Numerical modelling of natural convection and radiation heat transfer in advanced solar water heaters

Flat plate solar collectors of the type used in thermosyphon solar water heaters generally have high heat losses through a combination of conduction, convection and radiation heat transfer. A novel design has been proposed which aims to reduce the heat loss. A 2-D model has been created using Fluent and results have been compared with experimental results. The model has been extended into 3-D and preliminary results presented. These results show that the overall heat loss of the new design is very low, The convective flow within the collector is quite complex and three-dimensional. The 3-D model requires further refinement and optimisation to better correlate with experimental results.