Articles

This study presents a physics-based parametric optimization framework for thermoelastic energy harvesting from cyclic temperature variations using a cylindrical AISI 4340 steel rod. The model couples thermoelastic force and displacement, Euler buckling and yielding constraints, lumped-capacitance heat transfer, and mass-power multi-objective optimization. The feasible design space was evaluated as a function of rod diameter, length, temperature change, and load-transfer parameter. The results show that Euler buckling governs the practically relevant portion of the design space at moderate temperature changes, whereas yielding becomes increasingly restrictive at higher thermal loads. The Pareto-optimal solutions exhibit a clear mass-power scaling law, with the analytical prediction P<SUB>avg</SUB> ∝ m<SUP>2/3</SUP> closely reproduced by the numerical fit (n = 0.66717, R² = 0.999999). Under the baseline condition λ = 0.50, the maximum-power design produces approximately 0.16624 W, while a distance-to-ideal criterion identifies a substantially lighter compromise design with m = 223.0 kg and P<SUB>avg</SUB> = 0.09231 W. Refined optimization gives λ<SUB>opt</SUB> = 0.473 and P<SUB>max</SUB> = 0.170454 W, indicating a power penalty of only 2.47% when the simpler λ = 0.50 condition is used. Grid-refinement tests show changes below 0.006% in maximum power and below 0.5% in the compromise-design mass between the 250 × 250 and 500 × 500 grids. The results establish compact scaling and optimization rules for balancing structural stability, thermal response, mass, and average mechanical power in thermoelastic energy-harvesting elements.

The processes of technical and technological development are unequivocally linked to increasing energy consumption, with a significant portion of energy being produced from fossil fuels worldwide. The reserves of natural energy sources such as petroleum, gas, coal, and turf are finite. The transition to renewable energy sources has been ongoing for a long time, but share in global energy consumption remains lower than desired. The main limitations include limited availability, inability to operate continuously throughout the year, high costs, and a lack of materials and devices capable of withstanding high temperatures and pressures. The goal of our research is to create a device that generates electricity using a new type of renewable energy source based on the thermal expansion and contraction of materials. This paper presents the construction, details, and working principles of the new device. The primary focus is on utilizing materials and components that are readily available. The proposed method has own advantages, addresses some of the aforementioned limitations, and can be particularly beneficial for providing electrical energy in remote areas. Calculations indicate that the device built using this new method will be competitive with appliances that utilize other renewable energy sources in terms of features and efficiency.