About 40% of the energy utilized in data centers is used for cooling systems, and this percentage has increased significantly in recent years. Data center server racks receive indirect cooling from computer room air conditioning units (CRACs) or computer room air handler units (CRAHs), and chilled air is sent to the racks through a raised floor plenum to cool the server room. This approach is inefficient because the server room has excessive cooling while the IT equipment has inadequate cooling. The data center industry has begun to use thermally and energy-efficient single-phase liquid cooling solutions as a result of the tremendous increase in IT power density and energy usage. One of the most popular liquid cooling systems will be examined in the current study, which is based on numerous circumstances. Under various secondary coolant conditions, the hydro-thermal performance of different liquid-to-air and liquid-to-liquid coolant distribution units (CDUs) will be assessed experimentally using multi-racks loaded with different numbers of thermal testing vehicles (TTVs), and the system response to any change in the flow will be examined by disconnecting and reconnecting the TTVs cooling loops in the multi-racks through different sequences of transient events. Moreover, a set of rules and guidelines will be established to commission these units.
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This content will become publicly available on February 1, 2025
Experimental evaluation of direct-to-chip cold plate liquid cooling for high-heat-density data centers
Owing to the dramatic increase in IT power density and energy consumption, the data center (DC) sector has
started adopting thermally- and energy-efficient liquid cooling methods. This study examines a single-phase
direct-to-chip liquid cooling approach for three high-heat-density racks, utilizing two liquid-to-air (L2A)
cooled coolant distribution units (CDUs) and a combined total heat load of 128 kW. An experimental setup was
developed to test different types of CDUs, cooling loops, and thermal testing vehicles (TTVs) for different
operating conditions. IR images and the collected data were used to investigate the effect of air recirculation
between cold and hot aisle containments on the CDU’s performance and stability of supply air temperature
(SAT). Three different types of cooling loops (X, Y, and Z) were characterized thermally and hydraulically.
Results show that Type Y has the lowest cold plate thermal resistance and pressure drop, among others. In a later test that included a single rack at a heat load of 53 kW and a single CDU, the heat capture ratio for fluid was found to be 94%. Experiments show that using blanking panels on the back of the racks limits hot air recirculation and maintains a steady SAT in the cold aisle. Finally, the CDU performance was evaluated at a high heat load for the three racks at 128 kW, and the average cooling capacity of the units is 58.6 kW, and the effectiveness values for CDU 1 and CDU 2 are 0.83 and 0.82, respectively.
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- Award ID(s):
- 2209776
- NSF-PAR ID:
- 10529800
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Applied Thermal Engineering
- Volume:
- 239
- Issue:
- C
- ISSN:
- 1359-4311
- Page Range / eLocation ID:
- 122122
- Subject(s) / Keyword(s):
- Data centers Thermal management High power density racks Liquid cooling CDU
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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