1. Cooling Update (27 March 2014)
Rob van Weelderen,
Cryogenic Group, Technology Department, CERN

2. Overview Fluka Heat Loads + Explicit Design Margins
1.9 K Heat load limits for IT with – double HX in Q1 to Q3 + intermediate pumping
1.9 K Heat load limits for D1 – CP with –single HX and with/without intermediate pumping
Beamscreen cooling

3. Placing of cryo-equipment considered (variant 4)
Phase-separator &
Piping entries/exits
QRL-jumper
SM &
Phase-separator
Additional low pressure pumping
Q1,Q2a,Q2b,Q3: actively cooled for about 41 m, double-HXs needed
CP,D1 : actively cooled for about 16 m, single-HXs desired

4. D1 & IT: Fluka heat loads
However these values have to be augmented due to additional loads 
Courtesy L. S. ESPOSITO

5. D1 & IT: Fluka + additional heat loads
Heat Loads (W)
50 cm gap in ICs
50 cm gap in ICs3
Magnet cold mass
Beam screen
Q1A + Q1B
110
150
Q2A + orbit corr.
105 50
Q2B + orbit corr.
130 70
Q3A + Q3B
160 60 CP 45
D1 (160 mm)
100
Interconnects 25 85
beam-screen contact load 27
-27
static heat load
cryostat ends 16
electron cloud
image currents ?
Total
771
633
Q1-Q2A ~ 247 W,
Q2B-Q1B ~ 322 W,
D1+CP ~ 202 W,
Beam screens ~ 633 W
Image currents 0.5 W/m on BS (tbc)
What will be our design choice?
Propose + 20 % margin:
~ 925 W at 1.9 K,
~ 759 W at BS
beam-screen contact load
0.5
W/m
static heat load
cryostat ends 16 W
electron cloud
150
image currents ?

6. Minimal need
(569 W)
Practical T-regulation limit,
(800 W)
Hard limit,
HX overflowing
(1000 W)

7. D1 + CP (~14.9 m long) needed 202 W without contingency
"Power (W)"
"Double HX ID (mm)"
"single HX ID (mm)" 50 24 32
100 44
150 38 53
200 61
250 49
300
350 57
400
- Limited by vapour velocity (green is ok)
- No good regulation possible/HX-area (red, forbidden)
Using a full length double HX: 250 W at 2x49 mm ID, 2x58 mm Yoke-holes
Using a full length single HX : 125 W at 1x49 mm ID, 1x58 mm Yoke-hole
Not enough!
"Power (W), 6m 1HX"
"single 6m long HX ID (mm)" 40 35 45 50 55 60 65 70 75
- Intermediate pumping between CP and D1 and with single HX, limited by HX-area