Optimization of Ice Thermal Storage Systems Design for HVAC Systems

Ice thermal storage is promising technology to reduce energy costs by shifting the cooling cost from on-peak to off-peak periods. The paper discusses the optimal design of ice thermal storage and its impact on energy consumption, demand, and total energy cost. A tool for optimal ice storage design is developed, considering the charging and discharge times and optimal sizing of ice thermal storage system. Detailed simulation studies using real office building located near Orlando, FL including utility rate structure are presented. The study considers the effect of the ice thermal storage on the chiller performance and the associated energy cost and demonstrates the cost saving achieved from optimal ice storage design. A whole building energy simulation model is used to generate the hourly cooling load for both design day and entire year. Other collected variables such as condenser entering water temperature, chilled water leaving temperature, outdoor air dry bulb and wet bulb temperatures are used as inputs to a chiller model based on DOE-2 chiller model to determine the associated cooling energy use. The results show a significant cost energy saving can be obtained by optimal ice storage design through using the tool proposed in this paper