Session: K6-09: HEAT TRANSFER IN ENERGY SYSTEMS - WASTE HEAT II

Paper Number: 138213

138213 - High-Performance Solid-State Heat Engine Enabled by Radiative Thermal Switching 

Abstract: 

Thermodynamic cycles realized by varying temperature and electric field in solid-state pyroelectric materials can enable high-efficiency thermal-to-electrical energy conversion. The heat input and heat removal from the solid material, however, remains a bottleneck. Accomplishing this transient heat exchange through radiation switching could address this challenge. This work demonstrates the concept of radiative heat engines based on thermal-electrical cycles in a pyroelectric material coupled with active thermal emission control in an electrochromic layer. The heat input to the pyroelectric material is achieved using a pulsed laser heat source. The thermal emission from the pyroelectric is modulated by the electrochromic layer, which switches between highly reflecting to highly absorbing states in mid-IR wavelengths during heating and cooling processes of the thermodynamic cycle, respectively. We experimentally characterized and numerically modeled the energy conversion performance of the heat engine comprising a 350 µm thick Lead Zirconate Titanate (PZT) pyroelectric sample optically coupled with a custom-fabricated multilayer electrochromic stack (ITO/WO₃/Ta₂O₅/NiO/Au). We realized pyroelectric Ericsson cycles by modulating the thermal absorption/emission and electric field at 50 mHz cycle frequency. We demonstrate that, compared to conventional pyroelectric Ericsson cycle operation, thermal emission modulation (emissivity variation between 0.2 and 0.6) resulted in a 60% increase in power density and 40% increase in thermal-to-electrical energy conversion efficiency. This approach combining thermodynamic cycles with radiative thermal switching could realize high-performance solid-state heat engines and enable applications such as waste heat harvesting, solar energy conversion and wireless power transmission.

Presenting Author: Dip DUTTA University of Louisville

Presenting Author Biography: I am a PhD. candidate of Mechanical Engineering in University of Louisville. My research is related to solid-state pyroelectric thermal energy conversion.

Authors:

Dip DUTTA University of Louisville
Bimal Nepal University of Louisville
Dominic Smith University of Louisville
Sergio B. Mendes University of Louisville
Bikram Bhatia University of Louisville