A model has been developed to determine the least-cost cooling strategy for a building by using the building mass for thermal storage. The savings is achieved by subcooling the mass immediately before the peak utility rate period, thereby shifting a portion of the cooling load off-peak. The method described formulates an objective function based on the energy consumption of a simple building model. The building is subject to thermal loads from solar and ambient temperature influences. Daily energy use is broken up into three phases- coast-up, maintenance, and subcooling, which are multiplied by an appropriate energy cost to find the total daily cooling cost. The cooling cost is then optimised with respect to an appropriate independent variable. Analytical results using the characteristics of a light commercial structure have shown cooling cost savings of 18% when compared to base case simulations.

KEYWORDS: cooling load, cold sources, energy conservation, structure heat storage, energy storage, costs, subcooling, off peak electricity, models, energy consumption, electricity consumption.