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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)
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