Physics professor taps into the potential of thermoelectrics

BY SCOTT SIGLIN
For the Daily
Published January 25, 2005

Imagine Navy ships that have the stealth of an eagle, cars that can fuel themselves electrically with their own exhaust, computers that run 50 percent faster after being cooled and refrigerators that run quieter than the night.

These ideas may become realities in the near future because of thermoelectrics.

“Thermoelectrics has terrific potential for the future. We are trying to make thermoelectrics a mainstream part of the electrical industry” for industries and even household life, said Physics Prof. Ctirad Uher.

Thermoelectrics, at a fundamental level, is the conversion of two different forms of energy. The first thermoelectric devices turned electrical energy into heat, also known as thermal energy.

A typical thermoelectric device is comprised of two synthetic semi-conducting metallic bars which are connected together at the top of each bar. An electrical current is run through these conducting bars and the movement of electrons through these highly specialized conducting bars creates a temperature gap — where the top side becomes very hot, while the bottom side remains cold.

However, thermoelectric devices can also act in the opposite direction.

The temperature gap can be made into electrical energy — all that is needed is a hot and cold surfaces. Uher’s research attempts to make the process of thermoelectrics more efficient.

“The efficiency of a thermoelectric devise is determined by two factors, the materials used and clever designing.” His research is primarily focused on what materials the bars are composed of, and he believes the right composition of elements will produce higher efficiencies.

Currently, Uher is testing out several different elements that would allow the conversion of energy to proceed at a higher rate. Today, thermoelectric devices usually run with 5 to 10 percent efficiency, though Uher predicts the efficiency can be raised to 15 to 20 percent, which would yield up to three times as much energy as before.

Uher’s experiments try to take heat that is generated from an independent source, and convert that heat into useful electrical energy.

Today’s technology requires many thermoelectric devises to produce a decent amount of energy.

Many industrial companies are pushing for this type of research to boost up the efficiency and make more usable electrical energy from fewer devices.

Thermoelectrics are beneficial in more ways than just converting energy. “Thermoelectrics are quieter, have increased longevity comparatively and are healthier for the environment,” Uher said. He explained that thermoelectrics don’t use rotating, moving parts, thus reducing noise and wear and tear of most motors.

In addition, hazardous fluids, such as radiator fluid that cool the engine of a car, won’t be as needed and will reduce the emission of poisonous gases into the air.

Thermoelectrics could have a positive indirect relationship with the environment as well. Many car manufacturers and even the federal government are investing money into thermoelectric research. The basic idea is to attach these devises to the tailpipe of a car capturing the heat from the exhaust.

“(A third) of the exhaust from a car is wasted. It is just heat released into the air,” Uher says.

Currently, Uher and General Motors are working together to try and figure out a way to capture this thermal energy and convert it into electrical energy that could potentially power the car’s many other gadgets.

This in turn could reduce the gas mileage for many cars since the excess gas that is used now, won’t be needed in the future.

But Uher added that this decrease won’t be drastic.

“I could see a decrease in the amount of gas used, but it might be slight,” he said.

The Navy also wants to install thermoelectrics into their ships.

The heat from the boilers and the coldness of the water could potentially generate electrical energy that could be used for much onboard equipment, decreasing the total amount of noise. Ideally, the Navy would like to run completely on electrical energy.

Even simple household computers can benefit from thermoelectrics.

“The operational speed of a computer is 50 percent higher just by cooling it with thermoelectrics,” Uher said.

In terms of application, the horizons appear endless for thermoelectrics, and it comes as no surprise that corporate and industrial research and development efforts have advanced to tremendous speed.