Fabrication and Experimental Investigation of PCM Capsules Integrated in Solar Air Heater

Abstract

Problem statement: Thermal Energy Storage (TES) process can reduce the time or rate mismatch between energy supply and energy demand. Organic latent heat materials are suitable to use as storage medium, however, the low thermal conductivity of these materials slow the thermal response during charging and discharging processes. Approach: A solar air heater integrated with (PCM) has been designed, fabricated and tested indoor. The system consists of top glazed isolated duct, air pump and array of PCM capsules plays to absorb the radiation and storing the thermal energy to discharge to demand when no radiation. Two cases were tested for storage medium used pure paraffin wax and paraffin wax-aluminum composite, the aluminum mass fraction was 0.5% and powder particulate size was 70 μm. Most of these experiments focused on discharge process. The outlet air temperature and thermal storage efficiency of the system has been studied. Results: Experimental results indicated that the charging time was reduced by approximately 70% when used the paraffin wax-aluminum composite. The thermal storage efficiency reached the maximum magnitudes 71.9 and 77.18% at mass flow rates 0.05 and 0.07 kg sec^-1 for pure paraffin wax and the compound respectively. Conclusion: The discharging time was reduced by adding aluminum powder in the wax. The storage efficiency was increased after adding aluminum powder. The encapsulation procedure in this work was also explained.