S. Claudet - 31st May 2007Power refrigeration for LHC Power refrigeration at 4.5K & 1.8K for the LHC...

S. Claudet - 31st May 2007 Power refrigeration for LHC

Power refrigeration Power refrigeration at 4.5K & 1.8K at 4.5K & 1.8K

for the LHCfor the LHC

S. Claudet, CERN AT-ACRS. Claudet, CERN AT-ACR


ContentContent

Introduction

Required capacity and system architecture

4.5 K Refrigerators and 1.8 K Units

Recent achievements

Conclusion


Long tradition and experience with cryogenics and refrigeration

LHC, the largest helium refrigeration system ever built

IntroductionIntroduction

0

20

40

60

80

100

120

140

160

180

1960 1980 2000

Year

kW @

4.5

K

OMEGA,BEBC,

ISR Low-Beta

ALEPH,DELPHI,

LEP Low-Beta

LEP2

LHC, ATLAS, CMS

LEP2+

LH

C:

144

kW

LHC


Basic choices, design criteriaBasic choices, design criteria

Re-use of ex-LEP refrigerators to be upgraded for LHC requirements

Site constraints for infrastructure => 5 islands 1.8K Refrigeration units to be connected to all

types of 4.5K refrigerators

General features:• Cool-down & Warm-up: 600kW• No global redundancy but doubling critical items• Impurities: continuous capacity for 50 ppm(v) air, water


Layout of LHC CryogenicsLayout of LHC Cryogenics

Pt 3

Pt 4

Pt 5

Pt 6

Pt 7

Pt 8

Pt 1

Pt 2

Pt 1.8

Cryoplant DistributionPresent Version

Cryogenic plant

8 x 18kW @ 4.5 K

1’800 sc magnets

24 km & 20 kW @ 1.8 K

36’000 t @ 1.9K

130 t He inventory


ContentContent

Introduction



Recent achievements

Conclusion


Heat loads for a sectorHeat loads for a sector

Required capacity = Fo x (Fu.Qs + Qd)

• Fu: Uncertainty on static loads

• Fo: Overcapacity

Qs: Static heat leaks

Qd1: Dynamic « current »

Qd2: Dynamic « beam »

Early heat load inventory and follow-up, periodic update of cryogenic architecture and distribution scheme


Demands in refrigerationDemands in refrigeration

Evaluation of heat loads (static, dynamic)

Required capacity with appropriate margins

Convertion in Demands for Refrigeration

Process studies to validate feasibility

1

3

2


Possible cooling cyclesPossible cooling cycles

CC

CC

CC

LHe

Sub-atmosphericcompressor

4.5

K r

efrig

erat

or

Heat load

HP

MP

LP

1

2

3

“Mixed” Compression

P ratio ≈ 80

HX

Installed capacity: 125 g/s @ 15 mbar(i.e. ~2,4 kW @ 1,8 K)

Turn-down capability: 1 to 3

Return temperature at the 4.5 K Refrigerator: - Reduced mode: ≤ 30 K - Installed mode: ≤ 20 K

‘Stand alone’ capacity check (B interface closed)

Process & components identified as a challenge

Validation prior to series (1+n)

0.3 MPa4.6 K

0.13 MPa,20 -30 K

WC

S

1.8

K R

efri

ger

atio

n U

nit

LHe 1.8 K Q1.8K

CC

B

4.5 KRefrigerator

B

D

C

Col

d co

mpr

esso

rs

Tur

blne

Adsor-bers

LHC SectorLoad


Cryogenic architectureCryogenic architecture

Warm CompressorStation

Upper Cold Box

Interconnection Box

Cold Box


Lower Cold Box

Distribution Line Distribution Line

Magnet Cryostats Magnet Cryostats

Cold Compressorbox


Cold Compressorbox


Shaft

Sur

face

Cav

ern

Tu

nnel

LHC Sector (3.3 km) LHC Sector (3.3 km)

1.8 K Refrigeration Unit New 4.5 K Refrigerator Ex-LEP 4.5 K refrigerator 1.8 K Refrigeration Unit

Typical LHC even point


Checking all modesChecking all modes

At early project phase


ContentContent

Introduction



Recent achievements

Conclusion


Procurement strategyProcurement strategy

Sub-systems by type of functionality:• CERN defined interfaces and required performance

Great majority procured from industry:• Competitive performance based tendering

(capital and operation cost)

• Detailed studies, manufacturing, site installation, commissioning, performance assessment

Separate management of general services:• Interconnecting piping, controls, site utilities


Construction phaseConstruction phase

Industry available products:(storage tanks, piping, 4.5K refrigerators)

• Functional technical specifications adapted => tests

Extension of existing products(1.8K units, cryogenic lines, superconducting links)

• Complex performance & possible impacts

• CERN add. design & support to fabrication

Totally new products(Rad. tol. cryo thermometry - electrical feed boxes)

• CERN with full responsibility for developments and “built to print” fabrication contracts


LHC 18 kW @ 4.5 K RefrigeratorLHC 18 kW @ 4.5 K Refrigerator

Compressor stationsCompressor stations



Process cycle for Air LiquideProcess cycle for Air Liquide



Process cycle for LindeProcess cycle for Linde


18 kW @ 4.5 K Refrigerators18 kW @ 4.5 K Refrigerators

33 kW @ 50 K to 75 K - 23 kW @ 4.6 K to 20 K - 41 g/s liquefaction

P input : 4.2 MW

COP

< 250 W/W


1.8K Refrigeration units1.8K Refrigeration units

3.5 bar 6.5 bar0.50 bar

0.35 bar

4.0 bar


2400 W @ 1.8K Refrigeration units2400 W @ 1.8K Refrigeration units

0

10

20

30

40

50

60

70

80

1985 1993 2000Year of construction

Ise

ntr

op

ic e

ffici

en

cy [%

]

Tore Supra

CEBAF

LHC

Diam: 250mm


ContentContent

Introduction



Recent achievements

Conclusion


Progress overviewProgress overview

QSCB

Sector 1-2 Sector 2-3 Sector 3-4 Sector 4-5 Sector 5-6 Sector 6-7 Sector 7-8 Sector 8-1

QSRB

QURA

QUIAQUIB

Point 4Point 2Point 1.8 Point 6 Point 8

Sur

face

Cav

ern

QURC

QSCA QSCA QSCB

QSRB QSRB

QSCB QSCAQSCA QSCB

QSRB

QURC QURC QURC QURC

QUIC QUIC

QURA

Sha

ft

QSCC QSCC QSCC QSCC QSCC

Tun

nel

Storage Storage Storage Storage Storage

QURAQURA

Legend

Cryogenic Distribution Line

QSC_(A,B,C):QSR_(A,B):QURA:QURC:QUI_(A,B,C):

Warm Compressor StationSurface 4.5 K Refrigerator Cold BoxUnderground 4.5 K Refrigerator Cold Box1.8 K Refrigeration Unit Cold BoxCryogenic Interconnection Box

Commisionned & accepted

Under commissioning

Delivered / Under installation

Under fabrication

Ordered (Contract placed)

Under definition

Electrical Feed Box

Superconducting Link

QURC

QSCC

QSRA QSRA QSRA QSRA

QURC

QSCC QSCC

QURC

QUIC


LHC sector 78 - First cooldown

0

20

40

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280

300

15/01/0718:00

21/01/0718:00

27/01/0718:00

02/02/0718:00

08/02/0718:00

14/02/0718:00

20/02/0718:00

26/02/0718:00

04/03/0718:00

10/03/0718:00

16/03/0718:00

Time (UTC)

Tem

per

atu

re (

K)

Supply temperature Magnet temperature (average over sector)

Return temperature Thermal shields temp. (average over sector)

Thermal shield

temp.Supply

temperature

Return

temperature

Magnet

temp.

Re-start of active cooling for cryogenic

transfer lines

Re-start of active cooling for magnets

4.5 K

20 K

80 K


Ready to prepare for

2 K powering

tests


Ready for 2 K powering

preparation

Ready to prepare for 2 K powering tests


ConclusionConclusion

It has been possible to design, built, install and validate all LHC refrigeration sub-systems

Within a few weeks (2 to 6), the tuning with the 1st LHC sector has been made to allow magnet powering tests

Early indications have to be evaluated (heat loads, response time, controls, availability)

LHC commissioning: We are confident, and aware that it represents an enormous challenge with learning process, efforts and surprises!

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S. Claudet - 31st May 2007Power refrigeration for LHC Power refrigeration at 4.5K & 1.8K for the LHC...

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