Brandon White, Engineer, Experimental Research

Electricity demand from data centers in the U.S. could double or even triple by 2028, potentially accounting for roughly 12% of total national electricity consumption. The surge is driven by GPU‑accelerated AI workloads, which generate considerably higher heat fluxes than traditional servers. To keep pace with the growing need and to alleviate the potential drain on public utilities, manufacturers and researchers are pursuing advanced heat exchanger designs, utilization of waste heat, and sophisticated operational analysis [1].

Adiabatic air-cooled heat exchangers are a hybrid between dry and evaporative cooling. These units resemble API 661 induced‑draft, air‑cooled heat exchangers but add a fine water‑mist spray at the inlet of the finned bundle [2]. The mist cools the incoming air allowing higher heat rejection for a given fan power. Because water consumption must be minimized in dry regions, the spray is activated only when ambient conditions are favorable; otherwise, the exchanger operates in a conventional dry‑air mode.

Both dry‑air and adiabatic coolers rely on large‑diameter fans that can represent a sizable share of a data center’s power budget. Engineers are now applying computational fluid dynamics (CFD), finite‑element analysis (FEA), and machine‑learning‑driven optimization to develop next‑generation fan blades that reduce aerodynamic drag, lower motor torque, and maintain required static pressure at reduced speed (Figure 1). Recent prototypes have demonstrated fan‑power reductions while preserving airflow.

Figure 1. Example fan blade optimization workflows
Figure 1. Example fan blade optimization workflow

Already widely used in other processes, hydrogen fuel cells are now being considered for use in cooling applications in data centers. Fuel cells generate electricity through an electrochemical reaction rather than combustion. They produce significantly less waste heat than traditional generators, and the heat they do generate can be captured and repurposed through integrated heat‑recovery or absorption‑chiller systems. This capability opens the door to hybrid power‑and‑cooling architectures in which fuel cells not only supply clean, on‑site power but also support thermal management by driving secondary cooling loops. As operators push for higher energy efficiency, reduced carbon emissions, and greater resilience against grid instability, hydrogen fuel cells are gaining attention as a potential backbone for sustainable, distributed data‑center infrastructure [3, 4].

At the system level, digital twins are being employed to optimize data‑center layout and operation. A digital twin combines a high‑fidelity model of racks, aisles, and cooling equipment with CFD simulations of air flow, temperature, and humidity, all fed by sensor data and workload profiles. An optimization engine iteratively adjusts variables until target criteria are satisfied. This iterative, model‑based approach yields designs that are robust against future workload growth and climate constraints.

The waste heat from data centers is increasingly being utilized instead of rejected. Captured thermal energy can be distributed to nearby buildings for space heating, used in aquaculture facilities to maintain optimal water temperatures, or supplied to desalination plants employing multi‑effect distillation or forward‑osmosis processes. These synergies improve overall site energy efficiency and can generate additional revenue streams.

As data‑center heat loads and power usage continue to climb, innovation in heat exchange hardware, fan aerodynamics, clean‑power integration, and system‑level modeling will accelerate. HTRI remains committed to monitoring these developments, providing technical guidance, and helping our members adopt cutting‑edge heat‑transfer technologies that enhance efficiency, reduce carbon footprints, and increase operational resilience.

Click here to to read the first article in this series.

References

  1. J. Granderson, Powering the future: How data centers can overcome emerging energy challenges, 2025 Better Buildings & Better Plants Summit, Washington, DC, 30 April – 2 May 2025. https://betterbuildingssolutioncenter.energy.gov/sites/default/files/2025-05/2025Summit-Powering_the_Future_Data_Centers-Slides.pdf
  2. API STD 661: Air-Cooled Heat Exchangers for General Refinery Services (adoption of ISO 13706-1:2005), American Petroleum Institute, Washington, DC (2006).
  3. G. Saur, V. Arjona, A. Clutterbuck, and E. Parker, Hydrogen and fuel cells for data center applications project meeting: Workshop report, NREL/TP-5400-75355, (2019). https://docs.nlr.gov/docs/fy20osti/75355.pdf
  4. M. Kalyani, Cooling the new economy: Strategies for hydrogen, energy storage, AI infrastructure & more, 2026 Cooling Technology Institute Annual Conference, Houston, TX (8 – 11 February 2026).