Analytical model of solar energy storage using non—Newtonian Fluid in a saturated porous media in fully developed region: carboxymethyl cellulose (CMC) and graphite model

Abstract

Thermal energy storage systems are used mainly in buildings and industrial processes. In this study, solar energy storage by using a circular conduit filled with porous media that is saturated by a non-Newtonian fluid at constant heat flux was represented. The fully developed region was studied by solving the equations analytically, the non-Newtonian fluid parameters used in this model are carboxymethyl cellulose (CMC) properties. In addition, graphite was used as porous media. The heat flux data for Amman city was used in the equations in this study. The effect of Porosity and particle diameter and pressure on the performance of the model were discussed and sketched. As a result, the temperature of storage filled with CMC fluid is better than water in porous media. It is found that the power index of the fluid, porosity, particle diameter, pressure drop, and conduit radius effect inversely the temperature in energy storage. In January, the temperature variation in conduit at the same conditions reach for CMC-1 to 35 ℃ for n = 0.724 and to 85 ℃ for n = 0.7182 and to 190 ℃ for n = 0.7122. CMC-2 has a higher consistency index at the same concentration which means higher viscosity and less power index than CMC-1 so the temperature variation in conduit reaches 50 ℃ for n = 0.599 and 200 ℃ for n = 0.57. The stored energy of CMC-1 for n = 0.724, n = 0.7182, and n = 0.7122 is approximately 120 kJ, 300 kJ, and more than 600 kJ respectively, and the stored energy of CMC-2 n = 0.599 and n = 0.57 is 200 kJ and approach to 800 kJ at the same conditions and conduit.

Keywords

• solar energy storage
• non-newtonian
• porous media
• fully developed
• cmc