Selection of low temperature thermal power cycles

In today?s world, we are facing the problem of fossil fuel depletion along with its cost continuously increasing. Also, it is getting difficult to live in a pollution free environment. Solar energy is one of the most abundantly and freely available form of energy. Out of the various ways to harness solar energy, solar thermal energy is the most efficient as compared to photovoltaic technology. There are various cycles to convert the solar thermal energy to mechanical work, but Kalina cycle is one of the best candidates for high efficiency considerations. Therefore, the authors have proposed a novel Kalina cycle having the double separator arrangements to increase the amount of ammonia vapors at the inlet of turbine, and hence have tried to minimize the pumping power for double separator Kalina cycle by reducing the fraction of gas/vapors through it. Here, in this paper we have tried to compare ORC, Brayton cycle, and double separator Kalina cycle for low temperature heat extraction from parabolic trough collectors having arc-circular plug with slits. The effect of different operating conditions, like the number of parabolic trough collectors, mass-flow rate of fluids in different cycles, pressure difference in turbine are analyzed. The effect of these different operating conditions on different parameters like net work done, heat lost by condenser, thermal efficiency and installation cost per unit kW for double separator Kalina cycle, ORC, and Brayton cycle are studied.