Perpindahan panas pada alat penukar panas untuk menyimpan panas laten

ABSTRACT An experimental study to investigate the heat transfer rate and to calculate the total energy that can be stored in a heat exchanger for latent heat thermal energy storage system using the latent heat of fusion of a phase change material (PCM) has been carried out in this study. The heat storage container is a double pipe heat exchanger where the energy source fluid (hot water) flows through the inner tube (copper, of inside diameter of 12.5 mm, outside diameter of 16 mm and length of 149.5 cm), while the heat sink (storage PCM) fills the annular gap (outer tube made of PVC with inside diameter of 78 mm and thickness of 6 mm). The PCM used in this experiments is the paraffin wax with melting temperature of 44°C. Measurements were made of the temperature change of the hot water as well as of the paraffin wax. The heat transfer rate and the accumulative energy stored as a function of time was evaluated for different hot water flow rates and inlet temperatures. The melting rate of the PCM was also investigated visually. The experimental results with the parameter of hot water mass flow rates show that the heat transfer rate increases 181% at the time of 50 minutes from the initial process by increasing the hot water mass flow rate from 0.00764 kg/sec to 0.0221 kg/sec for the water inlet temperature of 70°C. The heat transfer rate at 50 minutes from the initial process for the experiment using hot water mass flow rate of 0.0221 kg/sec increases 97.2% by increasing the hot water inlet temperature from 60°C to 70°C. The accumulated energy stored at the PCM also increases by increasing the hot water mass flow rate for a constant inlet temperature and/or increasing the inlet temperature for a constant mass flow rate. The results of the visual investigation of the melting rate of PCM show that convection in the molten zone was found to be an important parameter affecting the heat exchanger performance