INTEREST OF AMMONIA-WATER ABSORPTION CHILLER TO ENHANCE CLOSED CYCLE GAS TURBINE PERFORMANCE DURING PEAK DEMAND. COMPARISON WITH CENTRIFUGAL CHILLER.

The study concerns a heat-to-power cycle at a maximal temperature of 515 degrees C generating 300 MWe. The specificity of the work is to consider an alternative cycle to traditional Rankine machine in order to avoid high pressure steam. The selection falls on a high pressure nitrogen turbo-compressor in a recuperated and intercooled Brayton cycle. Within a regulatory framework, the system is required to participate in the primary and secondary frequency settings. This leads of having the capacity to keep a reserve of electrical power to be provided to the grid on demand coming from the electrical network management. A very effective means is to cool the fluid at compressor inlet. Furthermore thermal energy storage tanks are used to charge and discharge thermal energy produced by a chiller. Two technologies of chillers are compared to accomplish cooling: ammonia-water absorption chiller and HFC (HydroFluoroCarbons) centrifugal chiller. Criteria for evaluation are: size, net power production and CAPEX (CAPital EXPenditure).