CO2 Transcritical Systems

With Australia following in the footsteps of Europe and their decision to phase-down high-GWP refrigerants (such as R404a), ISECO have been at the forefront of introducing new and proven technologies to our clients.  

One such new technology is the CO2 transcritical system (CO2TC), which utilises CO2 as the sole refrigerant in a medium and low temperature system. CO2 is a desirable refrigerant due to its very low GWP of 1 and because it is a naturally occurring gas that will not be phased out in the foreseeable future.  

A CO2TC system differs when compared to regular refrigeration systems in that it operates in two distinct modes, all based on ambient temperature. These two modes are explained below:

  1. Subcritical being the state in which ambient temperature is between 17°C and 20°C and the gas condenses into a liquid.
  2. Transcritical mode in which the condenser now acts as a ‘gas cooler’, where useful heat is removed from the gas; rather than latent heat through phase change.

ISECO have been heavily involved in the design of five different CO2T plants around Australia; spanning from cold and dry climates, to warm and humid environments.

Each of these five sites have slight variances in plant equipment, which are all being analysed to determine the most reliable and future-proof option that can also deliver on each site’s required capacities during peak summer months.