Thermal conductivity of sugar crystals and sugar bulks

The thermal conductivity of ungraded and graded white sugar, cube sugar, powdered sugar, candy sugar and of a sugar crystal assembled from very large candy was studied. The effective thermal conductivity of white and powdered sugar is chiefly determined by the thermal conductivity of sucrose and air, and the porosity of the disperse systems. The effective thermal conductivity of candy sugar is additionally dependent on the particle size and, with increasing particle size, on the temperature. Because of the adhesion of the sugar crystals, the effective thermal conductivity of cube sugar is about 40% greater than that of a white sugar pile and declines with the temperature, as in the case of a sugar crystal.