Waste Heat Energy Harvesting Using Olsen Cycle on PZN-5.5PT Single Crystals

This paper reports on direct thermal to electrical energy conversion by performing the Olsen (or Ericsson) cycle on [001]-poled 0.945PbZn1/3Nb2/3O3-0.055PbTiO3 (PZN-5.5PT) single crystals. The cycle consists of two isothermal and two constant electric field processes. The energy density was found to decrease with increasing cycle frequency while the power density increased. The maximum energy density obtained was 150 J/L/cycle for temperatures between 100 and 190oC and electric field between 0 and 1.2 MV/m at frequency 0.034 Hz. The maximum power density reached 11.7 W/L at 0.1 Hz for temperatures between 100 and 190oC and electric fields between 0.2 and 1.5 MV/m. Moreover, the dielectric constant and saturation polarization of PZN-5.5PT are reported for the first time at 0.1 Hz for temperatures between 100 and 190oC. Finally, the experimental results agree relatively well with predictions by a recently developed temperature-dependent property model already validated with PMN-32PT. Inter-sample variability and sample durability are also discussed.