Thermal performance of a pcm storage unit

This paper presents a two-dimensional model for the phase change, conductio n based heat transfer problem around a tube immersed in the pcm. The energy equation is written in the enthalpy form, and the heat and flow problems a re coupled by an energy balance on the fluid element flowing inside the tub e. The numerical solution is based upon the average control volume techniqu e and the ADI finite difference representation. The results obtained show t he effects of the variation of the ratio of the radius of the inner to the outer tube, Blot number, Stefan number and the working fluid inlet temperat ure on the solidified mass fraction, NTU and effectiveness. (C) 1998 Elsevi er Science Ltd. All rights reserved.