Integrated design optimization of heat exchangers for additive manufacturing in electrified automotive, aerospace and marine applications

The design optimization of heat exchangers (HE) is a key enabler for addressing the substantial amounts of low-grade waste heat generated by proton exchange membrane (PEM) fuel cells in transport electrification. Concurrently, advances in Additive Manufacturing (AM) technology introduce new opportunities for unprecedented HE geometries, supporting enhanced heat transfer, compactness, and reduced mass. This study proposes a structured optimization framework, based on validated methodologies, to support the rapid conceptualization and refinement of compact cross-flow heat exchangers compatible with Selective Laser Melting (SLM). The presented technique is applied to a literature case, achieving up to 50% mass savings and 31% improved heat transfer. Subsequently, it is extended to a nominal 100 kW cross-flow air radiator to maximize its thermal effectiveness, while minimizing component mass with respect to automotive, aerospace, and marine applications. The methodology quantifies how different optimization goals and application constraints influence the global and internal dimensions of the solution. Results exhibit that rectangular channels reduce overall component mass by approximately 33% and 13% compared to circular and combined circular-rectangular configurations. Circular channels show a compactness improvement on the range of 10%-20% with respect to rectangular ducts, increasing up to 30% for hybrid configurations. A dynamic simulation model completes the assessment by ranking non-dominated solutions using an application-specific coefficient of performance (CoP). Findings provide guidelines for future modular propulsion system design, indicating that mass-minimized designs are generally best suited for automotive and aerospace systems, whereas balanced mass-thermal optimization targets yield the highest CoPs for marine applications.