Towards carbon neutrality: An advanced hybrid indirect evaporative cooling solution for data centers in hot and humid regions

As 5G technology, cloud computing, and industrial digital transformation advance rapidly, the scale and number of data centers (DC) are expanding at an unprecedented rate. Characterized by high energy consumption and considerable heat release from electronic devices, DCs require continuous air conditioning (AC) throughout the year. In hot and humid regions, the efficiency of AC systems is significantly affected by environmental conditions. Indirect evaporative cooling (IEC), a widely adopted technology in DCs situated in dry regions, faces serious performance limitations in humid environments. In order to overcome the constraint and unlock the energy-saving potential, this study proposes a novel hybrid IEC system for DCs in hot-humid regions. The system integrates a liquid-desiccant-based IEC (LD-IEC) as the 1st-stage, in which the solution can be regenerated using solar heat, and a conventional IEC as the 2nd-stage. The system performance was analyzed under varying parameters, benchmarked against two reference systems, and evaluated through the year-round case study based on typical subtropical climate conditions. Results show that operating for 51.4 % of the year, it reduces the average annual supply-air temperature by 1.7 °C and decreases auxiliary cooling runtime by 61.1 % in Hong Kong. Additionally, the system achieves an annual coefficient of performance (COP_sys) of 30.7, representing a 58.3 % and 36.4 % improvement over the two baseline systems, respectively. Furthermore, the system achieves a COP_sys of 30.7, representing improvements of 58.3 % and 36.4 % over the two baseline systems, respectively. Even under the hotter and more humid climate of Singapore, the system reduces auxiliary cooling demand by 55 % and maintains a COP of 14.5, which remains notably higher than that of the reference systems.