Rear Door Heat Exchange
KX-RDHx P45
Passive Rear Door Heat Exchanger
A fanless door coil that neutralises up to 45 kW of rack exhaust using only the server fans already in the cabinet.
- Rated capacity
- 45 kW
- Per rack
- 45 kW
- Nominal Delta-T
- 10 K
- Nominal flow
- 65 L/min
- Supply water
- W15 – W25 (15 – 25 °C)
- Max pressure
- 6.0 bar
- Partial PUE
- 1.15
- Working fluid
- Treated water
The passive rear door is the least disruptive way to double a rack. It bolts onto the cabinet you already own, uses the server fans you already paid for, and needs nothing but a pair of water connections.
Nothing in the door can fail
There are no fans, no motors, no controllers and no power feed. The only thing in the P45 is a copper coil and a hinge. For an operations team that has to sign off on a new technology, “there is nothing in it to break” is a stronger argument than any efficiency figure.
The room stops needing containment
A P45 at duty returns cabinet exhaust to the room at or slightly below ambient. Once every rack in a row does that, hot aisle containment stops being load-bearing — the room has no hot aisle to contain. Several of our retrofits have removed containment structures entirely and gained the maintenance access back.
Where it runs out
A passive door depends entirely on the airflow the servers themselves produce. Around 45 kW that airflow stops being sufficient, and the honest answer is an active door or a move to direct-to-chip. We would rather tell you that at the survey than at the commissioning.
Technical data
Full specification
Values are at nominal duty. Ask us for the full performance map if you are working outside these conditions.
| Rated capacity | 45 kW |
|---|---|
| Configuration | Passive, fanless |
| Supply water temperature | 15 – 25 °C |
| Nominal Delta-T | 10 K |
| Nominal flow rate | 65 L/min |
| Air-side pressure drop | 18 Pa |
| Maximum working pressure | 6 bar |
| Coil | Copper tube, aluminium fin |
| Cabinet compatibility | 600 / 800 mm wide, 42 – 48 U |
| Electrical supply | None required |
| Dimensions (W × H × D) | 600 × 1,995 × 155 mm |
| Mass (dry) | 78 kg |
| Partial PUE contribution | 1.15 |
Module 05 — Flow envelope
Delta-T against required flow
This unit rejects 45 kW. Widening the temperature difference across the loop cuts the volume of water you have to move — and pump power falls with roughly the cube of flow.
- Required flow
- 65 L/min
- Return temperature
- 40.0 °C at W30 supply
- Relative pump power
- 100 % of nominal
Water at 4.18 kJ/kg·K, density taken as 1 kg/L. Pump power index scales with the cube of the flow ratio against this unit’s nominal 10.0 K design point.
Related
Others in this range
KX-RDHx A90
Active Rear Door Heat Exchanger
Fan-assisted door cooling to 90 kW per rack, with EC fans that modulate on cabinet exhaust temperature.
- Capacity
- 90 kW
- Per rack
- 90 kW
- Delta-T
- 10 K