LED Back Light Cooling for Display

Front view of Meter Panel Back view of Meter Panel

Display Back of Display

Heat Pipe Heat Sink

LED

Heat Pipe Heat Sink

Fin

Heat Pipe

Plate (Attached LED)

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

1

LED Head Lamp Cooling

Heat pipe (heat dissipation to frame)

Thermal performance Heat dissipation 15W LED temp. < 90oC at ambient 40oC under natural convection condition Advantage 1) High performance 2) High reliability (no fan)

Frame Heat sink

LED Head Lamp

2

LRU Cooling in Aircraft LRU unit example

Individual LRU packed in cabinet

Air flow by use airplane air

cooling system or in-built fan

Cooling concept

development example 1

Electronic

boards

Heat sink

LRU module

Heat pipe

Cooling concept

development example 2

Heat pipe

Heat pipe transfer heat

to chassis for cooling

Remote heat exchanger.

Heat pipe transfer heat to heat

exchanger outside of box.

Cooling concept

development example 3

Heat pipe

Heat sink

Advantages: Passive cooling, no

moving parts, reliable.

Higher heat transfer.

Robust design, low form

factor.

3

Vapor Chamber Base (4mm Thk.)

Solder (0.15mm Thk.)

Copper(0.3mm Thk.)

Ceramic (0.6mm Thk.)

Copper(0.3mm Thk.)

Casing

IGBT Die (0.2mm Thk)

Solder (0.15mm Thk.)

Cover

Silicon gel (optional)

Cooling IGBT

DC/DC Inverter for Motor Speed Control

Cooling of Power Semiconductor- Smart Grid

Cold Plate

4

Base: A1100, 700 x 330 x 20mm

Fin: A1100, 700 x 150 x 0.5mm, Pitch 9mm, 51pcs

Heat Pipe: D15.88 x 19pcs

Air Cooled Heat Pipe Heat Sink for IGBT 700

400

510

Cross-section of HP 5

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 shape heat sinks.

6

IGBT and Semiconductor Power Devices

Vapour Chamber

7

CPU

For Blade Server

MCM 1 KW Vapor Chamber Vapor Chamber for 2U-4U Server

Fins

Copper-Water Vapor Chamber

For Blade Server

Substrate TIM

Captive Hardware

Vapor

Vapor Chamber Heat Sinks for Server

8

Two dimensional

heat flow

Heat Pipes Copper Fins

Vapor Chamber Base

Heat In

Heat Out

Vapor Chamber

Heat Pipe Fins

Vapor Flow

Liquid Flow

0.160

0.180

0.200

0.220

0.240

0.260

0.280

0.300

20 25 30 35 40 45

Air Flow [CFM]

Rca

[oC

/W]

Design VC+HP (Test Results) Design VC+HP (Calculation)

Solid Base (Calculation)

250W GPU

Thermal performance of Vapour Chamber + Heat Pipes

Vapour Chamber + Heat Pipes for Graphic Chip

9

Ultra Thin Vapour Chamber

Ultra thin High heat dissipation

capability

Loop Heat Pipe

11

Distinguishing features: ① Porous structure only in evaporator ② Transport lines made from bare tube ③ Separated liquid & vapour flow

1

2

3

4

Evaporation

Heat transfer by vapour

Condensation

Liquid transport by capillary effect

Operating Principle

Evaporator Wick

Condenser

Liquid

Heat Source Heat Sink

Vapour Flow

Container

Liquid Flow

1 3

4

Liquid line

Condenser

Vapour channel

Liquid reservoir

Wick

Evaporator (grooved

tube)

Vapour line

Vapour channel (grooved portion)

Heat input

Heat output

1

2

3

4

Loop Heat Pipe: Concept

Loop Heat Pipe Advantages: ① High heat flux capability ② Long distance heat transfer ③ Orientation independent operation

12

Wick

Evaporator + compensation chamber (liquid reservoir)

Condenser (different configurations possible)

Vapour line

Liquid line

Liquid flow Vapour flow

Wick Liquid reservoir

Vapour flow channels

Bayonet tube (for uniform liquid

distribution inside wick core)

Loop Heat Pipe Design and Working

Why Loop Heat Pipe ?

High heat transfer capability

Longer distance heat transport

Orientation independent operation

No leakage issues (safe system)

No moving parts (reliable & powerless system)

Smaller system volume (two phase system)

High system performance at high heat loads

14

Loop Heat Pipe: Application Areas

15

Vehicle Thermal Management

16

Vehicles

Ground Transport: Automotive Air Transport: Aircraft

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

Challenges Thermal Control (Cooling/Heating) Energy Conservation

Objectives

Aviation Applications

Galley Heating Wing Anti Icing Engine Anti Icing

DM-Fuel Cell Cooling

Co-generation (Power + Heat) System

CPC Rack LRU

Thermal control: Heating

Thermal control: Cooling

Interior Exterior

1

2 3

Load cabinet

(Galley )

LHP

Condenser

Fuel cell

stack LHP

Evaporator

Vapour chamber or

heat spreader with

heat pipes

Vapour line

~ Electric

Output Water

purifier

Fuel

supply

system

Portable

water

Fuel in

By-products out

Liquid line

Air in

Air out

LHP-DMFC Cogeneration System

Heat exchanger

Cold

water In

Hot water

Out

18

> 1 m

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

Existing Anti Icing System

Hot air bled from the engine

compressor Air

exhausted

Internal swirl

Engine Anti Icing

Heat required: 5.75 kW/m

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

19

LHP based Ice Protection System H

eat

tra

nsf

er

dis

tan

ce: 5

m

Q = 2 x 6.9 = 13.7 kW

510 mm 45 mm 175 mm

Gravity

LHP Evaporator

Liquid reservoir

LHP System

Liquid line

Vapour lines

vapour from evaporator

Liquid to evaporator

Leading edge

Leading edge

Loop heat pipe condenser

Vapour line

Liquid line

Condenser details 20

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

Condenser plate

Vapour line

Liquid line

Heat spreader

Evaporator

CPC Rack Cooling

Nickel or Titanium wick

Charging line

Tube connector

Heat spreader

Liquid chamber From

liquid line

From vapour

line

Bayonet tube

10 mm

150 mm

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

Automotive Applications

22

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

Spreader plate

LHP Condenser LHP

Evaporator

Battery Stack

Heat Pipes

Loop heat pipe prototypes Loop heat pipe prototype

Condenser

Liquid line

Vapour line

1000 mm

Evaporator

Nickel wick with copper evaporator tube

Wick installed inside

evaporator

Loop Heat Pipe Prototype

Evaporator Internal Details

Ungrooved CC section

Grooved evaporator portion

Nickel wick

Copper tube

23

250 mm

Cylindrical Evaporator: Performance Results

Copper-water LHP with Nickel wick

Horizontal heat mode 50% charge ratio Heated length: 55mm (20 W/cm2)

0.11

0.13

Variable conductance

Constant conductance

24

Orientation Tests

25

Horizontal heat mode

Top

he

at m

od

e

0.5 m

0.25 m

1 m

1 m THM

0.5 m THM

0.25 m THM

Horizontal HM

40

50

60

70

80

90

100

0 100 200 300 400 500 600

Evap

ora

tor

Tem

pe

ratu

re, °

C/W

Heat Load, W

0.0

0.5

1.0

1.5

2.0

2.5

0 100 200 300 400 500 600

Tota

l Th

erm

al R

esi

stan

ce, °

C/W

Heat Load, W

Loop heat pipe was able to transfer > 500 W at any orientation

with heat source temperature < 100 ºC