Kysor Warren Refrigeration Systems
Kysor Warren designs and manufactures a full spectrum of commercial refrigeration systems built specifically for the demands of supermarket and food retail environments. Their lineup spans centralized parallel rack systems, distributed scroll systems, outdoor ground-mounted and roof-mounted units, and a complete CO2 transcritical platform — giving retailers and their refrigeration contractors a single-source solution that can be matched to virtually any store size, building layout, refrigerant strategy, or energy goal. Every system in the Kysor Warren portfolio is engineered to pair seamlessly with Kysor Warren display cases, but all are also fully compatible with third-party case lineups, making them a flexible choice for new construction, remodels, and retrofits alike.
Take a look below at the systems SEMS recommends for most applications.
Outdoor Horizontal (OHW / OHN) Centralized System
The OHW and OHN are ground-mounted outdoor centralized rack systems designed for retailers who want the reliability and performance of a factory-piped, fully integrated refrigeration unit without occupying interior machine room space. Both systems feature top-mount condensers that minimize the overall footprint length of the unit, keeping the ground-level installation compact while still delivering the full capacity range needed for a full-size supermarket. The factory-piped condenser assembly means less field brazing, faster installation, and a tighter, more predictable system from commissioning day one. The OHW is the wider-footprint variant suited to higher-capacity applications, while the OHN offers the same integrated outdoor design in a narrower profile for sites where ground space is more constrained. Both are available in configurations supporting up to 12 to 14 compressors, covering the full range of medium and low temperature loads in a single integrated outdoor unit.
Narrow Rack (NH2 / NHS) Parallel System
The NH2 and NHS are Kysor Warren's indoor centralized parallel rack systems, and the workhorses of the industry. Both are flexible, proven platforms that can meet the refrigeration needs of a broad range of retailers — from small independents to large-format supermarkets — in both new construction and replacement system applications. The NH2 features a horizontal receiver configuration that keeps overall system height manageable within a standard machine room while supporting up to 12 compressors, giving it a wide capacity range that scales to the size of the store. The NHS Slimline variant delivers the same proven parallel rack architecture in a narrower cabinet profile, purpose-built for retailers where machine room footprint is at a premium. Both systems are compatible with the full range of circuit and loop piping configurations and feature the straightforward, familiar design that makes them easy for refrigeration contractors to install and service. For retailers who need a dependable, high-capacity indoor centralized system with a long track record, the NH2 and NHS are the benchmark choices.
CO2 Transcritical Booster System
Kysor Warren's CO2 Transcritical Booster System represents the leading edge of natural refrigerant technology for supermarket refrigeration and is the right choice for retailers who need to get ahead of accelerating HFC refrigerant regulations while simultaneously reducing their long-term energy and operating costs. The system uses CO2 (R744) as its sole refrigerant — a naturally occurring substance with a global warming potential of just 1, compared to hundreds or thousands for conventional HFC refrigerants — and serves both medium and low temperature loads from a single integrated booster rack. Liquid CO2 is distributed throughout the store via insulated piping to each case and walk-in, with electronic expansion valves providing precise temperature control at every load. Kysor Warren has further advanced the platform with efficiency modules including the Full Transcritical Efficiency (FTE) module and the Extreme Temperature Efficiency (ETE) module, which are specifically engineered to optimize system performance in high-ambient conditions — including climates that regularly exceed 100°F — where standard transcritical systems can lose efficiency. With proven installations across a wide range of climates and store sizes, and backed by Kysor Warren's dedicated CO2 training program and service infrastructure, this system is a future-proof investment for any retailer planning for the regulatory and environmental landscape ahead.
Distributed (DSS / DSSII) Scroll System
The DSS and its updated DSSII variant are Kysor Warren's vertical-format distributed refrigeration systems, designed to be placed close to the refrigeration loads they serve — behind interior store walls, in back hallways, on mezzanines, or in retrofit applications where a traditional machine room is not available or practical. By locating the system near the cases rather than in a centralized machine room, the DSS reduces refrigerant line runs dramatically, cutting total refrigerant charge by up to 70% compared to a traditional centralized rack system. That reduction in refrigerant charge translates directly into lower leak potential, reduced regulatory compliance burden, and lower total cost of refrigerant over the life of the system. The DSSII incorporates a 35% reduction in brazed joints compared to previous models, which further reduces leak risk and simplifies field installation. The system supports up to six compressors across two stacked levels, accommodates both medium and low temperature suction groups, and features hinged front doors and sliding side doors for easy access to all serviceable components. For retailers expanding an existing store, remodeling, or looking to eliminate the machine room footprint entirely, the DSS and DSSII deliver distributed refrigeration performance in a compact, accessible, field-proven package.
