One of the most important challenge of our future is the balance between energy needs and production, in the framework of the CO2 commitments almost universally adopted or declared. As shown in [1], the total energy consumption is still a prerogative of fossil fuels, with a share close to 90 %; renewable energy, apart from the energy production from hydro, photovoltaic, biomass, waste and others, reach for 3-4 % since many years. This discouraging result calls for new conversion technologies based on renewables, if the concept of sustainability is really adopted. Concentrated Solar Power (CSP) plants technology could make the difference with respect to the other renewable technologies, thanks to “hybridity” in combining the concentrated solar energy source and the conventional power generation (actually steam turbine plants as energy conversion section). In the sector of energy production, parabolic through (PT) type is more promising. Recently, the Authors showed in [2,3] how convenient could be the utilization of gases as Heat Transfer Fluid, HTF, with advantages from a technological point of view in the heat collector section and, mainly, from the conversion section point of view, having the possibility to use gas turbines in which the HTF directly expands. In this work, the Authors discuss some thermodynamic and engineering aspects concerning the use of gases as HTF, limiting the attention to air and CO2 and they further discuss the performances of an innovative gas turbine power plant. It is based on a sequence of compressions and expansions, intercooled and reheated (inside linear solar receivers) respectively, in order to increase cycle specific work and efficiency. The paper focuses the attention on the optimum number of compressions and expansions: when it changes, pressure levels change too, requiring a series of reheating processes which operate in parallel, so increasing the overall solar receiver length and, definitively, investment costs. The optimization has been done adopting as design parameter the collector length per unit power which is the most sensible parameter defining investment cost.

A new conversion section for Parabolic Trough - Concentrated Solar Power (CSP-PT) plants

CIPOLLONE, Roberto;
2014

Abstract

One of the most important challenge of our future is the balance between energy needs and production, in the framework of the CO2 commitments almost universally adopted or declared. As shown in [1], the total energy consumption is still a prerogative of fossil fuels, with a share close to 90 %; renewable energy, apart from the energy production from hydro, photovoltaic, biomass, waste and others, reach for 3-4 % since many years. This discouraging result calls for new conversion technologies based on renewables, if the concept of sustainability is really adopted. Concentrated Solar Power (CSP) plants technology could make the difference with respect to the other renewable technologies, thanks to “hybridity” in combining the concentrated solar energy source and the conventional power generation (actually steam turbine plants as energy conversion section). In the sector of energy production, parabolic through (PT) type is more promising. Recently, the Authors showed in [2,3] how convenient could be the utilization of gases as Heat Transfer Fluid, HTF, with advantages from a technological point of view in the heat collector section and, mainly, from the conversion section point of view, having the possibility to use gas turbines in which the HTF directly expands. In this work, the Authors discuss some thermodynamic and engineering aspects concerning the use of gases as HTF, limiting the attention to air and CO2 and they further discuss the performances of an innovative gas turbine power plant. It is based on a sequence of compressions and expansions, intercooled and reheated (inside linear solar receivers) respectively, in order to increase cycle specific work and efficiency. The paper focuses the attention on the optimum number of compressions and expansions: when it changes, pressure levels change too, requiring a series of reheating processes which operate in parallel, so increasing the overall solar receiver length and, definitively, investment costs. The optimization has been done adopting as design parameter the collector length per unit power which is the most sensible parameter defining investment cost.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11697/16282
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