Dish Stirling cavity/receiver: thermal model and design optimization

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.This paper presents a thermal model for a dish Stirling cavity. Finite differences method has been applied to develop this theoretical model that enables the cavity efficiency optimization quantifying conduction, convection and radiation heat exchange. View factors of all surfaces involved have been calculated accurately to resolve the radiosity method. The model has been implemented in a tool that enables to vary receiver dimensions and materials in order to determine the optimal cavity design. Using this developed tool, there have been found some results that lead to an optimal cavity; regarding material properties, receiver absorptivity presents the biggest influence in cavity performance; and regarding geometry parameters, aperture ratio presents the biggest influence and aperture height shows an optimal value different from one to another aperture ratio.