Optimizing Horizontal Manifold Arrangement for Ground Source Heat Pump Using Orthogonal Testing

This study investigates the importance of improving the heat transfer efficiency of buried pipe systems by optimising the horizontal manifold layout in ground source heat pump systems under summer conditions. Based on the similarity theory, we developed a novel horizontal manifold layout method on a sandbox experimental bench. The heat loss of horizontal manifold in different scenarios (underground garage, lawn, square and road) was investigated by orthogonal tests. The study identifies the optimal layout of the horizontal manifold for different scenarios, with a special focus on how the new layout can effectively reduce the outlet temperature in a 20 underground garage environment. The new solution improves the overall heat transfer performance of the system by 37 % compared to the traditional horizontal manifold layout. The study highlights that even if individual component efficiencies are not optimal, a sensible system configuration can still optimise overall performance, and synergies between components need to be considered. Extreme variance analysis reveals the influence of five key factors on the heat transfer efficiency of the horizontal manifold, with surface temperature having the most significant effect. This study provides an integrated optimisation approach for ground source heat pump systems, which is particularly suitable for diverse application scenarios. These findings not only improve the performance of ground source heat pump systems, but also provide valuable guidance for practical engineering design, offering new perspectives on the application and optimisation of ground source heat pump systems.