Dr. HoSung Lee

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Thermal Design ExamplesHeat Sinks

Thermoelectric coolers and generators

Heat Pipes

Compact Heat Exchangers

Solar Cells

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Heat Sinks

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Thermoelectric Generators and Coolers

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p

n

p

n

np

p

pn

Positive (+)

Negative (-)

Heat Absorbed

Heat Rejected

Electrical Conductor (copper)Electrical Insulator (Ceramic)

p-type Semiconcuctor

n-type Semiconductor

Thermoelectric Generator

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Heat Pipes

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Compact Heat Exchangers

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Solar Cells

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Sun-tracking panels

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Solar Thermoelectric Generator (STEG)

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Solar Thermoelectric Generator

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Kusatsu Hot-springs TEG System

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1950s

2012

Thermoelectric Modules (old & modern)

Kerosene lamp and radio

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Thermoelectric Cooler Module

p

n

p

n

np

p

pn

Positive (+)

Negative (-)

Heat Absorbed

Heat Rejected

Electrical Conductor (copper)Electrical Insulator (Ceramic)

p-type Semiconcuctor

n-type Semiconductor

System Designers having difficulties•Most of manufacturers do not provide the material properties(Manufacturers’ proprietary information)

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Thermoelectric Modules

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Solar Thermoelectric Generator

Nature Materials 10, 532-538 (2011)

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Thermoelectric Heat Exchanger

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Thermoelectric Heat Exchanger This study investigates the feasibility of integrating thermoelectric

devices into a large-capacity liquid heat exchanger (up to 100 kW). Typically, thermal-electrical conversion is inefficient and thermoelectrics are only used in low-power applications (<1 kW). The incentive for using thermoelectrics, however, lies in their compact size, light-weight, high reliability, and sub-ambient cooling. In this study, a subscale thermoelectric heat exchanger is designed (see Fig. 1), fabricated and optimized for performance through testing and simulation. Specifically, direct fluid contact and jet-impingement were used to improve heat transfer at both hot and cold junctions of the thermoelectric. A schematic of the design concept can be seen in Fig. 2. This approach resulted in a five-fold increase in the cooling coefficient-of-performance. Experimentally validated predictions also demonstrated that a 100-kW heat exchanger is lighter per unit-power than comparable vapor-compression systems. This feasibility study raises the outlook of reducing thermoelectric technology to practice in large heat load applications.

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HYBRID SOLAR PANEL DIAGRAMHYBRID SOLAR PANEL DIAGRAM The hybrid solar panel that Yin designed has as its outermost layer a clear protective cover, followed by a layer of thermoelectric material, a layer with plastic tubes (called the functionally graded material interlayer) to carry water that will cool the other layers while also carrying away heated water, and a bottom layer of reinforcing plastic.Image: © COLUMBIA UNIVERSITY

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Air-to-Air Thermoelectric Heat Exchangers

BSST's parent company, ships more than

1.2 million thermoelectric Air to Air

devices to automobile seat manufacturers

annually, making possible the cooled and

heated car seats available on many car

models. Building on this technology and

manufacturing expertise, BSST has created

Air to Air devices that provide electronic

enclosure cooling at nearly double the

efficiency of standard thermoelectric

cooling devices.

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Air-to-solid Thermoelectric Heat Exchangers

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Liquid-to-air Thermoelectric Heat Exchanger

BSST's uniquely designed Liquid to Air

systems allow for significant cooling

power in a variety of form factors. In a

typical BSST configuration, ambient air

enters the device and is instantly chilled to

approximately 15 degrees Celsius. The air

is then blown over electronic systems or

critical components. The waste heat from

the process is removed by the liquid loop

(typically water, but other fluids can be

used).

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Cold Plate Cooler

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Bio-medical ExperimentTwo-Temperature Reference TEC

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Microprocessor Cooling (160W)

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Miniature Thermoelectric Coolers

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Thermoelectric Cooler for Telecom Laser

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Butterfly Package for Telecom Laser

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Butterfly Package for Telecom Laser

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Dimensions for Butterfly Package

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Butterfly Package for Telecom Laser Small sized

Relatively low price

Long lifetime

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Isometric View (ANSYS)

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Laser Butterfly

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Laser Butterfly

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High-Tech Radio inside the Wing of a Fighter Aircraft

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Remote Thermoelectric Generator Power generation: 120 Watts

Fuel: natural gas

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Thermoelectric Cooling Helmet

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Thermoelectric Exhaust Systems

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Waste Heat Recovery

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Auto Exhaust Can Generate Thermoelectric Power

About 40 percent of the energy from gasoline or diesel fuel is wasted as exhaust heat. If you can convert some of that heat to electricity, it can provide electric power for automotive accessories, relieving some of the burden from the engine resulting in better fuel economy. The device that performs this conversion is a thermoelectric generator and GM has been working on developing one to either assist or even replace the vehicle's alternator.

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Automotive Air Conditioning

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Automotive HVAC

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Automotive Thermoelectric Air Conditioner (TEAC)

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OTEC (Ocean Thermal Energy Conversion)

Bi-Te element size: 10 x 1.5 mm.Total number of n-p couples: 10,000 couples/Number of TEG modules: 500 modules.

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Develop Tables for Optimal Design

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Table 1 Optimal Power Output for ZT∞2=1

T∞* Nh Rr Nk ηth Wn* T1* T2* NI NV

1.0 0.1 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

1.0 1.0 0.000 0.000 0.000 0.000 1.000 1.000 0.000 0.000

1.0 10.0 0.000 0.000 0.000 0.000 1.000 1.000 0.000 0.000

1.005 0.1 1.564 0.063 4.36E-04 9.72E-08 1.003 1 9.93E-04 1.55E-03

1.005 1 1.564 0.063 7.27E-04 2.71E-07 1.005 1 1.66E-03 2.60E-03

1.005 10 1.564 0.063 7.80E-04 3.12E-07 1.005 1 1.78E-03 2.78E-03

1.01 0.1 1.564 0.063 8.70E-04 3.88E-07 1.006 1 1.99E-03 3.11E-03

1.01 1 1.564 0.063 1.45E-03 1.08E-06 1.009 1.001 3.32E-03 5.19E-03

1.01 10 1.42 0.65 8.51E-04 3.89E-06 1.01 1.005 2.05E-03 2.92E-03

1.015 0.1 1.564 0.063 1.30E-03 8.73E-07 1.008 1.001 2.98E-03 4.66E-03

1.015 1 1.416 0.356 1.28E-03 4.82E-06 1.011 1.004 3.09E-03 4.38E-03

1.015 10 1.421 0.649 1.28E-03 8.75E-06 1.014 1.007 3.08E-03 4.38E-03

1.02 0.1 1.564 0.063 1.74E-03 1.55E-06 1.011 1.001 3.97E-03 6.21E-03

Radioisotope Thermoelectric Generator (RTG)

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Curiosity Rover in Mars

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MMRTG cutaway

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Plutonium 238

Radioactive isotope of plutonium with a half-life of about 87 years and is a very powerful alpha ray emitter

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RTG

The heat produced by the decay of Plutonium-238 can be converted to electricity by a TEG

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Schematic Diagram of an RTG System

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RTG Applications in Industry RTGs are usually the most

desirable power source for unmanned or unmaintained situations requiring small amount of power for durations too long for fuel cells, batteries and generators

Satellites

Space Probes

Unmanned Remote Facilities

Lighthouse Beacons

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Pacemaker The latest pacemakers are

powered by radioactive isotopes for long life and weigh no more than 15 g and about 3 cm in diameter. The cost is about $10,000 to $15,000

It is made up of two parts: A pulse generator, which

includes the battery and several electronic circuits

Wires, called leads, which are attached to the heart wall

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Waste Heat Recovery Geothermal Energy

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Home Power Station

One possible use for thermoelectric generators is to provide supplemental or back-up electricity for home owners who use outdoor wood/biofuelfurnaces.

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TEG installation on Stove

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Heat Pipes in a Laptop Computer

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Heat Pipes for Cooling in a Laptop

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Design Temperature control of CPU

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Novel Heating System Could Improve Electric Car’s Range

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Buyers considering an electric car must bear in mind that using battery-powered heating and air conditioning can decrease the car’s range by a third or more (see “BMW’s Solution to Limited Electric-Vehicle Range: A Gas-Powered Loaner”). A New York Times reviewer recently ran into this problem on a test drive, ending up stranded with a dead battery (see “Musk-New York Times Debate Highlights Electric Cars’ Shortcomings”).

But a heating and cooling system under development almost eliminates the drain on the battery. The researchers are working with Ford on a system that they hope to test in Ford’s Focus EV within the next two years. The work is being funded with a $2.7 million grantfrom the Advanced Research Projects Agency for Energy.

The researchers describe their new device as a thermal battery. It uses materials that can store large amounts of coolant in a small volume. As the coolant moves through the system, it can be used for either heating or cooling.

In the system, water is pumped into a low-pressure container, evaporating and absorbing heat in the process. The water vapor is then exposed to an adsorbant—a material with microscopic pores that have an affinity for water molecules. This material pulls the vapor out of the container, keeping the pressure low so more water can be pumped in and evaporated. This evaporative cooling process can be used to cool off the passenger compartment.

Power saver: A proof-of-concept heating and cooling system for electric vehicles works without battery power.

Novel Heating System Could Improve Electric Car’s Range

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As the material adsorbs water molecules, heat is released; it can be run through a radiator and dissipated into the atmosphere when the system is used for cooling, or it can be used to warm up the passenger compartment. The system requires very little electricity—just enough to run a small pump and fans to blow cool or warm air.

Eventually the adsorbant can’t take in any more water, but the system can be “recharged” by heating the adsorbant above 200 °C. This causes it to release the water, which is condensed and returned to a reservoir.

An electric heater could be used for this purpose, says Evelyn Wang, a professor of mechanical engineering at MIT, who is leading the work. “But there so many sources of heat, such as heat from a solar water heater—so electricity wouldn’t have to be used,” she says. Fully recharging the system is expected to take about four hours, which is about what it takes to recharge some common electric vehicles at standard charging stations.

The basic concept behind the temperature control system isn’t new (see “Using Heat to Cool Buildings”). But it’s been difficult to make such a system compact enough for use in a car, especially because separate containers are normally used for evaporating and condensing the coolant. The researchers’ more compact design uses one container for both purposes.

The researchers are now developing materials that can adsorb more water, which would make it possible to use less adsorbant. One is a modified zeolite, a type of porous material that has long been used in catalysis. They’re also working on a material called a metal organic framework, whose properties can be systematically changed by varying the composition of organic materials that link microscopic clusters of metal. The researchers have added highly thermally conductive materials such as carbon-based nanomaterials to their adsorbant so the system can heat and cool more rapidly, which can also make it possible to shrink its overall size.

Solar Evacuated Tube Collector (heat pipe)

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Solar Heat Pipe TEG

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Heat Fins Along PipelineMelted permafrost could result in sinking or collapse of pipeline

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Pipeline Cross SectionHeat Fins Hot Oil Flow

Heat Pipes

Permafrost

Heat Conducts Down Support Beams

Condensation and Evaporation of Ammonia

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Heat Pipe Glove

frostbite prevention

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Heat Pipe Exchanger

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Compact Heat Exchangers

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Plate Heat Exchanger

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Thermoelectric Cooler

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Thermoelectric cooler

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Car seat climate control

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CLIMATE CONTROL .Thermoelectric based cooling/heating

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USS DOLPHIN AGSS 555 Thermoelectric Air Conditioning Test for Silent Running

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Spacecraft Using Radioisotope Thermoelectric Generators

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Thermoelectric generator module

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TEG Simulations (ANSYS)

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TEG Temperature Simulations

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Shell and Tube Heat Exchanger

Baffles

TubesShell fluid

constrained

Tube fluid

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Mesh Application – Corrections

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Vectors of Velocity Magnitude

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Hand phone charger by body heat

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Personal Mini Coolerthermoelectric cool/heat mini cooler Specifications: Dimensions: 2.75 (width) X 1.20 (thick) X 5.60 (height) Inches Cold Temperature: Up to 25℃ below Ambient Temperature Weight: 4.00 oz.(without batteries) Blue Disk: Polished & Anodized Aluminum,1.4 inch diameter Blue Disk Power: Four AA size NICKEL-METAL HYDRIDE (Ni-MH).1200 mA rechargeable Batteries.(Not supplied) or regular AA”Energizer” type batteries Case: ABS Plastic

Personal Mini Cooler

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Dispenser-Printed TEG Characteristics Planar thick film (strip)

TEG properties:

Dimensions 5 𝑚𝑚 ×640 μ𝑚 × 90μ𝑚

Material and 𝑍 𝑇 at 302 𝐾 N-type: Bi2Te3 epoxy composite

(𝑍 𝑇 = 𝟎. 𝟏𝟖)

P-type: Sb2Te3 epoxy composite (𝑍 𝑇 = 𝟎. 𝟏𝟗)

Manufacturing method Dispense printing

Primary materials mixed with epoxy resins to form inks

Size of TEG strips stacked in parallel

Size of one TEG strip

Performance of Thermoelectric materials

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Si Nanowires, (Nature Vol. 451, 2008, Caltech and UC Berkeley)

Silicon bulk ZT ≈ 0.01

Silicon nanowires ZT ≈ 1

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Thermoelectric Cooler driven by Solar Cells

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Solar Driven Thermoelectric Cooling Headgear

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Hybrid Solar Cell and TEG

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TEG with Solar Collector

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Heat Pipes for Cooling Microprocessor

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Solar Thermoelectric Generators

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Miniature Thermoelectric Devices

RMT

Snyder et al. (2003)

Thermoelectric Devices

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Miniature Thermoelectric Devices

TEC TEG

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Car Seat Cooling/Heating

Seat climate technology: We set tomorrow's standards for comfort

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Low-Grade (100 C) Heat Recovery

The End

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