By Jacob Wolfe, Global Key Account Manager, Armstrong Fluid Technology
The task of achieving maximum energy efficiency for mission-critical cooling applications is never straightforward. In data centers, in particular, extreme scrutiny of environmental performance is constant, in a situation which demands maximum reliability and zero downtime.
With energy requirements increasing steeply, driven largely by AI, availability of power from the grid is a major issue with the potential to limit expansion, as is the need to secure the goodwill of stakeholders such as local planning authorities. These issues are magnified by commercial and technological factors, such as the need for adaptability and flexibility to address short equipment update cycles.
In this complex landscape, the best way of setting up for future expansion is to build a system designed specifically for incremental expansion from the start. Rather than making a large, front-loaded investment in a plant room designed for a hypothetical full load, expanding in line with increasing demand for processing capacity provides more control over critical factors for efficiency, while achieving faster deployment, and futureproofing the development within an unpredictable sector.
The traditional approach of creating a cooling system capable of supplying 100% of demand from the outset is unsuitable for data centers for a multitude of reasons.
First, it involves unnecessary front-loading of investment in building services for the site and does not provide the necessary flexibility to increase incrementally over time.
Second, a cooling system designed for 100% demand at the outset (when actual demand is far lower during the early phases) involves significant risks of energy wastage due to the operation of over-sized equipment. Although the cooling technologies themselves are highly reliable, over-sizing the equipment increases the risk for technical issues. Simply put, it risks disappointing energy efficiency levels from the start, while complicating future efforts to change or expand the system.
The keys to effective incremental expansion of cooling systems in alignment with increasing processing capacity include modularity, repeatability, scalability, demand-based control, and active performance management.
Modularity: The best cooling systems for data centers are those that are designed on modular principles, specifically for incremental expansion. This ensures that additions to the system can be integrated quickly and seamlessly, without time-consuming and costly installation and commissioning, or additional development in-situ. In general, increasing ease and speed of expansion efforts while avoiding oversizing is always a good strategy.
Repeatability: To safeguard reliability and reduce risk, it is important that the modules have been carefully designed for the stringent demands of data center applications but are readily available as off-the-shelf products. Ad hoc equipment and customized systems are ineffective in these situations, as they introduce variables and unknowns that can adversely impact reliability due to unpredictability.
To create a cooling system which delivers in terms of both modularity and repeatability, it is helpful to think in terms of packaged plant or offsite-manufactured plantrooms. Examples would be System Envelope Fluid Management Station by Armstrong Fluid Technology which is fully assembled and tested before it leaves the Armstrong Fluid Technology factory, many potential project risks (such as poor system integration) are eliminated.
These types of solutions also help avoid energy waste that results from oversized plants, while potentially boosting profitability by preventing front-loading of capital investment, and providing repeatability of performance. Increasingly we are seeing data center operators with multiple sites moving toward integrated offsite-manufactured plantrooms, which can replicate the same cooling systems at each site. This speeds up the introduction and expansion of new facilities in this highly competitive industry sector and assists with day-to-day operation.
Scalability: With proper forecasting, plant capacity can be expanded using repeatable designs in a scalable fashion as each data center expands. As many of the companies establishing new data centers are international businesses, an equipment supply partner capable of manufacturing the same solution at multiple production facilities worldwide is also beneficial, as it helps to ensure continuity irrespective of the location of each data center.
Demand-based control: Data center cooling systems need to be reliable and efficient over wider ranges of operating conditions as the site expands. Thus, it is crucial that system components and control technologies are designed for variable demand and ultra-efficient performance at part-load. This requires variable-speed components (such as chillers, pumps, and fans) across the system, and a control strategy specific to the operating characteristics of variable speed devices. There are no exceptions to this, because constant-speed devices cannot solve the challenges of applications such as data center cooling.
When a variable frequency drive (VFD) is added to a compressor, pump, or fan to improve part-load efficiency, the energy saving potential is huge due to the pump fan laws which state that power is proportional to rotary speed cubed (PaN3). This would equate to a potential 400% increase in operating efficiencies. This is only possible, however, if the pump fan law relationship between pressure and rotary speed, along the Natural Curve, is maintained at the decreased speed.
Traditional control practices often fail to optimize this potential. Pumps, for example, are often set to maintain a fixed or minimum differential pressure across the pump supply and return headers. This means the pump will not have the freedom to operate along its Natural Curve and will consume more energy. Best practice is to utilize advanced integrated control across the system. In the case of variable speed chillers, integrated control ensures operation along the chiller’s Natural Curve for all operating scenarios, ensuring optimum efficiency at all loads.
Another important design principle is the employment of capacity-based (rather than demand-based) sequencing. With capacity-based sequencing, each pump would be taken up to 90% loading, for example, before the next pump was introduced. Demand-based sequencing, however, balances the load across the entire system, unlocking additional energy efficiencies which might otherwise remain under-exploited.
It’s important not to copy and paste the exact same HVAC solutions that are used for other applications, including those suitable for other mission-critical situations such as hospitals or laboratories. With data centers, the unpredictability of the sector itself must be met by flexibility in design methodology.
Jacob Wolfe is Global Key Account Manager at Armstrong Fluid Technology. Connect with Jacob Wolfe.
Jacob Wolfe, LEED AP, has worked in the heat transfer industry for over 20 years. He is responsible for Armstrong’s global data center market, focusing on hyperscale. Jacob has worked for leading global companies that focus on plate and frame type design in the HVAC, Petrochemical, O&G, Marine, Food, Refrigeration, Power, Renewables and Data Center applications.
Image: System Envelope – Fluid Management Station, a factory-assembled, modular pumping and control system in a single, compact package. By Armstrong Fluid Technology.
Also Seen On: acrjournal.uk 17 June 2026