This paper is based on findings resulting from ASHRAE Research Project RP-1313.

This paper identifies the primary factors that impact the optimal control of passive thermal storage. Optimal control strategies are determined with the objective of minimizing total energy and demand costs using an integrated optimization and building simulation tool. A fractional factorial analysis is employed to investigate how cost savings are affected by several building and system characteristics, utility rate structures, and climates. Utility rates, internal loads, building mass level, and equipment efficiency are found to have the largest impacts on cost savings, whereas building envelope characteristics do not have a significant impact. Although the magnitude of the savings is affected by climate, the relative impacts of each of these factors are largely independent of weather.

Units: Dual