Thermal energy harvesting is the process of capturing heat which is either waste energy given off by engines, machines and other sources or which is freely available in the environment and putting it to use. Thermal energy can then be converted into mechanical or electrical energy or may be used as heat to pre-heat water for domestic use or industrial processes.
The benefit of this technology isreduced demand for energy production, in particular fossil fuel consumption as it makes use of energy that is already present but not being utilised. In addition, the technology can extend the life of, or entirely replace, batteries.
Thermoelectric power generation modules or TEG’s are already used in many applications, such as space craft where they harvest heat given off by the decay of a supply of radioactive material and on domestic stoves for use in developing countries where electrical power is hard to supply, or not available, by other means. The same technology is also used in camping stoves for charging electronic devices and batteries in the field.
The future for thermal energy harvesting
An increased demand for more sustainable energy and advances in energy harvesting technology, in particular developments in thermoelectric devices, means we are likely to see thermal energy harvesting in a wide range of new applications in the near future.
Thermoelectric modules are finding their way into a range of wireless and other remote sensor and communication systems as replacements for batteries. This is because they offer a more environmentally friendly solution, and because they eliminate the need to replace a battery that has run out. This also makes it possible to place these systems where it would be impossible to replace batteries, such as harsh or hazardous environments.
TEG’s are also likely to be embedded in the structure of aircraft to power wireless condition monitoring sensors scattered through them. In this application the use of energy harvesting reduces the requirement for wiring saving weight and cost.
Thermoelectric generators are also being developed for powering wireless sensors in power stations, factories, pipe lines and district heating systems. The emerging sector of wearable electronic technology also offers potential for thermoelectric energy harvesting by powering devices with body heat. A number of projects are on-going to place thermoelectric generators in vehicle exhaust systems to supplement or ultimately replace the vehicle’s alternator with the aim of increasing overall fuel efficiency. A wide range of energy harvesting technologies are also being considered for intelligence and defence applications.
European Thermodynamics are a UK thermal management company and specialists in thermal energy harvesting, they have a series of TEG-related projects in various applications: http://www.europeanthermodynamics.com/research/ The company also sells thermoelectric generators with a wide range of performances through RS.