SoSo CAD

The engineer’s reference desk

Reference library

PUE calculationUPS runtimeCoolant water qualityTEDAŞTier / TS EN 50600

1,044 sources

Sources

961–984 / 1,044 sources

Technical guidePDF

Open Compute Project Foundation 2026

Single-Phase Direct-to-Chip Cold Plate Test Specification, Version 1.0.0 (OCP Cooling Environments: Cold Plate Sub-Project, effective September 3, 2026)

Reference the specification in a cold plate purchase requirement and state which tests, limits and sampling the customer requires, since many limits are examples.

  • Flow rate testing goes up to velocities below 1.5 m/s to ensure no erosion or leaks.
Liquid coolingReliabilityCommissioning
Read / Download

Monthly newsletter · free

Keep your reading list current

Once a month: new library sources, changes to Turkish regulations and upcoming data centre events.

White paperFree to read

Schneider Electric 2012

The Different Technologies for Cooling Data Centers

Use the 13 methods to seed the cooling-plant catalogue enum (dx_air, dx_glycol, dx_water, chw_crah, pumped_refrigerant, self_contained, rooftop, direct_fresh_air_evap, indirect_air_economizer)

  • 13 basic heat-removal methods are identified; 11 rely on the refrigeration cycle as the primary means
CoolingAirflow
Technical guideCitation

NREL 2017

Thermosyphon Cooler Hybrid System for Water Savings in an Energy-Efficient HPC Data Center: Modeling and Installation (NREL/CP-2C00-66690, February 2017)

Place a dry stage upstream of the tower and size it against the share of hours where warm return water exceeds dry-bulb temperature by enough margin, as the 9.4 °C transition point does here.

  • Building heat reuse peaks at 0.434 MW of a 0.910 MW load, leaving 0.496 MW to reject to atmosphere.
CoolingLiquid coolingWater
Technical guideCitation

NREL 2018

Thermosyphon Cooler Hybrid System for Water Savings in an Energy-Efficient HPC Data Center: Results (NREL/TP-2C00-72196, September 2018)

Check whether the warm return water from liquid cooling (here 84 °F after energy recovery) leaves enough temperature difference to ambient for a dry or hybrid stage, and size it against local dry-bulb hours.

  • First-year heat rejection: 10.5% building heat reuse, 42.5% thermosyphon and 47% cooling towers.
CoolingWaterLiquid cooling
Technical guideCitation

Uptime Institute 2013

Tier Standard: Operational Sustainability

Build an operational-readiness score in the operations module: staffing model (24x7 on-site for Tier III/IV intent), maintenance programme (PM schedule, CMMS), training/qualification and procedures (MOP/SOP/EOP)

  • Current edition effective 1 April 2013
OperationsReliability
Technical guideCitation

Uptime Institute 2018

Tier Standard: Topology

For Tier III/IV targets, accept only generator ratings flagged 'continuous' or unlimited-hours in the sizing module

  • Minimum 12 hours of on-site fuel at N design load is the baseline; many sites choose 24-72 h
ReliabilityElectricalGenerators
Technical guidePDF

U.S. Army Corps of Engineers (Headquarters, Department of the Army) 2002

TM 5-693 Uninterruptible Power Supply System Selection, Installation, and Maintenance for Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR) Facilities (31 May 2002)

Calculate availability from MTBF and MTTR before choosing a UPS configuration; apply the same method to single-unit, N+1 and dual-redundant layouts to compare the gain from redundancy with the cost of the added components.

  • C4ISR facilities require a reliability level of 99.9999 percent (the six-nine rule), which may call for greater redundancy.
UPSElectricalReliability
Read / Download
Technical guidePDF

Headquarters, Department of the Army (U.S. Army Corps of Engineers) 2007

TM 5-698-1 Reliability/Availability of Electrical & Mechanical Systems for Command, Control, Communications, Computer, Intelligence, Surveillance and Reconnaissance (C4ISR) Facilities (19 January 2007)

When writing an availability target into a data centre specification, state the measurement interval as well; the same downtime gives 95.83 or 99.86 percent depending on the interval.

  • With exponentially distributed failures, reliability at an operating time equal to the MTBF is only about 37 percent (e^-1 = 0.368).
ReliabilityElectricalCooling
Read / Download
Technical guidePDF

U.S. Army Corps of Engineers 2006

TM 5-698-2, Reliability-Centered Maintenance (RCM) for Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR) Facilities (6 October 2006)

At design stage carry out an FMEA for each critical system and record failure modes, effects and detection methods as input to the RCM decision logic; the text stresses that RCM starts in design and continues for the life of the facility.

  • For an exponential failure distribution with constant failure rate, an item with a 1000-hour MTBF has only a 37 percent probability of surviving 1000 hours of continuous operation.
ReliabilityOperationsCommissioning
Read / Download
Technical guidePDF

U.S. Army Corps of Engineers (Headquarters, Department of the Army technical manual) 2005

TM 5-698-3, Reliability Primer for Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR) Facilities (14 October 2005)

Draw the UPS, generator and chiller chain as a series-parallel block diagram and compute system reliability on paper first, with the product rule for series parts and the parallel formula for redundant ones.

  • Series system reliability is the product of element reliabilities: R = R1 x R2 x R3.
ReliabilityOperations
Read / Download
Technical guidePDF

U.S. Army Corps of Engineers (Headquarters, Department of the Army) 2006

TM 5-698-4 Failure Modes, Effects and Criticality Analyses (FMECA) for Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR) Facilities (29 September 2006)

At design stage run a functional FMEA of each critical system (power, generators, cooling); do not start without schematics, bill of materials, block diagram and the mission requirement.

  • The Risk Priority Number is Severity (1-10) x Occurrence (1-10), optionally multiplied by Detection: RPN = S x O x D.
ReliabilityOperationsElectrical
Read / Download

All 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.