A self-starting heat engine based on shape memory alloy for enhanced environmental adaptability

Abstract Shape memory alloy (SMA) heat engines offer a promising solution for waste heat recovery. Inspired by wearable devices such as smartwatches, which exhibit the ability of ‘co-movement with the heat source,’ this study focuses on improving the operational adaptability of SMA heat engines under dynamic thermal conditions. Despite their potential, traditional SMA-based heat engines are often constrained by their reliance on a fixed heat source, specific installation angles, and external startup mechanisms, which significantly limit their practical applicability. This paper presents a novel SMA heat engine with a magnetically assisted self-starting mechanism, which has been developed by means of magnetic field and dynamic simulations to construct a virtual prototype. Subsequently, the feasibility of this heat engine is analyzed and physically verified. At the core of this design is a unique operating principle that enables the device to function normally in the presence of a temperature difference and autonomously restart when the temperature difference disappears and then reappears, without requiring a specific installation angle or external activation. This reduces the device’s dependence on environmental conditions, thereby expanding its potential for broader applications.