A paper on the potential for passive cooling of ventilated roof systems in Malta, was presented at the Ninth World Renewable Energy Congress, by Perit Ruben Paul Borg and Perit Vince Buhagiar, following research that was conducted at the Faculty of Architecture and Civil Engineering, of the University of Malta.
The congress, which recently took place in Florence, Italy, was organised by the World Renewable Energy Network (UK) and hosted by the University of Florence (Centro ABITA).
WREN aims to promote the communication and technical education of scientists, engineers, technicians and managers in the field of renewable energy, and to address itself to the energy needs of both developing and developed countries.
It is one of the most effective organisations in supporting and enhancing the utilisation and implementation of renewable energy sources that are both environmentally safe and economically sustainable. The conference topics also included low energy architecture.
The paper, authored by Perit Buhagiar, Perit Borg and Mr Clyde Abela, discussed the thermal performance of reinforced concrete roofs with an air cavity, following experimental investigation.
A ventilated air cavity is created on reinforced concrete roofs, with the use of a modular formwork system, developed by Daliform Srl in Italy. The system consists of interlocking units manufactured from recycled plastics.
The units are placed onto the structural reinforced concrete roof, creating an air cavity, with the concrete screed being cast on top. The system is being utilised effectively in roof construction in various buildings in Malta.
The paper explores the potential for passive cooling of ventilated flat roof structures with an air cavity. A test rig was set up in the laboratory to investigate the thermal performance of monolithic and ventilated slabs respectively.
In the case of the ventilated slabs, the concrete screed was isolated from the underlying structural reinforced concrete, using the modular formwork system. The performance of the monolithic slabs, and the ventilated slabs was investigated for summer and winter conditions.
Results suggest that the vents should ideally be kept closed in winter. However, in summer, convective cooling reduces indoor surfaces temperatures, alleviating discomfort conditions, therefore reducing the demand for cooling.
The research, conducted at the University of Malta, was supported by Philip Pace and Sons Ltd of Attard, Malta, and by Daliform Srl of Italy.