This paper mainly studied the solid oxide fuel cell (SOFC)–micro gas turbine (MGT) hybrid power system. The key parameters that greatly influence the overall system performance have been studied and optimized. The thermodynamic potential of improving the hybrid system performance by integrating SOFC with the advanced thermal cycle system is analyzed. The optimization rules of main parameters of SOFC-MGT hybrid power system with the turbine inlet temperature (TIT) of MGT as a constraint condition are revealed. The research results show that TIT is a key parameter that limits the electrical efficiency of hybrid power system. With the increase of the cell number, both the power generation efficiency of the hybrid cycle power system and TIT increase. Regarding the hybrid system with the fixed cell number, in order to get a higher electrical efficiency, the operating temperature of SOFC should be enhanced as far as possible. However, the higher operating temperature will result in the higher TIT. Increasing of fuel utilization factor is an effective measure to improve the performance of hybrid system. At the same time, TIT increases slightly. Both the electrical efficiency of hybrid power system and TIT reduce with the increase of the ratio of steam to carbon. The achievements obtained from this paper will provide valuable information for further study on SOFC-MGT hybrid power system with high efficiency. Copyright © 2010 John Wiley & Sons, Ltd.

The optimization of the steam parameters of the heat recovery steam generators (HRSG) of Combined Cycle Gas Turbines (CCGT) has become one of the important means to reduce the power generation cost of combined cycle units. Based on the structural theory of thermoeconomics, a thermoeconomic optimization model for a triple pressure reheat HRSG is established. Taking the minimization of the power generation cost of the combined cycle system as the optimization objective, an optimization algorithm based on three factors and six levels of orthogonal experimental samples to determine the optimal solution for the high, intermediate and low pressure steam pressures under different gas turbine (GT) operation strategies. The variation law and influencing factors of the system power generation cost with the steam pressure level under all operation strategies are analyzed. The research results show that the system power generation cost decreases as the GT load rate increases, T₄ plays a dominant role in the selection of the optimal pressure level for high pressure (HP) steam and, in order to obtain the optimum power generation cost, the IGV T3-650-F mode should be adopted to keep the T₄ at a high level under different GT load rates.

In this paper, a tower solar collector‐aided coal‐fired power generation (TSCACPG) system is proposed and studied in order to save the fossil energy and protect the environment. The integration scheme of tower solar collector and conventional coal‐fired power plant is proposed. Based on the simulation platform TRNSYS, the TSCACPG system model is established and the dynamic performance of the TSCACPG system with the operating mode of coal saving is studied. The TSCACPG system performances of 1 day and 1 year are all discussed by using the DNI data of typical year in Chinese typical city of Dunhuang. Then, the sensitivity analysis of the TSCACPG system is carried out by changing the heliostat field scale (the size of the molten salt tower also changes accordingly). The annual performance of the TSCACPG system is also acquired. In consideration of the economic costs, the heliostat field area with the maximum annual solar‐to‐electric efficiency is selected as the optimal value. The results show that, for the case studied, the optimal heliostat field area is 101,400 m², and the maximum annual solar‐to‐electric efficiency is 16.74%. And under the optimal situation, the standard coal consumption rate of the original coal‐fired power plant is reduced from 301.5 g/kWh to 294.5 g/kWh.

Because of the effects of the nanostructure, phase change behaviors on flat and nanostructured surfaces display distinct features. In this work, the molecular dynamics simulation method is employed to investigate the onset temperature of explosive boiling (T_s) with various film thicknesses, pillar heights, and wettability. The simulation results show that T_s decreases with the film thickness on both wettability flat surfaces. However, the decreasing rates have the significant distinctions, where the difference between two surfaces of T_s with the identical film thickness decreases. In addition, the simulation results demonstrate that all the values of T_s on nanostructured surfaces are lower than those on flat surfaces with the same film thickness. With the increase of the film thickness, T_s presents a decreasing trend on both wettability and nanostructured surfaces, especially with the liquid film with the thickness over 6 nm, where a completely opposite conclusion compared to the flat surface is represented.