Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
RADIATOR IMPACT ON STIRLING CYCLE EFFICIENCY FOR SPACE POWER GENERATION
Submission Author:
Guilherme Borges Ribeiro , SP , Brazil
Co-Authors:
Ermerson Moura, Guilherme Borges Ribeiro, Izabela Henriques
Presenter: Guilherme Borges Ribeiro
doi://10.26678/ABCM.ENCIT2022.CIT22-0200
Abstract
With the increasing ambition of space agencies and the private sector, space missions are increasingly daring and focus on deep space missions, aiming to reach planets like Mars and Jupiter. For missions with these objectives to be viable, the spacecraft must have a high availability of energy to carry out the mission safely. Although solar conversion systems are well established for space application, they have a number of limitations such as the low solar incidence on more distant planets would make it impossible to apply a photovoltaic system. In this scenario, nuclear power generation systems are an alternative, as they can operate for long periods providing a high amount of energy. However, for these systems to become applicable, an energy conversion system with high efficiency and low mass must be applied. Dynamic conversion cycles, especially the Stirling cycle, is one of the best options, however, several components considerably increase the system mass, especially the radiator. This component used for heat rejection, can be responsible for more than 1/3 of the entire system mass. Considering this perspective, this work performed a finite time thermodynamic modeling of a Stirling cycle and an exergy analysis to evaluate the radiator impact on the system. With the model, it was possible to evaluate the impact of the radiator area on the cycle energy and exergy efficiency, map the radiator irreversibility; find the ratio of the increase in radiator mass to the increase in panel area; and through a figure of merit to find the best kg/kW system ratio that provides the greatest efficiency. With the results it was possible to identify that with approximately 70 m² of radiator area the system finds the best kg/kW ratio. These results may provide valuable theoretical insight into the future development of radiators for space nuclear power conversion systems.
Keywords
Radiator, Finite time thermodynamics, Efficiency, Stirling engine, Power generation
