Numerical Analysis of The Effects of Using Two Different Obstacles Inside the Solar Powered Hot Water Storage Tank On Thermal Stratification

摘要

In vertical type hot water storage tank, the temperature varies along the tank height. The cold and hot water is stored at the bottom and top of the tank, respectively. Storing hot water at the top has positive effect to supply hotter water to usage. Inserting obstacles inside the hot water storage tank leads higher thermal stratification. The obstacle prevents the mixing of fresh cold water enters to the tank and existing hot water inside the tank and so hotter water can be supplied to the usage and also hot water supply continues longer than without obstacle case. So, the popularity of the solar powered hot water systems would be increased. Two different cylindrical obstacle placed hot water storage tank type is analyzed numerically to get better thermal stratification inside the tank. The first obstacle has gap at the centre and 0.2 mm thickness. The second obstacle has no gap on it. These two obstacles are placed simultaneously. The first obstacle is placed to the certain distance position from the tank bottom and the second obstacle is placed to the next position from the first one. The numerical calculations are carried out by using Fluent code program. At results, using second obstacle after the first obstacle improved thermal stratification inside the tank. In the work, the temperature distribution inside the tank with and without obstacle is analyzed and compared with respect to thermal stratification.