Heat transfer enhancement using spiral fins in different orientations of Latent Heat Storage Unit

A comprehensive experimental analysis is reported to estimate the heat transfer enhancement in concentric tube type Latent Heat Storage Unit (LHSU) using spiral fins. An angle adjuster is provided in the experimental test facility to facilitate orienting the LHSU at different angles i.e. vertical (theta = 90 degrees), horizontal (theta = 0 degrees) and inclined (theta = 45 degrees). Total 45 temperature probes are installed in the annulus of the concentric tubes for accurate measurement of temperature in radial, axial and angular direction. Provision of fins expedites melting rate, which results in reduction in time required for energy storage. With the installation of the spiral fins, a maximum reduction in the charging time of 51.61% is observed when the test section is aligned in vertical (theta = 90 degrees) orientation. Inclined (theta = 45 degrees) and horizontal (theta = 0 degrees) test section offer 40.97% and 34.1% reduction in the melting time respectively. LHSU integrated with the spiral fins may enable its application to large scale solar thermal applications.