1

CO2 cooling of an endplate with Timepix readout

Bart Verlaat, Nikhef

LCTPC collaboration meeting

DESY, 22 September 2009

BVERLAAT@NIKHEF.NLBVERLAAT@NIKHEF.NL1

Contents

• Introduction to CO2 Cooling

• Overview of the current CO2 systems in HEP

• CO2 cooling for LCTPC

• Conclusions

2

Why is evaporative CO2 cooling good for HEP detectors?

3

CO2 allows small tubing

Why?Large latent heat & Low viscosity & High pressure

Allow high pressure drop

Allow low flow Low pressure drop

Low pressure drop Lower pressure drop

Allow very small tubing

Latent Heat of Evaporation

(KJ/

kg)

Be

tte

r

CO2

C3F8

Be

tte

r CO2

C3F8

0

100

200

300

-40 -20 0 20Temperature (ºC )

Liquid Viscosity

Temperature (ºC )

(Pa*

s) Be

tte

r

CO2

C3F8

1e-4

2e-4

3e-4

4e-4

5e-4

-40 -20 0 20

Temperature gradients in cooling tubes

4

Be

tte

r CO2

C3F8CO2

C3F8

0

5

-40 -20 0 20

Temperature (ºC )

dT/dP ratio

dT/d

P (

ºC/b

ar)

Be

tte

r

10

15

20

25

Super heated vaporSub cooled liquid 2-phase liquid / vapor

Dry-out zoneTarget flow condition

Tem

pera

ture

(°C

)

Fluid temperature

Low ΔT

-30

0

30

60

90

Increasing ΔTTube temperatureLiqui

d

2-phase

Gas

Low dT/dP ratio due to high pressure High pressure is good!

CO2 safety issuesPressure Equipment Directive (PED):• Stored energy determines the safety

class.• Stored Energy = Pressure x Volume

CO2 is environmental friendly, non-toxic and cheap

502-02-2009

1 1.5 2 2.5 3 3.5 4

x 10-3

-5

-4

-3

-2

-1

0

dPCO2

dTCO2

dPC3F8

dTC3F8Te

mpe

ratu

re (

ºC)

Pre

ssur

e (B

ar)

Tube inner diameter (mm)DCO2≈1.4 mm DC3F8≈3.6 mm

dP according to Friedel

ID Pressure at 30ºC

Stored energy

CO2 1.4mm 72.1 bar 11.1 J/m

C3F8 3.6mm 9.9 bar 10.1 J/m

50

25

00 20 40-20-40-60

Temperature (° C)

Pre

ssu

re (

Bar

)

CO2

C2F6

C3F8

Atlas IBL cooling tube sizing

150 Watt, -25ºC

How to get the ideal 2-phase flow in the detector?

DetectorCooling plant

Warm transfer

Chiller Liquid circulationCold transfer

2PACL method:(LHCb)

Traditional method:(Atlas)

Vapor compression system

Pumped liquid system

Hea

terCompressor

Pump

Compressor

BP. Regulator

Liquid Vapor

2-phase

Pre

ssur

e

Enthalpy

Liquid Vapor

2-phase

Pre

ssur

e

EnthalpyCooling plant Detector

6

CO2 systems in HEP

• 2 CO2 cooling systems have been developed for HEP detectors so far.– AMS-TTCS (Tracker Thermal Control

System)• Q= 150 watt• T=+15ºC to -20ºC

– LHCb-VTCS (Velo Thermal Control System)

• Q=1500 Watt• T= +8ºC to -30ºC

• Both systems are based on the 2PACL principle invented at Nikhef

7

AMS on the ISS

Velo of LHCb

Deep space =

Cold

Pump

• 2PACL was developed for the AMS-TTCS

• 2PACL also implemented in LHCb-VELO

8

AMS-Tracker

1 4

Liquid Vapor

2-phase

Pre

ssur

eEnthalpy

1

2 3

4 5

5

In 2-phase area T=Constant

P

32

Rad

iato

r

2-Phase Accumulator Controlled Loop (2PACL)

Q= 150 wattT= +15ºC to -20ºC

Pump

9

LHCb-Velo

• 2PACL was developed for the AMS-TTCS

• 2PACL also implemented in LHCb-VELO

1 4

Liquid Vapor

2-phase

Pre

ssur

eEnthalpy

1

2 3

4 5

5

In 2-phase area T=Constant

P

32

2-Phase Accumulator Controlled Loop (2PACL)

Chiller =

Also cold

Q= 1500 WattT= +8ºC to -30ºC

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

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

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

Time from 29 March clock time (Hours)

Measu

red Te

mpera

ture (ºC

)

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

Accumultor saturation temperature (TRPT102tsat) = Setpoint

TR 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

Time from 29 March clock time (Hours)

Measu

red Te

mpera

ture (ºC

)

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

Accumultor saturation temperature (TRPT102tsat) = Setpoint

TR 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

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 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

Time from 29 March clock time (Hours)

Measu

red Te

mpera

ture (ºC

)

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

Accumultor saturation temperature (TRPT102tsat) = Setpoint

TR 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

Time from 29 March clock time (Hours)

Measu

red Te

mpera

ture (ºC

)

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

Accumultor saturation temperature (TRPT102tsat) = Setpoint

TR 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

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 Accumulator saturation (Set-point) Evaporator temperature Condenser inlet

10

20

0

-20

-40

Tem

pera

ture

(ºC

)

-10

-30

The cooling tube temperature is:– Easy to control– Very stable– Independent of primary cooler

temperature

10

Accumulator temperature =

Cooling tube temperature

Accumulator temperature =

Cooling tube temperature

Temperature of space radiatorTemperature of space radiator

LHCb-VTCSLHCb-VTCS

Temperature of the chillerTemperature of the chiller

Tem

per

atur

e (º

C)

1 orbit (~1.5h)Time

AMS-TTCSAMS-TTCS

0

-10

-20

-30

11

Evaporator section

Component box on satellites exterior

Heat exchanger

Pump

Evaporator tube

TTCS Space radiator

The AMS-Tracker Thermal Control System (AMS-TTCS)

AMS

Accumulator

12

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

PLC

2 Concentric transfer lines

4m th

ick

conc

rete

shi

eldi

ng w

all

VELO

Passive hardware only

All the active hardware

The LHCb-Velo Thermal Control System (LHCb-VTCS)

13

Evaporator

The VTCS cooling plant

CO2 rack

Velo module with cooling block

The LHCb-Velo Thermal Control System (LHCb-VTCS)

Calculation of a LCTPC cooling tube Assumed TPC endplate layout

14

R1740

R400

Area ≈ 9m2 ≈ 5000chips/m2Heat load ≈ 5kW/m2Duty cycle ≈ 2% Total power ≈ 1kWPower per frame = 5 wattCooling temperature = 20ºC

~200 frames (~223x223)

-5

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 50 100 150 200 250

Tem

pera

ture

gra

dien

t (°C)

Quantity of frames

ID=2mm

ID=3mm

ID=4mm

ID=5mm

ID=6mm

ID=7mm

ID=8mm

Temperature gradients(As function of cooling tube diameter and length)

15

Radial temperature gradient (ºC)(Heat transfer end of tube)

Longitudinal temperature gradient (ºC)(Pressure drop)

0

0.1

0.2

0.3

0.4

0.5

0 50 100 150 200 250

Tem

pe

ratu

re

Gra

die

nt

ove

r Tu

be

Wa

ll

(C)

dT_HTC (ºC)

dT_HTC (ºC)

dT_HTC (ºC)

dT_HTC (ºC)

dT_HTC (ºC)

dT_HTC (ºC)

dT_HTC (ºC)

5010 20 30 40

Tube length (m)

Power per frame = 5 wattFrame length = 223mmHeat load = 22.5 Watt/m

X=0.33 (3x overflow)

ID~

2.2

mm

ID~

3m

m

ID~

4.3

mm

ID~

6.2

mm

1x2x

4x

6x

Similar to AMS-TTCS

TPC end plate cooling tube routing

16

Qty Frames / loop

Heat load per loop(W)

Tube length (m)

Inner diameter (mm)

1 loop 200 1000 48m 6.2

2 loops 100 500 24m 4.3

4 loops 50 250 12m 3

6 loops 34 171 8m 2.2

-0.80

-0.70

-0.60

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

0.0 2.0 4.0 6.0

Eva

pora

tive

tem

pera

ture

dro

p ('C

)

Mass flow (g/s)

Translated evaporative temperature drop of the AMS-Tracker test evaporater

22'C, 100 Watt

22'C, 200 Watt

22'C, 300 Watt

22'C, 400 Watt

ID=2.5mmL=10m

AMS test data (2001) 0.4ºC temperature gradient

Possible layout of the 6 loops option

Liquid supply ring (~5mm ID)

Vapor return ring (~8mm ID)

Cooling tube (~2.5mm ID)

Inlet capillary (~1mm ID)Restriction for flow distribution

LCTPC cooling tube performance (6 parallel loops)

17

Stratified

Process Path

Slug+SWSlug

Intermittent Annular

D

α=8,077

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0

100

200

300

400

500

600

700

0 0.2 0.4 0.6 0.8 1H

eat T

rans

fer

Coe

ffic

ient

[W/m

2K

]

Mas

s Vel

ocit

y [k

g/m

2s]

Vapor Quality [-]

Temperature 22 ºC Diameter 2.5 mmLength 8 mHeatload 171 WattMassflow 3.0 g/sVol. flow 0.24 l/min

Pump

18

LCTPC

Warm 2PACL very simple• Accumulator is CO2 bottle @ room

temperature• Cold source is cold water

Bottle temperature = Detector temperature

2PACL for LCTPC

Q= 1000 WattT= +20ºC

H2O (~12ºC)CO2 Bottle

1.5L/min

AMS-TTCS was tested in the same way(Cold test done with bottle outside in winter)

Conclusions

19

• CO2 cooling seem feasible for LCTPC• A 6 loop option looks reasonable

– Inner diameter 2.5mm– Length ~8m– Gradient < 1ºC – Heat transfer ~8000W/m2K– Already tested for AMS-TTCS

• A room temperature CO2 cooling system easy to realize. – Pump (LEWA LDC-1 with damper)– Heat exchanger (SWEP BDW16 DW-U)– Transfer tube (Concentric pipe in pipe)– Cold water (Available standard in lab)– Bottle (You get it for free if you order CO2)