Demand Response, Air-Conditioner, HVAC
Residential and commercial unitary air-conditioners (A/Cs) are one of the major sources of the growing electrical energy use and peak power demand. The growing need for electrical power demand can have an adverse impact in grid reliability, especially when there is not enough electricity generation, and can result in power outages. To prevent such instances, utilities offer their customers economic incentives to reduce power demand and usage at certain times in the day under demand response (DR) program. To fully take advantage of the DR program, however, the consumers need access to equipment and appliances that enable communication of rates and grid conditions, and offer integrated control capabilities to respond to the information received. These DR capabilities can be achieved either at the factory level or by retrofitting and installing add-on devices on the existing equipment. This paper discusses the results of experimental evaluation of a DR capable add-on retrofit controller on a 5-ton rooftop unit (RTU). A series of laboratory tests were performed to quantify and establish the power demand impacts of two distinct DR events, moderate and high, for a 5-ton RTU. The power demand implications were obtained and evaluated for two outdoor and two indoor conditions. Results indicate that the controller was capable of responding to both Moderate and High DR signals through a central gateway. For Moderate DR events, the average total power demand was reduced by up to 33%. For High DR events, potentially the average total power can be reduced by 60%. As expected, these DR events results in an increase in indoor temperature.