Thermodynamic investigation of novel hybrid plant with hydrogen as a green energy carrier

In this research, two thermodynamic cycles based on gas turbine (GT) have been thermodynamically modeled and compared. The basic cycle is a Brayton cycle with thermoelectric and a supercritical carbon dioxide cycle. In the proposed system, a supercritical carbon dioxide cycle with photovoltaic thermal (PVT) unit and a Kalina cycle have been added to the existing system to recover more dissipated heat from GT unit. Thermodynamic modeling of the mentioned cycles has been done with Engineering Equation Solver software. For each component of the systems, mass, energy and exergy balance has been carried out. Also, appropriate relationships are defined for evaluating systems. The results of energy analysis of the systems show that the proposed plant produces net power 33585 kW and the fuel flow in the combustion chamber is 1.67 kg/s. Also, the employed electrolyzer produces 16.90 kg/day of hydrogen. Also, the analysis of the second law showed that although the proposed system produces 18320 kW power more than the base cycle, it has more exergy destruction rate by about 1912 kW. The proposed system has energy and exergy efficiency by about 1.34% and 1.93% more than the basic system. The results of the exegy analysis also make it clear that the combustion chamber and PVT unit have the lowest exergy efficiencies. The parametric analysis indicated that the compressor pressure ratio and gas turbine inlet temperature have important influence on the overall performance of the system, while the effects of the working pressure of both supercritical carbon dioxide cycles are insignificant.