Ice Based Cooling System

I saw an article on Yahoo News recently about some large buildings in New York using ice for cooling in the summer [1].  Basically the way the system works is large tanks of water are frozen and the ice is used to cool air that is distributed throughout the building.  Throughout the day the ice melts as it cools the air in the building.  The obvious benefit of this type of system, is that it would reduce peak energy usage during the daytime, when all the other air conditioners in the city are turned on and using energy.  In a system where peak energy is more expensive at peak usage times, this could save money.  However, would this system really save any energy overall?  The article states that for one company, there is a savings of 2.15 M KW hours per year with the system.  The only way this is possible is if the process to create ice is more efficient than the process to air condition a building.  I believe the process that a typical refrigerator and air conditioner use are similar so I doubt if this is the case.  The benefit must come from the fact that the ice is created during the night when the outside temperature is lower, and there is no radiation energy from the sun.  Creating the ice below ground also could help because the temperature below ground is lower in the summer (make use of geothermal energy).  The drawback of this type of system would be up front costs to construct the large water holding tanks and the space required to house them.  The article states that the system has a good return on investment for very large buildings.  Does anyone know of any other example systems like this one?

[1] Long, Colleen. July 14, 2007. "System Relies on Ice to Chill Buildings." Yahoo News, Associated Press Story.