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[email protected] [email protected]
Evaporative CO2 cooling for thermal
control of scientific equipments
SLAC Advanced Instrumentation Seminars
March 28, 2012, 1:30 PM, Kavli 3rd floor
Bart Verlaat (Nikhef/CERN)
1
CO2 Cooling Seminar
• Introduction to 2phase cooling and fluid trade-off
• CO2 cooling modeling
• Introduction to the 2PACL CO2 circulation method.
• CO2 cooling in the AMS-Experiment.
• CO2 cooling in the LHCb Velo Detector
• Ongoing projects.
• Conclusions
2
3
What happens inside a cooling tube? Heating a flow from liquid to gas
Super heated vapor Sub cooled liquid 2-phase liquid / vapor
Enthalpy (J/kg)
Press
ure (Bar)
Dry-out zone Target flow condition
Tempe
ratu
re (°C)
Low ΔT
-30
0
30
60
90
Liquid
2-phase
Gas
Isotherm
Increasing ΔT
(Dry-out)
Liquid
Superheating
[email protected] Cooling efficiently scientific
equipment.
• What do we expect in general from a 2phase flow in scientific equipment? – Inside the equipment (Evaporator):
• Small additional cooling hardware (small diameter tubing)
• Large heat removal capacity
• Low temperature gradients – Low gradient from tube wall to fluid
– Low gradient over tube length (Isothermal)
– Outside the equipment (Circulation system) • Stable temperature
• Control over fluid condition in side evaporator
• Which fluid is most suitable?
4
Temperature profiles • To compare different fluids it must be understood which mechanism
contributes to the thermal performance.
• For efficient heat transfer: ΔT(ΔP+HTC) as small as possible
• For isothermal heat transfer: ΔT(ΔP) as small as possible
• As in general small cooling tubes are preferred, so lets introduce a new property to distinguish the heat transfer relative to the needed volume
5
ΔT(ΔP)
ΔT(ΔP) (Reduced
diameter) ΔT(HTC) (Reduced
diameter)
ΔT(HTC)
ΔT(ΔP+HTC) (Reduced
diameter)
ΔT(ΔP+HTC)
Tube length
Te
mp
era
ture
Vtube*ΔT(ΔP+HTC))
Q Overall Volumetric Heat
Transfer Conduction (W/m3K): Vtube*ΔT(ΔP))
Q Isothermal Volumetric Heat
Transfer Conduction (W/m3K):
[email protected] Fluid Trade-off (1) • Fluid trade-off regarding
temperature gradients, for simplicity: – Pressure drop: Friedel
correlation
– Heat transfer gradients: Kandlikar correlation.
6
0 1 2 3 4 5 6 7 8 9 100
1
2
3
4
5
6
7
8
9
10
Tube diameter (mm)
Heat
transfe
r gra
die
nts
(°C
)
Heat transfer temperature gradients
L=1 m, Q=100 W, T=-20 °C, VQ=0.5
CO2 (19.7 bar)
Ethane (14.2 bar)
R116 (10.5 bar)
Propane (2.4 bar)
R218 (2 bar)
Ammonia (1.9 bar)
R134a (1.3 bar)
Heat Transfer
dT(HTC)
(Dashed lines)
Total dT(dP+HTC)
(Thick lines)
Pressure drop
dT(dP)
CO2
ΔT(ΔP)
ΔT(ΔP)(Reduced diameter)
ΔT(HTC)(Reduced diameter)
ΔT(HTC)
ΔT(ΔP+HTC)(Reduced diameter)
ΔT(ΔP+HTC)
Tube length
Te
mp
era
ture
0 1 2 3 4 5 6 7 8 9 100
1
2
3
4
5
6
7
Tube diameter (mm)
Volu
metr
ic h
eat
transfe
r conduction (
W/m
m3K
)
Isothermal volumetric heat transfer conduction
L=1 m, Q=500 W, T=-20 °C, VQ=0.5
CO2 (19.7 bar)
Ethane (14.2 bar)
R116 (10.5 bar)
Propane (2.4 bar)
R218 (2 bar)
Ammonia (1.9 bar)
R134a (1.3 bar)
0 1 2 3 4 5 6 7 8 9 100
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Tube diameter (mm)
Volu
metr
ic h
eat
transfe
r conduction (
W/m
m3K
)
Overall volumetric heat transfer conduction
L=1 m, Q=500 W, T=-20 °C, VQ=0.5
CO2 (19.7 bar)
Ethane (14.2 bar)
R116 (10.5 bar)
Propane (2.4 bar)
R218 (2 bar)
Ammonia (1.9 bar)
R134a (1.3 bar)
Fluid Trade-off (2)
• Translating the temperature gradients to the volumetric heat transfer conductance – Clearly visible: CO2 is a winner in both overall and isothermal.
– Another interesting phenomena: The higher the pressure the more efficient. Is this maybe the simple answer to the perfect fluid?
7
Overall
Isothermal
CO2
CO2
[email protected] Is high pressure the answer to
an efficient cooling fluid?
• In fact it is, the higher the pressure: – The more the vapor stays compressed
– The smaller the needed volume
– But as well: lower gas speeds mean lower pressure drop.
• Other properties are also important: – High latent heat (=less flow)
– Low viscosity (=low pressure drop)
– CO2 is favorable for both properties.
• And on top of that pressure drop is less significant at high pressures as it doesn’t effect the boiling pressure as it would do at low pressure fluids.
8
[email protected] CO2 a perfect cooling fluid
for scientific use
• As shown, CO2 is a really good candidate cooling fluid if the following properties are required (In general for scientific and high-tech equipment): – Low mass and low volume cooling pipes
– Isothermal behavior
– High heat removal capacity
• The stability in time is a merit of the attached cooling plant, here fore the 2PACL principle was invented for particle detector cooling. – However high pressure fluids are less sensitive to
pressure changes, so in fact they are as well beneficial for stable temperature systems.
9
[email protected] CO2 heat transfer and
pressure drop modeling
• Nowadays good prediction models of CO2 are available. Especially the models of J. Thome from EPFL Lausanne (Switzerland) – See SLAC’s Advanced Instrumentation Seminar talk by
J.Thome @ 9 feb 2011
• Models are flow pattern based and are reasonably well predicting the flow conditions and the related heat transfer and pressure drop.
• The Thome models are successfully used to predict the complex thermal behavior of particle detector cooling circuits.
• A simulation program called CoBra is developed to analyze full detector cooling branches.
10
[email protected] Experimental heat transfer
data (measured at SLAC)
11
Interesting research on
heat transfer is done at
SLAC in a joint effort
with Nikhef.
M. Oriunno (SLAC) &
G. Hemmink (Nikhef)
[email protected] CoBra Calculator
(CO2 BRAnch Calculator)
• Iterative method chopping a long line in small elements (~1mm).
• Model can read simple configuration files giving simple tube geometry
• Heat leak and internal heat exchange between elements can be taken into account.
• CoBra is a very helpful tool for predicting the complex behavior of 2-phase flow.
12
Px,Hx
Px+1 = Px - dPx
Hx+1 = Hx + dHx
Qx = Qapplied + Qenvironment +Qexchanged
dPx= f(D,Q1,MF,VQ,P,T) or f(Cv)
dHx= Qtot/MF or pump work
dPpump=∑dPall
dHcondenser = ∑dHall
Tx,VQx and properties
derived from Refprop
Qx+1
dPx+1
dHx+1
Px+2,Hx+2
CoBra example calculation
• CoBra is able to analyze complex thermal
behavior of CO2 in long tubes
13
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-1
0
1
2
3
4
5
6
7
2mmID x 5m tube temperature and pressure profile. MF=0.3g/s, Tsp=-30ºC, Q=90, xend
=0.99
Branch length (m)
Delta T
(`C
) &
Delta P
(Bar)
1 2 3 4
dT Tube wall (ºC)
dT Fluid (ºC)
dP Fluid (Bar)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
50
100
150
200
250
300
350
5mx1.5mmID tube (4m heated), Mass flow=0.3g/s, Q=90Watt , T=-30ºC
Dry-
out
Mist
Annular
Stratified Wavy
Stratified
Bubbly
S
lug
Process path
Dry-out
Liq
uid
Slug
Annular
[email protected] Internal heat exchange and
ambient heating
14
Figure 7: CoBra calculation example of the IBL cooling tube. The branch has a 1mm inlet (1-4), a 1.5 mm cooling tube (4-8), a 2mm outlet (8-9) followed by a 3mm outlet (9-12). The dashed temperature profile is the actual sensor temperature taking into account the conductance of the support structure. The graph on the left has no internal heat exchange, the right graph takes internal heat exchange of the in and outlet tube into account.
0 5 10 15 20 25-2
0
2
4
6
8
10
12
14
16
IBL temperature and pressure profile. MF=0.8g/s, Tsp=-40ºC, Q=101.8, xend
=0.41
Branch length (m)D
elta T
(`C
) &
Delta P
(Bar)
1 2 3 4 56 78 9 10 11 12
Stave TFoM: 13ºC*cm2/W
Pixel maximum temperature:
-24.4ºC
dT Tube wall (ºC)
dT Fluid (ºC)
dP Fluid (Bar)
dT Pixel Chip (ºC)
0 5 10 15 20 25-2
0
2
4
6
8
10
12
14
16
IBL temperature and pressure profile. MF=0.8g/s, Tsp=-40ºC, Q=101.8, xend
=0.5
Branch length (m)
Delta T
(`C
) &
Delta P
(Bar)
1 2 3 4 56 78 9 10 11 12
Stave TFoM: 13ºC*cm2/W
Pixel maximum temperature:
-24.2ºC
dT Tube wall (ºC)
dT Fluid (ºC)
dP Fluid (Bar)
dT Pixel Chip (ºC)
Capillary
No Boiling
Boiling starts
Boiling starts
Figures from: DESIGN CONSIDERATIONS OF LONG LENGTH EVAPORATIVE CO2 COOLING LINES
Bart Verlaat and Joao Noite, GL-209, 10th IIF/IIR Gustav Lorentzen Conference on Natural Working Fluids, Delft, The Netherlands 2012
Comparison to test results
15
Figure 8: Temperature and pressure test results of the CMS pixel upgrade cooling branch (left) and the Atlas IBL cooling branch (right). Comparison with the CoBra calculator showed that the calculator is a promising tool for predicting the temperature and pressure gradients over long length cooling branches.
0 5 10 15 20 25-1
0
1
2
3
4
5
6
7
8
9
IBL temperature and pressure profile. MF=1.1g/s, Tsp=-26.71ºC, Q=73.5, xend
=0.36
Branch length (m)D
elta T
(`C
) &
Delta P
(Bar)
12 3 4 56 78 9 10 1112
dT Tube wall (ºC)
dT Fluid (ºC)
dP Fluid (Bar)
0 5 10 15-20
-18
-16
-14
-12
-10
-8
-6
Loop Length [m]
Tem
pera
ture
[°C
]
m = 1.48g/s | Qtotal
= 256.87W | Pin
= 26.40Bar | Tin
= -17.40°C | dP = 6.33Bar | dT = 10.86°C
0 5 10 1520
21
22
23
24
25
26
27
Pre
ssure
[B
ar]
Exp. Wall Temperature
Theory Wall Temperature
Theory CO2 Temperature
Theory CO2 Pressure
CMS detector (1.4mm)El
ect
ron
ics
(1.8
mm
)
Inle
t tu
be
(1.8
mm
)
Ou
tle
t tu
be
(1.8
mm
)Inlet tube
(1mm)
Outlet tube(3mm)O
utl
et
tub
e (2
mm
)
Detector(1.5mm)
Figures from: DESIGN CONSIDERATIONS OF LONG LENGTH EVAPORATIVE CO2 COOLING LINES
Bart Verlaat and Joao Noite, GL-209, 10th IIF/IIR Gustav Lorentzen Conference on Natural Working Fluids, Delft, The Netherlands 2012
CMS-B-PIX Atlas-IBL
[email protected] What circulation method can we use?
Detector Cooling plant
Warm transfer
Refrigeration method: (Atlas)
Vapor compression system
Hea
ter
Compressor
BP. Regulator
Liquid Vapor
2-phase
Pre
ssu
re
Enthalpy
If we remember slide 3, we see that proper
cooling takes place on the liquid side, while
compressors need gas as input. It is better to
invent a cycle staying on the liquid side.
=> externally cooled pump cycle.
3
What happens inside a cooling tube?Heating a flow from liquid to gas
Super heated vaporSub cooled liquid 2-phase liquid / vapor
Enthalpy (J/kg)
Press
ure (Bar)
Dry-out zoneTarget flow condition
Tempe
ratu
re (°C)
Low ΔT
-30
0
30
60
90
Liquid
2-phase
Gas
Isotherm
Increasing ΔT
(Dry-out)
Liquid
Superheating
[email protected] New cycle for particle detectors: 2PACL (The 2-Phase Accumulator Controlled Loop )
• The 2PACL has the following advantages: – Cycle stays on the liquid side, no heat required (experiment can be cooled unpowered
and no control heaters required)
– Evaporator pressure=(temperature) controlled with a 2-phase vessel away from the experiment. No local control nor sensing needed!
– All control hardware in a distant accessible cooling plant
– Primary cooling can be anything, no accurate temperature control needed as long as it is colder than the 2PACL 2-phase temperature.
– Inlet fluid state defined by physics => saturated liquid.
– Large temperature range (typical from room temperature down to -40°C)
17
Chiller Liquid circulation
Cold transfer
2PACL method: (LHCb)
Pumped liquid system,
cooled externally
Pump
Compressor
Liquid Vapor
2-phase
Pre
ssu
re
Enthalpy Cooling plant Detector
2PACL application in a
particle detector
18
Con
de
nser
Pump Transfer line
(Heat exchanger)
Evaporator inside
detector (4-5)
2-Phase
Accumulator
Heat in
1
2 3
4
5
6
P7
P4-5
Long distance
(50-100m)
HFC Chiller
Shielding wall
Capillaries (3-4)
for flow distribution
Cooling plant (controls &
actuators) in a safe and
accessible area
Only passive piping in
detector area. Manifolds
in accessible locations.
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
19
3
4&5 6
2
1
Liquid
7
Pressure control
with accumulator.
Change set-point.
Pump
1 4
5
3 2
6
7
Red dot (detector)
on saturation line.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
20
3
4&5 6
2
1
Liquid
7
Lowering saturation
pressure
Pump
1 4
5
3 2
6
Cooling 7
Red dot (detector)
follows saturation line.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
21
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
Cooling 7
Lowering saturation
pressure
Red dot (detector)
follows saturation line.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
22
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
Cooling 7
Lowering saturation
pressure
Red dot (detector)
follows saturation line.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
23
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
7
Set point reached
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
24
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
7 Heating
Increasing saturation
pressure
Red dot (detector)
follows saturation line.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
25
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
Heating 7
Increasing saturation
pressure
Red dot (detector)
follows saturation line.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
26
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
Heating 7
Increasing saturation
pressure
Red dot (detector)
follows saturation line.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
27
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
7
Set point reached
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
28
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
7
Switching on detector
Heat
Red dot (detector)
evaporation starts.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
29
3
4 5 6
2
1
Liquid
7
Powering detector
Pump
1 4
5
3 2
6
Cooling 7
Red line (detector)
in evaporation.
Heat
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
30
3
4 5 6
2
1
Liquid
7
Powering detector
Pump
1 4
5
3 2
6
Cooling 7
Red line (detector)
in evaporation.
Heat
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
31
3
4 5 6
2
1
Liquid
7
Detector is on
Pump
1 4
5
3 2
6
7
Red line (detector)
in evaporation.
Heat
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
32
3
4 5 6
2
1
Liquid
7
Unpowering detector
Pump
1 4
5
3 2
6
Heating 7
Red line (detector)
Evaporates.
2-phase (Evaporation)
Gas
Pre
ssure
Liquid
Isothermal line
Enthalpy
2-Phase Accumulator Controlled Loop
(2PACL)
33
3
4&5 6
2
1
Liquid
7
Pump
1 4
5
3 2
6
7
Detector power is off
2-phase (Evaporation)
[email protected] CO2 cooling projects in
particle physics
• 2 CO2 cooling systems have successfully been built for particle detectors – AMS-Tracker experiment on the International Space Station
– LHCb-Velo experiment for the Large Hadron Collider at CERN
• Many future CO2 cooling systems are under design: – Atlas Inner B-layer @ CERN
– CMS upgrade pixel @ CERN
– Belle-2 @ KEKb (Japan)
• Some are foreseen for the far future: – CMS upgrade tracker @ CERN
– Atlas upgrade pixel and tracker @ CERN
– LC-TPC for the future Linear Collider
34
The 1st CO2 cooling system in Space!
35
A CO2 cooling system for Alpha Magnetic Spectrometer (AMS)
Tracker Detector on the International Space station (ISS)
CO2 cooling
radiator
AMS on the ISS
AMS in the Shuttle
(STS-134, May 2011)
RADIATORE
condensatori
144 WATT TRDTOF
TRACKER
TOF
RICH
ECAL
MA
GN
ET
E
Cooling system
component boxes
(1 redundant) 150 Watt detector with
evaporator rings
AMS-Tracker Thermal Control System
(AMS-TTCS)
Primary cooling not
needed in space as
environment is cold.
Direct radiation to space
36
[email protected] AMS-Tracker with
CO2 cooling rings.
37
Inner plane evaporator rings
Tracker connections Inner plane thermal bars and hybrids
Inner plane silicon ladders
[email protected] AMS TTCS Cooling
performance in space (1)
-25
-20
-15
-10
-5
0
5
10
13:00 15:00 17:00 19:00 21:00 23:00 01:00
Tem
pe
ratu
re (
°C)
Time(HH:MM)
Pump inlet (PT02_P)
Accumulator (PT01_P)
Evaporator inlet (DS13-P)
Evap 1 (SensE)
Evap 2 (SensG)
Evap 3 (SensF)
Heat
exchanger
heating
Evaporator partly single
phase (gradients)
Accumulator
set point
change
Evaporator
fully 2-phase
Varying CO2 liquid
due to orbital
fluctuations 1 orbit (~1.5hour)
38
[email protected] AMS TTCS Cooling
performance in space (2)
-30
-25
-20
-15
-10
-5
0
5
10
15
200
8/0
6/1
1
10
/06
/11
12
/06
/11
14
/06
/11
16
/06
/11
18
/06
/11
20
/06
/11
Tem
pe
ratu
re (
°C)
Date (DD/MM/YY)
Pump inlet (PT02_P)
Accumulator (PT01_P)
Evaporator inlet (DS13-P)
Evap 1 (SensE)
Evap 2 (SensG)
Evap 3 (SensF)
Magnet Average
Solar Panel
orientation
change
Detector
switched-off
Soyuz
docking
39
[email protected] AMS TTCS Cooling
performance in space (3)
40
6 month stable at 0⁰C despite cold low beta periods
[email protected] CO2 cooling projects in LHC
41
27 km
Ca. 1
00
m
LHC
VELO detector: 1.5 kW@-30°C
(Running successfully since 2007)
Atlas IBL: 1.5 kW@-40°C
(Operational 2013)
CMS pixel: 15 kW@-20°C
(Operational 2014)
LHCb-Velo Thermal Control System
(LHCb-VTCS)
42
Evaporator Passive tubing only Cooling Plant
All active hardware
Transfer tube Concentric assembly
Cooling capacity: 1.5 kW@-30°C
44 2-phase
gas
R507a chiller
9
Condenser
Evaporator / Modules
Concentric tube
Pump
Restr
iction
Accumulator
1 2
7
6
543
8
2-phase
gas
Transfer lines(Ca. 50m)Cooling plant area VELO area
10
A
Start–up of the VTCS during October
2009 commissioning:
8:40 - Start-up with set-point -5°C
11:10 - Detector switched on
12:50 – Set point to -15°C
15:30 - Set point to -25°C
17:10 - Set point to -30°C
18:20 - Set point to -35°C (System Limit)
19:10 - Set point to -34°C
19:30 - Set point to -25°C
20:00 - Detector Switched off
18:15 18:30 18:45 19:00 19:15 19:30-45
-43.5714
-42.1429
-40.7143
-39.2857
-37.8571
-36.4286
-35
-33.5714
-32.1429
-30.7143
-29.2857
-27.8571
-26.4286
-25
Heatload (
W)
Tem
pera
ture
(°C
), L
evel(%
)
Time (hh:mm)
01-Oct-2009
Silicon temperature (°C) Accumulator Set-point temperature (°C) Pump liquid temperature (°C) Evaporator saturation temperature (°C) Accumulator liquid level (%) Detector heat load (W)09:00 12:00 15:00 18:00 21:00-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
0
100
200
300
400
500
600
700
800
Heatload (
W)
Tem
pera
ture
(°C
), L
evel(%
)
Time (hh:mm)01-Oct-2009
Accumulator Set-point temperature (°C) Pump liquid temperature (°C) Evaporator saturation temperature (°C) Accumulator liquid level (%) Detector heat load (W)
06:00 09:00 12:00 15:00 18:00 21:00-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Time (hh:mm)
Tem
pera
ture
(°C
), L
evel(%
)
0
100
200
300
400
500
600
700
800
01-Oct-2009
Heatload (
W)
Silicon temperature (°C) Accumulator Set-point temperature (°C) Pump liquid temperature (°C) Evaporator saturation temperature (°C) Accumulator liquid level (%) Detector heat load (W)
06:00 09:00 12:00 15:00 18:00 21:00-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Time (hh:mm)
Tem
pera
ture
(°C
), L
evel(%
)
0
100
200
300
400
500
600
700
800
01-Oct-2009
Heatload (
W)
Silicon temperature (°C) Accumulator Set-point temperature (°C) Pump liquid temperature (°C) Evaporator saturation temperature (°C) Accumulator liquid level (%) Detector heat load (W)
10-Accu liquid level
Detector power
A-Silicon temperature
10-Accumulator set-point
9-Pumped liquid
-35°C SP
-34°C SP
-30°C SP
VTCS Commissioning results:
Start-up and operation
45
T=20°C
T=0°C
T=-20°C
T=-40°C
T=
-40
°C
2-Phase (Liquid/Vapor)
Liquid
Freezing (Solid/Liquid)
9-Pump inlet
1. Increase pressure to
make liquid.
2. Pump at high pressure
and cool down in liquid
mode
3. Lower pressure to
desired set-point
4. Power-up detector
Lowest possible set-point
(liquid approaches
saturation line)
Switch-off detector
Start-up sequence
SP=-5°C
SP=-15°C
SP=21°C
(Start-up)
SP=-25°C
SP=-35°C
SP=-30°C
Enthalpy (kJ/kg)
Pre
ssu
re (
Ba
r)
VTCS Commissioning results:
Start-up and operation in the PH-diagram
Atlas IBL-cooling system (1)
46 New detector with smaller beam
pipe in space of current beam pipe
IBL detector:
• Ø80mm x 800mm
• 1.5 kW @ -40°C
• 14 staves with 1 cooling pipe
Carbon foam structure
1.5mm ID titanium cooling pipe
Pixel detector
chips
(70watt/stave)
[email protected] CMS upgrade pixel cooling
system • Replacement and
upgrade of current pixel detector
• 15kW @ -20ºC
• Very long serial lines with relative high heat flux
47
F-PIX
(Forward)
[email protected] KEK Belle-2 SVD and PXD
48
Belle-II pixel detector (Rapid Prototyping heat sink)
Belle-2 PXD and SVD, 1.5 kW@-30ºC
Common CO2 cooling plant
development with Atlas IBL
Belle-II SVD
detector
[email protected] CO2 cooling support
• To support the CO2 cooling projects in particle physics several test systems are under development:
• Cora (CO2 Research Apparatus) – Fixed test plant for CERN based research (0-2kW, +20 to -35ºC)
• Marco (Multipurpose Apparatus for Research on CO2
– Fully automatic (User friendly) CO2 test system for general use (0-2kW, +20 to -45ºC)
– Base design for future on detector cooling plants (Atlas IBL, Belle-2)
• Traci (Transportable Refrigeration Apparatus for CO2 Investigation) – Small test system for laboratory use
– New simplified 2PACL concept to reduce cost and complexity (0-350W, +20 to -40ºC)
49
Traci Cora Marco
[email protected] TRACI Transportable Refrigeration Apparatus for Co2 Investigation
• TRACI: A simplified new concept for providing a conditioned CO2 flow for cooling research.
• 2PACL principle simplified (few functions have been integrated) – Integrated 2PACL (I-2PACL )
– Patent of I-2PACL concept filed
• Goal: An easy to (mass) produce user friendly system – Operational from +25⁰C to -40 ⁰C
– Initial cooling power up to 350 Watt (depending on minimum temperature)
50
-50
-40
-30
-20
-10
0
10
20
30
9:00 10:30 12:00 13:30 15:00 16:30
Tem
pera
ture
(°C)
Time (hh:mm)
Chart TitleCO2 liquid temperature (at pump)
CO2 temperature
Accumulator saturation temperature
150 W on150 W on Power off
R404a Chiller
P,T
6
3
1
10
5
T
T
P
P T
T
CO2 loop
Local experiment box
R404a evaporator/CO2 condenser
CO2 pump
compressor
condenser
Heater
TEV
Acc
um
ula
tor
Concentric hose
Flow regulation
Experiment venting
Experiment connection
TRACI layout4
5
The TRACI factory
• Prototypes are already “mass produced” – 2 have been build (Atlas & LHCb)
– 3 under construction (Atlas, CMS & Nikhef/AIDA for development)
– Investigating a start-up company for real production
51
TRACI a modular design
52
CO2 piping in a 2D-
foambox
Commercial chiller
Control: Simple
conditioner and relay
logic
User interface:
• On/off and reset buttons
• Error indication
• Pressure controller
[email protected] MARCO Multipurpose Apparatus for Research on CO2
• MARCO is prototype CO2 2PACL system for multipurpose use.
• User friendly – Automatic experiment connection
– Automatic filling
• Designed according to CERN experiment standards. – Baseline concept for the detectors IBL
(CERN) and Belle-2 (KEK), common development with MPI-Munich.
– PVSS-Unicos control interface
• Low temperature design – 2kW@-45ºC
– Frequency controlled 2-stage chiller
53
[email protected] MARCO production
54
A CO2 2PACL build in MPI
Controls build
at CERN-DT
2-stage chiller for IBL
temperatures from
ECR-Nederland
Conclusions
• CO2 is a very good candidate fluid for applications were limited cooling space is available or limited additional mass is allowed.
• CO2 cooling is a good candidate if high power densities are present and an isothermal heat sink is required
• CO2 cooling is widely accepted in Particle Physics community as the future cooling method for the inner silicon detectors.
• The 2PACL concept has proven to be a good method for controlling evaporation conditions in distant set-ups
• 2 CO2 systems are operational in particle physics and perform well.
• Several new systems are under development including systems for testing
55
