A review of thermoelectrics research - Recent developments and potentials for sustainable and renewable energy applications

In recent years, thermoelectric (TE) devices have emerged as promising alternative environmental friendly applications for heat pumps and power generators since the environmental issues such as the global warming and the limitations of energy resources gradually drew worldwide attentions. Due to the green feature and distinct advantages, the thermoelectric technology have been applied to different areas in an effort of designing simple, compact and environmental friendly systems. The applied areas are extended from the earliest application on kerosene lamp to aerospace applications, transportation tools, industrial utilities, medical services, electronic devices and temperature detecting and measuring facilities. The application potentials of TE in directly conversing thermal energy into electrical power have been identified, especially for where the cost of thermal energy input need not to be considered, such as waste heat utilization, in the light of the present low efficiency of thermoelectric conversion. The capability of TE in producing thermal energy (in terms of cooling or heating) with the use of electrical power is also well identified. This paper reviews the status of the material development and thermoelectric applications in different areas and discusses the difficulties in terms of the commercialisations of advanced materials. Other than this, the main purpose of this paper is to present the great potential of achieving both environmental and economic benefits by exclusively utilizing thermoelectric applications in different areas. It also comes to the conclusion that the thermoelectric applications with the current conversion efficiency are economically and technically practical for micro/small applications. However, it would be transformed to a more significant green energy solution for improving the current environment and energy issues by using medium/large scale thermoelectric applications when the thermoelectric materials with a figure-of-merit over 2 come into commercial practice.