Numerical Simulation On Heat Transfer Characteristics Of PCM Solar Collector-storage Wall Enhanced By Vortex Generators

Passive solar buildings take advantages of solar resources skillfully for heating in winter without additional power equipment. This study addresses problem of low efficiency and poor heat release of the traditional solar collector-storage wall systems. By CFD software package, solar load model with sun ray tracing method is used to simulate solar radiation. A phase change solar collector-storage wall system model is established which is unsteady and three-dimensional. Based on Beijing meteorological parameters, the air flow and heat transfer are simulated between the glass and wall.By contrast with the solar radiation meteorological parameters, the choice of sun ray tracing method to simulate solar radiation is applicable, and the result is more reliable with the error less than6%. The simulation results show that, under present conditions, the thermal storage performance of PCM with phase transition temperature of320K is excellent. The capacity of evening and night increase17.4%compared with traditional wall. Analyzing heat transfer performance of different height delta wing vortex generators arranged in multiple rows on solar collector-storage wall surface, the result shows that6cm height vortex generators is the best, with wall surface average temperature3.7℃reduced, air outlet temperature2℃rising, and the convective heat transfer coefficient increased by13.9%.Finally, integrated application Tc=320K PCM and6cm high vortex generators together in the model, simulation results show that capacity of evening and night increase57.3%.The thermal efficiency of the wall has been significantly improved, and energy-saving effect is remarkable. The results provide useful reference for the design of efficient passive solar buildings.