Exergetic utilization of solar energy for feed water preheating in a conventional thermal power plant

This communication is based on exergy concept for the utilization of solar thermal energy in a Rankine cycle-based fuel-fired thermal power plant (FFTPP). It has been shown that solar thermal energy as an aided source for feed water preheating helps to reduce the exergy loss in feed water heater (FWH) of Rankine cycle and develops more work than that could have been produced in a solar thermal power plant (STPP). It has been found that this enhancement in work increases for low-pressure FWHs. For further illustration, a case study has been carried out of a typical 50 kW STPP and a 220 MW FFTPP. The effect of utilizing the same input solar thermal energy of typical STPP, if used as an aided source in a 220 MW FFTPP for feed water preheating is investigated. The work output of STPP is 59.312 kW, while the extra work output of FFTPP by using solar thermal energy of STPP is 90.27 kW. It has been found that the efficiency of work conversion of aided solar thermal energy in FFTPP is higher than the efficiency of work conversion in STPP. Copyright (C) 2009 John Wiley & Sons, Ltd.