A methodology for thermal analysis of complex integrated systems: Application to a micro-CHP plant

Abstract Thermal analysis and management studies are commonly conducted from early design stages of new products by numerical means. However, the application of three-dimensional tools for evaluating the thermal performance of multi-component systems, exhibiting high geometrical and phenomenological complexities may become unpractical in view of the long computational times. Therefore, a methodology for thermal analysis of complex thermal systems is developed to improve the overall numerical convergence rate. The methodology is based on an iterative two-way coupling procedure between two sets of simulations: simulation set where critical components are individual and fully simulated (component-level simulations); and simulation framework where the overall system is considered with hollow components (system-level simulation). A communication strategy between both simulation sets is established. The methodology can be readily applied for performing thermal management studies. A verification procedure for the suggested methodology is firstly carried out. Afterwards, the methodology is applied to investigate the thermal performance at the system-level of a fuel cell based μ - CHP unit, namely regarding the feasibility of components integration. The methodology application allowed the identification of critical hot-spots (with temperatures up to about 400 ° C ) on the surface of the unit internal components, mainly due to an inadequate insulation thickness and shape.