Dual-purpose power-desalination plant augmented by thermal energy storage system

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

This paper presents a novel application of a sensible Thermal Energy Storage (TES) system for simultaneous energy conservation and water desalination in power plants. First, the TES mitigates negative effects of high ambient temperatures on the performance of air cooled condenser (ACC) that cools a 500 MW combined cycle power plant (CCPP); next, the same TES satisfies the cooling requirements in a 0.25 mgd multi-effect distillation (MED) plant. Stack gases from CCPP are used to drive an absorption refrigeration system (ARS) which maintains the chilled water temperature in a TES tank. A process model integrating CCPP, ARS, TES, and MED has been developed to optimize the volume of the TES. Preliminary analysis showed that a tank volume of 2950 m3 was adequate in meeting the cooling requirements of both ACC and MED in both hot and cold seasons. The proposed TES has the potential to save 2.5% of the power loss in a CCPP/ACC on a hot summer day. Further, our modeling results reveal that a desalination capacity of 0.25-0.43 mgd can be achieved with top brine temperatures between 100 ºC and 70 ºC of MED. The proposed integrated system, process modeling and simultaneous advantages of enhanced CCPP performance and sustainable desalination system will be discussed in the presentation.