A mathematical model of solar energy storage ventilation system was built in order to calculate the heat storage during daytime and the ventilation rate during nighttime. Based on meteorological parameters of Kunming in China

phase change materials(PCM) were used at the temperature of 38 ℃

44 ℃

50 ℃ and 63 ℃ respectively to search the relationship between ventilation volume and the angle of chimney. The modeling calculation results show that for different phase change materials

and in any angle

the trend of heat accumulation is consistent

namely heat accumulation is smaller with a higher phase change temperature. Considering both the average hourly ventilation volume and the duration

the best angle of this system should be 45°

and the best phase change material should be 38 ℃ myristoyl.