Study On The Characteristics Of Inclined Solar Chimney For Strengthening Natural Ventilation

In order to alleviate the pressure of energy crisis, the use of natural ventilation as a way to improve the indoor thermal environment has been paid more and more attention in recent years. Natural ventilation is a better way without using any energy compared to the mechanical driving ventilation,for this reason it can greatly reduces the consumption of conventional energy, however, the amount of conventional ventilation produced by the natural ventilation is not enough and it’s really hard to meet people’s normal needs. Solar chimney is an equipment that using solar energy to enhance natural ventilation, which can effectively improve indoor air quality, at the same time, our country has rich solar energy resources, so the solar chimney strengthen the natural ventilation technology has a broad application prospect in our country.In this thesis, the inclined solar chimney is taken as the research object, firstly, FLUENT simulation software is used as the resarch platform,under the condition of the steady state, in view of the chimney under different solar radiation intensities and different structure size of natural ventilation rates, temperature fields and velocity fields has been studied and analysied by comparison results with each other. then on the basis of structure optimization design of tilting solar chimney are proposed. The research results have showed that the natural ventilation rates of the chimney with the increase of the intensity of solar radiation and the chimney height increases obviously, at the same time as the stack depth (which means the collection hot wall and glass wall spacing) and chimney increases with increasing of the Angle, but increase gradually smaller. Chimney structure optimization research shows that, in the collection hot wall under the premise of the same height, with a single set of hot wall induced by ventilation rate compared to multiple collection hot wall induced by the ventilation rate is larger.Under the stable condition of collection hot wall height and numbers, with the increasing of collection hot wall Angle, the induced ventilation rate increased more.Secondly, Based on the theory of heat transfer in the energy balance analysis, considering the collection hot wall under the premise of internal thermal resistance of thermal conductivity, proposed a predictable tilting solar chimney strengthen the unsteady heat transfer mathematical model of natural ventilation, on this basis,using the finite difference method for numerical calculations, in the mathematical model, the collection hot wall temperature, the temperature of the glass wall, chimney air flow channel parameters such as the average temperature of the air inside and the ventilation rate with the outdoor meteorological parameters and the distribution of chimney structure size are discussed respectively in detail in this paper. Working condition of the calculation results have shown that, regardless of whether it is working during the day or night, the above parameters is always under a state of changing. Collection hot wall temperature of each node has different rates of changing in different time, so the temperature lag phenomenon appeared in the process of heat transfer. In addition to get the parameters with the change of chimney structure size.Through the study of the characteristics of the inclined solar chimney to strengthen the natural ventilation, some conclusions that can optimize the solar chimney has been reached which is desired to be taken as a theoretical basis and guidance for the application and promotion of the natural ventilation technology of solar chimney.