Natural ventilation in a room with a horizontal cylindrical heat source, a window and bottom or top vents

Abstract

Thermally driven natural ventilation in a room with a typical window and an internal horizontal cylindrical heat source near the floor resembling a person lying on a bed is studied, as well as the effect of opening vents in the wall opposite the window. Five cases are studied, one with only the window, and a further four with either one or three vents located in either the bottom or top part of the wall opposite the window. The experiments are performed using a scaled room model, the background oriented synthetic schlieren technique and thermocouples. The theory for the steady flow in a room with a horizontal line heat source featuring two vents at distant heights with unidirectional flows is adapted for the window and bottom vent cases for which it is possible to obtain explicit expressions. Experimental results show that the coefficient related to the plume entrainment and the virtual origin position change depending on the configuration of openings. Nevertheless, considering there are no changes in the thermal plume, the theory predicts the interface height with differences of less than 20%. Opening vents in a room with a typical window and a heat source improves the conditions of the living space by reducing the temperature. The case which most improves interior thermal conditions is that with three top vents. These results can be useful as a reference in natural ventilation design for buildings in sites with low wind speed and a heat source near the floor.