Numerical Simulation of a Novel Dual Layered Phase Change Material Brick Wall for Human Comfort in Hot and Cold Climatic Conditions

Abstract

Phase change materials (PCMs) have a large number of applications for thermal energy storage (TES) and temperature reduction in buildings due to their thermal characteristics and latent heat storage capabilities. The thermal mass of typical brick walls can be substantially increased using a suitable PCM primarily based on phase change temperature and heat of fusion for different weather conditions in summer and winter. This study proposed a novel dual-layer PCM configuration for brick walls to maintain human comfort for hot and cold climatic conditions in Islamabad, Pakistan. Numerical simulations were performed using Ansys Fluent for dual PCMs layered within a brick wall for June and January with melting temperatures of 29 °C and 13 °C. This study examined and discussed the charging and discharging cycles of PCMs over an extended period (one month) to establish whether the efficacy of PCMs is hindered due to difficulties in discharging. The results show that the combined use of both PCMs stated above provides better human comfort with reduced energy requirements in Islamabad throughout the year than using a single PCM (29 °C) for summer or winter (13 °C) alone.

Investigation of PCM thermal effectiveness towards an optimised design of cooling building envelope

“…Both of these parameters are important in thermal comfortability analysis. Besides, the peak temperature reduction in the case of using PCM and the one that combining PCM with rockwool are the same 2 °C compared to the control set (brick only), therefore Experimental results [33] 16th…”

“…Besides, to setup the boundary conditions, a transient table with hourly temperature profile on 23 rd and 24 th February 2021 is inserted into the software as input of the 1D heat transfer from outdoor surface to indoor surface [25]. The heat transfer across the surface that in contact with outdoor air is taken as natural convection with heat transfer coefficient of 14 W/m 2 [33] whilst other surface are assumed adiabatic with zero heat flux. Apart from that, SIMPLE algorithm was applied for the pressure-velocity coupling, and the equations were all discrete from second order upwind scheme.…”

“…Second order upwind was selected because it used Taylor series expansion at the centroid of cell, thus will generate a more accurate result [34]. Besides, all the equations are set to converged at less than 10 -6 as suggested in [33]. Based on time independence study done in [33], 2940 time steps of 60 s was implemented for the calculation.…”

“…Besides, all the equations are set to converged at less than 10 -6 as suggested in [33]. Based on time independence study done in [33], 2940 time steps of 60 s was implemented for the calculation.…”

Geometry Effect of CaCl2·6H2O at Charging and Discharging Process as Latent TES

“…So far, very limited studies have reported using ANSYS (Fluent) to simulate the melting and freezing of CaCl26H2O or other PCM. Previous studies by Fiala et al [5], Rehman et al [6], and Wang et al [7] focus on the melting behaviour of CaCl26H2O. In addition, through an intensive study, Pan et al [8] have shown the agreement between the result of Numerical/simulation and experimental for comparing the melting patterns of CaCl26H2O confined in a vertical tube submerged in a water bath.…”