A cyclic machine uses a piston-cylinder device (closed system) and an ideal gas as a working fluid. The cycle consists of the following four reversible processes: 1→2 adiabatic expansion 2→3 constant-pressure heat addition 3→4 adiabatic compression 4→1 constant-temperature heat rejection (a) Sketch the T-S and P-V diagrams for this ideal gas cycle. Please indicate the different states with the numbers 1-4 on both diagrams. (b) For the working fluid as a system, determine if the quantities in the following table are positive, negative, zero or if we cannot say a priori. That is, fill in the table with +, -, 0, or ? ?T ?P ?V Q ?S W ?U 1→2 2→3 3→4 4→1 (c) Assume the above cycle is performed by 2 kg of an ideal gas with R = 287 J/kg-K and cv = 718 J/kg-K. The initial temperature and pressure are T1 = 300 K and P1 = 1 MPa, respectively. The lowest pressure in the cycle is P2 = 0.1 MPa and the temperature T3 = 280 K. Determine the values of ?T, ?P, ?V, Q, ?S, W and ?U for each process in the cycle, and also calculate the coefficient of performance assuming the cycle is used as a refrigerator.