Performance Evaluation Of Thermal Energy Storage For District Cooling Plant

The purpose of implementing thermal energy storage (TES) in a cooling system is to enhance the performance of the system in terms of energy and cost saving. The objectives of this research are to evaluate the performance of thermal energy storage and to develop a controlling strategy to enhance the performance of thermal energy storage of Universiti Teknologi PETRONAS Gas District Cooling (UTP GDC). One of the important components of the thermal energy storage is TES tank. The TES tank is a naturally stratified and rated at 10000RTh with 5400m3. Four electric chillers (EC) at a capacity of 325RTh are used to charge the tank. The ECs were designed to supplement the chilled water for charging the TES tank during the night time. The TES tank was discharged to supplement the chilled water requirements during the day. Hourly operating data of the TES tank and ECs were analyzed for one week in February 2010 and March 2010. The integrated capacity for both charging and discharging were calculated. Thermal performance for the storage tank in term of half-cycle FOM was quantified using performance metric similar to the figure of merit (FOM). The finding was that half-cycle FOM of the tank was low due to the small integrated capacity during charging and discharging period. Besides, it is also noted that the plant did not fully utilize the chilled water that was available in the storage tank. The plant need to consider adding the charging duration and increasing the flow rate to optimize their schedule and taking full advantage of TES utilization.