Advances in additive manufacturing (AM) enable new opportunities to design compact heat exchangers (cHEXs) by leveraging flexible geometries to improve energy and material efficiency. However, it is well known that reducing size in counterflow cHEXs can degrade effectiveness due to axial heat conduction through the solid material, which depends strongly on material thermal conductivity and wall thickness. Understanding the interaction between fundamental heat transfer mechanisms and manufacturing constraints is essential for designing next generation compact thermal systems that fully exploit AM's shaping flexibility. This study investigates how material selection and AM thin wall limitations influence the maximum achievable power density in compact plate heat exchangers. An optimization framework evaluates six materials including plastic, austenitic steel, Al2O3, AlN, aluminum, and copper under fixed pressure drop and effectiveness, while accounting for AM specific thickness constraints and a minimum plate spacing to address fouling risks. Results show that copper consistently yields the lowest power density despite having the highest thermal conductivity, whereas plastic achieves the highest power density across most optimization scenarios. Without manufacturing or fouling constraints, plastic outperforms the baseline steel design by nearly three orders of magnitude. With uniform plate thickness or fouling constraints, the performance gap narrows, making plastic and austenitic steel comparable. When material specific thickness limits are applied, plastic again leads in compactness due to its superior thin wall manufacturability. These findings highlight that AM constraints strongly affect cHEX compactness and that lower conductivity materials can outperform metals such as copper in power dense heat exchanger designs.

翻译：增材制造（AM）技术的进步为设计紧凑型换热器（cHEXs）带来了新的机遇，通过利用灵活的几何结构来提升能量与材料效率。然而，众所周知，在逆流式紧凑型换热器中，尺寸减小可能因固体材料中的轴向热传导而导致效能降低，该效应强烈依赖于材料热导率和壁厚。理解基本传热机制与制造约束之间的相互作用，对于设计充分利用增材制造形状灵活性的新一代紧凑型热系统至关重要。本研究探讨了材料选择和增材制造薄壁限制如何影响紧凑型板式换热器可达到的最大功率密度。通过一个优化框架，在固定压降和效能条件下，评估了包括塑料、奥氏体钢、Al2O3、AlN、铝和铜在内的六种材料，同时考虑了增材制造特有的厚度约束以及为应对结垢风险而设置的最小板间距。结果表明，尽管铜具有最高的热导率，但其功率密度始终最低；而塑料在大多数优化场景中实现了最高的功率密度。在没有制造或结垢约束的情况下，塑料的性能比基准钢设计高出近三个数量级。在均匀板厚或结垢约束下，性能差距缩小，使塑料与奥氏体钢表现相当。当应用材料特定的厚度限制时，塑料凭借其优异的薄壁可制造性再次在紧凑性方面领先。这些发现突出表明，增材制造约束强烈影响紧凑型换热器的紧凑性，且在功率密集型换热器设计中，较低热导率的材料可能优于铜等金属。