Ventilation of factory buildings by natural convection

Abstract

A building with an arbitrary number of point and line heat sources at the floor is considered. Fresh air flows in the room through windows; warm air leaves through roof louvres. Above the heat sources there are turbulent plumes. At the walls adsorption of radiation from the heat sources gives rise to natural convection flows. To model the complicated flow field, the building is subdivided into several regions: (1) Turbulent plumes above the heat sources; (2) turbulent wall boundary layer; (3) fresh air region with temperature equal to ambient temperature; (4) discharge air region with constant temperature higher than ambient temperature. Mass, momentum and energy balances are set up for each region. In addition well-known results are used for turbulent plumes and wall boundary layers due to natural convection. The pressure drops across entrance and exit openings have to be compensated by buoyancy forces. Thus, the interface position, the mass flow and the temperature in the discharge air region can be determined. The influence of different parameters is discussed. The interface has to be above a certain level to guarantee appropriate working conditions.