Question

a) Steam is to be boiled and compressed from 100 kPa and 323 K to 1000 kPa and 473 K.A heat loss of 20 kJ/kg occurs during the compression process. Neglecting kinetic energy and potential energy changes, determine the power input required for a mass flow rate of90 kg/min. Use the steam tables where necessary. Steam flows steadily through an adiabatic turbine. The inlet conditions of the steam are10 MPa, 400°C, and 80 m/s, while the exit conditions are 10 kPa, 92 percent quality, and30 m/s. The mass flow rate of the steam is 12 kg/s. Determine: (i)the change in kinetic energy (ii)the power output ) Does a heat engine that has a thermal efficiency of 100 percent necessarily violate: (i)the first law of thermodynamics? Explain (ii)the second law of thermodynamics? Explain d) An innovative way of power generation involves the utilization of geothermal energy-the geothermal power plant received hot water that exists naturally underground-as the heat source with a heat content of 420 KJ but at an unknown temperature. If a supply of hot water is discovered at a location where the environmental temperature is 20°C and therefore rejects 150 KJ of heat at 20°C. (i)What is the most efficient cycle that can be used as a good model the geothermal plant? Give reasons (ii)determine the temperature at the geothermal reserve (ii)determine the maximum thermal efficiency a geothermal power plant built at that location can have.

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