NANO NANO TECHNOLOGY TECHNOLOGY COOLINGCOOLING

GIRIJA SANKAR DASHGIRIJA SANKAR DASHEMBETICS SOLUTIONSEMBETICS SOLUTIONS

OVERVIEW• INTRODUCTION• CAUSES OF HEAT GENERATION• POPULAR COOLING TECHNIQUES

– PASSIVE HEAT-SINK COOLING– ACTIVE HEAT-SINK COOLING– WATER COOLING– HEAT PIPE

• NANOTECHNOLOGY• COOLING METHODOLOGY USING NANOTUBES• ADVANTAGES OF SELF COOLING• FUTURE DEVELOPMENTS• CONCLUSION

INTRODUCTION

This technique works by generating ions or electrically

charged atoms using electrodes placed close to one

another on a computer chip. Generated ions are passed

from electrode to electrode, with collisions between ions

and neutral air atoms propelling the air forward in what is

called the corona wind effect – the process that cools.

CAUSES OF HEAT GENERATION

•The amount of heat generated by an integrated circuit is

the prime cause of heat build up in modern computers, is a

function of the efficiency of its design, the technology used

in its construction and the frequency and voltage at which it

operates.

Popular Cooling techniques

• PASSIVE HEAT-SINK COOLING

• ACTIVE HEAT-SINK COOLING

• WATER COOLING

• HEAT PIPE

PASSIVE HEAT-SINK COOLING

• Passive heat-sink cooling involves attaching a block ofmachined to the part that needs cooling. More commonlyfor a personal-computer CPU, a clamp holds the heatsink directly over the chip, with a thermal grease orthermal pad spread between.

ACTIVE HEAT-SINK COOLING

• Active heat-sink cooling uses the same principle as passive, with the addition of a fan that blows over or through the heat sink. The air movement increases the rate at which the heat sink can exchange heat with the ambient air.

WATER COOLING

• Water cooling include the fact that a system is not limitedto cooling one component, but can be set up to cool thecentral processing unit, graphics processing unit, and/orother components at the same time with the samesystem.

HEAT PIPE• A heat pipe is a hollow tube containing a heat transfer

liquid. As the liquid evaporates, it carries heat to the coolend, where it condenses and then returns to the hot end.Heat pipes thus have a much higher effective thermalconductivity.

NANOTECHNOLOGY

Nanotechnology is a branch of engineering

that deals with the design and manufacture

of extremely small electronic circuits and

mechanical devices built at the molecular

level of matter.

COOLING METHODOLOGY USING NANOTUBES

• Carbon nanotube electrodes placed close to one another on a computer

chip and voltage is passed into the electrodes.

• When voltage is passed into the electrodes the negatively charged

nanotubes discharge electrons towards the positively charged electrodes.

• The electrons react with surrounding air, causing the air molecules to be

ionized just as electrons in the atmosphere ionize air in clouds.

• This ionization of air leads to an imbalance of charges that eventually result

in lightning bolts.

• To create lightning we need tens of kilovolts, but we do it with 100 volts or

less, in simple term, we are generating lighting on a nano-scale here.

• The researchers are able to create the ionizing effect with low voltage

because the tips of the nanotubes are extremely narrow and the oppositely

charged electrodes are spaced apart only about 10 microns, or one – tenth

the width of human hair.

• The ionized air molecules cause currents like those created by the “corona

wind” phenomenon, which happens between electrodes at voltages higher

than 10 kilovolts, or 10,000 volts.

• Clouds of ions created when electrons react with air can then be attracted

by the second region of electrodes and pumped forward by changing the

voltages in those electrodes.

COOLING METHODOLOGY USING NANOTUBES

• The voltages are rapidly switched from one electrode to the next in such a

way that the clouds of ions move forward.

• As the ions move forward, they make repeated collisions with neutral

molecules, producing the breeze.

• Voltages are switched at the right frequency so that the ion cloud is

constantly moving forward causing the breeze to flow.

• The pumping concept works with a region of electrodes made of many

series, each series containing three electrodes.

• The first in the series is the most positively charged, followed by an

electrode that has a less – positive charge and then a third electrode that is

negative.

COOLING METHODOLOGY USING NANOTUBES

• Switching the voltages from one electrode to the next causes the charges to

move forward, which in turn moves the ion clouds.

• Generated ions are passed from electrode to electrode, in the mode of a

charge – coupled device, with collisions between ions and neutral air atoms

propelling the air forward in what is called the corona wind effect

• The researchers nano sized the corona wind effect and combined it with

micro fluidic channels with embedded, megahertz – sequenced electrodes

to create suitable for pumping heat – laden air molecules literally through

the core of a chip and out the other side.

COOLING METHODOLOGY USING NANOTUBES

ADVANTAGES OF SELF COOLING

• Additional cost for providing external cooling (coolers, air – conditioner etc) can be eliminated.

• Size of computers will be smaller in near future compared to those used at present.

• No moving parts inside the computer, hence there will be more reliable and noiseless.

• Self – cooling of chips will increase the life expectancy of the chips and hence increase the life of appliance.

• Additional and more advanced circuitry can be designed and fabricated within a single chip.

CARBON NANORIBBONS FOR SMALLER, SPEEDIER COMPUTER CHIPS

Stanford chemists have developed a new way to make

transistors out of carbon nanoribbons.

A schematic of graphene nanoribbon field-effect transistor

FUTURE DEVELOPMENTS

• Silicon Nanowires Upgrade Data-Storage

Technology

• Integrated Nanowire Sensor Circuitry

CONCLUSION

• Nanotechnology is used in computers forimproving its efficiency. The nanowires, nanocooling techniques provides with high reliability,increased performance efficiency. It findsapplications in laptop computers, cell phones,sensing systems and many other types of portablemicroelectronics. It will also let us to fabricate anentire new generation of products that are cleaner,stronger, lighter and more precise.