A one-dimensional, implicit, finite-difference model of a single stratified thermal storage tank has been developed. The model covers variable flow rates for charging or discharging the thermal storage tank and conduction and turbulent mixing within the water for two different inlet configurations. In order to handle variable flow rates, a "conceptual buffer tank" algorithm was developed. Turbulent mixing occuring in the tank was simulated through thermal eddy conductivity factors, which were determined from experimental data. A decreasing hyperbolic function predicted the best variation of the eddy conductivity factors inside the tank. A general relationship between the inlet eddy conductivity factor and the ratio of Reynolds number over Richardson number was established for the inlets investigated. The simulation model adequately predicted the experimental data. In addition, the model reproduced hydraulic test data better than a recent one-dimensional model found in the literature.

Units: I-P