# Optimization of Airflow Organization in Bidirectional Air Supply Data Centers in China
## 5 Conclusions  
This study investigates a bidirectional data center located in a hot-summer and warm-winter region, employing CFD numerical simulations combined with field measurements to analyze airflow characteristics and thermal environment features. Multiple practical retrofit solutions are proposed, with comparative evaluations conducted on their respective airflow patterns and cooling performance. The main research findings are summarized as follows:  
(1) Under the current bidirectional air supply mode of the air conditioning system, the airflow distribution through perforated tiles exhibits distinct patterns characterized by either lower-middle/higher-end or higher-middle/lower-end configurations. The data center demonstrates excessive air supply from the cooling system, with cold air bypass dominating the overall airflow organization. However, severe mixing between cold and hot airflows is observed, resulting in imbalanced cooling capacity distribution and low cooling utilization efficiency. (2) Among the individual optimization strategies, the rack blanking panel strategy demonstrates the most significant thermal environment improvement. Compared to the baseline model, it achieves 46.9% and 37.7% reductions in SHI values for racks in bidirectional and unidirectional supply zones, respectively, significantly enhancing cooling utilization efficiency. In contrast, cold aisle door-only containment, cold aisle top-only containment, and fully contained cold aisle containment show limited performance improvements with SHI reductions of 1.30%, 0.43%, and 12.17%, respectively, exhibiting \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **Baseline Model** & **Case1** & **Case2** & **Case3** & **Case4** & **Case5** & **Case6** & **Case7** \\ \hline RTI & 0.786 & 0.782 & 0.784 & 0.800 & 0.740 & 0.733 & 0.755 & 1 \\ SHI & 0.230 & 0.227 & 0.229 & 0.202 & 0.132 & 0.137 & 0.056 & 0.027 \\ RCI\({}_{\text{HI}}\) & 0.992 & 0.985 & 0.972 & 0.984 & 1 & 1 & 1 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of thermal metrics across different airflow optimization strategies. minimal effects on cooling efficiency enhancement while increased SHI values are recorded in certain rack rows for these configurations. (3) Among combined optimization strategies, the \(\text{RCI}_{\text{HI}}\) is maintained at 1.0 across the computer room, indicating complete elimination of local hotspot risks. Rack blanking panels with fully contained cold aisle containment demonstrate superior thermal performance improvement compared to rack blanking panels with cold aisle top-only containment, which in turn outperforms rack blanking panels with cold aisle door-only containment. The implementation of rack blanking panels with full cold aisle containment achieves an SHI reduction to 0.027, corresponding to an 88.26% enhancement in cooling utilization efficiency. (4) Among all optimization configurations, rack blanking panels with fully contained cold aisle containment demonstrate optimal performance improvement. However, full containment may potentially create negative pressure or fire safety concerns. The implementation of additional fire protection measures would further increase retrofit costs. Under budget constraints, rack blanking panels with cold aisle top-only containment represents the primary alternative, followed by rack blanking panels with cold aisle door-only containment as the secondary option. This study validates the effectiveness of airflow optimization schemes in improving data center thermal environments, though certain limitations remain. Future work will focus on comprehensive lifecycle cost-benefit analysis, where an economic model incorporating initial investment, operational costs, and energy savings will be developed. Additionally, scalability analysis will be conducted to further validate the scheme's applicability and return-on-investment period across different geographical locations and facility scales. Conceptualization, Y.W. and J.Y. ; methodology, Y.W. ; software, Y.W. ; validation, Y.W.