Thermoelectric generators are devices which convert temperature differences into electrical energy, taking advantage of the Seebeck effect: the conversion of a temperature differential into electricity at the junction of two materials.
Although thermoelectric phenomena have been used for heating and cooling applications quite extensively (laser cooling, applications where temperature must be kept constant with great precision, etc.), electricity generation has only seen limited adoption in niche applications; it is only in recent years that interest has increased regarding new applications of power generation through thermoelectric harvesting.
IDTechEx research forecasts that the market for thermoelectric energy harvesters will continue to grow and reach over $950 million by 2024, as discussed in detail in the research report Thermoelectric Energy Harvesting 2014-2024: Devices, Applications, Opportunities.
The new applications are varied and the vertical markets benefiting from new devices range from condition monitoring in industrial environments, smart metering in energy market segments, to thermoelectric applications in vehicles, either terrestrial or other.
The IDTechEx report gives an overview of devices, materials and manufacturing processes, with a specific focus on emerging technologies that allow for new functionality, form factor and application in various demanding environments.
Whether it is operation in high temperatures or corrosive environments, applications with increased safety demands or components that need to be thin, flexible, or even stretchable, there is a lot of research and development work worldwide which is highlighted.
Market forecasts for thermoelectric energy harvesters (US$ million)
Source: IDTechEx Report "Thermoelectric Energy Harvesting 2014-2024: Devices, Applications, Opportunities"
Some of the most significant application sectors include:
Waste heat recovery systems in vehicles:
Most car companies, including Volkswagen, Volvo, Ford, BMW and GM in collaboration with NASA have been developing thermoelectric waste heat recovery systems in-house, each achieving different types of performance but all of them expecting to lead to improvements of 3-5% in fuel economy while the power generated out of these devices could potentially reach up to 1200W.
A significant milestone to be reached in these applications remains the ability to bring the cost per Watt to price points that will be tolerated by the already “squeezed for profit margins” automotive industry.
Wireless sensor network adoption:
Wireless sensors powered by thermoelectric generators in environments where temperature differentials exist would lead to avoiding issues with battery lifetime and reliability.
It would also lead to the ability to move away from wired sensors, which are still the solution of choice when increased reliability of measurement is necessary. Some applications have low enough power demands to operate with small temperature differentials, as small as a few degrees in some cases.
Examples of such device proliferation are already hitting the market by technology developers collaborating with industrial system integrators such as ABB and GE.
Consumer applications:
In these applications, the type of solution that thermogenerators provide varies: it could be related to saving energy when cooking by utilising thermo-powered cooking sensors, powering mobile phones, smart watches or other consumer electronics, even body sensing could become more widespread with sensory wristbands, clothing or athletic apparel that monitor vitals such as heart rate, body temperature, etc.
Finally, utilising solid assumptions based on the knowledge acquired through extensive primary research and the understanding of the way existing and new markets develop over time, 10-year IDTechEx market forecasts are included in the report.
[Dr Harry Zervos is Senior Technology Analyst, IDTechEx.]