Sensitivity and effectivity of Kim’s novel electro-thermodynamic cycle over Olsen cycle on waste heat recovering with high fluctuating temperature source using lead-free pyroelectric Ba(Zr0.1Ti0.9)O3

Abstract

A novel electro-thermodynamic cycle with a higher waste heat recovery efficiency than the conventional Olsen cycle was introduced by Kim et al. in 2015. Thus, in the present study, the importance of the temperature factors was investigated, revealing the sensitivity and effectiveness of the Kim cycle on the fluctuating properties of the applied heat source over the Olsen cycle. Power generation tests at different frequencies and temperature ranges were performed using nontoxic lead-free Ba(Zr0.1Ti0.9)O3 pyroelectric ceramics. As the frequency increased, the original isodisplacement process of the Kim cycle successfully improved the pyroelectricity and increased the internal electric field of the sample, thereby enhancing the energy density of the recovery process. This phenomenon compensated for the energy density loss from the poor heat conduction, which was the factor that saturated the power density when measured with the Olsen cycle. Therefore, the Kim cycle was more effective than the Olsen cycle when considering the fluctuating frequency factor. In addition, adjusting the temperature range factor induced a power density enhancement owing to the internal electric field increase mechanism. The power generation ability of the Kim cycle was significantly improved compared to that of the Olsen cycle. This research study revealed the sensitivity and effectiveness of the Kim cycle for recovering waste heat from a high-fluctuating rate source. Thus, the new Kim cycle has the potential to be investigated for its energy conversion ability in the next decade.

Enhancing low‐temperature energy harvesting by lead‐free ferroelectric Ba(Zr0.1Ti0.9)O3

“…As a result, the loop became thinner as the heating time decreased. The same phenomenon has been observed for the Olsen cycle in many previous reports 52–54,57 …”

“…For instance, a comparatively high energy-storage ability of 0.5 J/cm 3 reported by Zhang et al, 55 a piezoelectric coefficient d 33 of 268 pC/N by Shin et al, and especially a high 𝑁 𝐷 ∕(Δ𝑇 ⋅ Δ𝐸) value of 0.171 μJ/(cm 2 K V) which is considered potentially for pyroelectric applications. 56,57 Additionally, the BZT composition was reported to have a relaxor behavior induced by the replacement of Ti 4+ with Zr 4+ . The transition through a relaxor phase was a successful pyroelectric energy-harvesting design using lead-based materials such as Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 -PMN-PT 58 and (Pb,La)(Zr,Ti)O 3 -PLZT.…”

“…The same phenomenon has been observed for the Olsen cycle in many previous reports. [52][53][54]57 In Figure 8B, as the heating rate increased from 4.5 to 7.2 K/s (heating time reduced from 20 to 12.5 s), the extra energy density dominated the reduction, resulting in an enhancement of the energy density of BZT10 from 447 to 462 mJ/cm 3 . However, a further rise in the heating rate decreased the energy density due to quasi-equilibrium states.…”

“…The Ba(Zr,Ti)O 3 exhibits an excellent behavior in different aspects of ferroelectricity. For instance, a comparatively high energy–storage ability of 0.5 J/cm 3 reported by Zhang et al., 55 a piezoelectric coefficient d 33 of 268 pC/N by Shin et al., and especially a high$${\rm{\;}}{N_D}/( {\Delta T \cdot \Delta E} )$$ value of 0.171 μJ/(cm 2 K V) which is considered potentially for pyroelectric applications 56,57 . Additionally, the BZT composition was reported to have a relaxor behavior induced by the replacement of Ti 4+ with Zr 4+ .…”

Improvement of Power Recovery by Applying a Multi-Pulse Electric Field in the Thermoelectric Cycle Power Generation Process with Pyroelectric Materials

“…The ABCDA region of Figure 1 contains an illustration of this cycle. Yoonho Kim et al constructed a unique electro-thermodynamic cycle by merging the Olsen and Stirling cycles with a circuit made up of a diode and two switches (DSW circuit) [22,23,[29][30][31][32][33]. According to Figure 1, the Kim cycle consists of four processes: two isothermal processes (A-B and C-E), one iso-displacement process (B-C), and two isoelectric processes (E-A).…”