Field Investigation of the Small House with the Ventilated Roof Tiles

This paper investigates the thermal performances and heat gain reduction of a new roof tile design referred as Ventilated Roof Tile (VRT) compared with an ordinary corrugated concrete roof tiles (CCR). The outside dimension of each small house was 1.70 x 1.70 x 2.85 m3 (W x L x H) and inside dimension was 1.50 x 1.50 x 2.20 m3. The volume of each room was 4.95 m3. The gable roofs slope were 25o and surface area of VRT was 2.58 m2 per each side facing north and south. The VRT tile composed of upper cement plate 40 × 40 cm2 and lower cement plate 30 x 40 cm2. Between plates was 3 cm thickness air gap. The experimental results showed that the top surface of VRT was lower than CCR about 2.10°C for average temperature (from 6:00 18:00) and made VRT room temperature lower than CCR about 1.41°C for average temperature. VRT could reduce heat gain with air flow rate through the roof tiles gaps varied following the solar radiation, during time 8:00-17:00 the natural ventilation varied from 0.003-0.014 m3/s (10.6-50.0 m3/hr.). Observed that, during 17:00-18:00, the air flow rate is about 0.003 m3/s (10.8 m3/hr.) due to heat accumulated in the attic space and roof tiles.