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

• Published in: Solar energy 2017-11, Vol.157, p.441-455
• Main Authors: Bouhal, T., Fertahi, S., Agrouaz, Y., El Rhafiki, T., Kousksou, T., Jamil, A.
• Format: Article
• Language: English
• Subjects: CFD parametric study; Flat plates; Fluid dynamics; Hot water heating; Mathematical models; Numerical simulation; Optimization; Physics; Plates (structural members); Richardson number; Solar energy; Solar heating; Solar hot water storage tank; Storage tanks; Thermal stratification; Thermocline; Vertical orientation; Water heaters; Water storage; Water stratification; Water tanks
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2017.08.061

•CFD modeling of thermal stratification inside solar storage tank.•Thermal stratification enhancement via flat plate’s integration through numerical studies.•Investigation of the impact of flat plate’s positions and inclinations on thermal stratification.•Quantification of thermal stratification with a set of numerical results. 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.