ABSTRACTIncreased energy use and alarming pollution levels have forced scientific and engineering
community to seek for methods to reduce these
aspects. Sector wise energy survey in developed nations have indicated that the Transport, Residential buildings, Industry, Agriculture and other sectors use 42%, 39%, 18% and 1% respectively. The
building sector occupies major share and deserve more focus in energy conservation aspects, but not much studied. In India the sector wise energy use in 1996-97 is 15% in building sector, 12% in transport sector, 50% in industry, 24% in other sectors. More over the total growth in energy is over the five years period (1993-1998) is 48%. Where as building sector growth is 92% in the corresponding period. Thus, methods to assure energy consumption in building sector needs much attention. Use of air conditioners to obtain interior comfort is a major energy consuming element. Any effort to reduce the heat transmission across the building sector will reduce the energy use in air conditioners. Among the various elements of building structure, the roof exposed to sun contributes to about 40-60% of room cooling load. In this investigations use of hollow clay (HCT) tiled RCC roof having square, rectangular (Horizontal and Vertical orientation) circular and circular PVC pipe passages for reducing the heat transmission across the roof are studied using CFD software. The comparisons are made with ordinary RCC roof and RCC laid with weathering coarse roof for both summer and winter conditions. Thus, the result indicated that about 30- 60% reduction in energy is possible.