Numerical modeling and optimization of thermal stratification in solar hot water storage tanks for domestic applications: CFD study

This study aims to assess the thermal stratification inside a standard hot water storage tank such an important device of solar water heaters. A number of flat plates with different titled positions are integrated inside a vertical tank prototype. The purpose of this investigation is to numerically study the impact of the flat plate positions within a vertical storage tank, which operates during the charging mode, on the thermal stratification and to conduct the possible performance enhancements to achieve. CFD numerical comparison between two configurations was carried out and performance parameters such as temperature evolution, Richardson number and stratification number were calculated. It was shown that thermal stratification inside the storage tank is depending on the flat plate's positions. Thus, increasing flat plates in different positions inside the storage tank does not establish a suitable thermal stratification. Therefore, a superior thermal performance was achieved for the flat plate which is maintained at the middle height of the storage tank. Also, it was found that flat plate's integration at different angles improves the thermocline structure development.