Impact Assessment of Combined Compressed Air and Latent Heat Storage Systems on Gas Turbines

Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) is becoming increasingly attractive in power generation applications, whereby compressed air released from an artificial storage is preheated via sensible heat exchange and injected into an air turbine to generate electricity. Likewise, Latent Heat Storage (LHS) systems incorporating Phase Change Materials (PCM’s) are gaining popularity due to their advantages over the conventional sensible heat transfer systems. Therefore, combining these two forms of energy storage technologies appears to have great potential. Nevertheless, not enough technical literature is available on this combination when implemented in electrical power systems. To this end, this paper combined the use of the AA-CAES and the PCM-LHS systems and coupled them to a gas turbine and an air turbine, in an attempt to assess and compare the resulting overall system performance. The simulation results showed that a CAES volume reduction by 44% on average and thereby lower investments costs would be expected when the combination is coupled to a gas turbine, despite the seemingly higher roundtrip efficiency obtained when coupled to an air turbine. It was also concluded that the fuel consumption of the gas turbine is reduced by 50% on average when the compressed air is preheated via the PCM-LHS system instead of the gas turbine’s exhaust heat recovery system.