No abstract

Building performance evaluations in real local climate are essential to ensure the effectiveness of methods or strategies implemented to achieve the desirable effects or outcomes. A field study using a test building facility was performed to investigate the benefits of conductive ceiling insulation in real climatic conditions of Malaysia. The objectives of the research were to evaluate building thermal energy performance in four indoor environmental conditions: 24-hour natural ventilation (NV), office-hour (daytime) cooling, residential-hour (night-time) cooling, and lastly 24-hour cooling. The benefits were appraised by analyzing the thermal impact and cooling load (CL) savings. Results show that the degree of benefit and penalty are influenced by the indoor environmental conditions. Ceiling insulation reduced daytime thermal impact but led to nighttime thermal penalty due to thermal-lag. The effect was more significant in the attic than the living space underneath whereby in NV mode the attic and indoor temperature was reduced by 4.1 °C and 1.7 °C respectively. In the three cooling modes, the temporal and spatial benefits are evident by the cooling load (CL) savings of 3.65% to 16.88%. Therefore, whist it demonstrated adverse night-time impact, the daytime thermal and energy benefits outweigh the penalties.

No abstract

Roofs and walls are the main media for heat transfer for typical Malaysian buildings. In order to estimate the duration of uncomfortable periods, the environmental temperature of a building was determined over a period of time. A study of heat flux through a naturally ventilated was conducted by simulation. This study focused on heat transfer through the roof, ceiling and vertical walls. A Thermal Analysis Software was used for the modeling and analyses. A virtual test building model dimension 4m x 4m x 3m was created using conventional construction parameters for roof, ceiling, windows, door, walls and floor which meet the minimum requirement in Malaysian Standards. The results show that heat rate flux mostly peak at east wall before 12:00 hrs and west wall after 12:00 hrs. The heat rate flux through the roof is higher than that through the ceiling during daytime but lower at night as roof was the surface of most exposed to solar radiation. The proportion of heat through roof was 87% by radiation, 11% by convection and 2% by conduction. 97% of heat was transferred by radiation and 3% by conduction for ceiling and heat through wall was 88% by radiation, 8% by convection and 4% by conduction respectively.