Influence of the natural ventilation strategy on thermal and energy performance of mixed-mode office buildings

Author(s)

Fernanda Alves Pereira

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Civil, Arquitetura e Urbanismo
• Defense date: 2019-02-21

Examining board members

Leticia de Oliveira Neves; Karin Maria Soares Chvatal; Lucila Chebel Labaki

• Advisor: Leticia de Oliveira Neves

Abstract

Office buildings have a high energy demand, especially due to the use of air-conditioning systems to keep adequate indoor thermal conditions. Many strategies have been studied to ensure energy efficiency for those buildings, such as the hybrid ventilation system, also known as mixed-mode system. A gap between the expected and the real performance of mixed-mode buildings was observed in the literature review, as well as discrepancies between input data used in the literature and strategies adopted in practice, in particular to Brazil¿s circumstances. This research aims to investigate the influence of natural ventilation strategies on thermal and energy performance of mixed-mode office buildings. A field survey was performed, in order to collect information and build a database about architectural design strategies of mixed-mode office buildings located in the city Sao Paulo, Brazil. From the database, technical datasheets were developed for each visited building, and building energy simulations were performed. The simulations were developed based on three baseline models - one provided with single sided ventilation, the second provided with cross ventilation on adjacent facades and the third provided with cross ventilation on opposite facades. The single sided ventilation model showed the worst performance among the strategies. The cross ventilation models showed better results when combinations of design strategies were favorable to the use of natural ventilation. The increase of the window-to-wall ratio helps improving natural ventilation due to the larger opening area for ventilation and, in some cases, compensates the greater thermal gains from heat transfer through the glazing. The choice of the natural ventilation strategy is a design decision that also depends on the choice of the window type. The results showed the importance of jointly selecting the window effective opening area, the window-to-wall ratio and the solar orientation, in order to guarantee the best performance (AU)

• FAPESP's process: 17/21137-5 - Influence of the natural ventilation strategy on thermal and energy performance of mixed-mode office buildings
• Grantee: Fernanda Alves Pereira
• Support Opportunities: Scholarships in Brazil - Master