K&K Data Service Inc.Data Center Engineering Lab

Data Center Lab

Hydraulics and Transients

This series publishes working engineering analysis from K&K's data center program. Numbers are labeled [TARGET], [MODELED], [SENSITIVITY] or [FACT]; nothing here is field-measured data, and no article is a sealed engineering document. Each article states its own limits and open items.

Equipment cross section through the IT main hall and UPS and power room, with rack, battery and UPS envelope heights
Equipment cross section through the IT hall and power room (coordination study — not release).
  1. KK-DCL-033Raising Secondary ΔT From 6 K to 12 K Drops Two Pipe SizesDoubling secondary delta-T halves flow and moves the velocity screen by two nominal pipe sizes, which changes the structural and space case too.
  2. KK-DCL-034Isolation Raises Ring ΔP From 3.5 to 49.2 kPaThe isolation detour case, not the normal case, sets the ring pressure drop and therefore the pump duty point.
  3. KK-DCL-035Part-Load DLC Startup Runs Hotter Than Full Load If Valves ThrottleAt low load the flow regime leaves the turbulent band and the local film temperature can exceed the full-load case.
  4. KK-DCL-036Running Standby CDUs Saves 46% of Pump Energy, Not 56%Recommendation R-06's own factors — eight duty units' flow shared across eleven, each unit falling to 0.396 of full pump power — multiply to 0.545 of the duty-only baseline and a 46 % saving; the 0.436 and the 56 % printed beside them require a ten-unit baseline that the branch does not have.
  5. KK-DCL-037UPS Battery Minutes Do Not Equal Thermal Ride-Through SecondsElectrical autonomy and thermal autonomy are measured on different clocks, and the thermal clock is the short one.
  6. KK-DCL-038Electrical Ride-Through and Thermal Ride-Through Use Different ClocksPlotting ride-through seconds against coolant temperature rise on one figure shows where the two systems stop protecting each other.
  7. KK-DCL-039Steady Hydraulic Models Miss DLC Interlock, Inertia, and MaintainabilityThree unclosed items — leak interlock authority, thermal inertia and the parallel-maintainability service level — sit in the control, transient and contract domains, so the steady heat-balance and steady-hydraulic method that produced the rest of the basis cannot surface any of them.
  8. KK-DCL-040Put the Expansion Tank on Return, or Static Exceeds 600 kPaExpansion tank placement decides the static pressure reference, and the wrong side pushes local static above the component limit.