Thermal energy storage remains one of the most promising but underutilized technologies for integrating variable renewable generation and recovering industrial waste heat. However, conventional storage systems suffer from slow heat transfer rates that limit their practical performance and increase their physical footprint and capital cost. Additive manufacturing offers a solution by enabling designers to create internal geometries that would be impossible or prohibitively expensive to produce through traditional casting, welding, or machining methods.
The key advantage lies in topology optimization and architected structures. Powder bed fusion, directed energy deposition, and extrusion-based processes can now produce heat exchangers with lattice networks, triply periodic minimal surfaces, and embedded fluid channels precisely tailored to maximize surface area while minimizing flow resistance. These geometries are particularly valuable for phase change material systems, where thermal uniformity during melting and solidification directly determines system response time.
Current research demonstrates that AM-fabricated structures can improve heat transfer coefficients by 30–50% compared to conventional designs while reducing system volume. Topology optimization algorithms further enhance performance by iteratively refining geometries based on thermal and mechanical constraints. Material selection remains critical: metals like aluminum and titanium are preferred for sensible heat systems, while composite and polymer-based structures show promise for lower-temperature latent heat applications.
Despite these advances, significant challenges persist. Scalability from laboratory prototypes to production-scale systems remains limited, with cost-per-unit still exceeding conventional manufacturing for large volumes. Material compatibility with molten salts, phase change materials, and high-temperature working fluids requires validation. Long-term durability under repeated thermal cycling and corrosive environments is incompletely characterized.
The transition from material-centric to geometry-enabled thermal engineering represents a fundamental shift in how engineers approach energy storage design. As manufacturing costs decrease and material libraries expand, AM-enabled thermal storage systems could become standard in grid-scale applications, district heating networks, and concentrated solar power plants.
