where h = specific enthalpy (kJ/kg). v = specific volume (m3/kg). P = pressure (bar) = 105 N/m2.
Generally, the efficiency of a Rankine cycle can be increased by increasing the pressure in the boiler. To avoid the increase of moisture in the steam coming out from the turbine, steam is expanded to an intermediate pressure and reheated in the boiler. In a reheat cycle, the expansion takes place in two turbines. The steam expands in the high-pressure turbine to some intermediate pressure, then passes back to the boiler, where it is reheated at constant pressure to a temperature that is usually equal to the original superheat temperature. This reheated steam is directed to the low-pressure turbine, where is expanded until the condenser pressure is reached. This process is shown in Figure 10.10. The reheat cycle efficiency is given by
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