Experimental Analysis of PCM Based Helical Heat-Exchanger for Thermal Management of Buildings

Abstract

Over the past years, numerous methods are adopted for the storage of thermal energy. Among them Phase Change Materials (PCM) based thermal energy storage are deployed in storing high amount of heat with in a small range of temperature difference. This work investigates for an appropriate heat exchanger design to extract heat from PCM. It has been found that a PCM based helical heat exchanger can reduce mean air temperature by 4°C and reduce heat gain by 35%. A helical heat exchanger engaged in an aluminum tray filled with PCM is developed in ANSYS with inlet water temperature at 10°C is flowing through the coil for increasing heat extraction from PCM. Variation is made in pitch of helical coil from 1.7 cm to 3 cm. The least liquid fraction is obtained for 3cm pitch. Thus, the experiment is validated by considering the pitch of helical coil as 3cm and it has been fixed in an aluminum tray containing PCM with an inlet water temperature of 10 °C and flow rate of 0.3 l/min. The encapsulated PCM based heat exchanger is placed in a miniature room for three hours and a temperature drop of 4°C than mean air temperature in room is observed. The results show that using PCM for thermal energy storage can increases the amount of heat stored. The use of properly selected PCM and heat exchanger enables the process of thermal energy storing and release to become more efficient.

Keywords: phase change material, helical heat exchanger, thermal energy