Numerical Investigation of a Phase Change Material Building Integrating Solar Thermal Collector PCM-BST

Abstract

Sensible thermal energy storage (TES) systems can reduce energy environmental fluctuation dependency with the nocturnal energy needs usage in maintaining the building's comfort levels. In the present paper, phase change material (PCM) is introduced to improve the thermal energy storage capacity of a solar collector integrating a novel composite PCM/concrete wall. A mathematical model based upon the conservation and heat transfer equations has been developed using the enthalpy method. The equations that govern the problem were discretized with the control volume scheme and solved iteratively using the tridiagonal matrix algorithm (TDMA). The numerical investigation has been implemented into a personal fortran code. Many series of simulation runs were executed. The position of the PCM layer within the wall and the PCM melting temperature are varied in the range 0 cm ≤ xm ≤ 7.5 cm and 15 °C ≤ Tm ≤ 35 °C, respectively. The objective is to let inner temperature Tin swing close to a comfort threshold. The position of PCM close to the absorber improves the efficiency of the room heating with good nocturnal use of latent heat stored during the day. PCM melting temperature affects deeply the composite PCM/concrete wall/solar collector behavior. Lastly, PCM gained the system an important benefit which is the solar collector high-temperature isolation as to not reach the room and disturb the inside comfort zone by melting and solidifying. Those parameters can be considered as the primary pointers for PCM/wall integrated solar collector design. Also, a daily heating potential, Qh, and thermal load leveling, TLL, are introduced to evaluate the system performance.