Experimental and numerical study of thin ring and annular fin effects on improving the ice formation in ice-on-coil thermal storage systems

Cooling load demand during the warmest hours of summer days leads to an increase in electrical energy request, intensifying the peak load. Thus, to reduce electrical energy consumption in peak hours, cold energy storage systems are used. One of the most common methods in this area is ice on coil energy storage that deals with the problem of heat transfer rate decreasing during charging. In this paper, performance of two heat transfer enhancement methods including usage of thin rings and annular fins around coils are compared. First, the thermal behavior of the system is simulated and the sensitivity analysis is performed. Then, design parameters for experimental set up are selected based on the results obtained from the sensitivity analysis. For the case of annular fins, results show that the optimum operating point is deduced when the distance between two adjacent fins becomes 50 mm. According to the numerical results, the experimental tests are designed. It is shown that ice formation in the cases of using annular fins and rings will be correspondingly 21% and 34% higher with respect to the bare tube. Besides, freezing will be sped up by 15% in the case of using finned and ringed tubes. Accordingly, diagonal thin rings have better performance with respect to annular fins. The reason is that the ice formation rate in the central region between the tubes is enhanced due to the presence of thin rings in this region. (C) 2016 Elsevier Ltd. All rights reserved.