Grouping and grading strategies for duty cycling control of residential air conditioning

Duty cycling control (DCC) of air conditioning can bring significant peak clipping and energy saving benefits for city power grids. Being small scattered loads with different thermal comfort requirements, residential air conditioners (RACs) need grouping and grading DCC. Hence, after deriving the room temperature equations, this paper suggests a RAC grouping method based on the two indices of room characteristic temperature (RCT) and temperature change index (TCI). An energy saving maximization model is further presented for optimizing the grading DCC strategies of the grouped RACs, producing three duty cycles corresponding to three levels of thermal comfort. Results of a case study on a low-carbon residential quarter in Chongming District, Shanghai show that if not violating the residents' willingness, the RACs shall be assigned to the DCC grade of the smallest duty cycle so that greater energy saving effect can be achieved. However, RACs with high RCTs and TCIs might only be able to participate in the grades of large duty cycles for catering their thermal comfort requirement. With small single-point benefit though, DCC on RACs can produce significant energy saving and peak clipping effect if applied in large scale.