High Energy savings in building cooling by ROof TILEs shape optimization toward a better above sheathing ventilation (LIFE HEROTILE)

Description:

In Mediterranean regions, the solar radiation in summer can cause overheating of the building envelope (roof and walls) and the indoor environment, entailing the need for air-conditioning. Passive systems to limit solar effect mainly consist of ventilated facades and roofs as the elements which are most exposed to solar radiation. Vented roofs can greatly reduce heat due to solar radiation, but their performance is highly dependent on roof exposure and, more importantly, their perpendicular position to the wind. The benefit of so-called ‘above sheathing ventilation’ (ASV) significantly decreases when the wind direction shifts from perpendicular to parallel to the eaves line. ASV positively affects thermal insulation thanks to convective heat transfer. Buoyancy-driven ventilation becomes irrelevant even with a very weak wind, while the air permeability of tiles determines an increase in performance. Thus, roof tile vents could be considered the best solution for passive thermal insulation for buildings in hot and mild climates.

The LIFE HEROTILE project aims to design and produce two types of roof tiles (Marseille and Portuguese roof tiles, which cover more than 60% of pitched roofs in Europe) with a shape characterised by higher air permeability through the overlap of the tiles and improved energy performance through under-tile ventilation. An air inlet will greatly increase the inflow of air and therefore the heat disposal. In addition, the tile design will be independent of wind direction, since the inlet and outlet channels will let the air flow horizontally as well as top to bottom.

The tiles will be tested on real-scale buildings with seven different roof types located in different Mediterranean regions. The project’s ultimate aim is to demonstrate that the designed tiles can help save up to 50% of the energy for cooling buildings. According to these estimates, the technology – if widely adopted in the Mediterranean countries – could generate savings between 5 000 and 13 000 GWh of electricity per year, avoiding emissions of 1.5-3 million equivalent tons of CO2.

Project information

Lead

Industrie Cotto Possagno S.p.A.

Partners

Università degli Studi di Ferrara, Italy

TERREAL S.A.S., France

Monier Technical Centre GmbH, Germany

Azienda Casa Emilia Romagna di Reggio Emilia, Italy

Associazione Nazionale degli Industriali dei Laterizi, Italy

Source of funding

LIFE Programme