Numerical and experimental study of spherical capsules packed bed latent heat storage system

A numerical model to simulate a storage system composed of spherical capsules filled with PCM placed inside a cylindrical tank fitted with a working fluid circulation system to charge and discharge the storage tank. The simplified transient one-dimensional model is based on dividing the tank into a number of axial layers whose thickness is always equal or larger than a capsule diameter. It is also assumed that the temperature of the working fluid is uniform and equal to the average temperature of the layer. The solidification process inside the spherical capsule is treated by using a conductive one-dimensional phase change model with convective boundary condition on the external surface. The convection present in the liquid phase of the PCM is treated by using an effective heat conduction coefficient in the liquid region of the PCM. The solution of the differential equations is realized by the finite difference approximation and a moving grid inside the spherical capsules. The geometrical and operational parameters of the system are investigated both numerically and experimentally and their influence on the charging and discharging times was investigated.

[1]  Yildiz Bayazitoglu,et al.  Melting Within a Spherical Enclosure , 1982 .

[2]  Sih-Li Chen,et al.  An experimental investigation of nucleation probability of supercooled water inside cylindrical capsules , 1998 .

[3]  Kamal Abdel Radi Ismail,et al.  Ice formation around isothermal radial finned tubes , 2000 .

[4]  M. Prud’homme,et al.  A Heat Transfer Analysis for Solidification of Slabs, Cylinders, and Spheres , 1989 .

[5]  Kamal Abdel Radi Ismail,et al.  A numerical and experimental study on a parallel plate ice bank , 1999 .

[6]  Sung Hwan Cho,et al.  Phase change of spherical bodies , 1970 .

[7]  L. Milanez,et al.  Solidification in spheres: theoretical and experimental investigation , 1983 .

[8]  G. Domoto,et al.  Perturbation Solutions for Spherical Solidification of Saturated Liquids , 1973 .

[9]  S. H. Choi,et al.  Thermal characteristics of paraffin in a spherical capsule during freezing and melting processes , 2000 .

[10]  James M. Hill,et al.  Freezing a saturated liquid inside a sphere , 1983 .

[11]  Pu-hsüan Wang,et al.  Heat Transfer Science And Technology , 1987 .

[12]  R. Velraj,et al.  Experimental analysis and numerical modelling of inward solidification on a finned vertical tube for a latent heat storage unit , 1997 .

[13]  L. Tao,et al.  Generalized numerical solutions of freezing a saturated liquid in cylinders and spheres , 1967 .

[14]  Kamal Abdel Radi Ismail,et al.  PCM THERMAL INSULATION IN BUILDINGS , 1997 .

[15]  G. Poots,et al.  The inward solidification of spheres and circular cylinders , 1974 .

[16]  John Beek,et al.  Design of Packed Catalytic Reactors , 1962 .

[17]  A. Kürklü,et al.  Mathematical modelling of the thermal performance of a phase-change material (PCM) store: Cooling cycle , 1996 .

[18]  Kamal Abdel Radi Ismail,et al.  U-values, optical and thermal coefficients of composite glass systems , 1998 .