Experimental and numerical prediction of velocity and temperature fields in a room heated by a room air-conditioner

One of the great influential feature on room temperature distribution is the insulation quality of the room. Each room of the typical Japanese modern house has a low heat capacity, high insulation quality and large windows which are less insulated. Temperature near the window is naturally low. These factors make the thermal insulation of the room strongly uneven. When heating the room, the location of the heat source largely affects room temperature distribution as well. This kind of distribution will be emphasized using an air-conditioner. Room air temperature using heating equipment such as this has both a high temperature area due to the air jet discharged from the outlet and several low temperature areas due to drafts from the window. Such a wide temperature distribution does not contribute to the comfort of the occupants at all. On the other hand, the location of the heat source also influences the heat loss of the room. Thus, an appropriate location for the heat source will produce good thermal conditions and save on heating energy. In this paper, the distribution properties of room air temperature, velocity and heat loss are discussed experimentally and analytically. Measurements under heating condition were made in a full-scale model room in order to investigate the influence air-conditioner location has on velocity and temperature fields in a steady state, as well as heat load. The following results were obtained: (1) the influence of the direction in which the jet was blown from the air-conditioner was clearly seen in regions of different temperature distribution adjacent to the floor; (2) the heat loss calculated from these experimental results show several differences characterized by the direction of the blown jet and the difference between the maximum and minimum heat loss obtained from these four experimental results is roughly 15%; and (3) results from numerical analyses agree with experimental results.