UPDATE: New Danfoss high-pressure valves help safeguard CO2 systems

By Silvia Scaldaferri, Jul 17, 2014, 10:55 2 minute reading

Danfoss, Danish manufacturer of automatic controls and components for refrigeration and AC, has launched a new line of high-pressure components for transcritical commercial CO2 systems better able to withstand temperature and pressure rises during periods of standstill. The new range of GBC ball valves and NRV check valves, designed for 90 bar MWP, are the newest additions to Danfoss’ complete line of CO2 suitable components which help safeguard and energy optimise hi

Under normal operating conditions CO2 refrigeration systems are relatively simple to service and no less safe than any other commercial systems. However, when a system becomes non-operational, either due to unforeseen power losses or routine servicing, temperature has a tendency to rise which can result in increased pressure on the systems’ components. Although not harmful, CO2 refrigerant discharge into the ambient could prolong down-time as recharging may be necessary before operating again.

The GBC ball valves and NRV check valves are standstill capable transcritical components which feature a robust design to withstand high-pressure, thus minimising system down-time.

Other advantages include:

  • Less refrigerant discharge during non-operation
  • No need for costly backup systems
  • Energy efficiency and therefore cost efficiency


The NRV check valves for CO2 can be used either in hot gas defrosting lines or for internal (upstream or downstream) pressure relief of the isolated components when installed in parallel with GBC Ball valves.

The GBC valves for CO2 are manually operated shut-off valves approved for use in all parts of the system with pressure ratings lower than the below stated Maximum Working Pressure (MWP); typically the liquid, suction, gas bypass, and hot gas lines. The valves are specifically designed for intrinsic standstill security, meaning that the valves can withstand pressures normally arising when the refrigeration system is shut off, i.e. during serving or during unexpected power failure. 

In latest generation of CO2 ball valves we now ensure full bi-flow function. The ball includes pressure equalization to prevent trapped pressure and has access port for convenient service. The bi-flow function is enabled regardless of valve installation (horizontally or vertically) and assures leak tight sealing.

Technical specifications

The NRV and GBC valves are specifically designed for intrinsic standstill security. They feature:

  • Maximum Working Pressure (MWP) of 90 bar (1300 psi)
  • Up to 90 bar (1300 psi) differential when closed
  • Sealing materials developed specifically for CO2
  • Sizes up to DN22 (7/8”) available with copper connections
  • Ensure that refrigerant only flows in one direction
  • Compatible with Danfoss ADAP-KOOL controls

CO2 refrigeration on the rise

With experience in more than 2000 transcritical CO2 systems, Danfoss considers CO2 among the most attractive refrigerants in food retail applications. CO2 has become one of the most sustainable alternatives both from a safety and environmental perspective, offering: superior efficiency, integrated heat reclaim and a reduced carbon footprint.

More about Danfoss

Danfoss is a leading European manufacturer of a wide variety of components for CO2 refrigeration systems and air conditioning as well as commercial compressors and heating solutions. The company’s CO2 portfolio of standstill and transcritical controls includes: electronic expansion valves (AKVH), transcritical control valves (ICMTS and CCMT), gas bypass and liquid expansion valves (CCM) and filter driers (DMT).


By Silvia Scaldaferri

Jul 17, 2014, 10:55

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