Measurements of Barrel and EC HEX

13th April 2005 R.Bates, QM

Measurements of Barrel and EC HEX

R. Bates, M. Olcese, B. Gorski, QM for prototype builds


Contents

Details of the evaporative cooling system

Measurements made: Barrel HEX EC HEX

CERN Prototype QM-1 HEX

Pressure drops over pipe work

13th April 2005

The evaporative system in 175

General design of system close to final design

A’

C

F

F

P

pressureregulator

back pressure regulator

pump

condenser

oil freecompressor

heater

heatexchanger

capillary

cooling duct with detectors

liquid vapor

Free Access AreaUSA 15

Pressure Regulation Rackson the platform

UX15

Inner TrackerUX15

B

D

D’’

E

A

booster

D’


Details of off-detector section

to DCS (and interlock for the SCT)

to Heater control and

power supply

to interlock and DCS

to BPR

from PR

Temperature sensors on return tube (one of which is redundant)

Temperature sensors on modules

Sensor of the inlet liquid temperature after the HEX (to check efficiency)

Sensors of the vapor temperature after the heater

Heat exchanger

Detector structures

Hea

ter

Filter

Capillary

Sensor of the inlet liquid temperature before the HEX (to check efficiency and margin to decrease the pressure)


Detail of circuit tested Volume and Danfoss

meters for massflow measurements

Heat liquid after Danfoss to reach 35°C before HEX inlet Manual heater control

PLC controlled proto-heater

ELMBs with PVSS monitoring plus some manometer duplication

Keller high pressure transducer before capillary

Vapor returnHeater

PCap

Condenser

BPR

PR

Volume flowmeter

Compressor

PvaHEX

PlaCap

PvbBPR

PlHEX

PinFM

TlbHEX0

TvaHEX

TvbHEX

TinFM

TvaH

Mass flowmeter

Watercooled

HEXInlet

liquidHeater

TlbHEX1Barrel HEX

Heater representingdetector structures

TlaCap0

PlbCap

PlbHEX

TlbCap1

TlbCap0

PvHEX

TlaHEX1

TlaHEX0

Capillaries

TlaCap1


Enthalpy Diagram

A

A’

BC

D

D”

D’

E

FF’

D1”

E1

subcoolingSub-cooling

Boiling in the cooling circuit

Final Heater

Compression

Condensation

Pumping

Subcooling increases efficiency,

i.e. less flow required

Expansion in the capillary

Psat=exp(T)


Why sub-cooling

Cooling power = massflow x Enthalpy Max Enthalpy at -25 °C = 102 J/g No sub-cooling, liquid temp = 35°C

Power = massflow x 36 J/g : Endcap 9.6g/s, Barrel 14g/s No sub-cooling, liquid temp = 20 °C

Power = massflow x 53.7 J/g : Endcap 6.5g/s , Barrel 9.5g/s Sub-cooling to -10 °C

Power = massflow x 86.1 J/g Massflow reduction up to 2.4 times! Slightly lower as require Xu = 0.9 to cool inlet liquid in HEX

Endcap (35°C) = 5.7g/s, Barrel 7.8g/s Reduce the change in massflow as a function of TlbHEX

No sub-cooling 50% increase in massflow Sub-cooling <10% increase (small change in TlbCAP)


Pressure specificationsDesign pressure during normal operation at full power in the evaporative circuit (bara)

Outlet of liquid pump

Outlet of PR

Inlet capillary

Outlet capillary

Detector structures

Inlet of

BPR

Inlet to the compressor

Pressure 16 15-14 13 1.67 1.67 1.3 1

Max system pressure

Driven by 40 °C max inlet T

specification

Driven by -25 °C design T of on detector loop

350mbar pressure drop budget of on vapour side

1bar pressure regulation


HEX & massflow

HEX efficiency (and Massflow) must be sufficient to cool system with full power

Must cope with TlbHEX = 20°C to 35°C Sudden power changes in detector structures

Limited increase in Massflow as a function of TlbHEX Detector power

Vapour pressure drops to be as small as possible (50mbar)


Heat Exchangers Design is different for the three sub-detectors due to

different layout and geometrical constraints All countercurrent type Pixel: parallel type external. Al inlet and return tubes

glued together over 1.5m. Simple design, possible with small power load

EC SCT: inlet tube is coiled in spiral inside the return tube over less than 0.4m.

Barrel SCT: parallel type internal. Two inlet tubes are routed inside the return tube over a length of 1.5m and parallel to the return tube axis


SCT EC heat exchangers Several

prototypes made

Final design qualified

Pressure drop budget is met

QMUL is making a final prototype with final tubes


Endcap HEX - designs

1st failed due to boiling inside capillary HEX1 – HEX3 failed due to low efficiency

HEX name Design type Internal pipe Vapour return

Length (mm)

ID (mm)

OD (mm)

Length (mm)

ID (mm)

Free ID (mm)

HEX Capillary inside HEX 500 10 7.6

HEX1 CuNi pipe inside HEX 900 2.0 2.4 442 12 7.2

HEX2 CuNi pipe inside HEX 1900 2.0 2.4 380 12 7.2

HEX3 Cu pipe inside HEX 1900 2.0 3.0 380 14 8.0

HEX4 Cu pipe inside HEX 3000 2.0 3.0 380 14 8.0

QM-1 Cu pipe inside HEX 2764 2.0 3.0 361 14 8.0


Results with CERN HEX4

Minimum massflow to remove nominal detector power of 346.5W found for HEX = 5.7g/s

Inlet liquid temperature of 35°C maintained through out Massflow measured by volume meter Massflow measurement checked with energy balance

Know inlet liquid and outlet vapour pressure/temperature Know power into the system Can calculate massflow

Minimum massflow

Minimal massflows at 100% power

5.2

5.3

5.4

5.5

5.6

5.7

5.8

5.9

6

20 25 30 35 40 45

Temperature at HEX inlet (C)

Ma

ss

flo

w (

g/s

)

TlaHEX = -12.3 C

TlaHEX = -12.9 C

TlaHEX = -12.7 C

TlaHEX = -14.2 C

TlaHEX = -8.7 C

TlaHEX = -3.2 C

TlaHEX = -6.5 C

TlaHEX = -20.7 C

TlaHEX = -16.1 C

TlaHEX = -19.9 C

35 ºC basepoint:TlaHEX = -12.8 ºC

Baseline massflow = 5.7g/sfor TlbHEX = 35°C, 100% power


Results summary– CERN HEX4

TlbHEX=35C

100% power

TlbHEX=20C

0% power

Massflow (g/s)

5.7 5.74

TlaHEX -12.8 -25

Hex eff 0.81 1.0

Xi 0.17 0.1

Xu 0.76 0.1

Massflow Increase= 0.7%


Stability checks

Tests were performed to confirm that the system is stable Ran for more than 2 hours without

interference Rapidly (less than 1 minute) increase

detector power from 0 to 100% Repeated measurements to confirm

observations


0 to 100% power min massflow

Different HEX orientations

All with TlbHEX = 35°C, 100% power

V

min massflow (g/s) 5.5 5.7 5.4

PlbCAP (bara) 14.2 14.25

TlaHEX (°C) -15 -13 -6.5

Efficiency (%) .83 .80 .69

Xi 0.13 0.17 0.22

Xu 0.74 0.76 0.83

-45deg

V

L V +45deg

L


Only 2 capillaries open

Tested as some disks only have two circuits Only 2 EC HEXs has 2 capillaries (disk 1)

Tested in +45deg as worse case Efficiency of HEX reduced

Does not work for nominal massflow - now 3.98g/s Minimum stable massflow = 4.4g/s

Same flow if use 2 x large capillaries Could use 1large and 1small cap & increase pressure to test

TlaHEX = -20C, HEX eff = 0.92 DP HEX V = 35mbar, DP on cylinder = 46mbar

Change in massflow 100%(T=35°C) to 0%(T=20°C) 0.7% increase


QM-1

Inlet liquid pipelength reduced by8% to 2764mm

100% power

TlbHEX=35C

CERN HEX, 0deg

+45deg -45deg -45deg -45deg0%, TlbHEX=20C

Massflow 5.7 5.84 5.99 5.8 6.16 (+3%)

PlbCAP n/a 13.08 13.01 12.59 13.0

TlaHEX -12.8 -9.1 -7.6 -7.5 -14

Hex eff 0.81 .75 .72 .72 .92

Xi 0.17 .18 .22 .22 .11

Xu 0.76 .74 .78 .79 .11

Stable at 98% power and massflow of 5.84g/s (2.5% above baseline 5.7g/s)Max massflow 8% above baseline massflow: (+45deg, 0%(T=20) = 6.06g/s)


Barrel HEX

Contra-flow Two liquid inlet pipes Length 1.5m

Thermal enclosure bulk head

Heat exchanger

Heater

Demountable connector + electrical break

Demountable connector

Demountable connector + electrical break + filter

Return tube

Inlet tube

Capillary

Schematic 1: SCT barrel layout of cooling circuit from stave to heater

Vapour in

45

HEX out of page

x

z

-45deg geometry


Results

Nominal massflow of 7.8g/s shown to remove nominal detector power of 504 W

Inlet liquid temperature of 35°C maintained through out

Stability checks performed System measured for both ± 45deg Tested with cooling loop & barrel 6 manifold HEX vapour ΔP too high – but manageable


Results

100% power (504W)

TlbHEX = 35C

+45deg geometry -45deg geometry

Massflow (g/s) 7.8 7.8

TlaHEX (oC) 9.5 9.2

HEX Efficiency 0.43 0.44

Xi 0.34 0.34

Xu 0.98 0.98

P vapour (mbar) 145 140

P liquid (mbar) 120 130

Pressure after Cap 1.81 1.84


Changes in massflow for changes in TlbHEX and power

Power(%)

TlbHEX(oC)

Massflow(g/s)

% change inmassflow

P vapour(mbar)

P liquid(mbar)

TlaHEX(oC)

HEX eff

100 35 7.8 N/A 145 120 9.5 0.43

0 35 8.2 5 120 130 -1.25 0.6 *

0 23 8.8 13 75 170 -19.5 0.9

* Funny seen in the system. The operating conditions for a power cycle 100% to 0% power (TlbHEX = 35°C) resulted in a lower efficiency for the HEX and therefore lower massflows when compared to starting the system up. From start up the massflow for TlbHEX=35°C was 8.8 g/s. Not observed for -45deg geometry.

+45deg


Efficiency increases with lower TlbHEX

Barrel HEX conditions as a function of TlbHEX, for nominal massflow (7.8g/s) and 100% power (504W)

0.40

0.50

0.60

0.70

0.80

0.90

15 20 25 30 35 40

Temp of liquid before HEX (C)

Eff

icie

nc

y

-15

-10

-5

0

5

10

Te

mp

era

ture

(C

)

HEX efficiency HEX eff (loop) average TlaHEX TlaHEX (loop)

Xi Xu20C 0.15 0.7835C 0.38 0.99


Highest efficiency up to 75% power – 378W

HEX characteristics as a function of Detector Power

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.0% 20.0% 40.0% 60.0% 80.0% 100.0% 120.0%

Detector power (%)

HE

X e

ffic

ien

cy

-20

-15

-10

-5

0

5

10

15

Tla

HE

X (

C)

HEX efficiency at 20C HEX efficiency at 30C HEX efficiency at 35C

average TlaHEX at 20C average TlaHEX at 30C average TlaHEX at 35C

TlbHEX=35C75% powerMassflow = 8.6g/s


Stability 0 – 100% power

TlaHEX = 9.5C

TlbHEX = 35C

TvbHEX = -25C

TvaHEX = 14C


2hour run


System only slightly affected at 75% power

Vq=0.75

Vq=0.98


Barrel HEX with cooling loop

Vapour returnHeater

PCap

BPR

PvaHEX

PlaCap

PvbBPR

PlHEX

TlbHEX0

TvaHEX

TvaH

TlbHEX1Barrel HEX

Barrel cooling loop

TlaCap0

PlbCap

PlbHEX

TlbCap1

TlbCap0

PvHEX

TlaHEX1

TlaHEX0

Capillaries

TlaCap1

PvaLoop

TlaMod24

TlbMod1

TvbHEX

TlbMod1

TlaMod24

PLoop

PvbHEX

Liquid fromcooling rig

Vapour tocooling rig


Barrel HEX with cooling loopPlaCap

TlaCap0

TvbHEX

Capillary

TlaCap1

PvaLoop

TlaMod24

TlbMod1

PLoop Capillary

To HEX

TlaMod1

TlaMod24

TlbMod1 TlaMod1

TlaMod24 TlaMod24

M2

M3

M1

M7

M8

M6

M11

M12

M10

M2

M3

M1

M7

M8

M6

M11

M12

M10

M23

M22

M24

M18

M17

M19

M14

M13

M15

M23

M22

M24

M18

M17

M19

M14

M13

M15

TlaMod12

TlaMod12


Barrel HEX/Cooling loop test

Tested HEX with real cooling loop HEX performance the same with cooling

loop as with dummy load Cools first and final module Pressure drop over cooling loop

considerable – results in evaporation temperature changes

ΔP less for lower detector power and lower inlet liquid temperature


Cooling loop Press & Temps

Coolant Temperature, (oC)

Calculated saturation pressure, bara

Measured pressure, bara

Start of loop 1 -13.2 2.6 2.7

End of loop 1 -19.1 2.1

Start of loop 2 -13.2 2.6 2.7

End of loop 2 -19.2 2.1

In exhaust pipe few cm after manifold

-22.8 1.8 1.8


P in loop & manifold

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 100 200 300 400 500 600

Power (W)

Pre

ssu

re d

rop

ove

r lo

op

(b

ar)

top loop (DP sensors)

lower loop (diff 2 PAbs)

press drop over exhaust

over loop (DP#3 - DP exhaust)

Massflow 7.9VQ in 0.35VQ out 0.98





100% powerPman = 280mbarPloop = 540mbarPtotal = 820mbar


Smooth increase in P as function of outlet vapour quality

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0% 20% 40% 60% 80% 100% 120%

Outlet Vapour Quality

Pre

ssu

re d

rop

(b

ar)

DP #3 over upper loop (00.04)

DP over lower loop

press drop over exhaust

over loop (DP#3 - DP exhaust)


P for TlbHEX = 20ºC

For m=7.8g/s Vapour quality

reduced Pressure drop

reduced Still very high

Tevap reduced T < 3ºC

NOTE If reduce massflow

then VQ increase, P and Tevap rise

TlbHEX 35C 20CVQ inlet 0.38 0.15VQ outlet 0.99 0.78P TOTAL (mbar) 819 594P loop 538 365P manifold 281 229T start of loop -13.4 -16.6T end of loop -19.3 -19.2T (ºC) 5.9 2.6


Summary of HEX performances

Need more liquid at the outlet (higher efficiency)

for stability

Min flow cooling 100% of power with stable load transients 0%-100%-0%

50% more capacity


Pressure drop measurements

Pressure drops measured for: Inlet pipe work ID = 4 mm, Length = 10.8 m Outlet pipe work ID = 8 mm, Length = 6 m Final design of Endcap On-cylinder pipe work Prototype EC and Barrel Heaters HEX of each design: Liquid inlet & Vapour return Barrel cooling loop Barrel HEX to manifold pipe work

Final pipe work sizes predicted for heater exhaust to PPF1/PPF2 PPF2 to PPF3 (PR on racks)

EC Pressure drops - summaryFrom To Length (mm) ID (mm) Pressure drop (mbar)

Inlet

PP3 PP2 25000 6 45.9

PP2 PPF1 6000 4 55.8

PPF1 Inlet of HEX 800 3 23.5

HEX 3000 2 1000 (1200)

Total inlet side 1125.2 (1325.2)

Exhaust

PPF0 Inlet of HEX 2463 6&8 90 (130)

HEX 380 8 60

Outlet of HEX Inlet of Heater 140 8 2.5

Heater 390 8.7 43

Heater exhaust PPF1 470 6 26.7

PPF1 PP2 6000 10 44.2

PP2 PP3 25000 14 48

Total return side 314.5 (354.5)

Barrel Pressure drops - summaryFrom To Length (mm) ID (mm) Pressure drop (mbar)

Inlet

PP3 PP2 25000 6 86

PP2 PPF1 6000 4 104.5

PPF1 Inlet of HEX 800 2 222.9

HEX 2100 2 210

Total inlet side 623.5

Exhaust

Stave Exhaust Inlet of HEX 500 7.5 44.3

HEX 1700 13/10 170

Outlet of HEX Inlet of Heater 400 10 5.5

Heater 510 10 41

Heater exhaust PP2 6000 12 39.9

PP2 PP3 25000 16 52.7

Total return side 353.4


Extra slides


Photos

The main cooling rig

BPR


Condenser, volume meter, PLC


Power supplies for cooling loop heaters


Barrel cooling loop picturesFinal cooling loopBarrel 6 manifoldBarrel 3 pipe run manifold to HEX36 ceramic heaters


PicturesCapillary into loopPressure measurements just after capillaryPress sense 5cm after manifold on exhaust

Temperature sensors on pipeand on heatersInsulations around temp sensors


Barrel HEX & cooling loop

HEX at -45deg Loop horizontal


EC QM HEX prototype

First QM EC HEX at CERN


Pressure specifications High input P : MinPinlet > Psat(T=40°C) = 12.8bara MinPinlet= 13bara

Psat(T=35°C) = 11.3bara MinPinlet= 11.5bara Low evaporating pressure : P(T=-25°C) = 1.67bara Pressure drops

Liquid side Capillary to PR = 1bara PR to cooling rack = 1bara PR range (for flow regulation) = 1baraPressure from liquid pump = 16bara

Vapour side Pmin at inlet of BPR = 1.3bara Pressure drop from detector structures to BPR = 350mbara Pressure drop includes drop along Heater, (budget = 50mbar), HEX, on-

cylinder pipe work, and rest of pipe work to BPR. Higher massflow implies higher pressure drops in system

BIGGER pipes, bigger Heater etc And more powerful Heater


Number of circuits and capacity

Table 1: basic parameters and cooling capacity of the SCT evaporative circuits

Numbers of capillaries per circuit

Number of circuits

Nominal power load

Subtotal nominal power

load

[W] [kW]

SCT Barrel 2 44 504 22.2

SCT EC (3 sectors disk)

3 64 346.5 22.2

SCT EC (2 sectors disk)

2 8 241.5 1.9

TOTAL 116 46.3


Barrel +45deg, change in operating conditions of HEX as TlbHEX and power changes

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Measurements of Barrel and EC HEX

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