ABSTRACT
W. J. Yang and C. P. Lee performed a theoretical analysis of storage devices subject to step and sinusoidal variations of inlet temperature, although only a step change of temperature was analyzed for latent heat-storage devices. The National Bureau of Standards (NBS) recognized two other methods of testing storage devices, constant input and output heating rate, and variable input and output heating rate. Liquid systems require a flow measuring device, a pressure gauge, temperature sensors in the inlet and outlet of the thermal storage device under test, and a differential pressure measuring device. Marshall's mathematical model identifies four thermal conductances and two generic types of storage unit. Three time-varying partial differential equations in one physical dimension govern Marshall's mathematical model. The equations can be derived in a straightforward manner from energy balances on the heat-transfer fluid, the thermal-storage material, and the storage envelope.
