Active Rear Door Heat Exchangers
Reduce reliance on room-level air handling. The Gradian RDHx brings high-density cooling directly to the rack. Bridge the gap from air to liquid and prepare your infrastructure for the next generation of high-performance compute.
30 – 75 kW Cooling Capacity
N+1 Fan Redundancy
42U / 48U / 52U Compatible
Modbus RTU & TCP/IP Communications
What makes a Gradian RDHx?
Ready-to-Deploy Capacity
Standardized 30 kW to 75 kW configurations help accelerate procurement and deployment, while custom capacities remain available for application-specific requirements.
Built-In Redundancy
N+1 fan configuration allows hot-swap fan maintenance without opening the door, while an N+1 redundant power supply keeps cooling running through a power fault.
Broad Rack Compatibility
Compatible with 42U, 48U, and 52U cabinets in both 600mm and 800mm widths.
Technical specifications
| Power Supply | 90–290 VAC, 50/60Hz, C20 inlet |
|---|---|
| Communication | RS-485, RJ45, Modbus RTU |
| Liquid Connection | 1" clamp |
| Coolant | Air / PG25 |
|---|---|
| Airflow | 2,941 CFM |
| Liquid Flow | 55 LPM |
| Approach Temp (rated) | 11°C |
| Fan Configuration | 15+1 |
| Rack Width | 600mm |
|---|---|
| Rack Height (U) | 42U |
Need more capacity? Get in touch with a sales engineer →
Downloads
30 kW unitUpgrade the Rack. Not the Room
The challenge isn't cooling one more rack. It's introducing higher-density compute into infrastructure that was never designed for it. Replacing the entire cooling plant is rarely the answer.
Unlock Your Capacity
Room-level air handling has a ceiling. Capture heat at the rack and reject it straight into your water loop before it ever becomes the room's problem. Keep density climbing without a facility-wide overhaul standing in the way.
Rack-Level Heat Capture - Removes heat via rear-door coil before it enters the airstream, cutting reliance on room-level CRAH/CRAC capacity.
No Facility Redesign Required - Retrofits onto existing racks without new ductwork, floor tiles, or room air handler upgrades.
Scales With Density - Adds cooling capacity per rack as compute density rises, independent of overall room cooling design.
Fit the Racks You Already Have
You shouldn't have to standardize your racks around your cooling system. Cross-size compatibility and broad rack coverage mean you fit the fleet you already have.
Cross-Size Adapter Frames - Mount a 42U unit to a 48U cabinet (or similar mismatches) using interface adapters; no custom engineering required.
42U / 48U / 52U Coverage - One product line spans your full rack height range instead of requiring multiple SKUs.
600mm & 800mm Width Support - Matches both common rack standards without a cabinet swap.
Deploy Fast From Day One
Every day between install and online is a day of capacity you don't have. Close that gap fast. Everything you need to connect and commission arrives with your unit. Not on a separate PO three weeks later.
Matched Accessories Included - Flow control valves, quick-closing isolation valves, and primary-side hoses ship with the unit.
Streamlined Commissioning - Clamp-type liquid connections and pre-configured controls reduce on-site install time.
End-to-End Support Equipment - Load banks, refill carts, and flushing skids available to commission the full loop, not just the unit.
Questions, answered
An active RDHx replaces the back door of a server rack with an active cooling coil, capturing hot exhaust air as it leaves the equipment and carrying that heat away in water — keeping heat out of the data hall entirely.