D at RWTH Aachen Lutz Feld, Michael Wlochal (RWTH Aachen University) CEC Meeting, CERN 21....
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Cooling R&D at RWTH Aachen Lutz Feld, Michael Wlochal (RWTH Aachen University) CEC Meeting, CERN 21. 4. 2009
Transcript of Cooling R&D at RWTH Aachen Lutz Feld, Michael Wlochal (RWTH Aachen University) CEC Meeting, CERN 21....
Cooling R&Dat
RWTH Aachen
Lutz Feld, Michael Wlochal(RWTH Aachen University)
CEC Meeting, CERN21. 4. 2009
Outline of R&D Program
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o 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
o properties and performance of a CO2 cooling system– design, construction and commissioning of a re-circulating CO2 cooling
test system– according to Bart Verlaat (NIKHEF), who gave a lot of advice, a
recirculating system is needed in order to achive stable operating conditions
– investigation of operating conditions and performance as a function of temperature, load, time-dependent variations etc.
– gain confidence in CO2 cooling
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3 4 5 6
7
pre-cooling
pre-coolingcooling heating
Open CO2 Cooling System: „Blow System“
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T = -40°C
Room Temperature
T = -40°CR R R
Power SupplyCO2-
Sensor
Heating
Heat Exchanger
Balance
1 2
3
4
5
6
7
50…200 W
C
O2
Rupture Disk80 bar
Vent
Bypass
Rupture Disk20 bar
Valve to keep pressure at points (3)-(6)at saturation vapour pressure at cooling temperature
Valve to controlCO2 flow rate
Rupture Disk 20 bar
insp. glass
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3 4 5 6
7
pre-cooling
pre-coolingcooling heating
CO2 Enthalpy Pressure DiagramCO2 Enthalpy Pressure Diagram: „Blow System“
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liquid + gas gas
dry ice
Enthalpy internal energy expansion work
exchanged heat at constant pressure
H U pV
H
liquid
CO2 Enthalpy Pressure DiagramCO2 Enthalpy Pressure Diagram: Re-Circulating System
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liquid
liquid + gas gas
dry ice
Enthalpy internal energy expansion work
exchanged heat at constant pressure
H U pV
H
1
2
4 564 -> 5: detector load DQ
3DQ
heat removal
design considerationso load: 500 W maximumo CO2 temperature at detector:
-45°C … +20°Co precise temperature controlo precise flow measuremento continuous operationo safe operation (100 bar max.)
chiller temperature vapour pressure evaporation temperature
Re-Circulating CO2 Cooling Test System
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1
2
3
56
4
1
2
4 56
pum
p su
b-co
oled
liqu
id
4 -> 5: detector loadDQ
3
Pre
ssur
e
Enthalpy
DQ
Chiller 2
Chiller 1
flow meter
Implementation of Re-Circulating CO2 Cooling Test System
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Components
Chiller 1: Huber Unistat 815 (1.2 kW@-60C)
Chiller 2: Huber CC-505
Expansion Vessel: Swagelok 304LHDF4-1Gal
Levelmeter: Rechner SensorsKFS-1-500-365-PEEK-VA-3/4“
Heat Exchangers: SWEP B16DWx8/1P-SC-U
Pump: GATHER 1MX-X/12-11/X-SS/S/Q/K200/HDT/DS2D50
Flow Meter: Rheonik RHM015-T2-P1-SM0-M0-G1-N
Piping, fittings etc.: Swagelok
Frame: ITEM
Temperature Probes: various
Status & Plans
o most components for re-circulating CO2 cooling test system have been delivered
o system should be operational by June
o connect to pipe with dummy loads and temperature probes
o then perform tests of the cooling system – test the system under variation of load and temperature– test reliability and failiure modes
o then perform thermal and hydraulic measurements of– pipes– interfaces– detector modules– super-modules
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Questions to be answered
About the cooling system:
o Does the system operate reliably
– over the full detector temperature range -45°C … +20°C ?
– over the full detector load range 0 W … 500 W?
o What are the time constants
– at start-up?
– when temperature is changed?
– when the load is changed?
About the detector system:
o What are the thermal / pressure gradients along straight and bent pipes of various diameters?
o Does gravity have a negative impact on the cooling system performance?
o What is the optimal (i.e. low thermal resistance and low mass) interface between a 1-2 mm diameter
cooling pipe and a detector module?
o What is the optimal contact area for a given heat load?
requires rather acurate temperature measurements and stable system behaviour21. 4. 2009 Lutz Feld (RWTH Aachen University) 9
