Mega supermarkets called hypermarkets have high cooling loads due to the high volume of shoppers and the use of large number of heat-producing devices. Providing thermal comfort conditions and meeting the fresh air demands are critical issues in hypermarkets as they involve high initial investment and operating costs. Ice storage system (ice-ss) is a unique storage method which helps to reduce operating costs. In this work, the performance of the ice storage system integrated into the air conditioning system of the hypermarket in Ankara, Turkey is studied thermodynamically and economically. The ice-SS stores 47% of 8332 kWh daily total cooling load, which coincides with the period of electricity peak tariff. Thus, the ice-ss makes it possible to shut down the chillers during the electricity peak tariff hours. Based on the analysis of the data collected over the four years of operation, it is found that the ice storage system at the hypermarket facility has paid back its initial cost within the first 3 years of operation. The system has been operating since 2016 without any loss of performance and continues to reduce the energy cost of air conditioning by about half each year.