Analysis of Optimum Thickness of Glass Wool Roof Thermal Insulation Performance

Abstract

Countries in south east Asia are mostly experiencing tropical climate conditions. Therefore, the use of the air conditioning has been increased to reduce the tension and achieve thermal comfort inside the buildings. In order to reduce the energy consumption, thermal insulation has been introduced to lower down the indoor temperature. The main objective of this study is to determine the optimum thickness of the glass wool insulation. To conduct the study, a wooden room model is built based on the classroom that located at one of the Malaysian universities. The thicknesses of the glass wool insulation used in the experiment is 25 mm (one layer), 50 mm (two layers) and 75 mm (three layers). According to the results, the maximum temperature reduction for one layer of insulation is 1.0°C. Two layers of insulation reduces the indoor temperature by 1.3°C followed by the reduction of 1.5°C after applying three layers of insulation. The convection coefficient outside and inside is determined to calculate the heat flux of the roof with different insulation thickness. The heat flux gained by the roof reaches the highest value at 1 pm which is 0.648 W/m² without insulation. The heat flux has been reduced to 0.629 W/m² after applying one layer of glass wool insulation. The heat flux gained by the roof is further reduced to 0.573 W/m² and 0.518 W/m² when two and three layers of insulation are applied, respectively. Throughout the experiment, the temperature inside the room is reduced with the increase of the insulation thickness. Two layers of glass wool insulation has been selected as the optimum insulation thickness which is validated after performing calculation using the polynomial function as well as the cost analysis. Two layers of glass wool insulation yields a 27.40% of ROI per annum.

An Investigation of Thermal Comfort in Classrooms in the Tropical Savanna Climate

“…These investigations examined the thermal comfort of classrooms in temperate climates such as the UK, Denmark, and the Netherlands [15][16][17]; Mediterranean climates such as those in Italy, Portugal, and Cyprus [2,6,18,19] and subtropical climates such as those in Taiwan, Australia, and China [20,21]. Over this decade, several studies in naturally ventilated classrooms in the tropics have also been conducted [7,20,[22][23][24][25][26][27]. These investigations demonstrated that students quickly adapted to naturally ventilated classes and found comfort levels between 24 and 31 degrees Celsius [5].…”

Thermal Performance of Residential Roofs in Malaysia: Experimental Study Using an Indoor Solar Simulator

“…It was found that the combination of the stone wool and radiant barrier was able to reduce the attic temperature to as low as 30 • C when the insulations are installed directly below the cement roof tiles. Muhieldeen et al [22] examined the optimum thickness of glass wool as the roof insulation to reduce indoor air temperature and heat flux transmission. The results showed that the glass wool thickness of 25 mm, 50 mm, and 75 mm managed to lower the indoor air temperature by 1.0 • C, 1.3 • C, and 1.5 • C, and heat flux transmission by 3%, 12%, and 20%, respectively.…”

Impact of Insulation using Bio-sourced Materials on the Thermal and Energy Performance of a Typical Residential Building in Morocco

“…Muhieldeen et al, [11] evaluated the temperature variation inside a test room for several forms of thermal insulation, such as polyethylene, expanded polystyrene, and rock wool. The results showed that 5.2 cm of rock wool insulation offered the best temperature reduction inside the test room, at 3.85%, followed by 2.3 cm of expanded polystyrene and 0.5 cm of polyethylene insulation, with interior temperature reductions of 2.49% and 0.89% respectively.…”