4217 -- Thermal Performance of a Full-Scale Stratified Chilled-Water Thermal Storage Tank PDF

The thermal performance of a full-scale 1.47 million gallon (5300 m³), 44.5 ft (13.6 m) water-depth, naturally stratified chilled-water thermal storage tank with radial diffusers is analyzed. Controlled, constant inlet flow rate tests covering the full range of the system have been performed for both charge and discharge cycles. Thermal performance for these half-cycle tests is quantified using performance metrics similar to the figure of merit (FOM). Lost capacity, a new measure of performance with practical significance, is also presented. Uncertainty analysis shows that under some circumstances, particularly for tall tanks, lost capacity allows thermal performance to be quantified with less experimental uncertainty than FOM. Results of these tests indicate that discharge cycles performance is not as good as charge cycle performance at the same flow rate. However, the half-cycle figure of merit for all cycles tested was in excess of 90%, despite the fact that the inlet Reynolds number exceeded that recommended in the literature by up to a factor of five.

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