Air-Cooled Screw Chiller for Mission-Critical Cooling
Purpose-built for large, mission-critical cooling loads. Gradian's Screw Chiller features dual VFD-driven screw compressors in an air-cooled architecture, delivering dependable capacity for the most demanding, high-ambient environments.
550 Tons Cooling Capacity
Dual-Circuit, Dual-Compressor Architecture
Up to 16 EER*
(EER is dependent on design conditions)
What makes a Gradian Screw Chiller?
Dual-Circuit Redundancy
Two independent refrigeration circuits support capacity staging and continued operation, helping maintain cooling availability if one circuit requires service.
Water-Free Heat Rejection
Air-cooled condensers eliminate the need for cooling towers, condenser-water pumps, and water treatment systems, simplifying plant infrastructure and reducing site dependencies.
5:1 Turndown Range
Wide capacity modulation supports efficient operation across a broad range of loads, from partial to peak demand.
Technical specifications
| Cooling capacity | 550 Tons (561.83 tons at design conditions) |
|---|---|
| Design Conditions | 80°F / 70°F EWT/LWT, 105°F ambient |
| Efficiency | 15.41 EER / 4.52 COP / 0.779 kW/ton at design conditions |
| Refrigerant | R-513A |
| Capacity Modulation | Variable Frequency Drive (VFD), dual compressors |
| Power Supply | 460V / 3-Phase / 60Hz — SCCR 65kA |
|---|---|
| Power Consumption | 438 kW |
| Controller | Carel pco5 |
| Communication | BACnet IP/MS-TP, Modbus TCP/IP/RTU |
| Controls Tolerance | ±1°F |
| Compressors | 2 x CSH9583-280-4DU screw compressors |
|---|---|
| Circuits | 2 independent refrigeration circuits |
| Dimensions | 633"L x 95"W x 100"H |
| Weight (Ship / Operating) | 228,880 lbs / 236,120 lbs |
Add Capacity Without Adding Complexity
Every additional water loop creates more equipment to install, maintain, and manage. Gradian’s Air-cooled architecture removes cooling towers, condenser-water pumps, and water-treatment systems entirely, giving data centers a simpler path to large-scale chilled-water capacity.
Air-Cooled Heat Rejection - Eliminate the need for a cooling-tower loop.
Packaged System Architecture - Consolidate critical cooling components into one outdoor system. Includes self-redundancy (N+1)
Simplified Water Infrastructure - Avoid condenser pumps, piping, and water-treatment systems.
Keep Cooling Online, Even During Maintenance
Maintenance is essential, but that downtime can be costly. Dual independent refrigeration circuits let the system stage capacity and keep cooling available if one circuit needs service, protecting the uptime mission-critical facilities depend on.
Dual Independent Circuits - Split cooling capacity across two separate refrigeration circuits.
Capacity Staging - Run partial capacity on one circuit while the other is serviced.
Continued Operation During Maintenance - Keep critical cooling online instead of shutting down the whole unit.
Put Constrained Power to Better Use
Chillers don't operate at one perfect design condition, so their efficiency can't stop there either. VFD modulation and 5:1 turndown align cooling output with real facility demand across changing workloads, while soft-start capability reduces the electrical stress spikes a fixed-speed compressor would otherwise create.
Variable-Speed Compressors - Adjust cooling output as facility demand changes.
Reduced Startup Stress - Limit electrical stress during compressor startup.
5:1 Capacity Turndown - Match cooling output more closely to changing loads, rapid stabilization to avoid chilled water-valve hunting
Questions, answered.
An air-cooled screw chiller is a cooling system that uses screw compressors to circulate refrigerant and reject heat directly to outside air, eliminating the need for a cooling tower or condenser-water loop. This model uses two screw compressors across independent refrigeration circuits to deliver 550 tons of cooling capacity.
