Air Cooled Chillers

Air cooled chillers reject heat directly to ambient air through an integral or remote condenser, so they avoid the cost, footprint, water consumption, and chemical treatment associated with a cooling tower loop. They are usually the preferred specification when the facility has limited or no access to a tower water source, when site water restrictions apply, when the cooling load is small to mid-sized, or when the equipment will run outdoors year-round. Water cooled designs tend to win on absolute efficiency in larger central plants, but for stand-alone process loads up to a few hundred tons, a packaged air cooled chiller is often the more cost-effective solution over a 15 to 20-year lifecycle.

Our air cooled portfolio covers 1 ton through 720 tons. Smaller capacities from 1 to 3 tons are handled by the Accuchiller EQ Series; 4 to 40 ton requirements are typically met with the Accuchiller NQ or variable-speed NQV Series; and packaged outdoor units from 40 to 720 tons fall under the KSE Series. For applications with limited indoor space, a remote air cooled chiller separates the compressor and evaporator from the outdoor condenser. Packaged outdoor units locate the entire refrigeration circuit on the roof or pad, and only chilled fluid lines enter the building, which simplifies installation and frees up mechanical room space.

Standard units are rated for full capacity at 95°F ambient air, with capacity derates published for hotter conditions. Many models can be specified with high-ambient packages for sites that regularly exceed 105°F. For cold-climate operation, low-ambient options include head pressure control, condenser fan cycling or VFDs, and insulated reservoirs with heat tracing, so the unit can start and run year-round even when winter temperatures drop well below freezing. When you contact our sales engineers, providing the design summer ambient and the minimum expected winter temperature will let them recommend the right combination of factory options for your installation.

Sound levels for packaged outdoor air cooled chillers typically range from the mid-70s to mid-80s dBA at 10 feet, depending on the number of fans and the compressor type. For installations near occupied spaces or sensitive property lines, low-sound and ultra-low-sound options are available, including oversized condenser coils that allow slower fan speeds, larger-diameter low-rpm fans, fan VFDs that ramp speed with load, and compressor sound blankets. These options can reduce overall sound power by 5 to 15 dBA and are commonly specified for hospital campuses, schools, and mixed-use commercial sites where local ordinances cap nighttime noise.

That depends on the fluid in the loop and where the unit is installed. Units running a properly maintained glycol mixture with appropriate freeze protection can usually remain pressurized and idle over winter, with the controller in standby. Units running plain water in regions that drop below freezing must be drained completely from the chiller, the piping, and any exposed coils, or kept above freezing with heat tracing and controller-initiated low-load circulation. Our installation and operation manuals cover the recommended seasonal shutdown procedure for each series, and our service team can walk you through it before your first winter on the equipment.