A power cycle operates between two thermal reservoirs at 300 K and 800 K. The working fluid of the cycle is air, which can be considered to be an ideal gas. Specific heats are not assumed to be constant. An inventor claims that for a heat input of 250 kJ, the net work from the cycle is 80 kJ. The work generating component in the cycle is a reversible, steady state turbine. The inlet pressure and temperature are 1000 kPa and 600 K and the exit temperature is 550 K. The turbine receives 150 kJ/kg of heat from the high temperature reservoir and loses 10 kJ/kg of heat to the ambient at 298 K. (a) Prove whether or not the overall cycle is possible using second law arguments. (b) determine the work done by the turbine [kJ/kg]

A power cycle operates between two thermal reservoirs at 300 K and 800 K. The working fluid of the cycle is air, which can be considered to be an ideal gas. Specific heats are not assumed to be constant. An inventor claims that for a heat input of 250 kJ, the net work from the cycle is 80 kJ. The work generating component in the cycle is a reversible, steady state turbine. The inlet pressure and temperature are 1000 kPa and 600 K and the exit temperature is 550 K. The turbine receives 150 kJ/kg of heat from the high temperature reservoir and loses 10 kJ/kg of heat to the ambient at 298 K. (a) Prove whether or not the overall cycle is possible using second law arguments. (b) determine the work done by the turbine [kJ/kg]