Philadelphia Electric Company has tested an ice storage air conditioning unit for the three summer seasons of 1977, 1978, and 1979. The unit operates in the off-peak period and stores ice for cooling in peak demand period which follows. On the PECo system, the off-peak period isdefined as between 10 p.m. and 10 a.m. the following day.Based on three summers' tests, we have concluded:The air conditioning demand and the associated kWh consumption can be moved from the peak to the off-peak period.The capacity of a standard air conditioning condensing unit is significantly lower when used for iceproduction purposes.The development of more accurate ice control equipment is necessary to ensure successful operation of residential ice storage equipment.