Experimental investigation on inorganic salt solution’s undercooling degree under the action of porous media and different concentrations

Abstract

The undercooling degree of inorganic salt solution has great effect on the characteristic of phase change materials in cooling storage methods. Ammonium chloride solution was chosen as a kind of inorganic salt solution, and the experimental system was built to study the influence on supercooling degree of inorganic salt solution under the effection of concentration and porous media. The heat transfer enhancement method was studied by changing the concentration of inorganic salt solution and the diameter of pellets constituting the porous media. The experimental results show that with the increase in concentration, the value of inorganic salt solution’s supercooling degree and dispersion degree reduced, while the stability increased. The undercooling degree of the 15% ammonium chloride solution decreased by 17.5% compared to the 5% ammonium chloride solution. As the pellet diameter constituting the porous media decreased, the average value of the solution’s undercooling degree and dispersion degree also decreased, while the stability increased. The average value of the solution’s undercooling degree decreased by 21.7% when using 5-mm-diameter pellets compared to the ammonium chloride solution without porous media.