Natural and mixed convection cooling evaluation of a hybrid photovoltaic inverter

Abstract Temperature control of embedded systems have become a key factor for the design of more thermal efficient electronic devices. They are becoming smaller and more powerful, what results in a large heat dissipation which must be removed from the system. Heat sinks and forced convection are the usual alternatives used to keep components temperature bellow critical values. In this work, a commercial hybrid photovoltaic inverter is numerically simulated and its thermal behavior is investigated for natural, forced and mixed flow conditions. Experimental results, for a forced convection case, were also reported and used do verify the numerical results. The 3D model accounts for all equipment with high heat dissipation and most of the less important (for thermal analysis) electronic devices, as well as, the fluid regions. A finite volume solution is obtained using the OpenFOAM software, more specifically the chtMultiRegionFoam solver. Flow modeling uses the Boussinesq approximation to account for the natural convection effects, while the k-e formulation was used to close the turbulence model. Results have shown that with current computational capacity, such complex systems (in terms of geometry) can be modeled with just a few simplifications. The inverter could work using only natural convection to cool down the system, however the operating temperatures would be close to the limiting values. In terms of forced convection, it is highlighted the importance of the correct design for the cooling system, avoiding oversizing the overall systems.