Performance analysis of an improved power generation system utilizing the cold energy of LNG and solar energy

Since the conventional power generation systems recovering the cold energy of LNG have relatively low energy utilization, an improved power generation system utilizing the cold energy of LNG and low-temperature solar energy is proposed and analyzed in this paper. The improved system integrates a precooler and solar collectors into a double loop combined cycle system. A comparative analysis between the proposed system and conventional systems is done under the same optimization criteria. Then, the effects of system parameters including solar collecting temperature, heat source mass flow rate and double-loop condenser temperature on thermodynamic performance are also studied. The results show that the net power output and system thermal efficiency of the proposed system are 9.3% and 7.33% respectively higher than those of the conventional double-loop combined cycle system. Moreover, there is an optimal collecting temperature to maximize exergy efficiency and it is shown that a smaller heat source mass flow rate in a permissible range improves system performance. In addition, when the second-loop condenser temperature is around the phase change point of LNG, system performance declines slightly. The system performance thus has two optimal regions with the variation of the first and second-loop condenser temperature.