-There is a potential demand for heat exchangers capable of supporting working temperatures well above 900°C. Many different studies in the literature consider these components as critical for the implementation of externally fired gas turbines (EFGT) and externally fired combined cycles (EFCC). It is common sense that ceramics are the only alternative for the construction of these heat exchangers, but most part of the literature about heat exchangers usually considers only metallic materials for its construction. Consequently, the design of ceramic heat exchangers is not trivial and represents an actual technical challenge. In addition, different heat transfer modes are present simultaneously and as we all know that the geometry of heat exchanger decides the effectiveness of heat exchanger, two geometries are compared and discussed in this work. As a step in this direction, the present work presents the design of a ceramic heat exchanger using CFD and finite element structural simulations. The heat exchanger designed presents small dimensions in order to make it easier to construct a prototype and test it in the future.