Gon Kim

Advanced External Shading Device to Maximize Visual and View Performance

Controlling or avoiding direct sun beam shining into the interior is a key criterion for consideration in most architectural daylighting designs. This treatment is mainly intended to attenuate the adverse glare and contrast associated with direct sunlight and to lessen the negative contribution of direct sunlight on the cooling load. Window shades are commonly used in Korea to reduce heat gains in the form of direct beam radiation, particularly in summer. Very often they consist of non-movable structures, such as overhangs, vertical fins or composition of both, forming eggcrate-type systems, and ideally should be designed by incorporating these methods. One of the simplest sunlighting controls is Venetian blind. It plays a role in excluding direct sunlight but reflecting light to rear interior, while still allowing a view to exterior. The blinds also go far toward improving uniformity in illuminance. External shading devices are much more effective than internal shading devices. However, it is not popular because of cost, maintenance, and esthetic reasons. We developed an experimental configuration of external shading device, providing better performance of shading and view. A series of simulations and measurements have verified the differentiated advantages in illumination and building energy consumption by using this system.

Development of a Double-Skin Façade for Sustainable Renovation of Old Residential Buildings

The modernist movement in architecture has led to a building boom of a large number of high-rise buildings with glazed façades. These façades were aesthetically pleasing, but have a high energy loading. To address this, a double-skin façade (DSF) has been proposed to manage the interaction between the outdoor and indoor environments. A DSF can contribute to balance the demand for energy saving, thermal and visual comfort, and a high-tech image for building envelopes. The design of the DSF involves decisions on geometric parameters, glass selection, ventilation strategy, shading, daylighting, aesthetics, wind loads, and maintenance and cleaning cost expectations. This paper reports an experimental application of a DSF in an old apartment building which has been modelled in order to find the configuration to select design parameters that could minimize the energy demand and total carbon emissions. A simulation-based virtual environment program was used to determine the optimal sustainable features of the double-skin envelope. Results of the simulation are presented and discussed for four different cavity widths and ventilation modes of operation, highlighting the potential savings in comparison to the existing façade construction. The impact of internal shading within cavity space was also investigated.

Predicted Performance of Shading Devices for Healthy Visual Environment

The main purpose of using a shading device is usually to prevent excessive sunlight from delivering into the building and to distribute daylight entering a building more evenly in space. However, in the design of a vertical fenestration system, there are a variety of considerations related to the building type and daylighting potentials such as: latitude, climatic characteristics, the position of the sun and outdoor obstructions. To enhance the performance of sun lighting control, a shading device should play a more efficient role according to the building shape and orientation. This paper examines the method designed to improve both the indoor natural illuminance and open view for a better visual environment. The main aim of the proposed approach is to provide a simplified calculation for the several conditions of shading device shapes based on the computer simulation analysis. The proposed method was conducted by dividing the internal illuminance into four types of the shading device systems due to the direct sun radiations. This was calculated by a Desktop Radiance program. The room dimensions were based on a unit module of apartments of 6 m (width) × 6.9 m (depth) × 2.7 m (height) with a window measuring 4.5 m × 2.43 m. The variables considered were: a basic horizontal louver, a blind system and a proposed experimental shading device.

Energy Benefit of the Underfloor Air Distribution System for Reducing Air-Conditioning and Heating Loads in Buildings

Although there have been continuing efforts recently for low-energy buildings as parts of the low-carbon green growth movement, particular attention has been paid to architectural design, the elective control of façades, and the efficiency of Heating, Ventilation, and Air Conditioning (HVAC) mechanical systems. To maximize the gains from these efforts, it is essential to consider the energy distribution approach and its layout during the design stage of the building. To this end, air distribution principles in HVAC have grown in popularity in buildings. The method to deliver the energy is strongly associated with increasing concerns about indoor environmental quality on occupants’ well-being, as well as rising energy costs for space heating and cooling. This paper identifies types of air distribution systems for heating and cooling in buildings and addresses the potential energy benefit of an underfloor air distribution (UFAD or UAD) system over the conventional ceiling air distribution system. A series of EnergyPlus simulations shows performance differences between the two distribution systems. One result is that the potential benefits of an UFAD are clearly demonstrated for a large space with a high ceiling.

UV-Ray Filtering Capability of Transparent Glazing Materials for Built Environments

In terms of lighting for the built environment, both providing healthy light and eliminating harmful components of light are the key factors for consolidation and for health promotion. The ingredients of daylight are exceedingly complicated and are classified by the wavelength of light. Ultraviolet (UV) light, wavelength between 400 nm—10 nm, is more energetic and will penetrate more readily through obstacles than visible light. In spite of all their positive uses, UV rays are very harmful for anyone who spends a large amount of time in the sun without proper protection. Glass and film manufacturers produce optically functional glass panes to control UV and infrared rays of sunlight. In order to curb excessive penetration of UV rays, optically functional glasses have been proposed and the performance assessments of the glazed materials have been measured and reported in this paper. Various pair-glasses consisting of UV control glass and the conventional are manufactured and evaluated, providing the photometric data in terms of wavelength. In conclusion, UV protection glass is more effective in controlling UV rays of natural light. Obviously, clear glass treated with UV protection film would provide excellent control of UV penetration and a pair of clear and UV protection glass treated with UV protection film should be recommended; this achieves 96.7% UV protection performance from natural light.

Effect of Occupants’ Behaviour of Daylight Controls on Residential Visual Environment

This paper aims to assess how occupants perceived their visual environments of diverse luminous ambiences created by daylight in apartment buildings. Daylighting can have a large influence on environmental condition to improve ambience, visual comfort, well-being and health of occupants. Thus, it is essential to understand what visual adaptive actions for the satisfaction of occupants and how they respond to given visual environments. A purpose-built living room with balcony extension was situated at Kyung Hee University in Korea (latitude 37.17N, longitude 127.01E) to monitor data throughout a 1-month period in winter. Thirty-two subjects participated and each subject spent a day in the test room. All subjects were given the opportunity to have artificial lighting and blinds control over the lighting ambience appropriate for their activity. Physical measurements such as illuminance levels of vertical and floor-planes, window luminance were monitored simultaneously which were cross-linked to the subjective assessment of blinds control. Experimental results revealed the factors affecting the occupant use of shading systems; visual comfort, seating orientation and blinds types could have an effect. The results of this study should provide useful information on daylighting as a function of photometrical and behavioural factors for future application in building design.

Spectral Characteristics of UV Light Existing in Indoor Visual Environment

This paper deals with the spectral characteristics of ultraviolet (UV) ray in an architectural environment. Visual quality is one of the most important factors in the design of interior environment of building, conferring the necessary mood suitable to the built environment for the occupants’ required functions. Visual environment can also have an impact on the healthy status of the human beings affecting both the mental and physical wellbeing of the occupants. As a natural resource of lighting, daylight arrives on the surface of the earth as one of the electric waves composed of UV, visual and infrared rays. Visual ray plays a significant role in the formulation of the visual environment due to its superior sensitivity on human acuity. However, the UV rays being the more energetic ones would penetrate into built environments and they can be very harmful for the occupants. The spectral characteristics and intensities of UV rays can be affected by architectural features, such as the incident angles and locations of the measurement. This study investigated the impact of time on the measurement of the spectral characteristics of UV rays. Other factors such as the distance from the window and the incidence direction were also included in the study. The results were expressed in terms of distribution and intensity of the wavelength. The correlation among UV intensity, distance, time and direction was also established by the study.

Overall Environmental Modelling of Newly Designed Curtain Wall Façade Configurations

There has been a rapidly growing interest among contemporary architects in recent years in the innovative use of curtain walls as a building enclosure. A curtain wall is a glass and metal skin that wraps the entire building in a continuous, transparent layer. This modern design provides a relatively desirable environment for the occupants. The glass façade allows light and diffused views into the surroundings during the day and can become a glowing and aesthetically pleasing aspect of the skyline at night. The key visual features of curtain walls are the glazing appearance and sightlines, but the window selection plays a key role in determining the overall buildings environmental performance. The complex layering of glass should be strategic as well as artistic, balancing light and shade to optimize light and minimize heat gain. Recently, a series of curtain wall system have been developed with an emphasis on the technical issues, such as structural stability, energy efficiency, sustainable strategies, daylighting, and materials. This design case project explores in depth the overall environmental performance of the leading-edge curtain wall assemblies using computer programs such as Virtual Environment and Radiance, which allow estimation of total U-values and helps predict daylighting performance.

Optical Daylighting Performance of an Active Mirror System for Visual Sustainability of Residential Environment

This paper presents a newly developed mirror sunlighting system approach that would enable architects to consider daylighting goals by engaging the sunlighting system in early design process to make up for the handicaps of lower daylighting availability due to the geographical disadvantage of obstructed location of the building. A mirror sunlighting system was developed and installed in a building complex and its performance was measured in terms of illuminance and luminance with critical meteorological variables. The findings of this study make recommendations for use of appropriate optical daylighting systems for building applications and suggest directions for future development to facilitate wider acceptance of optical systems. The results of the case studies of recently-built examples indicate that the sunlighting system may retain some of the visual qualities of the spaces sustainability, such as maximizing daylighting. A series of analysis implied that the sky conditions should be carefully considered in the prediction of daylighting performance of a mirror sunlighting system.

Visual Environment Within the Already-built Underground Development in South Korea

The utilisation of underground spaces has been receiving more attention in Korea in recent years. However, due to continuous complaints of environmental quality from would-be occupiers, the developers must identify the possible negative aspects that could potentially relate to the physical characteristics of underground spaces to alleviate the impacts. This research aims to determine the sustainable design guidelines for underground developments in relation to the visual environments. At the first stage, the study focused on the evaluation of the already-built examples to assess the problems that exist in the underground spaces of high-rise offices recently built in Korea. The visual aspect in terms of illuminance and the human responses with regard to naturally occurring lighting in the underground environment are the issues of major concern. A series of model simulation has provided the advance configurations for the commonly used sunken structures. The study has also proffered skylight systems as a better sustainable solution for the underground development.