DIRECT WATER-HEATER LOAD CONTROL - ESTIMATING PROGRAM EFFECTIVENESS USING AN ENGINEERING MODEL

Most utility demand-side management strategies that involve direct load control have been developed using a pilot testing or demonstration program. Two appliances, electric water heaters and air conditioners, are the primary candidates for direct utility control. A utility can avoid pilot testing programs and proceed directly to program implementation if it designs and conducts a proper load research program in which average customer usage and instantaneous demand axe determined as a function of the variables that affect each of them. This paper describes a method to evaluate the potential effectiveness of a direct water heater load control program. Developed through a comprehensive load research program coupled with engineering insights into the energy use of the residential hot water systems, this method results in an algorithm that has been utilized to evaluate the potential for load control on three utility systems in the western U.S. Variables to be monitored through the load research are presented and a procedure is developed that will allow the system planner to determine if such a program will be cost-effective and successful compared to a program developed through a more traditional pilot or demonstration approach. This paper also outlines how the same methodology can be used for determining a procedure for the dispatcher to properly initiate and terminate a load control program without hot water recovery problems.