A practical approach to calculate the detailed spatial distribution of the heat transfer fluid temperature in thermosolar supporting boilers

Temperature of the oil used as the Heat Transfer Fluid (HTF) in power supporting natural gas boilers is the most critical factor due to the proximity of its degradation point to the working regime. Detailed predictions through Computational Fluid Dynamics (CFD) calculations are too expensive in both time and resources. This paper deals with an alternate, substantially more economical procedure to obtain the detailed temperature distribution inside the circulating oil in such kind of furnaces. The proposed approach consists in limiting the detailed CFD calculations for the critical part of the coils situated closer to the flame in the lower part of the furnace, where oil temperature is higher, with appropriate boundary conditions obtained from an ad hoc zonal calculation of the furnace.