Forced Duty Cycling of Air Conditioning Units for Load Management

This paper presents the results of testing done on a 50% forced duty cycle load management control strategy for both commercial and residential air conditioning installations. A total of nearly 1.5 MW of connected load was controlled by this program, with in excess of 500 KW of load relief observed at a total of 84 customer sites. The direct duty cycle control strategy was found to result in approximately 30% load relief during the control period and a 30% increase in load level immediately following the control period due to load recovery characteristics. Impact on space temperature was on the average approximately 2 degrees by the end of a six-hour control period. Some reported customer discomfort as well as high observed temperatures suggest that the forced duty cycle strategy may create some inequities. The data also suggest that for conservation reasons some customers operate near the edges of personal comfort even in the absence of load management control and that this strategy will cause some human discomfort. The encouraging results seen here, indicating an average 30% load relief, suggest that further examination of advanced control strategies is warranted.