Cooling with ice thermal storage can be the most cost-effective, reliable system approach to cooling different types of buildings. The ice thermal storage can reduce energy costs by shifting the cooling cost from on-peak to off-peak periods. The paper proposes an integrated approach to size and operate the ice thermal storage with different loads and weather conditions. The variables such as chiller and ice storage sizes and charging and discharge times during different seasonal conditions are considered. Different building types, locations, utility rate structure are investigated to evaluate the advantages of optimal ice thermal design and operation. 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. Two load estimation techniques are evaluated, including linear regression model and artificial neural networks. The results show a significant cost energy saving can be obtained by optimal ice storage design through the proposed approach.