Ice thermal storage AC technology aims to build ice store cool energy during night time with electricity off-peak hours by chiller. And then melting the ice during daytime, especially on-peak periods, so to reduce the electrical demand, promote power plant efficiency, save the system operation cost and improve the AC system performance. The main parts of the system are as follows: chiller, ice storage device, plate heat exchanger, glycol pump, cooling water pump, condensate pump, pressure sustainable device, pipeline, valves, and auto-control system.