TWO isentropic PROCESSES featured in the Carnot cycle are replaced by two constant-volume regeneration processes.Temperature at the beginning of isothermal compression is T2 = 127 C = (127 + 273) K = 400 KThe thermal efficiency of the Stirling cycle η = 1 \(- \frac{{{{\rm{T}}_2}}}{{{{\rm{T}}_1}}}\) = 50% = 0.5 = 1 \(- \frac{{400}}{{{{\rm{T}}_1}}}\)Or, 0.5 = 1 \(- \frac{{400}}{{{{\rm{T}}_1}}}\)Or, \(\frac{{400}}{{{{\rm{T}}_1}}}\) = 1 0.5 = 0.5∴ T1 = \(\frac{{400}}{{0.5}}\) = 800 KNow, HEAT transferred to the regenerator (Qreg) = Cv(T1-T2)(Qreg)= Cv (800-400) kJ/Kg∴ (Qr eg) = 400 Cv kJ/K