A Natural Refrigerant Solution

Hussmann’s cascade rack is a low temperature subcritical direct expansion refrigeration solution using CO2, a naturally occurring refrigerant. The use of CO2 as a refrigerant reduces the HFC charge with a minimal impact on energy efficiency to reduce the carbon footprint of the system.

Unlike CO2 secondary or liquid recirculation systems, cascade CO2 systems use a vapor compression cycle similar to traditional direct expansion systems. Instead of condensing against ambient air or water, the CO2 condenses against a primary refrigerant.

CO2 Cascade Environmental Advantages vs. Traditional Rack Systems:

• Rejecting heat to another refrigerant
  
  • Provides flexibility with regulatory changes
  • Designs include R-449A and R-513A to further reduce GWP
  • Reduces the efficiency impact of high ambient temperatures
• Use of a lower cost natural refrigerant
  
  • GWP of 1 vs. R404A with 3920
  • Approximately an 80% reduction in total refrigerant cost
• 60-70% Reduction HFC charge
  
  • All HFCs are removed from the sales area for low temperature loads
  • Primary HFC receivers sized for winter flooding charge
• 30-50% Reduction in carbon footprint
  
  • Reduction in the HFC charge
  • All low temperature circuits are CO2
  • Less HFC piping equals fewer HFC leaks
• Use of CO2 as refrigerant
  
  • Smaller diameter piping required
  • CO2 has 7x the volumetric efficiency of R404A which reduces line sizing tremendously