Nueva generación de centrales termosolares con colectores solares lineales acoplados a ciclos supercríticos de potencia

Abstract

The climate change is one of the main challenges for the humanity towards a peace future, prosperity and sustainability of society development. The world needs a new sustainable growth model, secure, durable and beneficial for all. Recognizing the sustainable development, the universal access to energy, and the secure access to energy are critical for sharing the prosperity and the future of our planet. For assuring and fostering the energy sources without any environmental impact, sustainable and with universal access, and getting the benefits from the Sun as energy resource. The thermosolar energy will play an important role for accelerating the transition between the fossil and the nuclear fuels towards renewable energy resources. This thesis deal with the integration and searching the synergies between the linear solar collectors (parabolic troughs and Fresnel), with the different state of the art heat transfer fluids (thermal oils, molten salts, direct steam generation) and power cycles (Joule-Brayton, Rankine). For developing these issues, the concentrated solar plants arrangements, heat transfer fluids, and power cycles state of the art are considered the starting points in this thesis (chapter 1), and will be analysed with the methodology described in (chapter 2). This is the reference, for assessing further improvements as the line-focusing solar plants with direct reheating (chapter 3), supercritical water Rankine cycles in line-focusing solar plants (chapter 4), and solar fields with molten salts as heat transfer fluid coupled to supercritical Carbon Dioxide Brayton power cycles (chapter 5). Reviewing the results obtained arise the requirement of optimizing the thermosolar power plants operation parameters, following the guidelines recommended by other authors (chapter 6), driving to the development of a new software, the Surpercritical Concentrated Solar Plants software (SCSP), for minimizing the solar field efficient aperture area by means of the multivariable optimization algorithms SUBPLEX, UOBYQA, and NEWOUA. With this tool the solar fields with thermal oil coupled to supercritical Carbon Dioxide Brayton cycles are studied (chapter 7), solar fields with direct steam generation coupled to supercritical Brayton cycles (chapter 8), and Dual-Loop solar fields also coupled to Brayton cycles (chapter 9), and the solar fields with molten salt or direct steam generation coupled to supercritical Ethane Bratyon cycles. In the chapter 11 is compared the behaviour of Carbon Dioxide with other supercritical working fluids in the Brayton cycles. Finally, in the chapter 12, are described the SCSP software capabilities, and in the chapter 13 are summarized and discussed the main results and conclusions and the further works derived from this these are proposed. This researching work constitutes a complete catalogue about the configurations and benefits, highlighting the innovative arrangements, advising the designer about the capabilities deducted from the combination of the solar fields and power cycles with different working fluids.