STR-Series Centrifugal Water Chiller

The STR is SKM's water-cooled centrifugal chiller range, spanning 200 to 2,700 TR on R-134a in two efficiency tiers: the U-Type ultra-high-efficiency variant achieves COP 6.9 (0.509 kW/TR) and the E-Type high-efficiency variant achieves COP 6.4 (0.549 kW/TR) at AHRI conditions. At the upper end of the range, a single STR unit can serve a large terminal building or multiple concourse areas from one centrally located plant item, minimising distribution infrastructure and operator headcount.

The compressor is a two-stage impeller with a dual-expansion refrigerant cycle that broadens the operating envelope. Continuous capacity modulation from 10% to 100% is achieved through inlet guide vanes and a movable diffuser working in tandem — a critical capability for airport terminals with large transient populations, where occupancy-driven load swings of 40–60% are common. An inter-stage economiser improves thermodynamic efficiency further, while triple-grooved condenser tubes maximise heat-transfer coefficient. A built-in oil pump and refrigerant-cooled oil cooler eliminate the need for an external oil-management circuit. The 7.5-inch colour touchscreen controller with BACnet, Modbus, and other BMS protocol support provides remote monitoring from a central operations desk.

The STR is sized for the largest commercial and infrastructure projects in the region: major international airport terminals and satellite buildings, district cooling plant stations, large hospital campuses, and multi-tower mixed-use developments. The breadth of the range — 200 TR to 2,700 TR in a single product family — allows a designer to specify STR across all phases of a phased airport expansion without switching chiller platforms.