Article Featured in Data Centre Review
By: Gordon Johnson, Senior CFD Manager, Subzero Engineering
The current and growing industry focus on sustainability has highlighted the need to work towards energy efficient data center designs, which, in turn, should provide the perfect combination of sustainable operating conditions. The end result being truly optimized data center performance.
Computational Fluid Dynamics (CFD) plays a vital role when it comes to data center construction, retrofit, and helping improve the efficiency and performance of legacy data centers. It allows the owner or operator to simulate endless combinations of racks, cabinets, cabling, and mechanical and engineering (M&E) equipment for greater optimization.
The owners and operators of these facilities may not be aware that they are literally blowing a lot of (unnecessary) cold air into the aisles in order to keep the servers, switches, routers, and the storage units cool. What they will know, however, is that this wasted air is wasted money. Worse still, emissions will be increased, hot spots will remain an issue, and they will eventually experience equipment failures.
Many data center managers know that something has to change to overcome this unsustainable situation, but they may not have a plan or strategy. This is where CFD is critical.
CFD is essentially an MRI of the data center, and when it comes to informed decision-making, the mantra ‘if you can’t measure it, you can’t manage it’ still holds strong. However, in the case of CFD, ‘if you can’t measure it, you can’t improve it’ may be more appropriate.
What is a CFD analysis?
CFD software creates a 3D model of the physical attributes within a data center, as well as the location and performance characteristics of the cooling units, IT equipment, power systems, and other significant components of the data center.
This ‘data center MRI’ provides a complete, detailed thermal understanding of the data center, providing insight relating to the physical layout of the space and equipment; the power equipment thermal dissipation and rack power density; environmental conditions; cooling capacity and air distribution effectiveness. This is the baseline model or the “as is” snapshot of how the data center is currently operating.
From the information obtained, additional CFD modeling will recommend how to optimize the operating environment while reducing energy and maximizing efficiency.
Many key benefits of CFD analysis include assessment of the data center layout and its performance; validation of proposed design changes, considerations for efficiency and reliability; accurate prediction/simulation of the cooling design process; the ability to assess temperature and airflow modeling; and reconditions for a cost-effective and energy efficient design.
CFD provides clarity
A data center CFD analysis provides the visibility that is essential when it comes to understanding both your existing operating environment and any potential design changes. CFD can also be used to test out ‘what if’ scenarios when it comes to new data center construction or modernization projects.
In essence, a CFD provides detailed, data-driven analysis of the cold supply air and the hot exhaust air throughout the data center, and identifies the potential overheating of IT equipment “hot spots”. Such analysis highlights the way in which energy costs can be reduced by optimizing and maximizing data center cooling. CFD is a tool used to virtually test legacy (and new) data center environments for active temperature, pressure and airflow, and to optimize the mechanical system directly to server heat loads (kW).
Armed with data from the CFD analysis, a suitably experienced technology partner, such as Subzero Engineering, can advise customers on impactful data center design changes, upgrades, or tweaks to improve operating improvements – all of which will help optimize and reduce energy usage.
For example, CFD modeling can demonstrate what impact a cold aisle containment (CAC) system will have versus a hot aisle containment (HAC) system. It will advise which method will save more energy, full or partial containment. After containment is installed, it will show if computer room air conditioning (CRAC) units can be turned off and how low fan speeds can be reduced on computer room air handlers (CRAHs). Finally, it will also inform the user on how high the operating temperature can be increased, while following the recommended thermal guidelines from AHSRAE.
The end result is that CFD based design improvements will provide customers with significant PUE, WUE, KW, kWh, carbon, and water reductions.
A logical conclusion
One of the major benefits of using CFD modeling and analysis is that it can quickly demonstrate how a containment solution will immediately reduce a data center’s energy cost and lower its environmental footprint.
Regardless of which type of containment is used, large energy savings can be achieved by optimizing the airflow and raising the supply temperature, while simultaneously eliminating hotspots. Additionally, containment improves the benefits and economic feasibility of other efficiency measures, such as digital scroll compressors, electronic commutation (EC) and variable speed drives, data center infrastructure management (DCIM) software, and building controls.
Further, by separating the cold supply air from the hot exhaust air, containment saves energy, thus reducing operating costs. Yes, there is the initial investment cost of installing the containment solution, but the potential return on investment (ROI) of 10-14 months means that, very quickly, end-users will achieve payback. What’s more, from that point onwards, they’ll be saving energy, reducing operating expenditure (OpEX) money, and reducing carbon emissions to become more sustainable.
A savings summary
Since 2015, we’ve kept track of the various savings we have achieved for our customers through the careful, considered optimization of their data center environments. The numbers are impressive: our customers have saved just under 3.5 billion Kilowatt hours, reduced water consumption by one and a half billion gallons and have a total carbon reduction of over 3.2 million tons – the equivalent of planting 17 million trees.
Along the way, we’ve also been able to help customers achieve up to a 29% energy cost reduction, and been able to reduce PUE (Power Usage Effectiveness) by an average of 0.4 and WUE (Water Usage Effectiveness) by an average of 0.3.
Subzero Engineering believes that a data-driven approach to digital infrastructure is essential and thanks to the use of CFD, we can simultaneously help our customers increase data center density, operating efficiency, and environmental sustainability by implementing optimized containment solutions.
However you choose to address the challenge and opportunity of improving the efficiency of your data center, it’s essential that CFD is used as a key tool in this process. Without CFD, whether you choose to implement an optimization program yourself, or to engage with a technology partner, you’ll neither be able to understand how your data center is performing right now, nor what improvements can be made into the future.