Waste heat recovery

Heat generated by industrial processes, urban facilities, traffic, etc. is ubiquitous. Much effort has been devoted to develop heat management strategies that maximize energy efficiency. Conceptually there are two different approaches to create value from heat. Heat can either be transferred to another location and be utilized again in the form of heat or heat can be converted into electrical energy. We are investigating thermoelectric materials that enable the direct conversion of heat flux into electric power.

Fig. 1: a) Scanning electron microscope image of a polished cross section of a nickel-rich TiNiSn Half-Heusler phase with metallic tin inclusions. b) Ternary phase diagram for TiNiSn proposed by us based on phase boundary mapping. Four three-phase regions are identified, within which the nickel content in the TiNiSn Half-Heusler phase is constant. c) Thermoelectric Half-Heusler module built at Empa.


We focus on Half-Heusler thermoelectrics materials and modules and developed all necessary steps for establishing a technological platform that bridges materials research and application. Half-Heusler materials are particularly promising thermoelectrics as they are based on abundant, non-toxic elements, combine thermal stability with mechanical robustness and demonstrate respectable performance in the relevant temperature range. We also developed a numerical model for matching the architecture of thermoelectric modules to heat exchangers for a given set of materials properties.

Swiss Federal Office of Energy, Swiss State Secretariat for Education, Research and Innovation.

Selected publications

[1] Y. Tang, X. Li, L.H.J. Martin, E. Cuervo Reyes, T. Ivas, C. Leinenbach, S. Anand, M. Peters, G. J. Snyder, C.  Battaglia. Impact of Ni content on the thermoelectric properties of half-Heusler TiNiSn, Energy Environ. Science, 11, 2018, 311.

[2] D. Landmann, Y. Tang, B. Kunz, R. Huber, D. Widner, P. Rickhaus, R. Widmer, H. R. Elsener, C. Battaglia. Fabrication, characterization, and application-matched design of thermoelectric modules based on Half-Heusler FeNbSb and TiNiSn, J. Appl. Phys. 125, 2019, 085113.

[3] C. Battaglia, R. Widmer, T. Helbling, L. Hug, B. Miller, W. Neumann, M. Götze, C. Sägesser, Y. Dubois, Potential of thermoelectrics for waste heat recovery, final report for Swiss Federal Office of Energy.

[4] Y. Tang, D. Landmann, B. Kunz, D. Widner, R. Huber, P. Rickhaus, R. Widmer, E. Cuervo Reyes, T. Durand, J. Hu, Y. Liao, E. Lo Schiavo, M. Hauenstein, C. Rovath, C. Graf, I. Papadimitriou, P. Dimopoulos, C. Battaglia, Thermoelectric on-board power generation from exhaust gas, final report for Swiss Federal Office of Energy.

Press release

The potential of thermoelectrics, Swiss Federal Office of Energy press release, 8.7.2016 (deutsch, français)