A mechanical vapor compression desalination system coupled with a transcritical carbon dioxide Rankine cycle

In this paper, a desalination system in accordance with the running principles of mechanical vapor compression (MVC), in which the steam compressor is driven by a transcritical carbon dioxide (CO2) Rankine cycle (CRC), is suggested. The integrated mechanisms between the two subsystems are revealed and analyzed through the corresponding mass and energy conservation. The turbine parameters, comprising the inlet pressure and temperature, are first specified to explore the relevant influence impacts, and the obtained results are applied to accomplish the sensitivity analysis focusing on the top temperature of the seawater boiler, ambient temperature and terminal temperature difference (TTD) of the MVC heater. In combination with the entropy generation values of the components both within the MVC and CRC subsystems, all the calculated results are sufficient to prove the practicability and availability of the combined desalination system, producing freshwater. It is found peak values of the freshwater production, mc = 1.29 kg s− 1 and gained output ratio (GOR), GOR = 2.42, arise at the prescribed parameter range. Based on the results from the sensitive analysis, it is found a more prominent freshwater production and energy conversion efficiency can result from a higher top temperature, a lower ambient temperature and TTD of the MVC heater. Furthermore, based on the detailed simulations for the heat exchanger configurations, it is obtained that the total heat transfer area arrives at At = 381.54 m2 at Tt = 353.15 K, with a total cost of Ct = 212,040.86¥.