1.)
Heat in the amount of 150 kJ is transferred directly from a hot reservoir at TH= 550 K to two cooler reservoirs at T₁ = 350 K and T₂= 250 K. The surrounding temperature is To= 300 K. If the heat transferred to the reservoir at T₁ is half that transferred to the reservoir at T₂, calculate:
(a) The entropy generation in kJ K-¹.
(b) The lost work.
How could the process be made reversible?
2.)
A nuclear power plant generates 750 MW; the reactor temperature is 315°C and a river with water temperature of 20°C is available.
(a) What is the maximum possible thermal efficiency of the plant, and what is the minimum rate at which heat must be discarded to the river?
(b) If the actual thermal efficiency of the plant is 60% of the maximum, at what rate must heat be discarded to the river, and what is the temperature rise of the river if it has a flowrate of 165 m³ s-¹?
3.)
A single gas stream enters a process at conditions T₁. P₁, and leaves at pressure P₂. The process is adiabatic. Prove that the outlet temperature T₂ for the actual (irreversible) adiabatic process is greater than that for a reversible adiabatic process. As sume the gas is ideal with constant heat capacities.