Whitepaper - The Cooling Technology of the RiMatrix S Data Centre
Rittal
The paper explains how Rittal's standardised, modular RiMatrix S data centre pairs server modules (Single 6/9, Double 6/9) with cooling modules that blow cold air directly in front of the racks. A worked 60 kW example converts the PUE improvement into kWh and CO2.
On this page
Overview
Cooling modules come in 70 kW (Single 6 server module) and 100 kW (Single 9) classes. The air temperature difference over rack height is only about 1 K from U1 to U42. The paper also notes that battery service life benefits from about 20 C storage temperature.
Free cooling uses a dry cooler, and its share depends on water temperatures and climate. In the example climate, ambient exceeds 22 C for only 343 h, so free cooling is usable 96.1 % of the year. Differential-pressure (cross-section) control with closed-loop fans keeps cold-aisle overpressure at only 1-2 Pa, supplying just the air the servers draw.
Server fan energy rises sharply above about 27 C inlet when fans go to 100 % speed, which ties the inlet setpoint to fan power. For a 60 kW centre at 30 kW average load, PUE falls from 1.3 to 1.1 with optimised control, saving 50,510 kWh and 29,801 kg CO2 per year. It is a manufacturer paper and the calculation rests on a single example climate and load profile.
Key points
- Cooling modules come in 70 kW (Single 6) and 100 kW (Single 9) classes.
- Air temperature difference from U1 to U42 is only about 1 K.
- Delta-P control keeps cold-aisle overpressure at only 1-2 Pa.
- In the example climate ambient exceeds 22 C for only 343 h, so free cooling is usable 96.1 % of the year.
- Server fan energy rises sharply above about 27 C inlet as fans reach 100 % speed.
- 60 kW centre at 30 kW average load: PUE 1.3 to 1.1 saves 50,510 kWh and 29,801 kg CO2 per year.
- Battery life benefits from about 20 C storage temperature.
Using it in design
- In the free-cooling estimator compute economiser hours from hourly climate data against the required water supply temperature and report the percentage of the year.
- Show the relationship between inlet setpoint and server fan power and warn above 27 C.
- Support delta-P based fan control as an option with a 1-2 Pa target.
- In the prefab module catalogue tie cooling module capacity to server module type.
Monthly newsletter · free
Keep your reading list current
Once a month: new library sources, changes to Turkish regulations and upcoming data centre events.
SoSo CAD
Check cooling capacity alongside your design
Review zone heat loads, available capacity and the capacity balance after the largest unit is lost in SoSo CAD.
Request a demo
Who should read it
Designers evaluating modular data-centre cooling and free-cooling hours.
Related standards
- ASHRAE TC 9.9
- The Green Grid PUE
Publication details
- Authors
- Rittal
- Publisher
- Rittal
- Year
- 2015
- Document number
- 5_4358
- Document language
- English
- Source type
- Manufacturer
- Access
- Free to read
- Licence
- Copyright retained; citation only — the publisher’s terms apply to the original document
Citation
Rittal (2015). Whitepaper - The Cooling Technology of the RiMatrix S Data Centre. Rittal. 5_4358. https://www.rittal.com/imf/none/5_4358/Rittal_Whitepaper_The_Cooling_Technology_of_the_RiMatrix__5_4358/
Events on this subject
Browse the events calendarAll content and rights belong to the respective authors and publishers. SoSo CAD provides only the citation, its own summary and a link to the source, and is not responsible for the sources' content.
Related sources
All sources on this topic
European Commission JRC 2025
2025 Best Practice Guidelines for the EU Code of Conduct on Data Centre Energy Efficiency (JRC141521, EUR 40267)
Design the facility to operate within the ASHRAE Class A2 allowable range and require A2 operation within warranty in IT procurement; plan separate environmental zones (practice 5.3.4) for legacy equipment.
- IT equipment AC/DC power converters should be rated at 90% efficiency or better across expected load ranges.
Open Compute Project Foundation 2025
Reference Designs for Data Center Heat Reuse, Revision 1.0
Provide a heat-recovery-station block in the site layout with space sized from capacity (plate HX footprint, 10 m2 per MW for heat pumps, about 43 m3 per MW per 30 minutes of storage) and a demarcation boundary to the heat host.
- ORC heat-to-power converts less than 4% of the heat to electricity at these low temperatures.
U.S. DOE FEMP / NREL 2024
Best Practices Guide for Energy-Efficient Data Center Design (Revised July 2024)
Weigh the supply air setpoint against server fan energy: raise it in small steps within the ASHRAE recommended range so the most demanding inlet nears 80 °F, only after air management is in place, and control to IT inlet temperature rather than return temperature.
- Compute racks reached 60 kW in 2013, and recent liquid-cooled racks exceed 125 kW.
European Commission, DG Communications Networks, Content and Technology (DG CONNECT) 2020
Energy-efficient Cloud Computing Technologies and Policies for an Eco-friendly Cloud Market: Final Study Report (SMART 2018/0028)
Use the regional and size-based values for first-pass PUE assumptions, but treat them as 2018-and-earlier averages and as historical context, not as a current target.
- German PUE in 2015: 2.1 for server rooms under 100 m2, 1.9 for 100-500 m2, 1.7 for 500-5,000 m2, 1.6 above 5,000 m2.
European Commission JRC 2020
Development of the EU Green Public Procurement (GPP) Criteria for Data Centres, Server Rooms and Cloud Services - Final Technical Report (JRC118558, EUR 30251 EN, 2020)
Ask in the specification for a designed PUE (dPUE) at a stated IT load (for example 50%) and conditions, under ISO/IEC 30134-2 or EN 50600-4-2, and write PUE demonstration at handover and the commissioning test into the contract.
- ASHRAE liquid cooling classes cited: W1 2-17 °C, W2 2-27 °C, W3 2-32 °C, W4 2-45 °C, W5 above 45 °C.
IEEE Transactions on Sustainable Computing (Institute of Electrical and Electronics Engineers (IEEE)) 2017
Metrics for Sustainable Data Centers
In data-centre comparisons, do not use PUE as a cross-facility metric; normalise for IT load, weather and location, or state the same conditions.
- Tier availability figures quoted: Tier I 99.671%, Tier II 99.741%, Tier III 99.982%, Tier IV 99.995%.