Combining direct and indirect free cooling for data centers via transformation into a building-scale heat exchanger

Data centers are pivotal to the global digital infrastructure but are responsible for substantial energy consumption and environmental impact, with cooling systems accounting for over 40 % of their energy use. This research addresses these challenges by proposing a novel dual-loop free cooling system that reduces reliance on traditional refrigeration-based cooling equipment, such as chillers or compressors. The system is designed to minimize capital and operational costs while maintaining an attractive power usage effectiveness across diverse climates. The proposed design transforms the data center structure into a counter-flow heat exchanger in which the hot and cold air streams are separated by a thermally and electrically conductive layer. The modular and scalable design can be incorporated into existing data center infrastructure, optimizing thermal management while reducing environmental footprint through a simplified, low-maintenance system. Using a combination of computational fluid dynamics simulations and theoretical models, we quantified the performance of the system under various climate conditions, including all 50 of the United States and several cities in other countries. The system consistently achieves a power usage effectiveness below 1.2 in cooler climates and maintains competitive performance in warmer, more humid regions. This research offers a sustainable, energy-efficient cooling solution that abides by industry standards and shows promise for broad application in data centers across the globe. • We design a simplified data center cooling system to reduce its carbon footprint. • This novel form of free cooling reduces or eliminates mechanical cooling equipment. • Theoretical model and simulations predict energy savings of roughly 30 %. • Optimal performance is obtained in cool and/or dry climates. • Can be retrofitted into existing data centers or integrated into new facilities.