200 kW per rack – only with liquid cooling: What firstcolos Rosbach-Neubau means for colocation
firstcolo is building the FRA7 data center in Rosbach: 250 million euros, 24 MW, up to 200 kW per rack. Why density depends on the cooling architecture.
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firstcolo has broken ground on FRA7 in Rosbach vor der Höhe: €250 million, 24 MW, up to 200 kW per rack. Two figures from this project reveal more about the next decade of data-centre development than any market forecast ever could. One is rack density; the other is the 20-year pledge to give away the waste heat.
Key Takeaways
- 200 kW per rack: This density is only achievable with liquid cooling. Anyone planning colocation today is already planning beyond air cooling.
- PUE below 1.2, 100 % renewable power: FRA7 voluntarily meets the efficiency standard that will soon become mandatory for new builds.
- Free waste heat for the city for 20 years: firstcolo is getting ahead of a regulatory requirement that other operators still treat as a future burden.
Related:Multi-cluster Kubernetes without a new Ops silo / German hyperscaler: who really has substance
FRA7 at a glance
firstcolo operates sites around Frankfurt, home to Europe’s largest internet exchange. FRA7 in Rosbach vor der Höhe is the company’s largest single building to date. Ground was broken in mid-June 2026, with opening scheduled for early 2027. The facility is engineered from the ground up for cloud, AI and high-performance computing-not legacy web-hosting loads.
| Metric | Value | Significance |
|---|---|---|
| Investment | approx. €250 million | one of Hesse’s largest digital investments |
| Power | 24 MW | capacity typical of large colocation campuses |
| Rack density | up to 200 kW per rack | only attainable with liquid cooling |
| Efficiency | PUE below 1.2 | below the threshold of upcoming mandates |
| Floor area | approx. 11,555 m² | renewable power, 20-year heat giveaway to the city |
What 200 kilowatts per rack means for planning
A classic colocation rack runs at 5 to 15 kilowatts. Even well-developed sites rarely exceed 40. The 200 kilowatts at FRA7 therefore represent not a gradual step up, but an entirely new order of magnitude. At this density, air can no longer remove the heat from the cabinet. Anyone aiming to run such loads must turn to direct-to-chip liquid cooling.
For operators and tenants alike, this carries an uncomfortable consequence. Deciding today to lease or build space for the next ten years is simultaneously a choice about the cooling architecture. A new air-cooled facility planned for 2026 will already be undersized for the GPU loads expected in 2028. Retrofitting to liquid cooling is possible, but costly and rarely clean. The question is no longer whether liquid cooling is coming, but whether your own site can support it.
The waste-heat clause anticipates the law
The second remarkable point isn’t in the performance specs. firstcolo will supply the data-centre’s waste heat free of charge to the town of Rosbach for at least 20 years, with the option to make it usable for climate-friendly heating. It sounds like marketing, yet it is a concrete regulatory advantage.
That is precisely where legislators are headed. Germany’s Energy Efficiency Act is turning efficiency and waste-heat topics into obligations for data centres, even though the latest amendment stretches some deadlines. Waiting until the rule forces you to act means installing the system expensively afterwards. Planning it from day one, as firstcolo has done, means meeting the requirement before it even takes effect.
Benefits of high density
- More compute on the same footprint
- Shorter distances, lower latency between nodes
- Higher efficiency when cooling keeps pace
Demands of high density
- Liquid cooling instead of air, often at the chip
- Stricter requirements for power delivery and redundancy
- A waste-heat concept that puts the heat to good use
What operators should take away
FRA7 is not an outlier; it is a harbinger. AI workloads are pushing rack densities upward. Cooling determines who can even accept those loads. A site built today without a liquid-cooling option will age faster than its depreciation schedule allows.
At the same time, firstcolo shows that efficiency and waste heat need not remain grudging obligations. Embedding them early avoids expensive retrofits and the headaches of the next regulatory amendment. For your own planning, that means cooling architecture and the waste-heat concept belong on page one of the requirements specification, not in the appendix.
Frequently Asked Questions
What is FRA7 by firstcolo?
A new data center in Rosbach vor der Höhe near Frankfurt. Construction began in mid-June 2026, with an opening planned for early 2027. Investment volume of around €250 million, power output of 24 megawatts, designed for cloud, AI, and high-performance computing.
Why are 200 kilowatts per rack so special?
Because a typical colocation rack operates at just 5 to 15 kilowatts. Such densities can no longer be cooled with air alone; direct liquid cooling is required. For your own planning, this means air cooling will soon fall short for AI workloads.
What’s the deal with the 20-year waste-heat commitment?
firstcolo will supply waste heat free of charge to the town of Rosbach for at least 20 years, with the option for climate-friendly heating. This aligns with the trajectory of the Energy Efficiency Act, which is increasingly mandating waste-heat utilization for data centers.
What does the PUE value say about efficiency?
It measures how much power, beyond pure IT load, is used for cooling and operations. The target figure firstcolo aims for is considered highly efficient and falls below thresholds set for new-build requirements.
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Source of cover image: AI-generated (July 2026)
Image source: AI-generated (July 2026)
