ABSTRACT. Thermal energy storage (TES) offers a significant benefit not only in shifting the superior electric power utilized by air conditioning systems from (on-peak) times to (off-peak) times but also reducing the air condition equipment size, improving operation of HVAC equipment subsequently reducing operation cost and save energy. An experimental study of storing ice systems involved in a bare U-tube coil submerged in distilled water as a phase change material is conducted in the present study. During the charging ( solidification) and discharging (melting) operations, the effects of modifying the ethylene glycol solution, Heat Transfer Fluid (HTF), temperature and flow rate on the charging/discharging time and the average charging/discharging rate are explored. The outcomes revealed that, time required for complete charging (solidification) decreased by decreasing HTF temperature and increasing HTF volume flow rate. Also, time required for complete discharging (melting) decreased by increasing HTF temperature and increasing HTF volume flow rate.