On the recovery of LNG physical exergy

The used fraction (or thermal efficiency) of a power cycle is limited by the maximum and minimum temperatures available. The construction of LNG terminals and the need to vaporize LNG offers a thermal sink at a very much lower temperature than seawater. By using this thermal sink in a combined plant, it is possible to recover power from the vaporization of LNG. To this purpose, in this paper complex systems are considered and their pros and cons are put in evidence. A system utilizing waste energy as heat source and with a single working fluid is analyzed with sufficient details. However, the use of a single fluid is not the best solution from a thermodynamic point of view. Thus, a series of cascading cycles is also synthetically outlined. It is to be remarked that in these systems both thermal source and thermal sink are exploited as exergy sources