ANALYSIS OF AN ORGANIC RANKINE CYCLE FOR AN INTEGRATION WITH INTERCOOLED GAS TURBINES

The use of an Organic Rankine Cycle is a promising choice for waste heat recovery at low/medium temperatures. Organic Rankine Cycle can be combined with a gas turbine through a diathermic oil circuit in order to convert gas turbine waste heat into electrical power, but diathermic oil presents a temperature operation limit (about 360-380°C). Thus, using an Organic Rankine Cycle to recover heat from exhaust gas from gas turbine, relevant exergy losses are present. However, in intercooled gas turbine configurations, exhaust temperature is low and so the Organic Rankine Cycle can be an interesting solution to improve the efficiency of power plant. In an intercooled gas turbine with high pressure ratio, the air temperature in the outlet from the first compressor is about 160-220°C and generally it is cooled by water: this waste heat can also be recovered by an Organic Rankine Cycle to convert the low-temperature heat into mechanical energy. This paper presents a study of an Organic Rankine Cycle integrated with an intercooled gas turbine. Thermodynamic analysis are carried out using four different organic fluids.