Thermal performance of an integrated collector storage solar water heater (ICSSWH) with phase change materials (PCM)

• We study the effect of phase change materials integration on the thermal performances of an ICSSWH.
• Two kinds and tree radiuses of the PCM layer are studied and the most appropriate design is presented.
• The use of phase change materials in ICSSWH is determined to reduce the night thermal losses.
• Myristic acid is the most appropriate PCM for this application regarding the daily and night operation.

In this paper, we propose a numerical study of an integrated collector storage solar water heater (ICSSWH). Two numerical models in three-dimensional modeling are developed. The first one which describes a sensible heat storage unit (SHSU), allowing validating the numerical model. Based on the good agreement between numerical results and experimental data from literature, and as this type of solar water heater presents the disadvantage of its high night losses, we propose to integrate a phase change material (PCM) directly in the collector and to study its effect on the ICSSWH thermal performance. Indeed, a second 3D CFD model is developed and series of numerical simulations are conducted for two kind (myristic acid and RT42-graphite) and three radiuses (R = 0.2 m, R = 0.25 m and R = 0.3 m) of this PCM layer. Numerical results show that during the day-time, the latent heat storage unit (LHSU) performs better than the sensible one when myristic acid is used as PCM. Regarding the night operating of this solar system, it is found that the LHSU is more effective for both PCMs as it allows lower thermal losses and better heat preservation.