Study Of Solar Chimney For Enhanced Natural Ventilation In Classroom

Natural ventilation, the main mean to improve indoor air quality and reducebuilding energy consumption, is widely used in modern building. However, the smallamount of pure natural ventilation quantity produced by buildings can’t satisfy thenormal needs of the people. Solar chimney can enhance natural ventilation in buildingsusing the solar energy. It is an energy-saving and environment friendly technology thatcan use the solar radiation to provide buoyancy for the air flow，then the heat energy isconverted to kinetic energy，the outdoor fresh air is brought into the room increasing theindoor ventilation volume. In this way, the indoor air quality is improved.The paper was illustrated by the example of vertical type solar chimney, which wasbased on the climate conditions of Qingdao，theoretical analysis and CFD numericalsimulation method were used to study the feasiblity of the solar chimney strengtheningnatural ventilation technology applied to the classroom. Mass conservation equation andenergy conservation equation of the solar chimney were analyzed, The k-epsilonturbulence model and the method of enhancing wall function were used to simulate theventilation performance of the solar chimney under steady-state conditions. The effectsof different solar radiation heat, the chimney height and diameter on the ventilation rate,temperature and velocity field were focused on. The results show that the classroomventilation rate was increased with the increase of solar radiation, chimney height anddiameter. Compared with the no chimney classroom, the added chimney classroom’stemperature and velocity field were improved, the temperature was reduced and thewind speed was increased.Each simulated condition was valued by analyzing the PMV-PPD index,non-uniform coefficient of temperature and velocity to determine economic suitablechimney structure reasonably. The height1.0m and diameter1.5m were selected as thesuitable chimney structure size finally.