Preliminary feasibility study on pyroelectric effect for cooling purposes

The evolution of power electronics world brings a continuous miniaturization of components with an increase in power density. Due to this, thermal management is becoming a critical limit for devices performance and reliability. Traditional cooling technologies go through limitations in efficiency, size, and adaptability, so exploring novel cooling mechanisms is becoming essential to address the increasing heat dissipation challenges in power electronics. Despite few advancements in conventional and even some emerging applications, the full potential of the pyroelectric effect, a thermally induced polarization phenomenon, for active cooling applications remains largely unexplored. Currently, no known system exploits this effect for convective cooling without the presence of any external electric sources or mechanical parts. This thesis investigates the feasibility of using the pyroelectric effect, particularly in Lithium Niobate crystals, as a driver for a particular electro-hydrodynamic (EHD) fluid motion, named p-jetting, to create a novel and compact cooling device. The aim is to experimentally verify whether such a system, or in general the p-jetting phenomenon, can outperform natural convection and operate without electrodes or mechanical components. The study includes a comprehensive literature review of existing electronics cooling methods, followed by theoretical modeling of the pyroelectric effect and its interaction with fluids. A custom experimental setup was developed, including 3D-printed test rigs and precision sensors. Key tests were conducted both at Politecnico di Torino’s SMALL Lab and CNR Isasi to evaluate jetting behavior, heat transfer characteristics, and design optimizations under controlled thermal and geometric conditions. Experimental validation confirmed the generation of fluid jetting due to the pyroelectric effect, especially when using mineral oil as the working fluid. A nozzle-free, electrode-free jetting phenomenon was observed, including a novel against gravity behavior. However, measured heat flux values (4.59 W/m²) and corresponding heat transfer coefficients (0.17 W/m²K) resulted significantly lower than those of natural convection. In addition, a clear relationship between jetting frequency and distance from the crystal was established. Even if current results show that pyroelectric-driven fluid motion is feasible and potentially useful for niche applications, the thermal performance is not yet competitive with conventional solutions. Nonetheless, the concept introduces a promising new direction for cooling research, especially in microscale or passive thermal management systems where simplicity and absence of moving parts are critical. This knowledge could potentially be applied in the future to improve the obtained results till satisfying values.