Summary of thermal manage ment meeting Summary of thermal management Summary of thermal management working group meeting, working group meeting, December 6 December 6 Presentations Presentations • Introduction (G. Viehhauser, Oxford) • Reutilisation of present tubing plant (G.V.) • Status reports for different coolants: – Light fluorocarbons (G. Hallewell, CPP Marseille) – CO 2 (A. Colijn, NIKHEF) • Flow control with thermostatic expansion valves (N. Hessey, FOM/NIKHEF) • Recent experience from cooling system commissioning (R. Bates, Glasgow) • From current cooling installation to future CS upgrade for ATLAS ID (V. Vacek, CTU, Prague) • Thermal Management Issues for Stave Structures (C. Haber, LBNL)
Transcript
Summary of thermal management meeting
Summary of thermal managementSummary of thermal management working group meeting, December 6 working group meeting, December 6
PresentationsPresentations• Introduction (G. Viehhauser, Oxford)
• Reutilisation of present tubing plant (G.V.)
• Status reports for different coolants:– Light fluorocarbons (G. Hallewell, CPP Marseille)
– CO2 (A. Colijn, NIKHEF)
• Flow control with thermostatic expansion valves (N. Hessey, FOM/NIKHEF)
• Recent experience from cooling system commissioning (R. Bates, Glasgow)
• From current cooling installation to future CS upgrade for ATLAS ID (V. Vacek, CTU, Prague)
• Thermal Management Issues for Stave Structures (C. Haber, LBNL)
Summary of thermal management meeting
MEANS COOLANTS
Summary of thermal management meeting
Issues: Try to use as much of the existing pipework as possible (mainly the tubing through the magnet to the ID volume) External components on access platforms and in USA15
can be considered less static:
Much hinges on delivery and evaporation pressure of final coolant, impedance to evacuate vapour,
critical temperature of chosen fluid
Summary of thermal management meeting
Operating temperature of silicon detectors
Can we estimate a Si operation temperature for sufficient safety margin @ L>>1034?
From Nobu Unno’s September 6th talk: -30°C on SCT Sensors, requiring (my guess) ~-45C evaporation
in on-detector cooling channels
15°C (Si – coolant) T Reasonable? Conservative?...
Summary of thermal management meeting
Power dissipation of silicon detectorelectronics
No estimate given (anywhere in this conference)of dissipation of electronics
(Given the much higher activity within the electronics+ reduced radius (1/r2) of new B layer, extra track /
background activity at luminosities ~ 1035
Summary of thermal management meeting
The fluids…Two (maybe 3) candidate fluids: C2F6, CO2 & (maybe still) C3F8
A few pros and cons:C2F6: Enthalpy ~ 100J/g, Pevap~ 4 bara @ -45°C, Tcrit ~ 20°C
Liquid delivery pressure in warm zones ≥ 30 bar
CO2: Enthalpy ~ 280J/g Pevap ~ 7 bara @ -45°C, Tcrit ~ 30°CHigher evaporation pressure higher HTCTriple point temperature ~ -56°C (dry ice formation) Liquid delivery pressure in warm zones ≥ 70 bar
Problems with the present CProblems with the present C33FF8 8 systemsystem(Which might require ‘external’ intervention)(Which might require ‘external’ intervention)
(1) Back-pressure regulators contribute substantial (& variable) insertion loss (CV variability) being mastered…;
(2) Significant insertion loss in deeply embedded hex’s, heaters;
(3) Very high compression ratio xacross compressors due to the very high choice of condenser pressure;
(1), (2) & (3) conspire to put the compressor in a regime of reduced throughput (pumping speed) and hotter operation
Cooling circuits have little margin for reducing Si temperature. Cooling circuits have little margin for reducing Si temperature. Also compressor cooling less efficient: Also compressor cooling less efficient:
(reduced flow of cooling gas) (reduced flow of cooling gas) expect a reduced MTBF? expect a reduced MTBF?
Summary of thermal management meeting
HEX DCSDetector DCSDet. environmental DCS
Heaters DCS
Off-detector layout, inc DCS
Summary of thermal management meeting
ATLAS pit(d ~ 92m)
ATLAS Surface Buildings
USA15
Remote Control Pressure regulatorsPin ~ 14bar
(flow proportional to heat load)
Compressors
Condensers operatingWith lower input pressure
than in USA15 location
Tracker
Examplegh(liquid)bar(C3F)
Example:gh(vapour)m
bar(C3F)
Toward a simplified circulator with reduced compressor stress(and enhanced compressor M.T.B.F.)
Tubing to be sizedfor dynamic P
Summary of thermal management meeting
There is yet space!
Summary of thermal management meeting
A ‘graded external fix’ approach to A ‘graded external fix’ approach to problems with the present Cproblems with the present C33FF8 8 systemsystem
(Integrable steps in the cooling system for the tracker upgrade)(Integrable steps in the cooling system for the tracker upgrade)
use compressor aspiration tank pressures (by varying compressor speed using motor speed controller) to control evaporation pressure in pixel and SCT circuits
Moduarity issues?Moduarity issues?
Summary of thermal management meeting
A ‘graded external fix’ approach to A ‘graded external fix’ approach to problems with the present Cproblems with the present C33FF8 8 systemsystem
IF APPROACH (1) DOES NOT SUFFICIENTLY INCREASEIF APPROACH (1) DOES NOT SUFFICIENTLY INCREASESi DETECTOR OPERATING TEMPERATURE MARGIN…Si DETECTOR OPERATING TEMPERATURE MARGIN…
APPROACH (2) Install ‘local’ (COLD C) condensers (service platforms) Condenser cooled either using LN2 /Gfrom liquid argon calorimeter cooling loops or a compressor system (R404A?)
How to circulate CHow to circulate C33FF88 primary coolant back to capillaries?: primary coolant back to capillaries?:
(2-i) Using liquid pumps (hydraulic or pneumatic drive for B field)(2-i) Using liquid pumps (hydraulic or pneumatic drive for B field)
(2-ii) Using 2(2-ii) Using 2ndnd (external) evaporator (external) evaporator & existing Haug Compressors in USA15& existing Haug Compressors in USA15
Summary of thermal management meeting
A ‘graded external fix’ approach to A ‘graded external fix’ approach to problems with the present Cproblems with the present C33FF8 8 systemsystem
IF APPROACH (1) DOES NOT SUFFICIENTLY INCREASEIF APPROACH (1) DOES NOT SUFFICIENTLY INCREASESi DETECTOR OPERATING TEMPERATURE MARGIN…Si DETECTOR OPERATING TEMPERATURE MARGIN…
APPROACH (2) Install ‘local’ (COLD C) condensers (service platforms) Condenser cooled either using LN2 /Gfrom liquid argon calorimeter cooling loops or a compressor system (R404A?)
How to circulate CHow to circulate C33FF88 primary coolant back to capillaries?: primary coolant back to capillaries?:
(2-i) Using liquid pumps (hydraulic or pneumatic drive for B field)(2-i) Using liquid pumps (hydraulic or pneumatic drive for B field)
(2-ii) Using 2(2-ii) Using 2ndnd (external) evaporator (external) evaporator & existing Haug Compressors in USA15& existing Haug Compressors in USA15
Summary of thermal management meeting
USA15
Remote controlpressure regulators
Pin ~ 14-17bar
Haug compressors in USA15
Low temperature condenser operating on GN2 (LN2 boiloff) or else R404a, ex
C3F8 compressor system(Condenser at highest point on ATLAS platforms)
Tracker
Liquid pump (possibly 2-stage):Hydraulic/pneumatic drive for high B-field operation
Must generate ~14-17 bar C3F8 capillary input pressure
2.i Enhancing Si operating temperature margin of the present C3F8 evaporative cooling system
Priming height(maximum possible)
h(liquid)m bar(C3F)
(boosts pump output)
Use Haug compressors tocool local condensers in UX
(no longer in primary cooling loop)
Summary of thermal management meeting
Principle of modified P-H cycle : recovery of present C3F8 system
P (T) between Evaporation & Condensation determined by sizing
