Direct ground cooling systems (DGCS) can provide comfort cooling to buildings without the use of any refrigeration-based cooling methods. DGCS is an emerging technology, commonly used for new office buildings in cold climates. This study aims to evaluate the energy-saving possibilities of a DGCS compared to a conventional chiller system for an existing office building. A typical Swedish office building with a chiller-based cooling system and in need of an energy renovation is taken as a reference case. Various possible renovation measures are applied on the building and to the cooling system, and the results are evaluated in terms of borehole design and building energy demand. The results show that applying the DGCS substantially reduces the building’s purchased energy, as chiller electricity demand is eliminated. In addition, implementing the renovation measures to reduce the thermal demand of the building could further reduce purchased energy. The results suggest implementing the DGCS after performing the renovation measures. This may lead to a considerable reduction in the required borehole length and hence in the drilling costs. Results from this study provide useful inputs for designing boreholes in ground-coupled systems for new and existing office buildings.

直接地面冷却系统 (DGCS) 可以为建筑物提供舒适的冷却，而无需使用任何基于制冷的冷却方法。DGCS 是一项新兴技术，常用于寒冷气候下的新建办公楼。本研究旨在评估 DGCS 与现有办公楼的传统冷却器系统相比的节能可能性。以一座典型的瑞典写字楼为参考案例，该办公楼采用基于冷水机组的冷却系统并需要进行能源改造。建筑物和冷却系统采用了各种可能的改造措施，并根据钻孔设计和建筑能源需求对结果进行了评估。结果表明，应用 DGCS 显着降低了建筑物的购买能源，因为消除了冷却器电力需求。此外，实施翻新措施以减少建筑物的热需求可以进一步减少购买的能源。结果建议在执行翻新措施后实施 DGCS。这可能导致所需钻孔长度的显着减少，从而导致钻井成本的显着减少。这项研究的结果为在新的和现有的办公楼的地面耦合系统中设计钻孔提供了有用的输入。