Exergy based parametric analysis of a cooling and power co-generation system for the life support system of extravehicular spacesuits

Providing electric power and managing the thermal condition for the astronaut are two of the essential functions of the spacesuit life support system in a distance extravehicular activity. This paper proposed a new conceptual portable life support system which combines the cooling and power supply functions for the astronauts with the metal-hydride, fuel cell and absorption chiller. The cooling and power balance models were developed on basis of the first-law of thermodynamics. The second-law based entropy generation, exergy destruction and exergetic efficiency models of the integrated life support system were established. A parametric study was performed to evaluate the effects of varying working conditions, including the hydride metal types, operating temperatures of the fuel cells, heat transfer effectiveness of the evaporator and the concentration of the working fluid pair used in the absorption chiller, on the exergy-based performance of the new life support system. Results indicate that the energetic efficiency and the exergetic efficiency of the integrated PLSS can up to 86.98% and 59.07% respectively.