Second Nature – SNMT2LX

Second Nature CO2 Cascade Refrigeration System


SNMT2LX – CO2 Combined System Technology

Second Nature Medium-Temp Secondary with CO2 Low-Temp Cascade. Sharing a common, medium temperature primary system, the SNMT2LX system combines a CO2 medium temperature secondary system (SNMT2) with a CO2 low temperature cascade system (SNLTX2) to further reduce refrigerant charge and consolidate duplicate components. Evaporator control uses Hill PHOENIX SmartValve™ technology with electronic expansion valves (EEV) on low temperature and simple solenoid valve control on medium temperature.

System Features

  • Second Nature® MT2LX system utilizes CO2 as a secondary coolant for the medium-temperature system and CO2 as a direct expansion cascade refrigerant for the low-temperature system.

  • A CO2 pump, typically installed as a primary pump with a parallel backup pump, delivers liquid CO2 through the supply distribution piping to both the low and medium-temperature evaporators.

  • Low-temperature evaporators designed specifically for CO2 direct expansion operation.

  • CO2 as a direct expansion refrigerant with better heat transfer properties compared to conventional HFCs.

  • Medium-temperature evaporators designed for fully-flooded CO2 secondary operation.

  • The low-temperature display cases and freezers are equipped with the Hillphoenix Smart Valve™ system with EEV’s for steady, automatic control of superheat leaving the evaporators.

  • Medium-temperature display cases and coolers are equipped with solenoid valves which control the flow of CO2 into the evaporators.

Benefits of Using Second Nature CO2 Refrigeration Technology

  • CO2 is considered a natural refrigerant with very low global warming potential (GWP=1).

  • CO2 is inexpensive refrigerant compared with HFC and is widely available.

  • An excess of 70 percent reduction in HFC refrigerant charge can be achieved. The entire primary refrigerant charge is confined to the machine room and condenser to enable simple leak detection and servicing.

  • The piping system utilizes a modified-loop copper piping system – CO2 lines are typically one to two sizes smaller than traditional DX piping systems.

  • Excellent material compatibility – most equipment for commercial refrigeration can be used.

  • Medium-temperature system uses CO2 as a two-phase secondary coolant taking advantage of CO2 ’s high latent heat capacity – this dramatically lowers flow rates (typical 90% reduction) and pumping power compared to conventional secondary fluids (e.g. glycols).

  • System energy performance equivalent or better than conventional HFC systems.

Second Nature CO2 Refrigeration System

Intertek Certification

Better Practices Make Better Systems

There are many reasons why Hillphoenix® Refrigeration Systems continues to lead the industry. Why? No matter what the application or the specific refrigeration need, we can offer our customers a wide variety of options and configurations. The simple answer is that we harness the best technologies and field-proven procedures and fit them to a higher set of standards.

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