This paper describes a study of the application of energy management including electric demand limit control in a 6656² ft table service restaurant located in Minneapolis, which contained 30 tons of rooftop air conditioning, a 74 kW electric dishwasher, and natural gas space heating. Strategies were developed for applying demand-limit and time-of-day controls on rooftop air-conditioning units, refrigeration equipment, ventilation equipment, and a dishwasher electric booster heater.

This study was conducted over a one-year period using a week-on/week-off test proceedure in which the energy management controls were in operation alternately for one week and then manually disconnected .for the following week. This testing method was chosen to reduce the effects of changes in the business operating proceedures, changes in the connected loads, electrical and irregularities in the climate that tend to distort results based on a year-to-year comparison. Extensive instrumentation was installed to monitor the operation o£ controlled loads, the impact on the space temperature, the operation of overrides and limit controls on critical loads, peak electric demand, and total energy consumption.

The study demonstrated that electric demand charges were reduced 19.7% and that electric energy usage charges were reduced 8.7%. The total annual savings was $2440 which represented a 13% savings on the total energy bill and a 48% return-on-investment on a system installed cost of $ 5083.

Units: I-P