1. The problem statement, all variables and given/known data Im working on the following problem and could need some help in answering them: Work is being produced from a cycle. In order to produce this work, energy is being taking from a high temperature sources at a ratio of 1000 kJ/kg and the extra energy is being deliver to a cold source in a ratio of 500 kJ/kg, the low temperature reservoir is 250 K. a) What is the maximum temperature that the high temperature source could be? b) What is the change in entropy of the system? 2. Relevant equations 3. The attempt at a solution a) I assume that the system consist of the both heat sources and the device/engine. The total entropy in any process is always: ΔStotal ≥ 0 where equality holds only for a reversible process. The entropy change for the sorroundings is 0, because only work is done on the sourrundings, and the entropy change for the device is 0 because the process in the device is cyclical. The entropy change is then: ΔStotal = -qH /TH + qL /TL ≥ 0 Rearranging to get the Temperature at the highest source: TH ≥ TL * qH / qL where TH = TL * qH / qL if the cycle is reversible and TH > TL * qH / qL if it is irreversible. but then it would have to maximum value? b) For Reversible process the entropy change for the system would be 0, and if TH →∞ then the maximum entropy that can be made in the system is ΔS = qL /TL?