![]() | Only 14 pages are availabe for public view |
Abstract Thermal energy storage system clearly benefits cooling system owners by reducing electric demand charge. However, the use of thermal storage systems is widely believed to increase overall cooling plant energy consumption. In order to avoid that, a properly design of cooling plant using thermal energy storage system which requires accurate modeling of each component and validated simulate for the dynamic response with time-varying loads. In addition to, the balance between the storage unit, chiller, and load variations that should be considered for optimal energy consumption. This study is devoted to experimentally describe the dynamic performance of the proposed indirect ice-based thermal energy storage system at several operating modes of charging and discharging. The temperature profiles of the phase-change material (PCM) inside the storage lank, and the brine solution (HTF) inside the storage tank were also described. In order to obtain these results a laboratory-scale ice-making unit existing in the thermal labis repaired and reconstructed for being used as indirect ice-based thermal energy storage system. For charging and discharging modes, in order to illustrate the dynamic behavior of the proposed storage system, sets of parameters studies for both charging and discharging cases were run including the effects of brine inlet temperature and mass flow rate on outlet brine temperature from the storage tank, charging rate (discharging rate), and state of charge were studied. F ram the results, it could be observed that there are temperature differences with height direction of the can, which attribute to the thermal convection and density variation of HTF. Consequently, the colder HTF will be at the lower part of the storage tank. So that the lower part reaches the final temperature faster than the higher part. On the other hand the temperature profiles of HTF pass through three stages, during the first stage the temperature change of the can rapidly decreases with height and is then maintained relatively constant during the second stage, where the latent heat of the PCM is removed, after this period the temperature change begins to increase again till reach the final state. It could be observed that, the required period for each stage decreases as inlet temperature decreases, where the thermal convection increases, or mass flow rate increases, which could be attributed to the effect of mixing, which increases as mass flow rate increases. |