BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 1

cooling for BGV modulescooling for BGV modules

trying to collect information toward a specification document

– Mostly of the cooling system, i.e. chiller+transfer line with given loads (not specifying the module cooling interface, which is considered fixed, designed by EPFL)

thanks to Petr Gorbounov– see also his contribution in

https://indico.cern.ch/conferenceDisplay.py?confId=283751

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 2

Help from EN-CV ?Help from EN-CV ?

Talked to Michele Battistin (18 dec 2013)

They have no resources for integration/installation on short noticeBut they can help for dimensioning and technical contact with companiesThey need some specs: cooling strategy, a sketch, acceptable T over modules, operating temperature at detector, acceptable temperature gradient over transfer line, pressure drop at detector (pipe diameter, series or parallel ?)Integration: I. MuttoniNote: Julabo chiller is good, must however ask perhaps for special pump (depending on required flow)

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 3

BGV moduleBGV module

fiber mats

cooling fluid in/out

dry air in/out

electronics/flex

thermal-insulating box(contains SiPM detectors that need to be kept cold)

~26cm

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 4

BGV systemBGV system

composed of 8 modules, arranged in 2 stations (distance between stations is about 1m)

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 5

transfer linetransfer line

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Side view inter-tunnel connecting holeSide view inter-tunnel connecting hole

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transfer line requesttransfer line request

General:Single phase liquid coolingType of fluid: 3M NOVEC 649 or similar (radiation! ~ < 100 Gy/year)

– not creepy, oily, ... Keep SiPM and electronics clean in case of fluid leaks!!

SiPM cooling pipe (2 per module): in/out diameter = 3/4 mm, 378 mm long, copper

– 16 pipes in total, connected in series or parallel ... expect suggestion from TS-CV

Operating temperature (at detector): settable between 20 and -40 C

– Module inside (SiPM and pipe) is flushed with dry air

Stability +/- 1K , gradient < 1K over one SiPM (thus 8K over one SiPM row ?)Assume 20 W heat load per module ? (conservative) dominated by heat leaks (insulation)

Transfer line:Transfer line must be fixed in place, before closure of machine (2014)Goes from near detector to just outside the connecting holeTotal length (3D path) is about 20m (minimum)Temperature drop over transfer line < 10 K (to avoid to low chiller temperature)Insulated, no frostAcceptable pressure drop over transfer line: don't care ?

– Must be dimensioned such as to allow flux of up to 20 l/min

to be measured in lab as soon as possibleto be measured in lab as soon as possible

turbulent flow: >0.5 l/min per SiPM pipe

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 8

transfer line: some picturestransfer line: some pictures

machine tunnel side (RA43)machine tunnel side (RA43)

service tunnel side (UA43)service tunnel side (UA43)

the wall hole

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 9

mod

ule

mod

ule

mod

ule

mod

ule

tunnel wall

sketch of BGV coolingsketch of BGV cooling

Thermal insulation up to module!

station 1

tunnel wall

transfer linechiller

service tunnel

dark box

mod

ule

mod

ule

mod

ule

mod

ule

dry air

station 2

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 10

backup / notesbackup / notes

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 11

BGV cooling specsBGV cooling specs Assume operating temperature: settable between 20 and -40 C at detector Stability +/- 1K Assume 20 W heat dissipation per SiPM module ? (conservative)

– to be confirmed by measurement!

– Max temperature gradient over 1 SiPM: 0.5 K

Max temperature gradient over 1 branch: 5K

– Minimum flow F needed per branch to get turbulent flow:

Take NOVEC: = 1766 g/dm3 at -40C

C = 1.1 J g-1 K-1, k = 0.059 W m-1 K-1

= 0.64 cP kin. viscosity = 0.4 cSt

http://www.pressure-drop.com/Online-Calculator/

Re = d v / = 4 F / ( d ) F = flow = v (d/2)2

heat transfer coeff:

h = ~ 0.023 Re0.8 (k/d) Pr0.33 = ~0.32 W cm-2 K-1 Pr = C ∙ / k = ~120

q = h ∙ A ∙ (Twall - Tfluid ) A = d L = 36 cm2

Acceptable pressure drop over transfer line: don't care ?

SiPM pipe:innner d = 3mm outer D = 4mmlength L = 377.5 mm

SiPM pipe:innner d = 3mm outer D = 4mmlength L = 377.5 mm

>10000 is turbulent>10000 is turbulent

d

velocity

take Re = 8842

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 12

LHCb chiller in point 8 (Petr Gorbounov)LHCb chiller in point 8 (Petr Gorbounov)

example called Julabo: do not guarantee it

works in radiation (10-100Gy/yr)

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 13

chiller, more powerchiller, more power

example called Julabo: do not guarantee it

works in radiation (10-100Gy/yr)

get picture at POINT8, what model ?get picture at POINT8, what model ?

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 14

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 15

BGV meeting 15-jan-2014 CERN Massimiliano Ferro-Luzzi 16

CoolantCoolant

C6F14 or NOVEC 649 ? Try NOVEC 649 and get

experience!