Performance Enhancement of Triplex Tube Thermal Storage Unit Using Paraffin Wax- Metal Foam

Abstract

ABSTRACT Latent Heat Thermal Energy Storage (LHTES) based on Phase Change Material (PCM) provides an encouraging solution for the efficient utilization of discontinuous energy from the renewable such as wind, solar, and so on. Prospective applications of the PCMs in the fields of thermal management and thermal energy storage are well recognized. Nevertheless, the main problem of these materials is their poor thermal conductivity which necessitates the incorporation of thermal response enhancement techniques. Porous metal foam as an effective conductivity enhancement approach along with Triplex Tube Heat Exchanger (TTHX) thermal storage structure filled with PCM was used to enhance the PCM charging rate. An experimental investigation is carried out to establish a comparative performance assessment on two TTHX configurations: TTHX without foam (simple TTHX) and TTHX with copper foam (foamed TTHX) using water as a Heat Transfer Fluid (HTF). The numerical simulation was done using ANSYS Fluent. The heat transfer fluid (HTF) was water flowing through the heat exchanger tube at oC, oC, and oC. The thermal behavior of two TTHX configurations Were investigated in terms of temporal variation of PCM temperature, PCM liquid fraction and energy stored for different opration condition of HTF inlet tempreture and mass flow rate . Experimental observations showed the foamed TTHX had a superior melting rate over the simple TTHX. For both TTHX configurations, the increasing of HTF temperature, the needed time for the process of charging decreases. effect of the temperature of HTF is significant for foamed TTHX, where the whole time of melting reduces for foamed TTHX and simple TTHX is (43%) and (34%) when the temperature of HTF is increased from (69ºC) to (75ºC). Furthermore, the overall enhancement can be performed with addition foam to LHTES of up to 44%, 36% and 33% III corresponding HTF flow rate compared with simple pure LHTES.further, The variation of flow rate has a little impact on thermal response for foamed THHX as compared with simple TTHX with consideration of flow rate variation. The highest accumulative energy stored enhancement reached up to (52%) was obtained by incorporating copper foam with TTHX at highest HTF temperature during melting process.