Abstract
Computer room air handling (CRAH) bypass (BP) method is an application that reduces the total fan power in air-cooled data centers by lowering CRAH fan speed. BP fans supply the complementary fraction of server airflow from warmer room air through lower-resistance floor openings into the plenum. Hence, chillers need to operate at lower temperatures less efficiently, which poses an optimization problem. The reduced-order modeling tools in the literature adequately predict fan power. However, they assume well-mixed temperature at rack inlets to deal with this optimization problem and fail to quantify the impact of ignoring temperature non-uniformities. This study includes an experimental verification of computational fluid dynamics (CFD) modeling for CRAH BP method in predicting temperatures in a data center test-cell. The subsequent parametric study uses both CFD and reduced-order modeling tools on a more representative quadrant of a large data center to investigate induced and forced CRAH BP in both enclosed and open aisle configurations as well as comparing various plenum heights, IT load and server airflow rate. Results indicate where reduced-order modeling tools perform reasonably well and where the need for CFD emerges and identify various favorable data center designs and operating conditions for CRAH BP method.
| Original language | English |
|---|---|
| Article number | 114685 |
| Journal | Applied Thermal Engineering |
| Volume | 166 |
| DOIs | |
| Publication status | Published - 5 Feb 2020 |
Bibliographical note
Publisher Copyright:© 2019 Elsevier Ltd
Funding
This study is funded by The Scientific and Technological Research Council of Turkey (TUBITAK) through the award number 118M238. Moreover, the experimental data used in this paper were measured by M. Koz and M.T. Yildirim at the Syracuse University Green Data Center Research Laboratory under NYSERDA award 41202. The authors are indebted to Prof. H. E. Khalifa, who was the Principal Investigator of this award, for allowing us access to these measurements. Computational resources for the grid-independence study were provided by the National Center for High Performance Computing of Turkey (UHEM) at Istanbul Technical University under the Grant Number 1006272019. This study is funded by The Scientific and Technological Research Council of Turkey (TUBITAK) through the award number 118M238. Moreover, the experimental data used in this paper were measured by M. Koz and M.T. Yildirim at the Syracuse University Green Data Center Research Laboratory under NYSERDA award 41202 . The authors are indebted to Prof. H. E. Khalifa, who was the Principal Investigator of this award, for allowing us access to these measurements. Computational resources for the grid-independence study were provided by the National Center for High Performance Computing of Turkey (UHEM) at Istanbul Technical University under the Grant Number 1006272019 .
| Funders | Funder number |
|---|---|
| TUBITAK | 118M238 |
| New York State Energy Research and Development Authority | 41202 |
| Syracuse University | |
| Türkiye Bilimsel ve Teknolojik Araştirma Kurumu | |
| Istanbul Teknik Üniversitesi | 1006272019 |
Keywords
- Computational fluid dynamics
- CRAH bypass method
- Data centers
- Optimization
- Reduced-order modeling