Simulation, energy and exergy analysis of compressed air energy storage integrated with organic Rankine cycle and single effect absorption refrigeration for trigeneration application

Abstract

Compressed air energy storage (CAES) is increasingly investigated as a viable technology for balancing electricity supply and demand. The main purpose of CAES is to overcome the intermittent problem when renewable energy is introduced. However, the round-trip efficiency (RTE) of the CAES system commercially developed is still low (around 54 %) and requires further improvement. This study proposed a novel combined cooling, heating and power (CCHP) system, which improves the RTE in two ways: (i) organic Rankine cycle (ORC), which recovers the waste heat and produces extra power; (ii) single effect absorption refrigeration, which delivers cooling capacity with further recovery of waste heat from the flue gas. Steady-state process simulation of the CAES system, ORC and single effect absorption refrigeration system was developed in Aspen Plus® software. The proposed system was evaluated through process, energy, and exergy analysis. The effect of various working parameters on the performance of the CCHP system was also analysed. The results indicated that under design condition, the proposed CCHP system can produce about 206 MW electrical energy, 28 MW heating and 0.2 MW cooling capacity. The RTE of the proposed system (at 66.35%) showed an improvement of 12.35% when compared with the CAES system commercially deployed. The overall exergy efficiency is about 51% and the total exergy destruction of the components of the system is 477 MW. The combustion chamber is responsible for more than half of the exergy destruction.