Status overview of the cooling

31 August 2015

Bart Verlaat, Raphael Dumps 1

Progress points

• Many progress wrt the Velo evaporator concept and safety system is achieved.– Connector-less evaporator concept (CLEC) intensively discussed and

getting more and more accepted– Tertiary vacuum concept based on CLEC on top secondary extension is

also becoming the baseline in peoples thinking– Discussions with mechanics people (Liverpool) will continue in Velo module

0 meetings on Tuesdays.• With a frozen evaporator concept the safety system can be designed

– Test set-up under construction at CERN to study impact of a leak (Vacuum-pressure vs CO2 leaked mass)

– Test set-up will / can be used to test safety system• Sizing of regulation valves in the manifolds have started.

– A study for new control valves– Valve size calculations

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The Connector-Less Evaporator Concept (CLEC)

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Module with long tubes and feedthrough connector mounted on the assembly jig. Connectors and tubes are brazed to the microchannel before module assembly The cooling lines are unrolled prior to

installation. The lines are routed on the side of the module base

The feedthroughs are bended towards tertiary vacuum by an access hole in the secondary vacuum stand-off

Expected rolled up size: ca 10x10cm

Connectors can be fixed to manifold in the tertiary vacuum box

Tertiary vacuum with CO2 manifolds

All

Upgrade Velo concept vs current Velo

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All inlet capillaries on 1 side. Return common (Manifold inside)

Electronics crates

Cable feedthrough

Tertiary vacuum with manifolds and safety valves

Cooling feed through with thermal stand-off

Out of the way space for cooling connector and flexible part

Cooling lines passing the module base on the side

Access flange

Cooling feed through

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• 2x 1/8” VCR Gland (D=1/4”)• 1/8” VCR glands without nuts are

very small and fit both through a 14mm hole (10mm would even work when staggered)

• A split nut à la IBL can be installed after insertion

Hole diameter 10-14mm

Braze connection (Cold)

O ring or copper seal connection (Warm)

Mounting possible from both sides

Atlas-IBL cooling line

Dgland flange=1/4” (6.35mm)

VCR split nut

1/8” VCR with split nut

Split nuts assembled after insertion

Custom

Standard Conflat

Prototype

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Tubes are firmly fixed to the base by an insulator spacer

2 spools with a diameter of 50mm, length 1.2m.(Can be roll on a better support)

Welded standard vacuum feedthroughCF15 on a stainless steel flange

Welded tubes on a vacuum feed trough(thermal insulator)

Temporaryholding support

2x module pitch

Connector can be used for testing (With connector saver), vacuum feedthrough as well

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D=1/4” (6.35mm)

1/8” VCR with split nutmounted after tube insertion(gain of space)

Installation of the connector through the vacuum flange

Venting CO2 in vacuum

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3.5 g/m3 => v=285 m3/kg

Far off scale

Ca 350 kJ/kg*1.6 g = 560 J to heat it up to ambient.

Condition of -30 C ⁰liquid

Condition of +20 C ⁰low pressure gas

• Module volumes and CO2 content @ -30ºC liquid (1076 kg/m3):

– Total module volume (1.42 mL): • 1.6 gram CO2 total

• Vacuum volumes (Eddy Jans memo, 5 November 2009) :– Secondary: 450 liter– Primary: 1715 liter– Maximum dP=10 mbar

• Loosing 1.6 gram of CO2 in the secondary volume gives a density of 1.6 g / 450 l = 3.5 g/m3

– 3.5 g/m3 density after warming up to 20’C gives a pressure of 1.9mbar

– Direct expansion without heat pick-up is ca half of the pressure

1 branch leakage is not problematic when proper shut-off

Possible shut-off concepts

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No return valve option

• This concept requires small passive no return valves.

• Actuator can be out of the tertiary vacuum • Inlet manifold will be leaked into the vacuum as well:

– Assuming a 4x0.7 tube & 1m long– Extra Volume: 5.3 ml = 5.7 gram– Pressure in secondary vacuum @ 20’C = 8.9 mbar13

1 Active NC valve needed and many miniature no return valves

Red volume will leak in vacuum

Green volume can stay pressurized. An additional pressure relieve can be included

Ambient Tertiary vacuum Secondary Vacuum

Valve is NC and actuated when a pressure increase in the Velo is detected. Eg. 1e-3mbar

Individual inlet shut-off

• This concept requires small passive no return valves.• 26 actuators in the tertiary vacuum

– Pneumatic valves very complex in a vacuum– Electrical valves NC have a constant heat load on the CO2 inlet

• Small volume leaked into vacuum– Pressure in secondary vacuum @ 20’C = 1.9 mbar

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26 Active NC valves needed in vacuum and 26 miniature no return valves

Red volume will leak in vacuum

Green volume can stay pressurized. An additional pressure relieve can be included

Ambient Tertiary vacuum Secondary Vacuum

Valves are NC and actuated when a pressure increase in the Velo is detected. Eg. 1e-3mbar

Full active shut-off

• This concept is very sensitive for trapping cold liquid– Each line needs a relieve mechanism– Open relieve mechanisms (Burst disc or safety valves) are a risk for the

modules (sudden cool dow n w hen activated)– A w arm safety volume is an option

• 52 Actuators in the tertiary vacuum– Pneumatic valves very complex in a vacuum– Electrical valves NC have a constant heat load on the CO2 inlet

• Small volume leaked into vacuum– Pressure in secondary vacuum @ 20’C = 1.9 mbar 15

52 Active NC valves needed in vacuum

Red volume will leak in vacuum

Green volume can stay pressurized. An additional pressure relieve can be included

Ambient Tertiary vacuum Secondary Vacuum

Valves are NC and actuated when a pressure increase in the Velo is detected. Eg. 1e-3mbar

Safety volume always contains warm gas

No-return valves or active valves are under consideration.

CO2 pumping in secondary vacuum

10

10-2

10-1

100

101

102

103

10-4

10-3

10-2

10-1

100

101

Pressure (mbar)

Mas

sflo

w (

g/s)

ACP28 CO2 pumping capacity

Pressure (mbar)

Mas

s flo

w (

g/s

)

ACP 28 pumping capacity for CO2

A constant CO2 leak of 0.1 g/s is tolerable (Almost a full microchannel flow)

At least 1 ACP28 pump is active, sometimes 2 work in parallel

Proposed test set-up

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395 liter (Current Velo = 450 liter, upgrade will likely to be less due to smaller hood)

PT,TTTT

PT,TT

PT,TTPT,TT

TT

Condensed reference volume Condenser to regulate CO2 temperature to be vented

Borrowed from Nikhef

FT

Concept Evaporator P&ID

12

PV110

nc

TT35036

To UT-Detector

30

30

60

52

EH39052TT39052

CV39052 EH30036 CV30038 PV30038

NV30142

NV30148

NV30242

NV30248

NV30342

NV30348

nc

nc

EH35036 CV35038 PV35038

NV35142

NV35148

NV35242

NV35248

NV35342

NV35348

PV35052

nc

PV35040

nc

PV35050nc

PV39060

nc

PV39030

nc

PV30040

nc

PV30050

PV59032PV59054

PV49060

PV49030

nc

nc nc

36

PT35052TT35052BD35052

52

PT35038TT35038

38

SA35052

SA30052

PT30038TT30038

38

Safety vent

By-pass with dummy load

Pre-heater

Safety vent

Pre-heater

nc

PV35052

52

PT30052TT30052BD30052

TT39032PT39032BD39032

32

TT30036

36

60

PT39058TT39058BD39058

58

VacuumAmbient

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Carel valves for CO2 applications

Manual valves we generally use

The Carel vales for CO2 well cover our application range. A manual knob is also available

Q = ca. 100xCv (kW) for dP=15 bar

21 kW

4.9 kW

1.1 kW

Valve sizing

• Flow distribution concept: – DP control of main liquid flow via by-pass– MF control of individual branches with a fixed DP

• To select the proper valve a Matlab simulation tool is set-up– Example shown for Lucasz plant.

• Evaporator data of velo and UT is needed to calculate LHCb plant case 14

0 2 4 6 8 10 12 14 16 18 200

10

20

30

40

50

60

70

80

90

100

Loop massflow (g/s)

Pre

ssur

e dr

op (

bar)

, V

alve

ope

ning

(%

)

LUCASZ LOOP OPERATIONAL SPACE. Quantity of loops:1xLoop control valve: E2V09, By-pass control valve: E2V05

Psp = 17 bar, dPsp = 30 bar, Pmax = 70 bar, Pint = 80 barPump type LDC1 (Velo type), VF = 62.69 lph

Stroke = 12.7 mm, Dcyl = 25 mm, Speed = 168 rpm

Loop Operational Area

Interlock Zone

Manifold Differential PressureBy-Pass Valve Opening

Requirement (MF=14 g/s, dP=20 bar

FT

Control Valve

Control Valve

Control Valve

DP

FT

Controlled liquid flow

Controlled liquid flow

Common 2-phase return

Constant flowFlow control

Flow control

DP control

Conclusions

• The discussions with the VELO about the cooling / safety configuration are progressing, people start to focus towards the same direction– Safety system study at CERN?

• Most input for system manifold is arriving, so concept can progress sufficiently for sizing towards transfer line and plant

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