In a Central European climate, that threshold difference translates to more than ten times the annual free cooling hours, according to vendor figures
Decision Lens
This is a cooling technology story, which sits at the edge of the Global Head of Data Center Energy remit. It earns attention on two specific grounds: first, the energy efficiency delta claimed is large enough to affect OpEx forecasts in European markets; second, an active EU regulatory process targeting PFAS-classified synthetic refrigerants could disrupt existing chiller procurement strategies before end-of-life cycles conclude. Neither claim has been independently verified — both originate from vendor-reported case study data published by ATMOsphere, a natural refrigerants industry publisher.
90-Second Brief
In recent days, zudek, an Italian industrial refrigeration manufacturer, reports delivering an ammonia (R717) chiller to a financial-sector data center in Baden-Württemberg, Germany in 2024, replacing an R407C unit of equivalent cooling capacity. The vendor states the replacement achieved 43% better energy efficiency and annual savings of approximately €185,752. The efficiency gain is attributed primarily to extended free cooling availability: 2,131 annual hours versus 195 hours for the replaced synthetic refrigerant chiller, enabled by a higher ambient temperature threshold for free cooling activation. The European Chemicals Agency is reviewing a universal PFAS restriction proposal that could affect synthetic refrigerants, including some HFOs, adding a regulatory dimension to long-term chiller procurement decisions in the EU.
What’s Actually Happening
According to Zudek and ATMOsphere’s trade reporting, the company has deployed ammonia chillers in five data centers since building its first R717 data center unit in South Africa in 2013, with two installations in Germany. The Baden-Württemberg case study is the most recent disclosed deployment.
The reported efficiency advantage stems from the physical properties of ammonia as a refrigerant combined with a system architecture change. The Zudek Airmatik chiller is reported to enable free cooling from 10°C ambient (partial) and 6°C (full), whereas the prior R407C system required ambient temperatures below −4°C to initiate free cooling. In a Central European climate, that threshold difference translates to more than ten times the annual free cooling hours, according to vendor figures.
The system design separates glycol to the external circuit, circulating only water inside the facility, which Zudek states reduces pump energy load due to lower fluid viscosity. Safety mitigations described include automatic fan speed escalation on outdoor leak detection (ammonia being lighter than air) and air extraction systems with optional scrubbers on indoor installations.
Ammonia remains uncommon in data center cooling, and Zudek acknowledges market caution persists. The company has not disclosed specifics on a current data center project it is reportedly developing.
The PFAS angle is a developing regulatory risk, not a concluded rule. The European Chemicals Agency is reviewing — not finalizing — a universal PFAS restriction. Some HFOs used in data center cooling are classified as PFAS and would potentially be affected. Zudek positions ammonia as outside PFAS scope, making it a candidate hedge against that regulatory outcome.
Why It Matters for Global Heads of Data Center Energy?
For European portfolio operators, the PFAS question is the higher-priority strategic signal. If the universal PFAS restriction advances, operators holding long-duration chiller assets running HFO-based refrigerants face potential stranded equipment risk ahead of planned replacement cycles. The timeline and final scope of the restriction remain uncertain, but procurement decisions for large cooling infrastructure made today carry a 15–20 year asset horizon.
The energy efficiency differential, if replicable at scale, is material. A 43% reduction in cooling-side energy consumption across a multi-MW deployment translates to meaningful reduction in total facility PUE and, at current European electricity prices, significant annual cost avoidance. However, these figures derive from a single vendor case study and one site. Independent benchmarking at scale has not been reported.
For energy budget owners, cooling-side efficiency gains are a lever that does not require grid interconnection queue management or PPA renegotiation — it operates within the fence line. That makes it more directly actionable than many supply-side options, albeit at a smaller scale of impact.
The Forward View
The regulatory trajectory on PFAS in the EU is the variable to track. If the European Chemicals Agency restriction moves toward adoption, demand for PFAS-free refrigerant alternatives — including ammonia, CO₂, and hydrocarbons — will intensify across the European data center market. Operators that have not mapped refrigerant exposure across their European cooling assets are likely underestimating transition risk and transition cost.
On the efficiency side, ammonia chiller deployments in data centers remain sparse. The barriers — safety code compliance, operator familiarity, and installation complexity — have limited adoption outside industrial refrigeration contexts. Whether the efficiency economics are sufficient to overcome those barriers at meaningful scale remains an open question that one vendor case study cannot resolve.
What We’re Uncertain About?
Several material uncertainties apply to the figures and claims in this article:
- The 43% efficiency improvement and €185,752 annual savings are vendor-reported from a single case study. Independent verification has not been conducted.
- The free cooling hours comparison (2,131 vs. 195 annually) depends on local climate conditions in Baden-Württemberg and may not generalize to other European markets or climates.
- The PFAS restriction proposal is under review, not finalized. Scope, timeline, and exemptions are not determined.
- Zudek’s total installed base in data centers is five sites as of this reporting. Scale effects, long-run maintenance costs, and operational reliability data across diverse deployments are not available from this source.
- Cost of system changeover, including downtime risk and installation complexity relative to conventional chillers, is not disclosed in the case study.
One Question to Bring to Your Team
Across our European data center portfolio, what percentage of our installed chiller capacity runs on refrigerants that would be classified as PFAS under the current EU restriction proposal — and what is our replacement timeline exposure if that restriction is finalized within the next five years?
Sources
- Naturalrefrigerants — Zudek R717 Chillers: Natural Refrigerants for Data Centers (Link)
