Numerical investigation of the influence of heat emitters on the local thermal comfort in a room

In this paper a numerical analysis of the effect of heat emitter characteristics on the local indoor thermal comfort condition in a room is presented. A dynamic model, able to evaluate the 3D distribution of the mean radiant temperature in the whole volume of a thermal zone is developed. The model allows a fast evaluation, in terms of computational time, of the view factors associated to the inner points of a room thanks to the use of the MATLAB Contour Double Integral Formula (CDIF) routine. The new tool has been used in order to obtain, by means of a series of dynamic yearly simulations, a comparison among different heat emitters (i.e. in-slab radiant floor, in-slab radiant ceiling, lightweight radiant ceiling, radiator, radiant vertical wall and all-air systems) in terms of 3D distribution of the local operative temperature in a room. The knowledge of the 3D distribution of the operative temperature enables the local analysis of the indoor thermal comfort conditions established in the room during the year. The local Predicted Mean Vote (PMV) distribution within the room is calculated for each considered configuration. The results allow to quantify how the reduction of the maximum surface temperature of the emitters, which can be experienced when the envelope thermal insulation is increased, can create more uniform indoor thermal conditions by reducing the differences existing among the heat emitters.