All machines from jet engines to microprocessors generate heat, as do manufacturing processes ranging from steel to food production. Thermoelectric generators (TEGs) are solid-state devices able to convert the resulting heat flux directly into electrical power. TEGs therefore have the potential to offer a simple, compact route to power generation in almost every industrial sector. Here, in a Roadmap developed with wide-ranging contributions from the UK Thermoelectric Network and international partners, we present the science and technology that underpins TEGs. We outline how thermoelectric (TE) technology capable of generating power outputs from microwatts to tens/hundreds kW, and potentially to MW, can have an impact across a wide range of applications in powering devices, ranging from medical to building monitoring, the internet of things, transportation and industrial sectors. The complementary application of TE technology in cooling affords additional opportunities in refrigeration and thermal management. Improved waste-heat harvesting and recovery and more efficient cooling offer significant opportunities to reduce energy usage and CO2 emissions. We provide an overview of the key challenges associated with the development of new materials and devices that offer higher power output, while matching TE solutions to the wide range of applications that would benefit from energy harvesting. There is an existing supply chain to develop, manufacture and integrate thermoelectric devices into a broad range of end-user sectors all with global market potential: the full realisation of which will require new state-of-the-art manufacturing techniques to be embraced in order to drive down costs through high-volume manufacturing to widen the application base.

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Realising the potential of thermoelectric technology: a Roadmap

A dynamic model for thermoelectric generator applied to vehicle waste heat recovery

3D model of thermoelectric generator (TEG) case study: Effect of flow regime on the TEG performance

Prediction of the fuel economy potential for a skutterudite thermoelectric generator in light-duty vehicle applications

The performance of a modified solar chimney is studied numerically and experimentally. In this solar chimney, the classical solar collector array is replaced by a heat exchanger located in the middle section of the chimney. The natural convection inside is simulated by the commercial Computational Fluid Dynamics (CFD) code COMSOL. This software is used first to perform an optimization of the power output and to determine the optimal dimensions of the chimney prototype. From the parameters obtained numerically, a two-meter high chimney model is built to measure temperature profiles and power output of the chimney. The comparison between numerical and experimental results shows a difference lower than 6.2% for the power generated. Our prototype achieves a higher power density in comparison with other reported prototypes based on conventional solar chimney concept of similar height.

Modified solar chimney configuration with a heat exchanger: Experiment and CFD simulation

Thermoelectric generator (TEG) has received more and more attention in its application in the harvesting of waste thermal energy in automotive engines. Even though the commercial Bismuth Telluride thermoelectric material only have 5% efficiency and 250°C hot side temperature limit, it is possible to generate peak 1kW electrical energy from a heavy-duty engine. If being equipped with 500W TEG, a passenger car has potential to save more than 2% fuel consumption and hence CO2 emission reduction. TEG has advantages of compact and motionless parts over other thermal harvest technologies such as Organic Rankine Cycle (ORC) and Turbo-Compound (TC). Intense research works are being carried on improving the thermal efficiency of the thermoelectric materials and increasing the hot side temperature limit. Future thermoelectric modules are expected to have 10% to 20% efficiency and over 500°C hot side temperature limit. This paper presents the experimental synthesis procedure of both p-type and n-type skutterudite thermoelectric materials and the fabrication procedure of the thermoelectric modules using this material. These skutterudite materials were manufactured in the chemical lab in the University of Reading and then was fabricated into modules in the lab in Cardiff University. These thermoelectric materials can work up to as high as 500°C temperature and the corresponding modules can work at maximum 400°C hot side temperature. The performance loss from materials to modules has been investigated and discussed in this paper. By using a validated TEG model, the performance improvement using these modules has been estimated compared to commercial Bisemous Telluride modules.

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Min Gao

Papers

Improved thermoelectric generator performance using high temperature thermoelectric materials