A HOUSE IN TANZANIA TO MEET GOD. NATURAL VENTILATION

In this paper it is presented a method of calculation for the design, sizing and verification of natural ventilation for the "St. Maria del Carmelo" in Dar es Salaam – Tanzania, a house to meet God. A wind tower is adjacent to the bell tower and is called to collect the wind to enter into an underground pipeline. There are two principles that govern the dynamics of natural ventilation: 1. the hot air, being less dense than cold air, tends to rise, thus generating the "chimney effect"; 2. the circulation of the wind around and above the building that creates a pressure difference. Another factor that causes current of air is the temperature, the more it increases more and the gas expands decreasing its density. So if the day is captured the cooler air and faster at a height higher than that of the soil, the latter being then channeled into an underground conduit, through which disperses heat still decreasing its temperature, then when this air will enter the church in touch with people, it will tend to heat up quickly, thus leading to the chimney effect, flowing so naturally by the openings at the highest altitudes of the structure. This phenomenon is even more accentuated by the presence of the solar chimney placed on top of the roof which causes a greater pressure difference between the air captured and the one that enters the environment. The study of the natural ventilation system, first shown, it was particularly complex due to the large volume of the church (designed for 2,000 faithful) and the local weather conditions. In the paper, after a brief presentation of the architectural design of the church, the basic criteria are discussed for the design of this particular ventilation system.