Method and apparatus for power load shedding

A duty cycling apparatus for controlling the electrical power demand of a space conditioning load means comprising:

• timing means for sensing the ON and OFF half-cycle times of the thermostat means associated with the space conditioning load means;
• information storage means for storing information relating to said sensed ON and OFF half-cycle times of said thermostat means associated with said space conditioning load means;
• means for initiating overriding control over the ON-OFF switching means associated with said space conditioning load means overriding said thermostat means at the inception of a load-shedding interval;
• load-shed control means for controlling the ON and OFF half-cycle times of said space conditioning load means during a load-shedding interval based on individually determined load-shed ON and OFF half-cycle times derived from stored information in a manner such that the thermostat state determines whether said space conditioning means is ON during any part of each of said reference ON half-cycle times and said space conditioning means remains OFF during the load-shed OFF half-cycle regardless of thermostat state;
• means for returning control over said ON-OFF switching means of said space conditioning load means to said thermostat means after a load-shedding interval;
• and
• signal receiving means for receiving externally generated command signals.

A non-synchronizing system for power load-shedding in a central power distribution network supplying a plurality of space conditioning means comprising:

• separate load-shed duty cycler means connected to each of the space conditioning means participating in load-shedding, said load-shed duty cycler being connected in a manner which allows it to shut off the power supply to said space conditioning means, said load-shed duty cycler means also being connected to the thermostat control associated with the space conditioning means;
• signal receiving means associated with said load-shed duty cycler to receiver command control instructions from the power supplier as required for power load-shedding;
• load-shed cycle control means in said duty cycler, said load-shed control means including timing means for timing the natural ON and OFF cycle times of said thermostat means, information storage and retrieval means for storing and retrieving information including information supplied by said timing means related to said ON-OFF cycle times and control means for controlling the cycling of said space conditioning based on load-shed ON and OFF cycle times derived from said stored natural cycle time information;
• and
• anti-synchronization means in said load-shed control means including phasing-in means implemented at the inception of the load-shedding interval which causes the initial load-shed ON-OFF cycle to correspond to the natural half-cycle in effect at the inception of load-shedding and wherein said load-shed control means thereafter patterns ON and OFF load-shed half-cycles based on stored information derived from a sequential pair of natural half-cycles contained in said stored information wherein said ON load-shed half-cycle is a permissive ON half-cycle and said OFF load-shed half-cycle is a positive OFF half-cycle to thereby preserve the random natural diversity of the plurality of space conditioning means.