Data centres: cooling
CRAH / CRAC units, the chilled-water loop, hot and cold aisles, supply air and the energy view. Back to Buildings and chillers · Building automation
2 units with a remaining-life estimate
Equipment tree
Click a check to see why an alarm would be raised, in your chosen level.
- Data hall
- Cold aisle and hot aisle (containment)
- Supply air to the racks
- CRAH / CRAC units (three on duty, one standby in the worked example)
- Chilled-water loop
- Chilled-water valves and coils
- Chillers and pumps
- Free-cooling heat exchanger (waterside economiser)
- Cooling towers
- Energy
- Whole-site energy: IT, cooling, fans, pumps, losses (the energy view below)
Air and water loop in one line
Working checks
Evidence level is shown on every row. Each check says what is wrong now, and how sure we are from the test.
| Check | Equipment | Evidence level | Result |
|---|---|---|---|
| CRAH / CRAC | Held-out test on simulated records: passed | Named in 8 of 10 held-out tests of 12 faulted records each. | |
| CRAH / CRAC coil | Held-out test on simulated records: passed | Named in 8 of 10 held-out tests; air side and water side are named as a pair, not told apart. | |
| Containment, floor, blanking panels | Held-out test on simulated records: passed | Bypass named; small recirculation leaks cannot be told apart from bypass. | |
| CRAH valve | Held-out test on simulated records: passed | Named in 9 of 10 held-out tests. | |
| CRAH fan | Held-out test on simulated records: passed | Named in 10 of 10 held-out tests. | |
| CRAH fan drive | Held-out test on simulated records: passed | Named in the latest held-out tests (8 of 8 strong faults). | |
| Supply plenum and ducts | Held-out test on simulated records: passed | Named in 10 of 10 held-out tests. | |
| Plate heat exchanger / economiser | Held-out test on simulated records: passed | Named in 9 of 10 held-out tests. | |
| Chiller | Simulated test: passed | 6 of 6 in the building-chiller test; 0 false calls in 16 healthy and look-alike records. | |
| Chiller condenser | Held-out test on simulated records: passed | 2 of 2 in the held-out plant test; 1 of 1 in the tower test. | |
| Cooling tower | Held-out test on simulated records: passed | Held-out tower test passed on condenser tube fouling; tower pieces are covered by the plant checks. |
Case studies
Real data first.
We do not have a real data-centre cooling data set to show. We are not filling this slot with simulated data. If you can share trends from one CRAH loop, the Connect page explains how we read them without writing anything back.
The same chilled-water loop physics as a data-centre plant. On rig data it had not seen, all four marks passed: 12 of 12 severe fault groups named right and none of 8 healthy periods alarmed (lab rig, large faults only). FrostByte (TH Wildau), CC BY-NC 4.0 · shown one-to-one only; do not copy or forward · credit TH Wildau.
8 of 10 tests passed every mark. Across the ten, 99 of 120 single faults were named after onset and 76 of 80 strong faults. 1 of 14 healthy records raised an alarm and 4 of 40 look-alikes did.
9 of 12 single faults named after onset, 0 of 3 healthy raised. Smaller faults (a supply-air rise of 1 K, a stuck-open economiser, a fan cap that never binds) are not claimed.
What is not claimed yet
- No real data-centre cooling plant has been tested yet. Apart from the FrostByte chiller rig card, every data-centre result above is from records built by our test team where the answers are kept held-out and marked once.
- Economiser stuck open is not claimed: in the held-out run the exchanger alarm fired instead.
- Small hot-aisle leaks cannot be told from bypass air by the readings alone.
- The energy view is a calculator for your own meter readings. It does not claim to predict a future value.
Energy view: PUE-style
Type in the average power from your own meters over a period. Example numbers are filled in; replace them. This is a calculation on your numbers, not a prediction.
Free-cooling hours come from the heat exchanger in the equipment tree: when it fouls, the cooling line in this view rises on cool days. Read the two together.
Connect
CAPMAC only reads. For a building automation system it can read BACnet/IP points through a read-only connector (optional extra, installed only when used). It never writes, overrides or releases a point. See the Connect page.