Experimental Study Of Solar Chimney For Natural Ventilation And Its Design Method

In recently years, more emphasis is given to energy conservation and passive system in order to maintain a clean environment. Natural ventilation is thought of as a low energy cooling strategy which can provide comfortable and healthy indoor environment, at low capital and maintenance cost. So people give more attention on ventilation which can improve indoor environment . Ventilation is generally defined as a supply of outside fresh air to the interior for air healthy and comfortable indoor environment. For natural ventilation, there are two causes force air flow through the building ,namely,(i) wind force (ii) thermal or temperature force or stack effect. A solar chimney generates air movement by buoyancy forces, hot air rises and exit from the top of the chimney , drawing cooler air though the building core in a continuous cycle. Researchers had educed some conclusions from theory, numerical and experimental investigation, but more research concerned how to maximize solar gain and seldom to think over optimize design of solar chimney.Based on theory analyse, a vertical roof solar chimney enhance natural ventilation model was experiment studied. The solar chimney has internal dimensions of 2000mm height,1000mm length. Under the condition of heat flux and chimney gap variety, we research chimney interior temperature field and velocity field. Results showed that airflow creased with chimney gap augmentation, the optimum of chimney gap to height cannot found in our study scope, and the airflow and air velocity crease with creation of solar radiant intensity, and air velocity decreased with the creation of solar chimney gap. Air temperature and velocity is more higher near the heated surfaces than their in the middle chimney. Meanwhile temperature and velocity boundary layer form near the heated surface. Because of heat radicalization, temperature and velocity boundary layer also exist near cold surface.