The advantages of air cycle technology compared with convention vapour compression refrigeration systems include: 
  • Uses air as refrigerant instead of chemical refrigerants such as CFCs, HCFCs or HFCs. (All chemical refrigerants are environmentally harmful).  
  • Potential for higher reliability and lower maintenance costs:  
  • Fewer components & components can be replaced quickly without the need for refrigerant recovery.  
  • Tolerant to leakage (automatic air top-up).  
  • No need for refrigerant recovery or handling equipment.  
  • No need for certified refrigeration engineers or handlers.  
  • Tolerant to extreme operating temperatures (vapour compression systems can fail or trip-out during exceptionally hot weather).  
The principal reason why air cycle technology has not been widely used outside the aerospace sector is its perceived poor energy efficiency compared with conventional vapour compression refrigeration systems. However, recent studies by BRE and FRPERC have shown that improvements to turbine machinery, coupled with the fact that air cycle cooling systems can provide high grade heat recovery, mean that air cycle systems can be competitive with vapour compression systems in buildings that require simultaneous heating and cooling.  When used for train air conditioning air cycle systems have been shown to have lower overall life cycle costs than vapour compression systems due to the air cycle's higher reliability, reduced maintenance requirements, and no need for refrigerant handling infrastructure. 
back to refrigeration....