1. An adiabatic heat exchanger is used to heat cold water at 8°C entering at a rate of 3 kg/s by hot air at 150°C entering also at rate of 3 kg/s. If the exit temperature of hot air is 30°C, what is the exit temperature of cold water? Use constant specific heats at room temperature.
2. In a water heating system, cold water at 5°C flowing at a rate of 5 kg/s is mixed adiabatically with hot water at 80°C flowing at a rate of 2 kg/s. What is the exit temperature of the mixture?
3. Steam expands in an adiabatic turbine from 4 MPa and 500°C to 0.5 MPa and 250°C at a rate of 1740 kg/h. What is the power output of the turbine?