Samenvatting

This report examines the possibilities of using a solar chimney in a highland tropical climate to promote thermal comfort, air‐quality and energy consumption. The study is carried out using modeling and simulation techniques and is conducted at the Federal University of Viçosa in Brazil. A model is built to simulate room temperature, humidity and CO2 concentration as being functions of several parameters. The methodology chapter describes the mathematical models of the individual parameters as well as the integration into the overall model. The modeled parameters influencing temperature, humidity and CO2 concentration are: the spatial characteristics of the room; the amount of people seated in the room; the amount of solar radiation received on the external surfaces; the weather; the ventilation and the air‐conditioner usage. The type of ventilation that is used in this model is natural ventilation, caused by a solar chimney. The solar chimney working principle is based on a physical phenomenon: hot air rises. The ventilation rate is a function of the spatial characteristics of the room and of the difference between the inside and outside
temperature. The solar chimney potential is being tested by compairing four scenarios: 1st using neither the solar chimney nor the air‐conditioner; 2nd using only the air‐conditioner; 3rd using only the solar chimney; 4th using the solar chimney and air‐conditioner in combination. The simulation is ran for the four scenarios and for different seasons in the year. The thermal comfort is discussed by the measure of PMV, a indicator for the level of thermal satisfaction. The air‐quality is discussed on the basis of CO2 concentration. Simulation results show that solar chimney ventilation can reduce air‐conditioner electricity expenditure to less than 80% of the initial expenditure for a summer day. The air‐conditioner electricity expenditure is reduced to only 10% of the initial usage for a winter day. The solar chimney guaranties high indoor air‐quality whenever the outside temperature is below 25°C