Use of latent heat storage to conserve energy during drying and its effect on drying kinetics of a food product

Abstract

The present study aimed at investigating the feasibility of using a latent heat storage (LHS) with paraffin wax as a phase change material (PCM) to store excess solar energy and release it when the energy availability is inadequate or not available. First, attention was given on the heat transfer characteristics of the PCM during the charge and discharge periods of the LHS. The effects of inlet hot air temperature in the range of 70–90 °C and inlet air velocities of 1 and 2 m s −1 on the charge time were determined, while during the discharge period only the effect of inlet ambient air velocity was considered. The effect of the use of LHS on the drying kinetics of sweet potato and the ability of the LHS to conserve energy during drying of sweet potato were also determined. It was found that the drying rate of sweet potato increased with a decrease of the inlet ambient air velocity. The amount of the energy extractable from the LHS was 1920 and 1386 kJ min kg −1 and the energy savings was 40% and 34% when using an inlet ambient air velocity of 1 and 2 m s −1, respectively.