The primary function of environmental control systems in aircraft is to address various cooling and heating challenges arising from high-speed flight conditions. In this context, balancing and managing the heat generated both inside and outside the aircraft is of critical importance.
External Heat Sources
Although thermal insulation prevents a significant portion of this heat from being transferred into the aircraft, heat gained through aerodynamic heating and solar radiation leads to an increase in cabin temperature.
Internal Heat Sources
Heat generated by electronic, electrical, and mechanical equipment, as well as by occupants onboard, constitutes the internal thermal load of the system. Maintaining cabin temperature at a safe and comfortable level for the crew is of vital importance. This balance is achieved through VCCS (Vapor Cycle Cooling System) and ACCS (Air Cycle Cooling System).
Today, there are two main types of cooling systems in use, which can be applied individually or in combination:
The air cycle system, based on converting thermal energy into useful work,
The vapor cycle system, in which latent heat is removed through the evaporation of a liquid refrigerant.
