Wong Nyuk Hien

Applying Natural Ventilation for Thermal Comfort in Residential Buildings in Singapore

Abstract This paper explores the potential of using natural ventilation for indoor thermal comfort in residential buildings in Singapore based on climatic data analyses. A typical year of weather data was selected by statistical analyses of weather data over a five-year period in Singapore. The characteristics of weather data for a typical year were analyzed with regard to temperatures, wind speeds, and wind directions. Thermal comfort models for natural ventilation applicable for Singapore were used for the assessment of thermal conditions. It was found that by applying natural ventilation, a thermally comfortable indoor environment can potentially be provided for a large number of hours in the year with optimum of facade designs for residential buildings (negligible heat sources). The study also developed facade design guidelines based on the required indoor air velocities for thermal comfort.

The use of performance-based simulation tools for building design and evaluation — a Singapore perspective

Abstract This paper provides an overview of some of the state-of-the art performance-based simulation tools available for the design evaluation of environmental quality in buildings. Through an extensive industry survey, it reveals the extent of usage of performance-based simulation tools for building design and evaluation in Singapore. It highlights particularly the difficulties encountered in the usage and the needs of the industry for such tools. Recommendations are also given as to how to promote the pervasive use of such simulation tools to enhance the design process.

Thermal Impact of Strategic Landscaping in Cities: A Review

Abstract Greenery in cities has long been recognized as an ecological measure to mitigate some environmental issues. The chapter discusses three major types of urban greenery: public green areas, rooftop gardens and vertical landscaping from both a systematic and thermal benefit point of view. Much related research carried out worldwide is reviewed. In order to achieve strategic landscaping in cities, some general guidelines are given.

Air Temperature Distribution and the Influence of Sky View Factor in a Green Singapore Estate

This paper investigates, first, the influence of vegetations to the air temperature distribution and, second, the correlation between air temperature and sky view factor (SVF) to understand whether the trees have adverse impact especially to the nighttime air temperature since trees reduce the SVF values. Air temperature and SVF measurements were conducted in a green Singapore estate, One-North, from November 1, 2007 to March 31, 2008. The field measurement results show that daytime air temperature difference between dense greenery area and less greenery area is 2.4 K and the nighttime air temperature difference is 1.1 K. The temperature maps study provides a clear picture on the air temperature distribution across the One-North estate and concludes that parks or clusters of trees are able to maintain both daytime and nighttime air temperature at a cool level. Statistical analysis was conducted to analyze the correlation between air temperature and SVF. During daytime, there is a significant and good correlation between air temperature and SVF. The higher the SVF, the higher is the air temperature. Trees reduce the sky openness and provide shading to the environment. At nighttime, there is a weak correlation between air temperature and SVF. Thus, there is no adverse impact, i.e., reduction of nighttime net long-wave loss, due to the reduction of SVF by trees.

Computer-Based Performance Simulation for Building Design and Evaluation: The Singapore Perspective

This article provides an overview of the usage of performance-based simulation tools for building design and evaluation in Singapore based on an extensive industry survey. It highlights the status and difficulties encountered in the usage and the needs of the industry for such tools. Recommendations are also given to promote the pervasive use of such simulation tools.

An Assessment Method for Existing Greenery Conditions in a University Campus

Abstract It is widely known that greenery has positive impacts to the environment. It is necessary to consider greenery as an important element in any contemporary urban planning. However, planners, estate managers and property managers are not able to asses existing greenery conditions in terms of quantitative data in order to achieve their goals in maintaining or improving the greenery condition. Thus, it is impossible to set a framework or plan to improve the environmental quality. The objective of this research is to develop a framework for planners to evaluate and to improve the greenery conditions in planning the urban environment.

A Climatic Responsive Urban Planning Model for High Density City: Singapore's Commercial District

Local climate condition and urban morphology affect air temperature generated within urban canopy layer which related to urban heat island (UHI) intensity and later impacts on outdoor thermal comfort and urban energy usage. Climatic responsive urban planning by careful consideration on urban morphology parameters of urban corridor width, building height, urban surface materials, sky view factor (SVF) and vegetation help to improve urban environment quality. This study mainly focuses on commercial district and observes impacts of various urban structures configurations towards air temperature by interpolating climatic and urban morphology predictors. The urban structures indeed show relation with level of air temperature generated although vegetation also contributes in reducing air temperature through its evapotranspiration process. Therefore the understanding of relation between urban morphology with thermal performance and UHI benefits in future urban planning and development.

Performance of greenery systems in Zero Energy Building of Singapore

Aiming to be “City in a Garden”, greenery systems are widely developed to be integrated into buildings in Singapore. Zero Energy Building of Singapore as a test bed for several green building technologies also tested the greenery systems. Vertical greenery systems and extensive rooftop greenery systems were installed and the thermal performance was being monitored. The paper discussed on the performance of the greenery systems in reducing heat gain into the building and cooling down the ambient air temperature. The study was conducted by field measurement of the surface temperature and the ambient air temperature.

Comparison of STEVE and ENVI-met as temperature prediction models for Singapore context

In urban areas, natural land soil has been replaced by asphalt roads and concrete buildings, which absorb and retain more heat during the day, creating the Urban Heat Island (UHI) phenomenon. Current studies show that UHI impact mitigation strategies are to increase the open spaces to allow urban ventilation and plant green cover. To complement this, a temperature prediction model could be effective for simulating and quantifying the temperature reduction for every developed strategy. This paper will look into two prediction methods: STEVE and ENVI-met. Screening Tool for Estate Environment Evaluation (STEVE) is a prediction tool which is able to calculate the T min , T avg and T max of the point of interest for certain urban settings. The temperature at that particular point is the result of its surrounding environment within the buffer zone. Output data from STEVE will be used as a database for a Geographic Information System (GIS) to produce temperature maps. ENVI-met is a Computational Fluid Dynamics ...

Performance of passive design features in Zero Energy Building of Singapore

Zero Energy Building (ZEB) of Building and Construction Authority (BCA) in Singapore is a retrofitted building with different green building design features and technologies. It is used as a test-bed for innovative building designs and energy efficient building solutions, particularly for existing buildings. The study focused on the performance of shading devices and lightshelves in providing daylighting and affecting the thermal comfort in naturally ventilated classrooms under afternoon sun. Field physical measurements were conducted to compare the space with and without the passive design elements. For the shading devices, the complete setting configuration showed higher mean radiant temperature reduction of around 1°C - 2°C. The illuminance level of the complete setting configuration showed around 100 lux more reduction than the 4panel configuration. For the lightshelves, the reflective surface improved about 100 lux at 1pm and did not improve much afterward. The mean radiant temperature showed a lag of half an hour. The zone with the reflective surface was heated up earlier and in overall, the temperature was increased of around 1°C deeper in the room.