Design and performance evaluation of a multi-layer heat exchanger for cruise ship energy systems

Heat exchangers in cruise ship energy systems must achieve high thermal effectiveness while maintaining acceptable pressure losses in limited space. This study investigates how fin arrangement, material, thickness, and layer count influence the performance of multi-layer heat exchangers, and whether an artificial neural network (ANN) can provide reliable predictions of pressure drop for design optimization. A phased methodology was applied, beginning with single-layer benchmarking through experiments to evaluate straight and staggered fins in PETG and aluminum, followed by validated CFD simulations of three and eight-layer exchangers. Results showed that staggered fins increased outlet temperature by 6–12 % compared to straight fins, though at the cost of a 5–10 % increase in pressure drop. Aluminum fins improved thermal effectiveness by 15–20 % relative to PETG depending on thickness, while thinner fins reduced hydraulic resistance. Three-layer exchangers were more effective at lower NTU, whereas eight-layer designs provided superior performance at higher NTU due to increased surface area. Experimental validation confirmed energy balance within ±5 %, and a fitted correlation reproduced CFD with ≈0.3 % deviation. The ANN achieved R2 = 0.998 and RMSE ≈ 10, offering fast hydraulic predictions. The findings provide design guidance for selecting fin geometry, material, and layer configuration in compact maritime heat exchangers.