Abstract
This study investigates the utilization of heat from the exhaust gas and the exhaust air of gas turbine with air bottoming combined cycle (GT-AB) by using steam and absorption bottoming cycles in different combinations. For the utilization of heat from both sources, the results indicate that the maximal efficiency occurs at a GT pressure ratio of 11, the AB pressure ratio is 6 for utilization of heat of the GT exhaust gas and 3 for the utilization of heat of AB exhaust air. The results indicate that for maximal efficiency, utilization of heat from the GT exhaust gas and the AB exhaust air is best performed by the absorption system in a cogeneration plant. However, when the cooling effect of the absorption cycle is used to lower the compressor inlet temperature of the GT and AB cycles, it was found that utilization of heat from the GT exhaust gas by the absorption cycle and utilization of heat from the AB exhaust air by the steam cycle produces the maximal power output.
•Utilization of heat from the exhaust gas and air of GT-AB are investigated.•Maximal efficiency occurs at pressure ratios of GT and AB of 11 and 3.•Utilization of heat from both sources is best performed by cogeneration plant.•Utilization of heat from the GT by AC and from AB by ST gives maximal power output.