A student is using a bathtub with separate hot and cold water faucets. The student turns on both faucets and adjusts them to create a pool of warm water in the tub. The tub's drain is open, so the faucets must be kept running to maintain the pool of water. The hot water faucet provides 40.0°C water at 0.100 kg/s, and the cold water faucet provides 15.0°C water at 0.250 kg/s. The local environment (ground state) is at 0.101 MPa and 18.0°C. Neglecting all flow stream kinetic and potential energy and assuming the tub itself is insulated, determine.
a. The temperature of the mixed water in the tub.
b. The second law availability efficiency of the tub as a mixing type heat exchanger.