An experimental investigation of the effects of the number of capsules and operating conditions on the performance of encapsulated ice storage system

摘要

It is crystal clear to everyone that ice thermal energy storage (ITES) systems provide significant advantages in reducing cooling costs, balancing energy supply and demand profiles, and shaving the peak loads. When the thermodynamic performance of the ITES is compared with conventional AC, the following two points are critical: (i) ITES tends to increase the coefficient of performance (COP) of the system thanks to the lower ambient temperature during the nighttime (the charging period of ITES). (ii) It may cause a lower COP as a lower operating temperature is required to produce ice. In numerous papers, it has been reported that ITES can increase or decrease COP. This experimental study deals with the influences of the number of ice capsules and operating temperatures on the thermodynamic performance of the ITES-integrated cooling system. Results indicate that nighttime operation with the ITES provides higher COP and lower energy costs due to lower ambient temperature and no solar radiation. The highest COP value of the chiller is observed as 13.55. The highest COP during the charging period is found to be 8.99 when the storage medium is 0.3 m3, the charging temperature is -10 degrees C, and the ambient temperature is about 8 degrees C. The efficiency of discharging period is calculated to be 99.97 . The best overall COP is observed to be 17.53 for the case at a storage medium volume of 0.3 m3 and a charging temperature of -12 degrees C. This is about three times higher than a conventional cooling system that works under ordinary daytime runs. Consequently, nighttime operations with ITES can reduce electricity consumption by 30 and cooling costs by 62 .