Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
THERMODYNAMIC OPTIMIZATION OF THE ENERGY DENSITY IN AN ORGANIC RANKINE ENERGY STORAGE SYSTEM
Submission Author:
Maury M Oliveira Jr , MG
Co-Authors:
Maury M Oliveira Jr, Antônio Maia, Matheus Porto
Presenter: Maury M Oliveira Jr
doi://10.26678/ABCM.COBEM2021.COB2021-1599
Abstract
The increased demand for large-scale energy storage systems to support electric grids worldwide has led to the development of new energy storage systems to mitigate the effects of the intermittent nature of both solar and wind energy, two of the main alternatives are the Compressed Air Energy Storage (CAES) and Liquid Air Energy Storage (LAES) systems. However, CAES systems have a low energy density coupled with a high operation pressure, and LAES systems require high investment because of the air liquefaction process. The Organic Rankine Energy Storage (ORES) system has been proposed as an alternative to both of these systems as it can operate at lower pressures and closer to environment temperatures with a reasonably high round-trip efficiency (up to 73%) and relatively low cost per unit energy compared to both, CAES and LAES. However, previous models of the ORES system have only achieved an energy density of 2.3 kWh m-3, lower than both that of CAES and LAES systems, 3 to 6 kWh m-3 and 180 kWh m-3, respectively. This work aims to perform a thermodynamic optimization in an ORES system for the maximization of the energy density whilst remaining with a round-trip efficiency of at least 50 %. A genetic algorithm will be used in the optimization process to maximize energy density with expander input superheating degree, expander input pressure, and storage tank volume as decision variables using a transient thermodynamic model of the ORES system. Since the performance of this system is strongly dependent on the working fluid, two fluids that have shown good results of efficiency and cost will be evaluated during the optimization process, namely R141b and R365mfc. An increase of, at least, 50 % in the energy density is expected for each of the evaluated working fluids to achieve a more competitive energy storage system.
Keywords
Thermomechanical Energy storage, thermodynamic analysis, Organic Ranking Energy Storage, Energy density
