How to Build a Better Thermoelectric Cooler

The quest to improve electronics cooling has been ongoing for years, and while no company has developed the ideal solution, some companies are moving the needle on advancing cooling technology. One such company is Sheetek, a young Austin, TX-based company that has developed a patented multi-stage thermoelectric device architecture, called Centum®, that can be used for refrigeration coolers, energy harvesters, and custom thermoelectric cooling solutions.

The Centum® C3 coolers have a two-stage design with 21 to 238 thermocouples per stage. They can be designed with ΔT  of 97◦C to 110◦C. Typical sizes range from 10 x 10 x 2.8 mm to 40 x 40 x 3.7 mm with a choice or metal substrates and various finishes.  Sheetak’s technology is covered by 26 patents.

Design News interviewed Sheetak’s Founder and CEO Uttam Ghoshal to learn about the company’s technology.

What is different about your technology that is different from existing cooling approaches?

Uttam: Traditional thermoelectric coolers that rely on the Peltier effect are very large and not hermetically sealed. Their reliability is poor. We went to a wafer-scale semiconductor manufacturing approach to design our thermoelectric cooling technology. The parts look like silicon chips and we can scale them in different configurations.

What breakthroughs were needed to make this technology feasible?

Uttam: One key challenge is sandwiching semiconductors between metal electrodes. We had to develop better barrier materials and better annealing processes and develop better thermoelectric materials that don’t heat up rapidly. Previously, when you elevated the temperature, the metals tended to diffuse into the semiconductor and degrade performance.

What thermoelectric cooling products are you developing using this technology?

Uttam: We’ve developed coolers under the Centum® brand name for applications such as medical diagnostics, refrigeration and heat pumps, imaging sensors, power electronics, semiconductor test and measurement, defense, aerospace, and automotive.

How can the technology be used for energy harvesting?

Uttam: Our Centum® energy harvesting devices will find applications in wireless sensors for IoT devices, wearable devices, and waste heat harvesting in energy, chemical, and industrial processes. Some customers are looking into building and Smart Cities applications. We can generate milliwatts of power that can be used in Bluetooth and other wireless communications, to power a bunch of IoT devices where the user does not want to run a whole power line.