Mohd Hamdan Ahmad

A Preliminary Study of Thermal Comfort in Malaysia′s Single Storey Terraced Houses

Abstract In a tropical climate, passive cooling is difficult to achieve with respect to mass housing design. A good house design keeps the indoor environment favorable and comfortable during most of the year without the use of any mechanical devices. Terraced houses are typical examples with low comfort problem that need particular consideration. Low air velocity and high air temperature are experienced during the daytime and the wind effect is not well captured, especially in the single sided ventilation. Use of natural ventilation has been increasingly examined as an energy–efficient means to provide thermal comfort as well as a healthy indoor environment. This paper discusses the validation of Computational Fluid Dynamic (CFD) results and the measurement of thermal comfort in Malaysia′s single storey terraced houses. The thermal environment and comfort conditions were investigated using field measurement and CFD technique. Validation of CFD FloVent was carried out through the comparison of field measurements. Comparison of the results between simulations and measurements illustrated a good agreement. The simulations were performed on a selected day in a one–year climate condition. The results indicated that the design of single storey terraced houses is not effective in providing natural ventilation for achieving thermal comfort. The microclimate condition surrounding the terraced house indicated very low wind speed. Therefore, modification of the natural ventilation mechanism using a solar chimney as induced ventilation needs to be manifested and evaluated.

Optimum Overhang Geometry for Building Energy Saving in Tropical Climates

abstract In hot and humid climates, one draw back of using shading devices is the risk of reducing daylight level which in turn increases the use of artificial lighting. It is important to understand the magnitude of energy consumption for cooling and lighting when shading devices are adapted in order to propose optimum external horizontal shading strategies as design solutions. This study investigates the effect of six different alternatives of external horizontal shading devices on incident solar radiation, transmitted solar heat gains, natural-light penetration and energy consumption. The study was carried out using a standard, single fenestration perimeter office room in a typical high-rise office building. The investigation is conducted using eQUEST-3, which is a dynamic energy simulation program supported by DOE2.2 calculation engine. The results showed several optimum geometry of the external horizontal shading device depending on incident direct solar radiation, transmitted solar heat gains, natural-light penetration and energy consumption. This study concludes, considering the trade off between total heat gain and natural-light penetration to optimize the total energy consumption as the best option in designing external solar shading in hot and humid climates.

Internal Shading for Efficient Tropical Daylighting in Malaysian Contemporary High-Rise Open Plan Office

In tropical climate, there is actually abundant quantity of daylight but yet to be utilised. The excessively high and unpredictable external illuminance could cause non-uniform indoor illuminance distribution and visual discomfort. In order to improve daylighting quality in contemporary high-rise open plan offices, proper design of internal shading should be investigated. A base model was derived from previous case studies for simulation using Radiance. Various venetian blinds, vertical blinds and light shelves were configured for the experiment. Daylight factor (DF) was evaluated for quantitative performance; work plane illuminance (WPI) distribution and vertical plane luminance ratio were investigated for qualitative performance. The findings demonstrated that generally blinds were not a good potential for daylight utilisation but good in reducing luminance contrast. Light shelves improved performances in DF and WPI distribution but increased the luminance contrast. Hence, integrations of light shelves and partial venetian blind (45° closed) were proposed as the effective designs for all orientations. The highest improvements of 31.8% in WPI distribution and 66.7% in luminance ratio were achieved for south and east orientations, respectively. This paper demonstrates that with proper internal shading design, effective daylighting depth can be significantly improved from typically used 2.5 H rule of thumb to 3.6 H.

The effects of direct sunlight on light shelf performance under tropical sky

As daylight is dynamic, there is no one common solution for all scenarios. Understanding of sky conditions is the fundamental to effective daylighting. It is more critical in tropical climate where the sky is predominantly intermediate with inconsistent presence of direct sunlight (DSL). Thereby, daylighting performances of several light shelf configurations were experimented with physical scaled model under actual tropical sky conditions. External illuminance and indoor work plane illuminance (WPI) levels were measured concurrently in a reference model and a test model for comparisons. Daylight ratio or daylight factor and WPI uniformity ratio were computed for analysis. From the results, different optimum cases were identified for various sky conditions. Light shelves performed the best under intermediate sky with DSL from low angle. The highest improvement in WPI at deep room area and WPI uniformity were 24.87% and 364.96%, respectively. The performances of light shelves under overcast sky were better than light shelf under intermediate sky without DSL. This paper concluded that designing light shelf by responding to changeable sky conditions and DSL is more crucial than considering the façade orientations. Dynamic light shelf was proposed to configure the optimum cases for each tropical sky conditions.

Developing a BIM-based process-driven decision-making framework for sustainable building envelope design in the tropics

There is a rising concern for sustainability in the built environment. Therefore, numerous sustainable building certification and rating systems are developed throughout the world. However, the current methods of measuring, predicting, and optimising the sustainable building design have relied on a number of disjointed analyses to meet the discrete requirements for various building systems. The recent development of Building Information Modelling (BIM) technology allows complicated building modelling to be digitally constructed with precise geometry and accurate information to support various building project stages. Thereby, this study aims to integrate decision-making (DM) for sustainable building envelope design with BIM functionalities by considering the tropical climatic contexts in Malaysia. Several regional sustainable building certification systems and related literature were reviewed to identify the importance of evaluation and DM criteria. The findings were then compared with various BIM tools in terms of their applications, functions and workflows, in order to formulate a process-driven BIM-based DM framework (DMF) for sustainable building design in Malaysia. The proposed DMF will address the difficulties of DM in the early design development process, and will also allow for specific trade-off analyses of sustainability and objective-based optimisation using BIM.

Lessons from Sukur Vernacular Architecture: A Building Material Perspective

This study presents the lessons from the vernaculars Architecture of sukur kingdom with a focus on the use of building materials as a sustainable means for solving problems facing present-day architecture in issue of sustainability; in particular the critical housing situation in the developing countries. Through a case study of the ancient vernacular Architecture of sukur the result shows that stakeholders in the construction industry could reflect on how this building materials and the techniques in operation in their region by translating it in a modern way to address those striking design problems through solving them from the masters builders.

Courtyard Geometry on Solar Heat Gain in Hot-Dry Region

This paper attempts to show the geometric effects of a courtyard under the force of hot and dry climates. A courtyard house is an internal open space around which all the habitable rooms are clustered. The main objective is to review the effects of courtyard geometry on changing the energy consumption of courtyard buildings in order to decrease the emissions of CO2. Literature review on courtyard in hot and dry climate suggest various type of the evaluation of previous results proves that the orientation and the proportions are two important factors for the amount of acquired solar energy in courtyard buildings in order to reduce energy consumption in hot-dry regions. They should be considered in the design stage where the designers can take full advantage. Future, can also be established guidelines for efficient courtyard design in Yazd to reduce energy consumption.

Performance and resistance of paint used as exterior finish in salt laden environment

Purpose – Painting of buildings predates civilization. The primary purpose was to add beauty or aesthetics to the built environment. It was also to showcase the level of civilization, taste and fashion drive of the people. However, modern findings have proved that paint (when applied as a finishing coat on buildings) can elongate the service life of such buildings due to some characteristic properties it contains and modern additives that are included at production stage. This paper aims to examine some of the properties inherent in paint through which resistance to failure and better performance is enhanced, aesthetics is maintained and maintenance is reduced. It also examines whether these qualities subsist in all environments. Particular attention is given to its resistance to the impact of saline air when used around the Atlantic Ocean.Design/methodology/approach – The research adopted a qualitative and quantitative approach with empirical analysis in examining the performance of paint used in salt la...

One city; two conditions: exigent parameters for paint performance in Lagos, Nigeria

Tropical buildings are subjected to many militating elements of climate, prominent among which are insolation and rainfall. However, the study area has an additional influence from the Atlantic Ocean which is just a few meters away from the buildings. The sea breeze is laden with high salt content which has adverse effects and reactions on the materials used for building finishes. The outer skin-external surface of any building does not have any protection in most cases due to its function as the protective layer. However, the influence of this prevalent saline air differs from one part of the study area to another due to distance. The study bifurcated the city through a survey approach into two zones AB external finishes; climate; frequency; impact; maintenance; paint; performance; saline air; salt

Energy-Saving Experimental House in Hot-Humid Climate of Malaysia

In 2015, we constructed a full-scale experimental house in the city of Johor Bahru, Malaysia, in order to determine comprehensive energy-saving modification techniques through passive cooling for existing urban houses in the hot-humid climates. First, this chapter presents the results of numerical simulation to examine optimum combinations of modification techniques for the urban houses. Second, this chapter analyses the results of full-scale field experiments conducted in the above-mentioned experimental house to confirm the resulting effects of proposed modifications. The proposed modifications include (1) roof insulation, (2) external wall outer insulation, (3) external shading, and (4) forced ventilation (for the whole house and for the attic).