cryogenic engineering cern, march 8 - 12, 2004
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Cryogenic Engineering, CERN, March 2004
KKCryogenic Engineering
CERN, March 8 - 12, 2004
• Temperature reduction by throttling and mixing
• Temperature reduction by work extraction
• Refrigeration cycles: Efficiency, compressors, helium, hydrogen
• Cooling of devices
Cryogenic Engineering, CERN, March 2004
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T 1warm
T Uwarm
T 2kalt
T 0kalt
Q 0
.Q.
Abb. 1.2.1 Von selbst ablaufender Prozeß Abb.1.2.2 Aufgabe der Kältetechnik
cold cold
Process running by itself Process needing driving power
Mankind had an intellectual difficulty with the production of refrigeration: We could not learn it from nature.
The problem: One has to add energy to remove energy.
Cryogenic Engineering, CERN, March 2004
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warm
kalt
P?
P?
Q 0
.
warm
kalt
P
Q ab=Q O+P
Q 0
.
. .
Abb. 1.2.3 Zuführung der Antriebsleistung? Abb. 1.2.4 Kältemaschine
cold cold
Where should the outside power be applied
Solution: One needs an additional sytem: The
refrigerator
Cryogenic Engineering, CERN, March 2004
KKRefrigeration cyle
• Refrigerant
• Method to increase pressure
• Method to reduce entropy
• Method to reduce the temperature
• Method to transfer the refrigeration
• Recuperation
T-s Diagramm
Flow Diagram
Refrigeration
M in im umInput P ower
T a
T 0
E ntropy
Cryogenic Engineering, CERN, March 2004
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Tw
Tc
T
S
T
S
Tw
Tc
isentropic adiabatic
Cooling power
Widen the low-temperature end of the cycle as shown in the T-S diagram
Work Work
Ideal Real
S1 S2
AB
C D
AB
C D
Cryogenic Engineering, CERN, March 2004
KKCompressor and Aftercooler
• Purpose: Increase the pressure and reduce entropy
• Types of compressors
• Volumetric compressors: piston, screw
• Turbocompressors
Cryogenic Engineering, CERN, March 2004
KKPiston compressor
Oilfree labyrinth piston compressors. Preferred by CERN until about 1980.
Cryogenic Engineering, CERN, March 2004
KKScrew Compressor
Oil flooded screw compressor preferred at CERN since about 1985.
Cryogenic Engineering, CERN, March 2004
KKScrew compressor principle
Cryogenic Engineering, CERN, March 2004
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Cryogenic Engineering, CERN, March 2004
KKScrew Compressor Installation
Cryogenic Engineering, CERN, March 2004
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A B C D
Fig. 2 Low Temperature Options
Cryogenic Engineering, CERN, March 2004
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Cryogenic Engineering, CERN, March 2004
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10
100
1000
10000
100000
1,5 2 2,5 3 3,5 4 4,5
Refrigeration Temperature (K)
Re
frig
era
tio
n R
ate
(W
)
B
AE
CD
RIA
LHC
CEBAF
Tore Supra
ELBE
HERA
Tevatron
A Cold Ejector
B Cold Piston Compressor C Cold Turbocompressor, One Stage D Cold Turbocompressor Multi Stage
E Warm Vacuum Pump
Fig. 3 Cold Compressor diagram [3]
Cryogenic Engineering, CERN, March 2004
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Cryogenic Engineering, CERN, March 2004
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The four-stage LHC cold compressors1st stage
Cold Compressor Cartridges of 2.4 kW @ 1.8 K Refrigeration Units
IHI-Linde
Cold compressor impeller
Cryogenic Engineering, CERN, March 2004
KKIsentropic Efficiency of Cold
Compressors
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
12
12'is HH
HHη
Tem
pera
ture
(T
)
Entropy (s)
P1
P2
1
2
2'
Cryogenic Engineering, CERN, March 2004
KKFlow Compliance of “Mixed” Compression
N2
N3
Stall line
Choke line
Volumetric
P inter
Flow
P out (fixed)
P inter
P in (fixed)
Hydrodynamic
Volumetric
For fixed overall inlet & outlet conditions, coupling of the two machinesvia P inter maintains the operating point in the allowed range
N1
Flow (variable)
Cryogenic Engineering, CERN, March 2004
KKHow to evaluate efficiency and to identify
losses• When discussing expanders, we shortly
talked about reversibility• In power engineering there is always a best
method to do something, i. e. no unnecessary losses = reversibility
• Losses can be idebtified by the deviation from reversibility
• Comparison is the input power• We have to give refrigeration a value in the
scale of the input power• Carnot ratio
Cryogenic Engineering, CERN, March 2004
KKThe definition of exergy
• Minimum amount of work to produce refrigeration
• Exergy= Mimimum Power= Q*(Ta-T0)/T0
• Minimum amount of power to change the state of a fluid from an initial state 1 to a final state 2:
• e2-e1 = h2-h1 + Ta*(s2-s1)
Cryogenic Engineering, CERN, March 2004
KKCycle for liquefaction of
hydrogenThe Exergy Mountains
Prometheus(prehistoric)
Min
imu
m P
ow
er
to o
bta
in
Heati
ng
or
Cool in
g (
W/W
)
Cryogenic Engineering, CERN, March 2004
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Specific exergy of cold copper and helium
0
1000
2000
3000
4000
5000
6000
7000
8000
1 10 100 1000
Temperature
Sp
ecif
ic E
xerg
y (k
J/kg
) Copper (100*)
20 bar
2.2 bar
1 bar
Cryogenic Engineering, CERN, March 2004
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Stored exergy in the cooled-down LHC
Mass (tons)
Specific Exergy (MJ/kg)
Stored Exergy (GJ)
Helium 96 6.8 660 Metal 36.000 0.065 2.340 Total 3.000 Magnetic energy
10
Cryogenic Engineering, CERN, March 2004
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• Helium is recovered from natural gas
Cryogenic Engineering, CERN, March 2004
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Annual Helium Recovery and Sales (USA)
0
20
40
60
80
100
120
140
1960 1970 1980 1990 2000
Year
Vo
lum
e o
f H
eli
um
(M
ill
Nm
3 /ye
ar)
Sold
Recovered
Difference: Added or removed from reserve
Cryogenic Engineering, CERN, March 2004
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1999 Helium World Production (Estimated by U.S. Geological Survey)
Produced 106
Nm3/year
Liquefied 106 Nm3/year
Shipments per year
Shipments per week
United States 118,0 69,0 (export 29,3)
2450 49
Algeria 16,0 16,0 550 11 Russia 4,2 4,2 150 3 Poland 1,4 1,4 50 1 Total 139,6 90,6 3200 64 (15.000 l/h)
Cryogenic Engineering, CERN, March 2004
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00 1910 20 30 40 50 60 70 80 1990
LIQ
UE
FA
CT
ION
RA
TE
YE A R
0,1
1
10
100
1000
10000
0,4
4
40
400
4000
40000
RE
FR
IGE
RA
TIO
N R
AT
E
Wl/h
Development of the size of helium refrige-rators and liquefiers in the last century.
Cryogenic Engineering, CERN, March 2004
KKC.O.P. of Large Cryogenic Helium Refrigerators
Cryogenic Engineering, CERN, March 2004
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Joule-Thomson Wet ExpanderCollins (ca. 1965)
JT - TurbineFNAL 1975
Double JT - TurbineDESY HERA 1985
Triple JT -TurbineCERN LEP 1990
18 23 23 28 30Efficiency (%)
COP (W el /W refr ) 224240290290370
Fig. 4 Development of the Joule-Thomson Stage of Large Helium Refrigerators
Cryogenic Engineering, CERN, March 2004
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HX 1
HX 3
HX 4
HX 5
HX 6
HX 7
HX 10
HX 9
HX 11
HX 8
HX 2
5 - 8 KShield
40 - 80 KShield
2 K Load
T 1
T 2/3
T 4/5
T 6T 7
T 8
T 9
CC 2
CC 1
CC 3
Cryogenic Engineering, CERN, March 2004
KKTable 1 Cryogenic Accelerator and Fusion Projects
Project Location Capacity
(kW at 4.4 K) No. Refr
Refr. below 4.4 K Status
Accelerators Tevatron Fermilab 30 2+12 1.2 kW at 3.6 K operation RHIC Brookhaven 25 operation HERA DESY 30 3 4 kW at 3.7 K operation CEBAF TJNAF 12 5 kW at 2.0 K operation LEP CERN 72 4 stopped S-DALINAC Darmstadt 0.4 0.1 kW at 2.0 K operation ELBE Rossendorf 0.6 0.2 kW at 1.8 K operation LHC CERN 144 8 2.4 kW at 1.8 K construction Oak Ridge 12 5 kW at 2.0 K construction TESLA DESY 140 7 5 kW at 2.0 K adv. planning RIA [1] Argonne 30 8.6 kW at 2.0 K early planning SIS 100+200 GSI Darmstadt 20 ? early planning SASE-FEL BESSY 12 3.6 kW at 1.8 K early planning
Fusion MFTF Livermore 12 2 stopped JET Culham 1.5 2 0.6 kW at 3.8 K operation Tore Supra Cadarache 2 0.3 kW at 1.75 K operation TOSKA Karlsruhe 3 2 kW at 3.7 K operation LHD Toki 8 operation Wendelstein Greifswald 4 3 kW at 3.5 K construction SST-1 India 1 construction KSTAR Korea 10 construction ITER ? 120 planning
Cryogenic Engineering, CERN, March 2004
KKHistory of gas liquefaction
Cryogenic Engineering, CERN, March 2004
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History of use of liquid hydrogen
Hydrogen Bomb
HeavyWater
Commercial Supply
Rockets
Cold Neutron SourceBubble Chambers
Cryogenic Engineering, CERN, March 2004
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Cryogenic Engineering, CERN, March 2004
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Cryogenic Engineering, CERN, March 2004
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Liquid Hydrogen
FuelledRocket
Cryogenic Engineering, CERN, March 2004
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BEBC (Big European Bubble Chamber at CERN)
Cryogenic Engineering, CERN, March 2004
KKLiquid Hydrogen Fuelled Car
Cryogenic Engineering, CERN, March 2004
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Cryogenic Engineering, CERN, March 2004
KKLiquid hydrogen tank in car
Cryogenic Engineering, CERN, March 2004
KKHydrogen
0
2
4
6
8
10
12
14
0 50 100 150 200 250 300
Temperature (K)
Sp
ecif
ic E
xerg
y (M
J/kg
)
0.1 MPa
2
10 MPa
4
6
e - H2
20,4
Cryogenic Engineering, CERN, March 2004
KKFuture Large Scale Hydrogen Liquefier
Feed
Product
Helium -Neon-Cycle
Propane
Hydrogen Com pressors
ColdH 2 Com pressor
M ain Com pressorBrake Com pressors
of T urb ines
HydrogenExpander
Expected Efficiency:60 % of Carnot7 kWh/kg LH2
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