Air-standard. The working fluid is air modelled as an ideal gas; combustion is replaced by external heat addition and exhaust by external heat rejection.
Steady operating conditions. Every device runs at steady state, steady flow.
No change in kinetic or potential energy. Velocity and elevation terms are neglected across all components.
Property model. Cold-air-standard uses constant specific heats evaluated at 298.15 K (cp = 1.005 kJ/kg·K, k = 1.4); variable-cp air uses a temperature-dependent cubic fit (Çengel Table A-2c) with enthalpy and entropy from its integrals.
Components. Compression and expansion are isentropic unless an efficiency below 1 is set; heat addition and rejection occur at constant pressure; intercoolers return the flow to T₁ and reheaters return it to T_max.