Entrance Effect on Thermal Stratification of Solar Storage Tank

Nedanstående innehåll är skapat av Mimers Brunns besökare. Kommentera arbete

The hot water storage tank is the most important component in small SDHW systems concerning the system thermal performance. The build up of thermal stratification inside the storage tank has the advantages of improving energy quality of domestic hot water and of increasing the thermal efficiency on the collector side. The most effective way to preserve energy quality and avoid destratification is to avoid the cold water jets entering the tank during the discharge process. The factors influencing the degree of mixing during draw-offs are numerous. They were extensively investigated in different previous studies, based on both theoretical and experimental approaches. In this thesis, the inlet effect in a marketed solar storage tank (Metro tank) on thermal stratification is analyzed through theoretical approach. The storage tank model is generated and meshed by using the grid generation tool Gambit. The temperature and velocity field around the cold water inlet device are calculated with Computation Fluid Dynamic (CFD) simulation toolbox FLUENT. The simulation results are compared with the thermal experiment carried out in a pervious study, with temperature measurement of different levels inside the tank during and after a draw-off test. The purpose of this study is to generate a valid tank model and gather the information about the mixing effect, which is influenced by the inlet device geometry and operating conditions during and after the draw-off. A sensitive study is further carried out for dif...