Energy and exergy analysis of a novel combined system for power and water production by combining the recompression supercritical carbon dioxide cycle and the humidification-dehumidification desalination cycle

Multigeneration system is one of the solutions to increase the productivity of existing thermal energy sources. In this paper, a novel combined system for simultaneous generation of power and fresh water by using a constant temperature heat source such as a nuclear reactor is introduced. This system consists of a recompression supercritical carbon dioxide cycle for producing power and a humidification-dehumidification cycle for producing fresh water by using wasted heat of the first cycle. In order to simulate the combined system, a code has been developed in EES software, and the simulation results are validated for each of the cycles. Then, in order to energy and exergy analysis of the combined system, by considering the temperature of 755 °C and the heat rate of 1 MW for the heat source, the effect of the main variable parameters including pressure ratio (Pr), mass fraction (x), temperature of water inters to the humidifier, and water to air mass ratio in the desalination cycle (̇ ⁄̇ ), on the performance of the combined system has been investigated. And the results show that at the optimum operating condition, the exergy efficiency of the combined system is increased from the common value of 65% to 73%, and exergy efficiency of the precooler as the main cause for exergy loss in the recompression S-CO2 cycle, has increased less than 50% to approximately 99%.