Preprint for publication: "Gyroid-Based Heat Exchangers for Heat Transfer Intensification: Additive Manufacturing and Practical Considerations"

In heat exchanger design, an important factor is maximising the heat transfer performance and its efficiency. Since these characteristics depend directly on the heat transfer surface area, extended surfaces are a common means of enhancing heat transfer. In the past, the geometry of heat transfer surfaces was rather simple due to the available, cost-efficient production technologies, mainly shaping and material subtraction. However, over the last decade, additive manufacturing, often referred to as 3D printing, has matured into a technology for producing parts from a range of materials, including plastics and metals. Such technology has opened completely new possibilities for the shapes and complexity of the parts produced. In relation to heat exchangers, additive manufacturing allows the manufacturing of intricate heat transfer structures. Triply periodic minimal surfaces and gyroids, their most common representatives, are highly promising structures for enhancing heat transfer due to their high surface-to-volume ratios. The paper addresses the design, preparation, and practical considerations of a heat exchanger with a gyroid-based structure and its additive manufacturing. This includes the methodology for preparing the geometry for two heat transfer fluids, including the solution of the inlets and outlets and their connection to the gyroid structure. Three modelling approaches were compared: graphical modelling, parametric modelling, and artificial intelligence-based generation. Parametric modelling using MATLAB was identified as the most suitable method due to its precision and flexibility. A gyroid structure was generated using an implicit function, converted into an STL format, and further refined in CAD software. The model was then 3D printed using an ASA material. Key challenges included an insufficient wall thickness, high mesh complexity, and printing limitations. These issues were resolved through iterative optimisation, resulting in a manufacturable and structurally stable design. As a result, the proposed workflow demonstrates the feasibility of integrating computational modelling and additive manufacturing for advanced heat exchanger design.