LED Back Light Cooling for Display
Display

Back of Display

Heat Pipe Heat Sink

LED
Front view of Meter Panel

Plate(Attached LED)

Back view of Meter Panel

Thermal performance
Heat dissipation 10W
FinLED temp. < 90oC at ambient 65oC
under natural convection condition
Advantage
1) Silent (no fan)2) High reliability (no fan)
Heat Pipe

Heat Pipe Heat Sink
1

LED Head Lamp Cooling
Heat sink

Frame

LEDHeadLamp
Heat pipe(heat dissipation to frame)
Thermal performance
Heat dissipation 15W
LED temp. < 90oC at ambient 40oC
under natural convection condition
Advantage1) High performance2) High reliability (no fan)2

LRU Cooling in Aircraft
Cooling concept
development example 1

LRU unit example

LRU module

Cooling concept
development example 2
Heat pipe

Electronicboards

Air flow by use airplane air
cooling system or in-built fan

Heat sink

Heat pipe Remote heat exchanger.
Heat pipe transfer heat to heatexchanger outside of box.

 Heat pipe transfer heatto chassis for cooling

Cooling concept
development example 3

Advantages:
 Passive cooling, nomoving parts, reliable.
 Higher heat transfer.
 Robust design, low form
factor.

Individual LRU packed in cabinet
Heat sink
Heat pipe3Cooling of Power Semiconductor- Smart Grid

DC/DC Inverter for Motor Speed Control

Cooling IGBT
CoverSilicon gel (optional)
IGBT Die (0.2mm Thk)
Solder (0.15mm Thk.)

CasingCold Plate

Copper(0.3mm Thk.)
Ceramic (0.6mm Thk.)
Copper(0.3mm Thk.)
Solder (0.15mm Thk.)
Vapor Chamber Base (4mm Thk.)

4

Air Cooled Heat Pipe Heat Sink for IGBT
700

400510

Base: A1100, 700 x 330 x 20mm
Fin: A1100, 700 x 150 x 0.5mm, Pitch 9mm, 51pcs
Heat Pipe: D15.88 x 19pcsCross-section of HP
5

IGBT and Semiconductor Power Devices
Examples of some heat sinks for semiconductor power device

Heat pipe with ceramic insulator
joints for cooling high power (kW)thyristor.

Metal saw machining technology
can produce any size and shapeheat sinks.
6

Vapour Chamber

7

Vapor Chamber Heat Sinks for Server
For Blade Server

For Blade ServerFins

Copper-Water Vapor Chamber

Vapor
CaptiveHardware
CPU
MCM 1 KW Vapor Chamber

TIM

Substrate

Twodimensional
heat flow

Vapor Chamber for 2U-4U Server8

Vapour Chamber + Heat Pipes for Graphic ChipFins

Heat Pipe

Heat Out

Copper Fins

Heat Pipes

Heat In

Vapor Chamber
Vapor Flow

Liquid Flow

Thermal performance of Vapour Chamber + Heat Pipes
0.300
0.280

Vapor Chamber Base

250W GPURca [oC/W]

0.260
0.240
0.220
0.200
0.180
0.160
202530354045Air Flow [CFM]
Design VC+HP (Test Results)

Design VC+HP (Calculation)

Solid Base (Calculation)9Ultra Thin Vapour Chamber
 Ultra thin High heat dissipation
capability

Loop Heat Pipe

11

Loop Heat Pipe: Concept
Vapour channel(grooved portion)

Liquidreservoir

Evaporator(groovedHeat inputtube)

Wick

1

Operating Principle
1 Evaporation
2 Heat transfer by vapour
3 Condensation
4 Liquid transport bycapillary effectWick

4Vapourchannel

2Vapour line

Liquid line

Evaporator

1Condenser

3Heat output

Loop Heat Pipe Advantages:① High heat flux capability② Long distance heat transfer③ Orientation independent operation

Heat Source

WickVapour
Flow
Liquid Flow

Container

Condenser

3Liquid4
Heat Sink
12

Distinguishing features:① Porous structure only in evaporator② Transport lines made from bare tube
③ Separated liquid & vapour flow

Loop Heat Pipe Design and Working
Evaporator + compensationchamber (liquid reservoir)

Liquid line

Vapour line
Vapour flow
channels
WickCondenser (differentconfigurations possible)

Vapourflow

Liquid flow

Bayonet tube (foruniform liquid
distribution insidewick core)

Liquidreservoir

Why Loop Heat Pipe ?

 High heat transfer
capability
 Longer distance heattransport
 Orientation
independent operation

 No leakage issues (safesystem)
 No moving parts (reliable& powerless system) Smaller system volume(two phase system)
 High system performanceat high heat loads14

Loop Heat Pipe: Application Areas

15

Vehicle Thermal Management

VehiclesGround Transport: Automotive

Challenges
 High heat load
 Long distance heat transport Variable Orientation
 Acceleration & Vibrations Issues
 Multiple heat sources

Air Transport: Aircraft

Objectives
 Thermal Control (Cooling/Heating) Energy Conservation

16

Aviation Applications
1

CPC Rack

LRU

Thermal control: CoolingInterior
32DM-Fuel Cell Cooling

Exterior

Galley Heating

Co-generation (Power + Heat) System

Wing Anti Icing

Engine Anti Icing

Thermal control: Heating

LHP-DMFC Cogeneration System
Fuel cellstack
Fuelsupplysystem

Air out

Fuel inElectricOutput~

Vapour chamber orheat spreader withheat pipes
Vapour line

LHP
Evaporator
Air inBy-products out
Liquid line

Waterpurifier>1mPortablewaterLoad cabinet(Galley )Hot water
Out

Heat exchanger

LHPCondenser

Coldwater In

Specifications:Large scale
Heat load: 0.5 – 1 kW
Distance: > 1 m

18

Existing Anti Icing System

Heat required: 5.75 kW/mInternalswirlAirexhausted

Hot air bledfrom the engine
compressor

Engine Anti Icing

Wing size:
B737 (Small plane): 9 m
B777(large plane): 20 m
19

LHP based Ice Protection System
Specifications:Large scale
Heat load: 0.5 – 1 kW
Distance: > 1 m

Liquid line

vapour fromevaporator
Leading edge
Liquid toevaporator

Heat transfer
distance: 5 m

Leading edge
Vapourlines

Gravity

LHP System

Liquidline
Vapourline

510 mm 45 mm

Q = 2 x 6.9 = 13.7 kW

175mm
Liquid reservoir
LHP Evaporator

Loop heat pipe
condenser

Condenser details
20

CPC Rack Cooling
Condenser
plate

Liquid line

Heat
spreader150 mm

Evaporator

Fromvapour
line

10 mm

Nickel or Titanium wick
Tube connector

Bayonet tube

Heatspreader
Liquid chamber

FromCharging liquid lineline

Vapour line

Specifications:
Small scale
Heat load: 30 – 50 W
Distance: 100- 150 mm

Automotive Applications

Battery Cooling Heat load: 0.5 – 1 kW
 Distance: 0.25 – 1 m

LED Headlamp Cooling Heat load: 25 – 50 W
 Distance: > 150 – 250 mm

BatteryStackSpreader
plateHeatPipes

LHP
Evaporator

Loop heat pipe prototypes

LHP
Condenser

Loop heat pipe prototype

22

Loop Heat Pipe Prototype
Evaporator
1000 mm

250 mmVapour line

Liquid line
Grooved evaporator
portionCondenser
Nickel wick

Ungrooved
CC section

Copper tubeNickel wick with copper evaporator tube

Wick installedinsideevaporator

Evaporator Internal
Details

23

Cylindrical Evaporator: Performance Results
VariableconductanceConstantconductance Horizontal heat mode
 50% charge ratio Heated length: 55mm (20 W/cm2)

 Copper-water LHP with Nickel
wick

0.13
0.1124

100

Top heat mode

Evaporator Temperature, °C/W

Orientation Tests
9080
700.5 m600.25 m

50
400Total Thermal Resistance, °C/W

1m

100

200

300
400
Heat Load, W500

Horizontal heat mode

600

2.5Loop heat pipe wasable to transfer > 500W at any orientation
with heat source
temperature < 100 ºC

2.0
1.5

1.00.5 m
THM

0.25 m
THM1m
THM

Horizontal
HM

0.5
0.0
0100

200

300
400
Heat Load, W500

60025