Thermal Performance of Residential Buildings in Lisbon. with Large Glazing Areas

M. Tavares H. Gonsalves1 and J. Bastos2

1 INETI, Department of Renewable Energies, Campus do Lumiar do INETI, 1649-038 Lisbon, Portugal
2 FA-UTL, Department Technology of Architecture, Polo Alto da Ajuda, 1349-055 Lisbon, Portugal
^Corresponding Author, marcia. tavares @ineti. pt


This work presents the results of an experimental study of residential buildings (multi-family apartments) with glazing areas greater than 75% of the total facade area, and for different solar exposures in Lisbon. These buildings were designed after the implementation of the first Portuguese Buildings Thermal Regulation and they are intrinsically related with the construction and architecture practiced in the last few years. The analysis includes the thermal behaviour of the apartments selected for the study during the summer (2007) and winter (2007-2008). During the monitoring process important data were obtained to assist in the understanding of the thermal performance of the observed units. The main thermal exchanges in a building generally take place through the transparent elements and these can be considered an element of great flexibility and adaptation to climatic variations. The mean of the interior temperature means in the different monitored compartments during the hot season was approximately 27°C (some cases close to 29°C), while in the cold season 21°C (some cases close to 18°C).

Keywords: Glazing areas, thermal behaviour, heating, cooling, thermal comfort

1. Introduction

The energetic optimization reveals how important is the building envelope, as the main element between the exterior and interior conditions. The conduction and convection transfers through glass present a similar behaviour of the opaque elements with the possibility of the air change control between the interior and exterior — opening or closing the windows. Meanwhile, radiation becomes the principal factor because its portion is transmitted directly through the glass to the interior.

The non-opaque envelope can be considered an element of great importance in the control of radiation, ventilation and natural illumination. A more dynamic element, easier to adapt and adjust to obtain the desired interior conditions, in other words, it presents a comparatively greater degree of adaptation control and flexibility to the climatic variations than the opaque envelope. In addition, glass and other transparent materials are essential elements for the successful application of the majority of the passive solar heating systems. The heat transfers occur differently depending on the types of materials and proportions being applied in a specific building (opaque and non­opaque envelope).