Melting Behavior of Phase Change Material in a Solar Vertical Thermal Energy Storage with Variable Length Fins added on the Heat Transfer Tube Surfaces

Ramalingam Senthil,Aditya Patel,Sahil Ganeriwal,Rohan Rao

doi:10.14710/ijred.2020.29879

Abstract

This paper investigates the melting behaviour of phase change material (PCM) in a vertical thermal energy storage system with provision of thin rectangular fins of uniform and variable lengths on the heat transfer tube surfaces. The selected PCM and heat transfer fluid (HTF) are paraffin wax and water, respectively. The HTF is passed through the helically coiled copper tube of 10 mm diameter to melt the PCM. The time required to complete the melting of PCM in the system with fins is found to be five hours, whereas for the system without fins it is five hours and forty minutes, for the same conditions of constant water temperature of about 70°C and flow rate of 0.02 kg/s. HTF tube with fins is observed to be more effective with a 13.33% faster rate of melting when compared to that of the HTF tube without fins. Such a fast charging process will be helpful in storing maximum energy within a short period/duration of time shorter duration in for solar thermal and heat recovery applications during lean production times. ©2020. CBIORE-IJRED. All rights reserved

Highlights

Solar energy utilization is one of the fastest-growing and cost-competitive renewable energy resources worldwide
The fins are found to be beneficial due to the additional heat transfer area and the contact with the phase change material (PCM), and the temperature trend is at a faster rate when compared to the heat transfer fluid (HTF) tube without fins
The average temperature of PCM with fins is observed to be around 5.5% more temperature that that of the PCM storage without fins as per Fig. 4

Summary

Introduction

Solar energy utilization is one of the fastest-growing and cost-competitive renewable energy resources worldwide. The thermal requirements during the night and early morning necessitated the development of thermal energy storage (TES) for solar energy systems. TES is a type of energy system that uses the concept of both sensible and latent heat to store the captured heat energy from compact solar thermal collectors and waste heat recovery systems, without loss. TES provides the stored heat use fort at a later time for applications like heating and drying. Thermal energy can be stored either as sensible or latent heat. Latent heat storage (LHS) has a higher capacity to store energy per unit volume compared to sensible heat storage due to latent heat of phase change. PCM’s have a low thermal conductivity between 0.1-0.7 W/m-K. The present review of literature focuses on the improvement of the thermal conductivity of PCMs using fins

Methods

Results

Conclusion