A proposed method for generating electricity from solar irradiation is to concentrate the irradiation into a cavity that is placed within a large container of a salt with a high melting temperature. If all heat losses are neglected, part of the solar irradiation entering the cavity is used to melt the salt while the remainder is used to power a Rankine cycle. (The salt is melted during the day and is resolidified at night in order to generate electricity around the clock.)

Consider conditions for which the solar power entering  the cavity is q_sol = 7.50 MW and the time rate of  change of energy stored in the salt is E_st =3.45 MW.  For a cavity opening of diameter D_s = 1 m, determine  the heat transfer to the Rankine cycle, q_R. The temperature  of the salt is maintained at its melting point,  T_salt = T_m = 1000°C. Neglect heat loss by convection  and irradiation from the surroundings.

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Ést = 3.45 MW Salt 1000°C T = salt Mirror D₂ 9R Sun Heliostats