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.