Experimental and Performance Analyses with Frequently Discrete Usage of the Hot Storage Tanks

Hot water storage tanks are devices with high energy consumption, used widely in residential, industrial and commercial sectors. The hot storage tank is a key device in numerous applications such as electrical heaters, solar thermal storage, solar electrical energy production and many others. Its superior technology is favorable for the designers and has a great impact on the market competition. Hot water storage tanks were studied under continuous usage feature, for different inlet types, flow rates, thermal stratification in static and dynamic modes, both experimentally and numerically. The real discrete usage feature has not been analyzed in a proper way. In this study, the experimental and performance analyses with frequent discrete usage of the hot storage tank were performed. Different flow rates of 3, 6, and 9 l/min with 5, 10 and 20 min discrete usage waiting periods were studied. It was found that the thermocline thickness and mixing number increases for both increasing the flow rate due the increment in turbulent mixing potential and increasing the waiting period due to the increase in heat transfer time available between the hot and cold layers. The real data was drawn as is to permit further analyses and data comparison to other researchers. The effect of waiting periods can be used in solar HST to maximize the efficiency of solar collectors as the solar collector efficiency is high at low temperatures.