Thermal study of school buildings in winter conditions

Abstract

In this paper, a thermal study of a school building with real occupation levels in winter conditions is presented and a software that evaluates the air quality and simulates the thermal response of buildings with complex topology in steady-state and transient conditions is used. After validation, the numerical model is used, in the first phase, to evaluate the occupants’ comfort levels in several spaces, while in the second phase two solutions, to improve acceptable thermal comfort and air quality levels (1) the electric air-heating systems, with predicted mean vote control, and (2) three solar collectors, placed instead of the roof area, used to heat the air in uncomfortable spaces are studied. The software is based on energy and mass balance integral equations that considers all conductive, convective, radiative and massic phenomena and internal heat generation in the building. In the radiative phenomena, which are very important in this region, all shading effects, incident solar radiation and radiative exchanges in all indoor and outdoor surfaces will be considered, and the mass phenomena, which are very important in thermal and air quality studies, internal mass generation, mass exchanges among compartments and between them and external environment will be considered. The considered school building, located in the south of Portugal, has three levels, 97 compartments, 1277 main bodies and 211 windows with simple transparent glass. This simulation took place on a winter day with clear sky and with 800 occupants. In this study, where a project of a school building with acceptable thermal and air quality levels is presented, the solar radiation (very intense in this region) will be used in order to reduce the school building's energy consumption levels.