1-2 Adiabatic reversible pumping of saturated water at pressure P1 = 7.5 kPa to P2 = 1000 kPa. 2-3 Isobaric heating and evaporation in the steam generator to T = 225°C 3-4 Adiabatic expansion to condenser pressure P4=P1 in irreversible turbine, quality x4 = 0.92. 4-1 Isobaric condenser.
The small steam power is heated from a geothermal source at 230°C. The plant uses relatively low temperatures and pressures for the following standard vapor power cycle:
1-2 Adiabatic reversible pumping of saturated water at pressure P1 = 7.5 kPa to P2 = 1000 kPa.
2-3 Isobaric heating and evaporation in the steam generator to T = 225°C
3-4 Adiabatic expansion to condenser pressure P4=P1 in irreversible turbine, quality x4 = 0.92.
4-1 Isobaric condenser.
a) First draw a schematic and a T-s diagram for the process.
b) Create a table with the values of temperature, pressure and specific enthalpy at points 1-2-3-4.
c) What is the thermal efficiency of the cycle?
d) What is the isentropic efficiency of the turbine?
e) For a power production of 135 kW, determine the mass flow rate and the volume flow rate at turbine inlet.
f) For comparison, determine the efficiency of a Carnot engine operating between minimum and maximum temperature reached in the cycle. The difference between the efficiencies is due to irreversible losses: list all losses that occur.
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