the alice water cooling systems

30/10/2008 Engineering Forum on Cooling for the LHC Detectors

1

The ALICE water cooling systems

A.TauroA.Tauro


2

Outline

• ALICE cooling organization• Overview of the ALICE water cooling systems• Main problems found during the commissioning of the

detectors– TPC– ITS

• Solutions adopted case by case• Conclusions


3

ALICE cooling organizationALICE cooling organization

CoolingcoordinatorCooling

coordinator

Detector exptsDetector expts

Detector expts

TCTC

TS-CV/DC

• Cooling coordinator:– Provides the interface between the

cooling experts/TS-CV/external companies and the technical coordination (TC)

– Responsible for the installation and testing of cooling services

– Follows the commissioning stages

• Sub-detector cooling experts:– Provide technical specifications

– Perform prototyping and/or mock-up tests

– Commission the final system

• TS-CV/DC:– In charge of the fabrication, installation,

operation and commissioning of the cooling plants

Cooling plantCooling plantCooling plant

Cooling servicesCooling servicesCooling services

CERN techs or ext comp


4

Updates and reviewsUpdates and reviews

• Regular status updates:– Installation -> weekly planning meetings

– Commissioning -> daily commissioning meetings

– Technical board and technical forum

• Cooling reviews dedicated to each sub-detector aiming at discussing:– Detector protection and safety (interlocks, HW protections, relief valves,

…)

– Cooling performances

– In case of problems -> engineering change requests (re-routing of lines, cooling plant modifications)


5

Example: ALICE TB June ‘08Example: ALICE TB June ‘08

PLANT DCS INTERLOCK REMARKS

TPC FEE Some faulty heaters → reparation in June

OKP → Plant

Plant → LV (to be tested)

Cavitation in some lines

TPC RRTank release valve

must be replaced

Need to integrate conductivity measurement

P → TPC FEE plant (to be checked)

Low efficiency

FMD OK OK (same as TPC)P → Plant

Plant → LV, HV-

TOF

Need calibration of chilled water valve

Tank level transmitter replacement

OKPlant → LV (to be tested)

Overpressure is not an issue

PHOS FEE OK NOP → DSS → Plant (will be installed in June)

Detector T=30°C

No safety devices

PHOS CRY OK OK NOImprove line insulation


6

Example: ALICE TF Oct ‘07Example: ALICE TF Oct ‘07

Pressure test Water cleaning Remarks

TRD Jan 07: 10 SRs Sep 07: 6 SRsUpper sectors after TPC to IP

HMPID Feb 07 Filter cleaned

TOF Aug 07: 4/6 crates, 1/6 FEE Fittings/pipes required

TPCJan-Aug 07: C side,

MNF

Jun 07: A sideOnly MNF missing

Pressure test/cleaning was repeated after rerouting

PHOS-EMCAL

Aug 07Pressure test for PHOS crystal pipe not done

SDD+SSD Apr 07Jun 07

MNF: Sep-Oct 07Fine mesh filter (50um)

SPD Apr 07 Jun 07 -


7

The ALICE experiment

forward muonspectrometer

Central detectors


8

The L3 magnet in 2006…


9

ALICE front viewALICE front view


10

…and how it looks like now


11

Location of the cooling plants Location of the cooling plants in the UX25 cavernin the UX25 cavern

TOF, EMC, CPV, PHOS

TRD

TPCHMPID

SSD & SDDSPD

PHOS


12

Services through the L3 door


13

Installation of pipes in the Installation of pipes in the ALICE cavernALICE cavern

Installation: 1 and ½ year, 7 teams, ~20’000 mt of pipes (40% stainless steel), ~3700 press fittings

Test: about 500 over-pressure tests (~3’400hrs in total)


14

ALICE cooling plantsALICE cooling plants

Cooling plants:• 7 units (5 water, 2 evaporative). Most of them are shared between detectors• 5 produced by TS/CV-DC, 2 outsourced (Italy, Russia)• PHOS is the only -25°C, all the others work at +16,+18°C• Leakless operation• First unit (SPD) delivered beginning 2006, last one (PHOS) beginning 2008• Total value of cooling plants >1MCHF

0 50 100 150

Power removed[kW]

Flow[m3/h]

SPD

HMPID

SSD, SDD

TPC, FEEC, Res. Rod

TRD, TPC Screen

TOF, EMC, PHOS, CPV

C4F10 water


15

ΔP return

ΔP supply

ΔPdetector

Ppump

Ptank

h

Pin < PatmPout

Jose Direito TS/CV/DC, 13.05.2008

The leakless operationThe leakless operation

It works only if Pin < Patm

Not all the loop is under-pressure!!!

ΔPdetector vs flow must be knownΔPreturn should be calculated


16

The TPC cooling


17

Temperature uniformity across Temperature uniformity across the TPC volumethe TPC volume

• Ne/CO2 is a ‘cold’ gas, with a steep dependence of drift velocity on temperature

• Uniformity of the temperature field must be extremely good (ΔT ≤ 0.1 K)

• 18x2 trapezoidal read-out chambers each one consuming 720W

• Complex system of heat screens and cooling circuits

• Heat screens:– outer radius toward the TRD– inner radius shielding from the ITS

services– readout chamber bodies shielding

from the FEE heat dissipation– FEE towards the outside

• Cooling circuits:– resistive potential dividers– front-end electronics


18

Front end electronics cooling Front end electronics cooling pipespipes

• 0.5 mm copper tubes connected to 3 mm Si-tubes, without clamp or bracket

• Connection tested to withstand > 2 bar overpressure. But…

… it could happen that the pipes are not properly plugged after an intervention for which they have to be disconnected

-> what happen if one hose become disconnected ?


19

Test with dummy sectorTest with dummy sector• Test with dummy sector done in 2007 in the UX25 cavern• Demonstrates that if a Si-pipe bunches-off there is a leak inside the chamber• The plant takes 40s from the leak before stopping the water circulation• -> P sensors installed on each chamber input line• Continuous monitoring of pressures to verify underpressure operation• Exceeding the threshold would immediately trigger an ALARM and stop circulation

40 s


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““Cavitation” problemCavitation” problem• For some sectors it has been observed ad

audible noise coming from the pipes• These sectors exhibited a Pout < 50 mbar• “Cavitation”, potentially dangerous

condition. Increase of the flow resistance due to bi-phase liquid

Pthreshold

• Increasing the tank pressure solves the problem but then makes the startup impossible

• Startup: need to kick up the pressure in order to get rid of the air in the pipe

• Solution: switch from startup tank pressure (e.g. 350 mbar) to running mode (e.g. 500 mbar)


21

Routing of cooling lines

pressure sensor threshold

Siphons in linesSiphons in lines• In some sectors there was no flow• The reason was the presence of

important siphons in the lines• These lines have been re-routed

sectors with new routing

• After re-routing of these lines the problem was solved


22

New lines installed

Re-routing of TPC linesRe-routing of TPC lines


23

ROC temperaturesROC temperatures


24

Skirt temperaturesSkirt temperatures


25

The laser system is used for precise position inter-calibration for the readout chambers and allows online monitoring of temperature and space-charge distortions, both of the order of a few mm


26

The ITS cooling


27

Layout of the ITSLayout of the ITS

• Only SPD uses C4F10 coolant

– low material budget, long-term stability against corrosion, chemical compatibility, minimal temperature gradients, cooling duct temperature above the dew point

• SDD and SSD share the same (water) cooling plant

• ITS uses stainless steel pipes


28

SPD commissioningSPD commissioning• Extensive (2 years) pre-commissioning

in the lab– In normal operation, if a sudden failure of the

cooling were to occur, the temperature at the module would increase at a rate of 1 °C/s

– Continuous monitoring and a fast, reliable safety interlock on each module are therefore mandatory

• DCS and interlocks also tested in the lab

• Problems encountered in real installation

– Low or zero flow in some loops. Due to different pipe layout with respect to lab

– Still some liquid back into compressor. Heaters added


29

The SSD cooling

Two thin (40 μm wall thickness) phynox tubes


30

The SSD FEE chips


31

50um filter150um filter

Cleaning of the lines. June ‘07Cleaning of the lines. June ‘07• In June 2007, before connecting the ITS to the cooling plant the pipes were cleaned by

circulating water• Found metal chips, dust particles which could have damaged the detector• Water circulation continued for several days• Filters of different mesh replaced at every time• -> lesson learnt: use extreme care during pipe installation. Plug them before connecting the

detector


32

Water leak. July ‘07Water leak. July ‘07• In July 2007, after 2 days of run with the nominal flow, a water leak was detected inside the

ITS barrel (probably due to an open in the SDD region)• Mylar foil acted as drain, water level not high enough to reach ladders• In order to be leak proof, it was then decided to allow to work only in sub-atmospheric region

inside the detector• As for the TPC, pressure sensors were introduced in order to read the pressures at the

detector


33

Problems and solutionsProblems and solutions

• When lowering the tank pressure to be underpressure at the detector, the “cavitation” problem appeared– Solution: 1) re-routing of some lines, 2) changing the inner pipe diameter

• Given the different routing of the lines, the flows amongst the loops were not equalized– Solution (SDD): upgrade the plant with flowmeters and pressure regulators– Solution (SSD): install balancing valves on input-output lines

• SSD and SDD have different flows and different ΔPdetector -> each one found an optimum value for Ptank and Ppump– Solution: install back-pressure regulators (SSD) + input pressure regulator (SSD) to decouple as much as possible the two systems

• The loops were difficult to drain– Solution: install bypass into cooling plant and manual valves in each line


34

Add 3 lines 16/18 till here

Add 2 lines 16/18 till here

Add 5 lines 16/18

Add 3+2 lines 16/18

Add 5 lines 16/18

The new lines

Cost: 50KCHF


35

N2 and Compressed air supply

LD

VEA-4

QR-7

N2 @ 6 bar

Flow

can be a

djuste

d a

t the flo

wm

eter

PS3

VEA-5

QP - 1

VEA-1

Boitier Orange

PS2

SSD supply manifold

SDD supply manifold

SSD 4-ladder groups:8 outlets x 2 x 0.96L/min

= 15.36 L/min

SSD 5-ladder groups:8 outlets x 2 x 1.2L/min

= 19.2 L/min

Chilled water

HT

R -

S28

500

W

HT

R -

S21

TT

S21

VP- S28i

500

W

TT

S28H

TR

-S

18

500

W

HT

R -

S11

TT

S11

VP- S18i

500

W

TT

S18

VP- S21i

QR-1

RWA

VMA-S

MSSD exchangerSDD exchanger

FOA-1

SDD 2-ladder groups:8 outlets @ (2 x 0.6L/min) = 9.6L/min

250

W

250

W

HT

R -

D18

HT

R -

D11

TT

D11

VP- D18i

TT

D18

VP- D11i

SDD end-ladders of 2-ladder groups:

8 outlets @ (2 x 1.2L/min) = 19.2 L/min

500

W

500

W

HT

R -

D28

HT

R -

D21

TT

D21

VP- D28i

TT

D28

VP- D21i

SDD 4-ladder groups:5 outlets @ (2 x 1.2L/min) = 12L/min

500

W

500

W

HT

R -

D38

HT

R -

D31

TT

D31

VP- D38i

TT

D38

VP- D31i

SDD end-ladders of 4-ladder groups:

5 outlets @ (2 x 2.4L/min) = 24L/min

100

0 W

100

0 W

HT

R -

D48

HT

R -

D41

TT

D41

VP- D48i

TT

D48

VP- D41i

CA- 1

LW1

TTD

183.02.01

CERN/TS/CV/DC

LHC - Fluids - EXPERIMENTAL HALL

SSD+SDD cooling plant : P&I diagram (with upgrades) Version 5

M. Santos2008-Jan-10

LHCF222???

DM

QR - 5QR - 3VP- 1

OT1

PP

QR - 2

TT1

PT 2

FT1

CT1

VTA - 1QR - 4

UV

UV

PR - S2PR - S1

VTA - D1 VTA - D2 VTA - D3 VTA - D4

8 + 8 = 16 returns from SSD

SSD return manifolds

VP

-S

21r

VP

-S

11r

VP

-D

3141

r

VP

-D

1121

r

SDD return manifolds

8 + 5= 13 returns from SDD

QR-S1 V-D1 V-D2

VMA-DM

TTWin

PI 2

VR- 1 PT1

PI1

PPV-1VEA-2

PPV-2VEA-3

DG

PS1

LT

N2 for tank flushing

N2 for membrane

70L/h tap water

VP- 2

PPV-3 VP- 3

PI3

PT3

QP - 3FOA-2V-1

VP- S11i

FT

D1

FT

D2

FT

D3

FT

D4

FT

S2

FT

S1

FT

D11A

FT

D11C

FT

D18A

FT

D18CFT

D21A

FT

D21C

FT

D28A

FT

D28C

FT

D31A

FT

D31C

FT

D38A

FT

D38C

FT

D41A

FT

D41C

FT

D48A

FT

D48C

PR

-D11

A

PR

-D11C

PR

-D18

A

PR

-D18C

PR

-D21

A

PR

-D21C

PR

-D28

A

PR

-D28

C

PR

-D31

A

PR

-D31C

PR

-D38

A

PR

-D38C

PR

-D41

A

PR

-D41C

PR

-D48

A

PR

-D48

C

VP- D3141r

“D” concerne SDD “r” concerne

le retour

Nomenclature des vannes retour

4 chiffres: composition des 2 vannes

d’injection (i) correpondantes a ce retour:VP-D31i et VP-D41i

QR

–S

11iA

QR

–S

11iC

QR

–S

18iA

QR

–S

18iC

QR

–S

21iA

QR

–S

21iC

QR

–S

28iA

QR

–S

28i

C

QR

-D

1121r

A

QR

-D

1121

rC

QR

-D

314

1rA

QR

-D

3141r

C

QR

–S

11rA

QR

–S

11r

C

QR

–S

21rA

QR

–S

21r

C

QR-S2

PIS1

PIS2

PPV-4

TTS

Corrosion monitoringQR - CORRin

QR - CORRout

QR - DrainSDD

QR - DrainSSD

VEA-6

The SSD-SDD plant upgrade

Cost of the upgrade: 150KCHF

By-passes for Circuit Draining

Two actuated valves on the common returns with remote positioning control to decouple return pressure from the SDD

Pressure regulator for the SSD

Manual valves on all SSD returns and supplies

5 enlarged return valves+ forks for the 18mm OD SDD pipes

Pressure regulators for SDDFlowmeters for SDD


36

Conclusions

• The ALICE cooling organization has been described. The cooling coordinator acting as a reference for all the cooling matters

• The leakless operation is effective only if Pin<Patm and it doesn’t guarantee that there are no leaks

• P sensors are fundamental in leakless systems. They should be part of the design of the cooling system

• It is fundamental to measure ΔPdetector vs flow and to have a good estimate of ΔPreturn. Piping inside the detector must be robust

• An optimized routing of the lines is crucial to minimize the impedance and to avoid siphons. Max care must be taken in the cleaning procedures

• Test test test is always the key

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