1 Steam tables are frequently used to obtain values of inter

1. Steam tables are frequently used to obtain values of internal energy or enthalpy for solving problems in which there are changes in these properties. Use values from the steam tables E5 and E6 in the Appendix of your textbook for this problem. Assume that internal energy is not dependent on pressure, allowing values from the table at the correct temperature to be used even if the pressure is different. Enthalpy of the liquid, however, does depend on pressure. Make an adjustment for pressure by adding ?(PV) to the value read from the table. For ?(PV) calculation you can use the specific volume at the saturated pressure, the pressure difference is the desired pressure minus the saturation pressure.
Complete the table below using values from the steam table and adjusting enthalpy values for pressure differences as needed.
Desired Conditions
Values from Table, at saturation pressure
adjusted enthalpy values
Phase
Temp, C
Pressure, Bar
Psat at given T
Vol, m3/kg
Internal Energy
Enthalpy
d(PV) for liquid
Enthalpy
Liquid 0.01 0.00611 0.00611 0.001 Zero 0 0 0 Liquid 25 1.01325       Liquid 100 1.01325       Vapor 100 1.01325       Liquid 25 10       Liquid 179.9 10       Vapor 179.9 10       
Liquid water flowing at 12.0 liters per minute is drawn into a pump from a reservoir at 1.00 atm pressure, 25oC.   The pump raises the pressure of the liquid to 10.0 Bar. This pressurize water enters a boiler, coming out as saturated steam at 10.0 Bar. Determine the rate of work needed for the pump and the rate of heat needed for the boiler. You should be able to use values from above.
Before Pump After Pump After Boiler Temperature, C 25 25 Pressure, Bar 1.0 10.0 10.0 condition Sub-cooled Sub-cooled Saturated Mass flow, kg/s    Specific volume, m3/kg    Internal Energy, kJ/kg    Enthalpy, kJ/kg       

Solution

Desired Conditions Values from table at sat. pressure Adjusted Enthalpy Values Phase Temp C Pressure Psat Vol m^3/kg Internal Energy kJ/kg Enthalpy kJ/kg d(PV) Adjusted Enthalpy Liquid 0.01 0.00611 0.00611 0.001 Zero 0 0 0 Liquid 25 1.01325 1.01325 0.001 105 105 0.101325 105.101325 Liquid 100 1.01325 1.01325 0.00104 419.00 419.00 0.105378 419.105378 Vapor 100 1.01325 1.01325 1.67 2510.00 2680.00 169.21275 2849.21275 Liquid 25 10 0.0317 0.001 105.00 106.00 0.00317 106.00317 Liquid 179.9 10 10 0.001130 761.00 763.00 1.13 764.13 Vapor 179.9 10 10 0.194 2580.00 2780.00 194 2974