Numerical Heat Flux Simulations on Double-Pass Solar Collector with PCM Spheres Media

Abstract

A transient two-dimensional (2D) mathematical model for double-pass solar collector with phase change material (PCM) spheres media in the lower channel has been developed. Numerical simulations model based on applying mass, momentum, and energy balances on finite volumes method are carried out. The governing equations inside the two channels, together with the energy equation in the absorber, insulating and glass cover walls were solved iteratively in a segregated manner. To show the effect of the presence of the PCM, a comparative study was undertaken between a collector with different PCM spheres, a collector without spheres, and another using gravel for thermal storage. To see the effect of the nature of PCM used, two different types were studied in various configurations, parallels and series. The study concluded that the presence of the PCM spheres at the bottom of the absorber is the best configuration and allows increasing the outlet temperature. Also, with combining several types of PCM we can improve significantly the thermal performance of collector.