Best Chillers for Colocation, Hyperscale and AI Data Centers (2026 Buyer's Guide) November 9, 2026 By Paul Johnson, Technology & R&D, G&D Chillers Short answer: The best chiller for a data center depends on facility type. Colocation sites usually favor air-cooled, oil-free magnetic bearing chillers with free cooling; hyperscale campuses favor large centrifugal plants built from repeatable modules; and AI facilities need chillers that run efficiently at warm chilled water supply temperatures of roughly 18 °C to 32 °C (64 °F to 90 °F) for liquid-cooled racks. This guide compares the main chiller technologies by facility type and shows where each fits, including G&D Chillers' GDX Series. Start with an accurate load number first: our step-by-step guide to calculating data center cooling requirements walks through it. What types of chillers are used in data centers? Four compressor technologies cover almost every data center chiller on the market. They differ mainly in capacity per unit, part-load efficiency and maintenance. Compressor type Typical capacity per chiller Part-load efficiency Oil management Best fit Oil-free magnetic bearing centrifugal ~70 to 1,000+ tons, modular Excellent (variable speed) None Colocation, enterprise, AI, hyperscale modules Conventional (oil-lubricated) centrifugal 300 to 3,000+ tons Good with VFD Oil system required Large water-cooled hyperscale plants Screw 100 to 500 tons Good Oil system required Phased growth, higher-density retrofits Scroll 20 to 300 tons Fair (staged) Hermetic, low service Edge, telecom, small data rooms Capacity ranges are typical industry values. Check each manufacturer's certified ratings. What is the best chiller for a colocation data center? For most colocation facilities, the best chiller is an air-cooled, oil-free magnetic bearing chiller with integrated free cooling. Colocation loads ramp up slowly as tenants move in, so the plant spends years at part load, which is where variable-speed oil-free compressors are most efficient. Air cooling also removes cooling towers, water treatment and makeup water, which simplifies permitting and lowers water use. Colocation operators should look for: Strong part-load efficiency (IPLV/NPLV), not just full-load kW/ton N+1 redundancy at the chiller level (see our N+1 redundancy guide) Fast restart after a power interruption Low-GWP refrigerant options that meet current EPA rules G&D's GDX Air is built for this profile: Danfoss Turbocor oil-free compressors, EC axial fans, electronic expansion valves and capacities from 250 kW to 2,000 kW per unit. "Colocation is a part-load business for most of its life. Selecting a chiller on its full-load rating alone is the most common mistake we see. The efficiency that pays the power bill happens at 30 to 70 percent load." — Paul Johnson, Technology & R&D, G&D Chillers What is the best cooling system for a hyperscale data center? Hyperscale campuses need very large, repeatable cooling blocks, so the best system is usually a modular chiller plant that is copied building by building. Where water is plentiful, that means large water-cooled centrifugal chillers with cooling towers; where water is scarce or the climate is cool, it means arrays of air-cooled oil-free chillers with free cooling. The deciding factors at hyperscale are water availability, delivery schedule and supply-chain depth, not just efficiency. Large water-cooled centrifugal plants are supplied by OEMs such as Trane, Carrier, Johnson Controls (York) and Daikin. Air-cooled oil-free modules, including G&D's GDX Series, suit operators who want to reduce water consumption and add capacity in predictable blocks. What are the best chillers for AI data centers with high-density racks? The best chillers for AI data centers are ones that stay efficient at warmer chilled water temperatures. Direct-to-chip liquid cooling lets facility water run far warmer than the 7 °C (45 °F) used in legacy plants, which cuts compressor work and extends free cooling hours. ASHRAE's liquid cooling classes (W17 through W45) define facility water supply temperatures up to 45 °C (113 °F). Most current GPU deployments are designed in the W27 to W32 range. For AI loads, look for: A wide chilled water supply range, including elevated setpoints Fast load-following, because GPU training loads swing quickly High ambient capability. GDX Air delivers full-load capacity at up to 45 °C (113 °F) ambient A clean interface to CDUs (see our CDU guide) How do the leading data center chiller options compare? Option Compressor Capacity range Free cooling Air or water cooled Refrigerants Best fit G&D GDX Air Danfoss Turbocor oil-free magnetic bearing 250 to 2,000 kW Available Air R-134a, R-1234ze, R-513A, R-515B Colocation, enterprise, AI, water-constrained sites G&D GDX Free (GDX-Cool) Danfoss Turbocor oil-free magnetic bearing 250 to 2,000 kW Integrated coils Air R-134a, R-1234ze, R-513A, R-515B Low-PUE projects, cooler climates G&D Air-Cooled Screw Screw Up to 930 HP per skid Integrated option available Air Low-GWP options Phased buildouts, higher density G&D Scroll Tandem scroll 20 to 300 tons No Air [VERIFY] Edge, telecom, NOCs G&D Axion Two-stage centrifugal 1,400 to 3,000 RT [VERIFY] Water [VERIFY] Large water-cooled plants, new builds and retrofits Large water-cooled centrifugal (various OEMs) Oil-lubricated or oil-free centrifugal 300 to 3,000+ tons Via waterside economizer Water R-134a, R-1234ze, R-513A, R-514A Hyperscale campuses with water access How should you choose a data center chiller? Use this order of decisions. Each step narrows the field before you compare brands. Confirm the load and growth plan. Size to the IT load plus redundancy, then plan how capacity will be added over time. Decide air-cooled or water-cooled. Water availability, local water cost and climate usually decide this. Set the chilled water temperature. Warmer supply water, within ASHRAE guidance, lowers energy use and increases free cooling hours. Choose the compressor technology based on part-load profile and maintenance capacity. Check refrigerant compliance against EPA Technology Transitions rules for your install date. Confirm lead time and factory testing. A chiller that arrives late delays the whole building. Our data center cooling cost guide covers the capital and operating trade-offs in more detail. Frequently asked questions What is the most efficient chiller for a data center? Oil-free magnetic bearing centrifugal chillers are among the most efficient at part load, which is where most data centers operate. Pairing them with free cooling and warmer chilled water setpoints gives the lowest annual energy use. Are air-cooled chillers good for data centers? Yes. Modern air-cooled chillers with free cooling are widely used in colocation and enterprise sites because they eliminate cooling tower water use and simplify maintenance. What chilled water temperature do AI data centers use? Liquid-cooled AI racks are commonly designed for facility water supply temperatures in ASHRAE's W27 to W32 classes, about 27 °C to 32 °C (81 °F to 90 °F), depending on the server vendor's requirements. How many chillers does a data center need? Enough to carry the full design load with at least one unit out of service (N+1). Critical facilities often use N+2 or 2N. Start with our cooling requirements calculator. Does G&D Chillers make data center chillers? Yes. G&D Chillers builds the GDX Series of oil-free magnetic bearing chillers for data centers in Junction City, Oregon, with every unit factory run-tested before shipment. Talk to an application engineer. See G&D's data center cooling platforms or download the Data Center Cooling Buyer's Guide.