NUMERICAL SIMULATION OF BUILDINGS THERMAL BEHAVIOUR AND HUMAN THERMAL COMFORT MULTI-NODE MODELS

In this work two numerical models are presented. The first one simulates the buildings thermal response and evaluates the internal air quality, while the second one simulates the human and clothing thermal systems and calculates the thermal comfort level in non-uniform environments. The results obtained by the first model are used as input data in the second one. These programs will be used in the simulation of the thermal behaviour of a building, in project phase, located in the South of Portugal in a Winter day with clean sky, and in the evaluation of the thermal comfort level that an occupant is subjected, in a compartment located in the second floor with a window turned towards West. INTRODUCTION The topic of numerical simulation of building thermal behaviour and human thermal response has been studied by several authors. The first topic was analysed, for example, by Ozeki et al. (1992), Cammarata et al. (1994) and Mendes and Santos (2001), while the second one has been studied, for example, by Fiala et al. (1999), Huizenga et al. (1999) and Farrington et al. (2001). In the philosophy used in the present work, the building thermal behaviour model is used, in the first phase, to calculate not only the temperatures evolution in compartments and building bodies, but also the contaminants mass evolution in the compartments. In a second phase, these informations are used by other model, that simulates the human and clothing thermal behaviour simultaneously for a group of persons, to evaluate the thermal comfort level that an occupant is subjected inside the several compartments and in different locations of interest. The first numerical model, that simulates the building thermal response and evaluates the internal air quality, considers all spaces and all building bodies. This model calculates not only the temperature of the air inside the different compartments, the several windows glasses, the different interior bodies (furniture, curtains, climatization systems,...) located inside spaces and the several slices of the building main bodies (doors, walls, ground, roofs, ceilings,...), but also the water vapour mass inside spaces and in the interior surfaces and the mass of contaminants (CO2, O2,...) inside spaces. It also calculates (1) the real distribution of incident solar radiation in the internal and external surfaces, (2) the view factors between different interior surfaces in each space, (3) the radiative heat exchange between internal surfaces, using the radiosity method, (4) the radiative heat exchange between building external surfaces and the surrounding bodies, (5) the heat and mass transfer coefficients by convection, between the surfaces and the air, (6) the glasses radiative coefficients, (7) the relative humidity inside different compartments and (8) the mass transfer between different spaces and between several spaces and the external environment. The second numerical model, that simulates the human body and clothing thermal responses and analyses simultaneously several persons inside a space, considers each human body divided in 35 cylindrical and spherical elements. This model calculates not only the temperature of the human body tissue slices, arterial and venous blood, and clothing slices, but also the mass of blood and transpired water in the skin surface and clothing slices, in each element. It also calculates the (1) human posture, (2) view factors between the human body elements and the surrounding surfaces, (3) heat exchange between the body and surrounding surfaces, using the radiant temperature, (4) solar radiation that each element is subjected inside the compartment, (5) the heat and mass transfer coefficients by convection and (6) the thermal comfort level in non-uniform environments, using the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indexes (see ISO 7730 (1994)). Eighth International IBPSA Conference Eindhoven, Netherlands August 11-14, 2003