Mazran Ismail

A comparative study between unvented and vented attics powered by the hybrid turbine ventilator in Malaysian houses

Vented attic is a design technique that provides a better solution to reduce solar heat gains trapped in a roof attic. However, its application in the tropical climate is very rare if not, ignored, especially in Malaysian houses. This paper seeks to identify, and compare the performance of attic ventilation by a single hybrid turbine ventilator for a specific volume under both unvented and vented conditions. The study was done in an actual roof attic (10 m3) located in Universiti Sains Malaysia. The results indicate that the reduction of the attic air temperature was 6.4°C, while stabilising the level of relative humidity to about 40–50% which is higher than that for an unvented attic by 10%. Furthermore, the findings reveal that by incorporating a 50 W poly-crystalline solar panel with a turbine ventilator of Ø 45 cm, the peak value of the attic air velocity had exceeded 1.3 m/s when the solar radiation was observed to be around 800 W/m2.

Aerodynamic Characteristics of Airfoil Cruise Landing and High Lift Configurations in Simulated Rain Environment

In this paper, heavy rain effects on the aerodynamic efficiency of National Advisory Committee for Aeronautics (NACA) 23015 airfoil cruise and landing configurations and NACA 64210 high lift configuration have been studied. For this study, preprocessing software Gridgen has been used for creation of geometry and mesh, and fluent software is used as a solver. Discrete phase modeling (DPM) in a Langrangian frame of reference has been used to simulate the rain particles dispersed in continuous phase using two-phase flow approach. The coupling between the two phases and its impact on both phases has been included. In discrete phase model (DPM), the wall film is modeled by the injected rain particles. In a simulated rain environment all the cruise, landing, and high lift configurations of airfoils showed a significant decrease in lift and increase in drag in heavy rain environment. In this study, it is found that the heavy rain causes premature boundary-layer transition at low angle of attack (AOA) and separation at high AOA. The water film layer formed on the surface of the airfoil is thought to alter the airfoil geometry and increase the mass effectively. In the simulation for NACA 23105 the increase in drag is less contrary to simulations done for NACA 64210 high lift configuration airfoil, for which the aerodynamic efficiency degradation is much higher. The relative differences appeared to be related to the susceptibility of each airfoil to premature boundary-layer transition. Postprocessing software like MATLAB, Tec plot, and Origin are used to see the effects of the heavy rain, and the results obtained are compared with the experimental results. It is strongly believed that this study will be useful for the aviation engineers and scientists to design the airplanes and UAVs capable of flying in severe weather conditions and to train the pilots to control the airplane in heavy rain conditions well.

Synthesis and antimicrobial activity of some indole derivatives

Bromination of 2,3-diphenyl-5-methylindole (I) (using 3 mol) with bromine gave the 4,6-dibromo derivative (II) which upon oxidation gave the corresponding 2-benzamido benzophenone derivative (III). Bromination (using 6 mol) with bromine afforded the tetrabromo derivative (IVa) which reated with amines to form the corresponding 5-substituted aminomethyl derivatives (IVb-d). Further bromination ofII using only 1 mol gave the tribromo derivative (Va) which in turn reacted with amines to formVb-g. The antimicrobial activities of compoundsI, IVa, IVc, Va, Ve, Vf andVg were studied.

Energy Efficient Skylight Design in Tropical Houses

Skylight roofing construction isa practical complement to electric lighting even in various climatic conditions. However, a purely energy efficient building that ignores what the environment can contribute, particularly in tropical regions, will consume more energy. This problem can be found in landed houses specifically in Malaysia due to high impact of solar radiation and the length of the daylight period all year round. The lack of understanding the potential of skylight design is one of the main challenges. This paper aims to examine several passive glazing materials in the form of glass and plastic as well as dimensions and orientations under the Malaysian environmental conditions to determine the efficiency of this skylight construction design. The study was carried out by computer simulation to specify the thermal and daylighting loads in a specific room size. The resultsshow the significance of polycarbonate glazing as an efficient skylight material in the tropical houses. This materialdelivers well distributed natural light with less heat impact. This study provides useful quantitative and qualitative information for building professionals and architects in the tropics.

Application of Phase Change Materials (PCMs) in Building Walls: A Review

The rapid growth of the population and overcrowded of urban areas forced building construction sector to focus more on economic consideration rather than climatic requirements. As a result, achieving comfortable living spaces was fully dependent on mechanical systems, which caused more energy consumption and greenhouse gas emissions. Passive design strategies become an attractive alternative to tackle this problem and to reduce the negative impacts on our planet. Phase Change Materials (PCMs) store superior amount of latent heat when changing their phase compared to sensible heat. PCMs application in buildings helps to lower indoor temperature and reduce temperature fluctuation and total hours of overheating. Additionally, PCMs can also absorb the internal heat dissipated by household equipment, lightings and occupants’ activities. All this help to improve building indoor environment. This paper aims to review PCM applications for building walls. It was found that PCMs might be incorporated to building walls as pre-fabricated PCM-enhanced elements such as PCM-enhanced wallboards, panels, bricks and blocks. In addition, it might be incorporated on the site to fresh mixtures such as concrete, plaster and mortar and applied to buildings. The thermal performance of building walls was improved in all cases resulting in heating and cooling load reductions. Moreover, many researchers found that applying night ventilation further improves the thermal performance of PCMs in building walls.

A Review on Indoor Environmental Quality (IEQ) Attributes for Malaysian Post occupancy Evaluation (POE) in Green Office Building

Green buildings represent sustainable design and construction that require a holistic interaction between all components of a building that are environmentally responsible throughout a building’s life cycle from the beginning until the completion. A green building should deliver its occupants with a comfortable indoor environment that will satisfy their comfort needs and enhance the productivity while working in the building. Among the numerous efforts in the emerging green building is the establishment of green building certification systems worldwide that is considered as one of the most prominent and systematic approaches to the continuous effort in promoting outdoor and indoor environmental sustainability. The benefits of these tools are they can guide the development of construction industry towards its best practice and improve the quality of building for tenants and occupants. Previous literature revealed that Indoor Environmental Quality (IEQ) assessment in green rating standards such as the LEED United State and BREEAM United Kingdom does play a significant role in the certification process of green building. Thus, the IEQ comprises several main aspects such as temperatures, humidity, noise, lighting, space design, structural systems and last but not least the building envelope design. Therefore, the main objective of this paper is to review the aspects of IEQ in Post-Occupancy Evaluation (POE) study previously conducted by researchers around the world. The paper will focus on the development of IEQ assessment attributes that can be used in POE for an office building in a hot and humid climate. It will also provide an emphasis on the relationship between IEQ and Post-Occupancy Evaluation (POE) in determining post occupant’s satisfaction. It is hoped that these research findings will bring benefit to green certification bodies in Malaysia such as the Green Building Index (GBI) and GreenRE Malaysia in evaluating office building in post-occupancy stage.

Relationship Between Indoor Environmental Quality (IEQ) and Occupant’s Satisfaction in Malaysian Rated Office Building: A Pilot Study

Green building development is an upcoming topic and is driven mostly by the growing awareness of the environment impact of construction on the satisfaction, health, performance, well-being and productivity of its occupants. Therefore, the purpose of this study is to identify the relationship between Indoor Environmental Quality (IEQ) and occupant’s satisfaction in a Platinum rated GBI’s office building located in the heart of Kuala Lumpur, Malaysia. Data were collected through self-administered questionnaire from the building occupants and analysed using Statistical Package of Social Science (SPSS) and Structural Equation Modelling (SEM) Smart PLS. This analysis was conducted in obtaining the level of reliability and validity of the data in measuring occupant’s productivity in relation with the IEQ. Subsequently, the result of the Variance Inflation Factor (VIF) for each of the variables shows that there are no collinearity issues in between the attributes.

Fieldwork measurement of indoor environmental quality (IEQ) in Malaysian platinum-rated green office buildings

An Indoor Environmental Quality (IEQ) fieldwork assessment was conducted in the Platinum-rated GBI office building located in Putrajaya Malaysia. The aim of the study is to determine the current indoor performance of the selected green office building. The field measurement consists of several IEQ parameters counted under the GBI Malaysia namely the Thermal Comfort of temperature, relative humidity, air movement and heat transfer as well as solar radiation. This field measurement also comprises of the measurement for the background noise, visual lighting and Indoor Air Quality (IAQ) focusing on the aspect of carbon dioxide concentration. All the selected indoor parameters were measured for the period of five working days and the results were compared to the Malaysian Standard. Findings of the field measurement show good indoor performance of the Platinum rated office building that complies with the GBI standard. It is hoped that the research findings will be beneficial for future design and construction o...

Turbine Ventilator as Low Carbon Technology

There is a growing awareness among the general public, energy developers, and governments worldwide to look for renewable and alternative energy systems that capable of reducing the amount of carbon emissions. In response to the scenario, the last century has seen tremendous progress in technological development of low carbon technologies and green energy resources for building applications. The deployment of these technologies not only contributes to a significant percentage of carbon dioxide emission reduction, but also aids to reduce energy consumption and mitigate environmental impact. The need for such eco-friendly technologies in buildings has underpinned significant increases in the application of wind-driven ventilation techniques. This includes turbine ventilator, a wind-driven ventilation device or air extractor that is commonly used in attic, rooftop spaces or loft to facilitate ventilation, control high energy consumption, and improve indoor environment. In order to gain a deeper understanding into existing knowledge in this field, this paper discusses low carbon technology concept and characteristics of turbine ventilator. Furthermore, physical and operating parameters that influence its performance are also discussed.

Solar Induced Ventilation Strategy in Contemporary Tropical Buildings: A Review

Recent development in passive cooling studies have shown that stack ventilation could be a potential strategy in providing effective natural ventilation strategy for a building in the windless region, and in the deep plan building where cross ventilation has limited function. However for the building in tropical climate where the indoor–outdoor temperature differential is very low, this strategy is often regarded insignificant to provide sufficient ventilation needed for occupants comfort. This constraint has prompted several researchers to develop some solar induced ventilation strategies that can maximize free energy available from the sun and high solar radiation of tropical climate to heat building cavities and increase the temperature difference, thus improving the applicability of the stack ventilation strategy in suctioning the indoor air and extracting it out through the upper outlet areas. This book chapter presents the potential and limitations of the solar induced ventilation strategy in the tropical region, particularly in its subtypes of tropical rainforest climate and tropical monsoon climate by discussing its ventilation performance based on the results of previous studies, state-of-the art technologies and several significant examples of its applications in the contemporary tropical buildings.