A proposed closed system heat engine mimics the Carnot engine except that the heat rejection compressive process is not isothermal. The process has a 100 K change in temperature. The engine has 5 kg of air as the working fluid. Heat is supplied to the air at 1000 K and rejected by the air at an initial temperature of 500 K. The volume doubles during heat addition. At the end of compression, the pressure is 750 kPa. Assume the work is 900 kJ during the heat rejection process. Calculate the net cycle work in kJ assuming air is an ideal gas with constant specific heats.