The underwater thermal glider utilizes ocean thermal energy to change its buoyancy, which enables it to ascend and descend. A Phase Change Material （PCM） as the working fluid inside the thermal engine tubes is sensi...The underwater thermal glider utilizes ocean thermal energy to change its buoyancy, which enables it to ascend and descend. A Phase Change Material （PCM） as the working fluid inside the thermal engine tubes is sensitive to the surrounding seawater temperature, whose effects are different with the various displacements and gliding angles of the glider. In this paper, the effects of the displacement and the gliding angle on the performance of the thermal engine were studied numerically and experimentally. On this basis, the ways to eliminate the negative effect of a thermocline on the performance of the thermal engine were obtained. The results show that the displacement and gliding angle affect the transition time of the PCM. There exist the threshold values of the displacement and gliding angle for the normal work of thermal engine. There are two means of eliminating the negative effect of a thermocline on the performance of the thermal engine and improving glider performance： one is to increase the displacement, and the other is to decrease the absolute value of the gliding angle. There is also another better way to improve glider performance.展开更多
Global concern for depleting fossil fuel reserves have been compelling for evolving power generation options using renewable energy sources. The solar energy happens to be a potential source for running the power plan...Global concern for depleting fossil fuel reserves have been compelling for evolving power generation options using renewable energy sources. The solar energy happens to be a potential source for running the power plants among renewable energy sources. Integrated Solar Combined Cycle(ISCC) power plants have gained popularity among the thermal power plants. Traditional ISCC power plants use Direct Steam Generation(DSG) approach. However, with the DSG method, the ISCC plant’s overall thermal efficiency does not increase significantly due to variations in the availability of solar energy. Thermal Energy Storage(TES) systems when integrated into the solar cycle can address such issues related to energy efficiency, process flexibility, reducing intermittency during non-solar hours. This review work focuses and discusses the developments in various components of the ISCC system including its major cycles and related parameters. The main focus is on CSP technologies, Heat Transfer Fluid(HTF), and Phase Change Material(PCM) used for thermal energy storage. Further, study includes heat enhancement methods with HTF and latent heat storage system. This study will be beneficial to the power plant professionals intending to modify the solar-based Combined Cycle Power Plant(CCPP) and to retrofit the existing Natural Gas Combined Cycle(NGCC) plant with the advanced solar cycle.展开更多
基金Project supported by the Special Research Fund for the Doctoral Program of Higher Education (Grant No. 20090073110012)the National Natural Science Foundation of China (Grant No. 50979058)
文摘The underwater thermal glider utilizes ocean thermal energy to change its buoyancy, which enables it to ascend and descend. A Phase Change Material （PCM） as the working fluid inside the thermal engine tubes is sensitive to the surrounding seawater temperature, whose effects are different with the various displacements and gliding angles of the glider. In this paper, the effects of the displacement and the gliding angle on the performance of the thermal engine were studied numerically and experimentally. On this basis, the ways to eliminate the negative effect of a thermocline on the performance of the thermal engine were obtained. The results show that the displacement and gliding angle affect the transition time of the PCM. There exist the threshold values of the displacement and gliding angle for the normal work of thermal engine. There are two means of eliminating the negative effect of a thermocline on the performance of the thermal engine and improving glider performance： one is to increase the displacement, and the other is to decrease the absolute value of the gliding angle. There is also another better way to improve glider performance.
文摘Global concern for depleting fossil fuel reserves have been compelling for evolving power generation options using renewable energy sources. The solar energy happens to be a potential source for running the power plants among renewable energy sources. Integrated Solar Combined Cycle(ISCC) power plants have gained popularity among the thermal power plants. Traditional ISCC power plants use Direct Steam Generation(DSG) approach. However, with the DSG method, the ISCC plant’s overall thermal efficiency does not increase significantly due to variations in the availability of solar energy. Thermal Energy Storage(TES) systems when integrated into the solar cycle can address such issues related to energy efficiency, process flexibility, reducing intermittency during non-solar hours. This review work focuses and discusses the developments in various components of the ISCC system including its major cycles and related parameters. The main focus is on CSP technologies, Heat Transfer Fluid(HTF), and Phase Change Material(PCM) used for thermal energy storage. Further, study includes heat enhancement methods with HTF and latent heat storage system. This study will be beneficial to the power plant professionals intending to modify the solar-based Combined Cycle Power Plant(CCPP) and to retrofit the existing Natural Gas Combined Cycle(NGCC) plant with the advanced solar cycle.
