1 GL-2008 8th IIF/IIR Gustav Lorentzen Conference on Natural Working Fluids Bart Verlaat National Institute for Subatomic Physics (NIKHEF) Amsterdam, The

1

GL-20088th IIF/IIR Gustav Lorentzen Conference on Natural Working Fluids

Bart VerlaatNational Institute for Subatomic Physics

(NIKHEF)Amsterdam, The Netherlands

CO2 COOLING FOR THE LHCB-VELO EXPERIMENT AT

CERNCDP 16 - T3-08

Copenhagen, 9 September 2008

2

Table of Contents

• Introduction to Particle Physics research, NIKHEF and CERN.

• Introduction to the LHCb and the VELO detector.

• Explanation of the VELO Thermal Control System (VTCS).

• Commisioning results of the VTCS.

• Conclusions and outlook.

[email protected]@NIKHEF.NL

3

Introduction to NikhefNational Institute for Subatomic Physics

Amsterdam, the Netherlands

Alpha Magnetic Spectrometer on the International Space Station

The Large Hadron Collider related experiments at CERN in Geneva

27 km

Ca.

100

m

Nikhef participates in particle physics experiments world-wide:– Particle accelerator

experiments– Astro-particle

physics experiments

Goals of the particle physics research:– What is matter made of? – How do forces work? – Where did matter come

from?

Starts tomorrow!

(Details at the end)


LHC

ISS

4

Electron

HadronProton beam

Proton beam

LHCb Detector Overview

Muon

LHCb Cross sectionGoals of LHCb:Studying the decay of B-mesons to find evidence of CP-violation(Why is there more matter around than antimatter?)

20 meter

Vertex Locator


5VELO Thermal Control System CO2 evaporator section

Detectors and electronics

23 parallel evaporator stations

capi

llarie

s

and

retu

rn h

ose

•Temperature detectors: -7ºC •Heat generation: max 1600 W

The LHCb-VELO Detector (VErtex Locator)


6

22 August 2008The VELO has seen particle tracks from an LHC test!

The Velo Detector

Heat producing electronics

CO2 evaporator(Stainless steel tube casted in aluminum)

Detection Silicon


7

VELO Cooling Challenges

• VELO electronics must be cooled in vacuum.– Good conductive connection– Absolute leakfree

• Maximum power of the electronics: 1.6 kW

• Silicon sensors must stay below -7°C at all times (on or off).– To avoid thermal runaway of the

irradiated silicon

• Adjustable temperature for commisioning.

• Maintenance free in inaccessable detector area


8

The 2-Phase Accumulator Controlled Loop (2PACL)

2PACL principle ideal for detector cooling:

- Liquid overflow => no mass flow control

- Low vapor quality => good heat transfer

- No local evaporator control, evaporator is passive in detector.

- Very stable evaporator temperature control at a distance (P4-5 = P7)

Con

dens

er

PumpHeat exchanger

evaporatorRestrictor2-Phase

Accumulator

Hea

t in

Hea

t in

Hea

t out

Hea

t out

1

2 34

5

6

Liquid Vapor

2-phase

Enthalpy

Pre

ssu

re1

2 3

45

6P7

P7P4-5


Long distance

9

VTCS Accumulator Control

Thermo siphon heater for pressure increase(Evaporation)

Cooling spiral for pressure decrease(Condensation)

Accumulator properties:• Volume: 14.2 liter (Loop 9 Liter)• Heater capacity: 1 kW• Cooler capacity: 1 kW• System charge: 12 kg (@23.2 liter)• System design presure: 135 bar


++

+_+

_

Heating

Cooling

Setpoint Temperature

Temperature

Pre

ssur

e

Evaporator Pressure

Pressure drop

PIDPset

Tset

Paccumulator

ΔPfault

10

3.6 m

2.6

m

2 R507A Chillers:1 water cooled1 air cooled

2 CO2 2PACL’s:1 for each detector half

55 m

Accessible and a friendly environment

Inaccessible and a hostile environment

2 Evaporators 800 Watt max per detector half

VELO

LHCb-VTCS Overview(VELO Thermal Control System)


PLC

2 Concentric transfer lines

4m th

ick

conc

rete

shi

eldi

ng w

all

11

VTCS Schematics2x CO2 2PACL’s connected to 2 R507A chillers

(Redundancy)

Lots of sensors and valves

TR_AC101

TR_PM101

Tertiary VTCS Right Detector (TR)

TR_PT101TR_PT104

TR_PT102

TR_VL101

TR_VL103

TR_VL104 TLR_VL105

TR_VL106

TR_VL107

TR_VL108

TR_VL109

TR_VL110

TR_VL111

TR_VL113

TR_LT101

TR_BD103

SA_HX105 / TR_HX101 SB_HX105 /

TR_HX102

SA_HX108 / TR_HX103

TL_HT103

TR_HT104

SB_HX108 / TR_HX104

TR_HT101

TR_VL102

TR_PT103TR_HT102

TR_BD101

TR_BD102

TR_BD104

TR_BD106

TR_BD107

TLR_VL101

TLR_PM101

TLR_VL107

TLR_VL109

TLR_VL110

TLR_VL111

Liquid to concentric tube

Vapor mixture from concentric tube



TL_AC101

TL_PM101

Tertiary VTCS Left Detector (TL)

TL_PT101TL_PT104

TL_PT102

TL_VL101

TL_VL103

TL_VL104TL_VL105

TL_VL106

TL_VL107

TL_VL108

TL_VL109

TL_VL110

TL_VL111

TL_VL113

TL_LT101

TL_BD103

SA_HX103 / TL_HX101

SB_HX103 / TL_HX102

SA_HX107 / TL_HX103

TL_HT103

TL_HT104

SB_HX107 / TL_HX104

TL_HT101

TL_VL115

TL_VL102

TL_PT103TL_HT102

TL_BD101

TL_BD102

TL_BD104

TL_BD106

TL_BD107

TLR_PT103

TLR_HT102

(101)

(103) (104)

(106)

(105)

(112)

(115)

(116)

(117)

(118)

(121)

(123)

(122) (114)

(113)

(120)

(107)

(102) (119)

(110)

(108)

(109)

(101)

(103) (104)

(106)(105)

(111)

(112)

(115)

(116)

(117) (118)

(121)

(123)

(122)(114)

(113)

(120)

(107)

(110)

(108)

(109)

(124) (124)

(112)

(115)

(122)

(114)

(113)

TL_VL112 TR_VL112

TL_HT105

(125)

TR_HT105(125)

TR_FL101

TL_FL102 TR_FL102

TL_FL101

TR_HX105

(102) (119)

Tambient

TL_VL114

TLR_VL115

TR_VL115

TR_VL114

TLR_VL114

TL_S.01

S.02

S.04

S.05

S.03

S.15

S.16

S.17

S.19

S.18.01

S.18.02

S.09.29

S.20

S.21

S.22

S.23

TLR_S.20

TLR_S.01

TR_S.01

S.02

S.05

S.04

S.03

S.23

S.15

S.16

S.17

S.18.01 S.18.02

S.19

S.22

S.20

S.21

S.12.29S.09.29

S.12.29

TR_AC101

TR_PM101

Tertiary VTCS Right Detector (TR)

TR_PT101TR_PT104

TR_PT102

TR_VL101

TR_VL103

TR_VL104 TLR_VL105

TR_VL106

TR_VL107

TR_VL108

TR_VL109

TR_VL110

TR_VL111

TR_VL113

TR_LT101

TR_BD103

SA_HX105 / TR_HX101 SB_HX105 /

TR_HX102

SA_HX108 / TR_HX103

TL_HT103

TR_HT104

SB_HX108 / TR_HX104

TR_HT101

TR_VL102

TR_PT103TR_HT102

TR_BD101

TR_BD102

TR_BD104

TR_BD106

TR_BD107

TLR_VL101

TLR_PM101

TLR_VL107

TLR_VL109

TLR_VL110

TLR_VL111





TL_AC101

TL_PM101

Tertiary VTCS Left Detector (TL)

TL_PT101TL_PT104

TL_PT102

TL_VL101

TL_VL103

TL_VL104TL_VL105

TL_VL106

TL_VL107

TL_VL108

TL_VL109

TL_VL110

TL_VL111

TL_VL113

TL_LT101

TL_BD103

SA_HX103 / TL_HX101

SB_HX103 / TL_HX102

SA_HX107 / TL_HX103

TL_HT103

TL_HT104

SB_HX107 / TL_HX104

TL_HT101

TL_VL115

TL_VL102

TL_PT103TL_HT102

TL_BD101

TL_BD102

TL_BD104

TL_BD106

TL_BD107

TLR_PT103

TLR_HT102

(101)

(103) (104)

(106)

(105)

(112)

(115)

(116)

(117)

(118)

(121)

(123)

(122) (114)

(113)

(120)

(107)

(102) (119)

(110)

(108)

(109)

(101)

(103) (104)

(106)(105)

(111)

(112)

(115)

(116)

(117) (118)

(121)

(123)

(122)(114)

(113)

(120)

(107)

(110)

(108)

(109)

(124) (124)

(112)

(115)

(122)

(114)

(113)

TL_VL112 TR_VL112

TL_HT105

(125)

TR_HT105(125)

TR_FL101

TL_FL102 TR_FL102

TL_FL101

TR_HX105

(102) (119)

Tambient

TL_VL114

TLR_VL115

TR_VL115

TR_VL114

TLR_VL114

TL_S.01

S.02

S.04

S.05

S.03

S.15

S.16

S.17

S.19

S.18.01

S.18.02

S.09.29

S.20

S.21

S.22

S.23

TLR_S.20

TLR_S.01

TR_S.01

S.02

S.05

S.04

S.03

S.23

S.15

S.16

S.17

S.18.01 S.18.02

S.19

S.22

S.20

S.21

S.12.29S.09.29

S.12.29


12

LHCb-VTCS Cooling Components

VTCS Evaporator

Pumps

Accumulators

Condensers

Valves


13

VTCS Units Installed @ CERN

July- August 2007

CO2 Unit

Freon Unit

14

13 13.5 14 14.5 15 15.5

-100

-75

-50

-25

0

25

50

75

Clock time (hour)

Tem

pera

ture

(°C

) P

ress

ure

(B

ar)

Leve

l (%

)C

oolin

g/H

eatin

g P

ow

er (%

kW)

VTCS 2PACL Operation From start-up to cold operation (1)

2 Pump head pressure (Bar)

4 - Accumulator pressure (Bar)

1 Pumped liquid temperature (°C)

5 – Evaporator temperature (°C)

4-Accumulator liquid level (vol %)

4- Accumulator Control: + = Heating - = Cooling _

+

4

1

2

7

7

7

7

1

2

7

4

+7

-7


15

AccumulatorCooling

= Pressure decrease

13 13.5 14 14.5 15 15.5-50

-25

0

25

50

75

Clock time (hour)

Tem

pera

ture

(°C

)

Pre

ssure

(B

ar)

VTCS 2PACL Operation From start-up to cold operation (2)

AB

C

D2 - Pump head pressure (Bar)

4 - Accumulator pressure (Bar)

1 – Pumped liquid temperature (°C)

5 – Evaporator temperature (°C)

50 100 150 200 250 300 350 4005x100

101

102

2x102

h [kJ/kg]

P [bar]

-40°C

-20°C

0°C

20°C

40°C

0.2 0.4 0.6 0.8

VTCS start-up and operating cycles

1

3,5

810,13

1

3 5

8

9,10,13

1

35

8

9,10131

3 5

8

9 10 13

CB

D E

A

50 100 150 200 250 300 350 4005x100

101

102

2x102

h [kJ/kg]

P [bar]

-40°C

-20°C

0°C

20°C

40°C

0.2 0.4 0.6 0.8

VTCS start-up and operating cycles

1

3,5

810,13

1

3 5

8

9,10,13

1

35

8

9,10131

3 5

8

9 10 13

CB

D E

A

20 °C

0 °C

-20 °C

-40 °C

1

2

4

A

BC

D Path of 54

41

2

5

2

5

4

1

5

5

Enthalpy

Pre

ssu

re

Set-point range


16

March ’08: Commisioning of the VTCSDetector under vacuum and

unpowered

10 15 20 25 30 35 40 45 50 55 60 65 70-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30

Time from 29 March clock time (Hours)

Mea

sure

d Te

mpe

ratu

re (º

C)

C-Side CO2 Cooling System Performance During Detector Vacuum Tests(29 march 08 - 31 March 08)

Accumultor saturation temperature (TRPT102tsat) = SetpointTR Evaporator Temperature (TRTT048pvss)

Condenser Inlet (TRTT101pvss)

Condenser Out- / Pump Inlet Temperature (TRTT112pvss)

Pump Outlet Temperature (TRTT120pvss)

C-Side RF-Foil temperature (TRTT043pvss)C-Side Module Base Temperature (TRTT038pvss)

Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC

2 Days + 6 hours cooling under vacuum at several set point temperatures

Start-up

10 15 20 25 30 35 40 45 50 55 60 65 70-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30


Mea

sure

d Te

mpe

ratu

re (º

C)


Accumultor saturation temperature (TRPT102tsat) = SetpointTR Evaporator Temperature (TRTT048pvss)




C-Side RF-Foil temperature (TRTT043pvss)C-Side Module Base Temperature (TRTT038pvss)

Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up

Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up

10 15 20 25 30 35 40 45 50 55 60 65 70-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30


Measure

d Temp

erature

(ºC)


Accumultor saturation temperature (TRPT102tsat) = Setpoint

TR Evaporator Temperature (TRTT048pvss)




C-Side RF-Foil temperature (TRTT043pvss)

C-Side Module Base Temperature (TRTT038pvss)

Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up

10 15 20 25 30 35 40 45 50 55 60 65 70-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30


Measure

d Temp

erature

(ºC)









Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up

Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up Condenser outlet / Pump sub cooling Pump outlet RF-foil

10 15 20 25 30 35 40 45 50 55 60 65 70-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30


Measure

d Temp

erature

(ºC)









Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up

10 15 20 25 30 35 40 45 50 55 60 65 70-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30


Measure

d Temp

erature

(ºC)









Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up

Sp=-10ºC

Sp=-20ºC

Sp=-30ºC

Sp=0ºC

Sp=-25ºC

Sp=-30ºC

Sp=0ºC


Start-up Accumulator saturation (Set-point) Evaporator temperature Condenser inlet


1716.5 17 17.5 18 18.5

-40

-20

0

20

40

60

80

Clock time (Hour)

Tem

pera

ture

('C)

, Liq

uid

leve

l (vo

l %),

Powe

r (%

kW o

r Wat

t)

Total C detector load (% kW)Evaporator Temperature ('C)Accumulator Liquid Level (vol %)Acumulator heating/cooling (% kW)Module VL11-C power (Watt)Module VL11-C cookie temperature ('C)Module VL11-C NTC00 temperature ('C)Module VL11-C NTC01 temperature ('C)

SP=-25°C

SP=-5°C

(3 sept 08)


Accu level

Module Heat load

Silicon temperature

Evaporator temperature

Accu Heating/Cooling

24 June ’08: After a succesful commisioning of the detector at -25°C, the setpoint is increased to -5°C.

And has been running since then smoothly!

80

60

40

20

0

-20

-400 0:30 1:00 1:30 2:00

Time (Hour)Te

mp

era

ture

(°C

), P

ower

(W

att)

, Le

vel (

vol %

)

Detector half heat load (x10)

-7°C

18

CO

2 li

quid

dT=

4.5

°CC

oolin

g bl

ock

dT=

0.0

4°C

1 hour

Evaporator Pressure 31.15 bar = -4.18°C

Cooling block temperature = -2.8°C

CO2 liquid temp= -42°C

Evaporator liquid inlet temp = -4.40°C

Evaporator vapor outlet temp = -4.44°C

Accumulator Pressure 30.54 bar = -4.90°C

Det

ect

or o

ffse

t fr

om a

ccu

cont

rol:

0.7

°CCO2 heat transfer dT=1.4°C

VTCS performance overview for a setpoint of -5°C (Detector switched on, fully powered)[email protected]@NIKHEF.NL

dP=

0.6

bar

= 6

.2 m

sta

tic h

eigt

h

Fluctuations from the untuned chiller

19

Summary• The VTCS has successfully passed the 1st commissioning phase

and is ready to be used in the experiment• Operational temperature range is between 0°C and -30°C set

point• It has run for 2½months continuously without any problem • It behaves very stable (<0.1°C fluctuation), with the chiller still

to be tuned.• The silicon temperature is below the required -7°C @ -25°C set

point temperature. (This is consistent with the prediction)

Lessons learned• The accumulator sometimes gives the pump a 2-phase

mixture => cavitation. Problem is solved by connecting the accu to the inlet of the condenser instead of the outlet where it is now.

• Operational temperature range of the evaporator is larger than expected. This is due to the “Duck Foot Cooling 1 ” principle of the transfer line.

• Next time we keep the system more simple, adding redundancy is not always adding reliability………


1 The way a duck can have cold feet without loosing body heat, by exchanging heat between the in- and outlet bloodstream.

20

Outlook

• The VTCS is not yet finnished, some things have to be done:– Implementing automatic back-up procedure.– Changing the accumulator connection.– Tunning the chiller.– Analyse data for publication.

• Other CERN detectors (Atlas/CMS) have shown interest in the VTCS for their inner tracker upgrades.– Challenge: Scaling of the 1.6kW VTCS to a 100kW

system. – Bigger chalenge: Convince a few hundred physists

to do so.

• Construction of a mini desktop 2PACL CO2 circulator for general purpose laboratory use.

Documents

1 GL-2008 8th IIF/IIR Gustav Lorentzen Conference on Natural Working Fluids Bart Verlaat National Institute for Subatomic Physics (NIKHEF) Amsterdam, The