• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.551-556
• /
• 2008

Possibility of the remote eavesdropping through window glass is investigated using a laser sensor. Various thicknesses and types of glass windows are excited by maximum length sequency (MLS) signal and the vibration sound is detected by a laser doppler vibrometer. Intelligibility of the detected sound is evaluated using the speech transmission index (STI), which is based on the modulation transfer function (MTF). In order to identify the disturbing effect, different level of disturbing wave is generated by an outside speaker and a window shaker attached on the glass window. On the different thickness of glass windows, decrease effect of the speech intelligibility is analysed.

• Journal of Korean Living Environment System
• /
• v.20 no.2
• /
• pp.233-237
• /
• 2013

Daylighting affects the luminous environment and provides comfortable environment to the occupants. However, excessive daylighting might have negative influences on the visual comfort. Skylight, light intensity and distribution, and insolation could cause glare effects on the occupants. This study analyzed the effect of fenestration on the interior glare effects, and verified luminous environment adjustability through mock up test of conventional fenestration and 'Convergence Window System' by analyzation of luminance, luminance contrast, and glare effect. Consequently, room installed Convergence Window System was improved luminance contrast and PGSV Level.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.24 no.5
• /
• pp.422-427
• /
• 2012

This study investigates on the relationship between total load which is caused by infiltration and insulation thickness against compensation effect. As the result of experiment, the PVC(Synthetic resins sash) window frame in airtightness is superior to the AL(Aluminum sash) window frame. In this study, as the increasing of insulation thickness in reference building does not reduce significantly cooling load, the compensation effect due to airtightness against infiltration is very small. But the compensation effect against infiltration can be closely related with heating load. Therefore, the proper thermal insulation thickness can be needed respect to cooling and heating load.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.7
• /
• pp.429-435
• /
• 2010

Although recently revised building code requires 15~20% increased thermal insulation performance for window systems, since the code is focusing on winter heat loss, it is not satisfactory to contribute on reducing rapidly rising cooling load in summer. Window systems have great impact on building heat gain and loss. Therefore technological development for window system specialized in shading solar gain in summer is an urgent matter. This study evaluates the performance of sun shading and thermal insulation for blind integrated window system. Also, computer simulation evaluates the effect of heating and cooling energy consumption reduction for an individual unit(floor area of $85m^2$) of a multi-family housing. Physibel Voltra, a heat transfer analysis software, was used to analyse the effect of energy consumption reduction, and the energy load was converted to the cost to compare the actual effect of economical benefit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.9 no.3
• /
• pp.300-311
• /
• 1997

A theoretical method was developed to analyze the effect of low-$\varepsilon$ coatings which have influence on thermal performance of vacuum windwo glazing and double pane glazing. The overall heat transfer coefficient(U) value and thermal performance were analyzed by theroretical method on various kins of windows. TRNSYS program was used to analyze total heating and cooling energy consumption on the model building which has various windows. As the result, better thermal insulation can be achieved on the vacuum window glazing than double pane glazing when low-$\varepsilon$ coating was done on the surface of glass. Total heating and cooling energy consumption was almost same on the double pane window glazing but was lessened on the vacuum window glazing when the window size of south direction increased. Therefore, low-$\varepsilon$ coating was very necessary for vacuum window glazing in order to improve thermal insulation performance and efficient energy conservation can be achieved by vacuum window glazing at the real building which has large window.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.9 no.4
• /
• pp.484-496
• /
• 1997

The fluid flow and heat transfer characteristics of conjugate forced and natural convection in the triple-glazed airflow window, where the outer air passes through a space contrived between the interior and exterior window panes, were studied numerically by a finite volume method for the elliptic form of the Navier-Stokes equations. The investigation focused on the influence of window geometry, ventilastion rate and solar energy on the temperature, velocity distribution and thermal performance of the airflow window. The comparison between the triple-glazed airflow window and the enclosed triple-glazed window was also made to evaluate the effect of buoyancy upon which the thermal performance of the window depended.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.9
• /
• pp.635-640
• /
• 2010

This study is suggested tilt window type to be restrained solar radiation through vertical window type in buildings. The shading and aesthetical effect of buildings would be solved by installation of tilt window type. For investigate optimum an angle of tilt window and building azimuth in reference region, the distance of transmitted solar radiation is calculated. The results of calculation showed optimum an angle of tilt window is obtained $7^{\circ}$ that the distance of transmitted solar radiation is 20% of 1.5m of balcony width. In case of an tilt window angle of $7^{\circ}$, the optimum building azimuth is showed $SW15^{\circ}{\sim}SE15$.

• KIEAE Journal
• /
• v.7 no.4
• /
• pp.57-62
• /
• 2007

At the moment, the reduction of building energy consumption is a unavoidable task of mankind for conserving global environment. Decreasing overall U-value of building envelope and air infiltration, especially in Korean climate condition with clear four seasons, are the obvious solutions for the objective. Thus low glazing ratio with small window openings are required for heating and cooling load reduction in buildings. Using larger window openings could provide better natural ventilation but it also increases the direct solar radiation penetration into indoor space, heat gain in summer and heat loss in winter. On the other hand, the ventilation rates decreasing problem with smaller window openings could be occurred. As a solution for it, the use of casement window can cause increasing natural ventilation rates by wing wall effect. This paper focuses on deduce the most efficient opening type of casement window in Korean climate. To estimate ventilation performance of each opening types, CFD simulation was used. The best performance of opening type in every wind direction is opening both windows to the center and the most appropriate opening type for Korean climate is also opening both windows to center.

• Journal of Korea Foundry Society
• /
• v.29 no.2
• /
• pp.86-94
• /
• 2009

The effect of austenitizing temperature and time on the processing window of 3.60wt%C - 2.50wt%Si - 0.80wt%Cu ductile cast iron and that of the amount of copper added were investigated. The second stage reaction at 400oC was retarded with increased austenitizing temperature. The widest processing window was obtained at the lower austempering temperature with the increased time at the same austenitizing temperature. The width of the widest processing window was decreased with the increase of time at the same austenitizing temperature. The width of processing window was increased with the increased amount of copper added.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.9
• /
• pp.888-894
• /
• 2007

The speech sound is detected by the vibration measurement of the window glass. In this study, we investigate the effect of the disturbing waves by background noise and window shaker excitation on the speech intelligibility of the detected sound. Based upon Modulation Transfer Function(MTF), speech intelligibility of the sound is objectively estimated by Speech Transmission Index(STI) As the level of the disturbing wave varies, variation of the speech intelligibility is examined. Experimental result reveals how STI is influenced by the level and frequency characteristics of the disturbing wave. By using a customized window shaker for disturbing sound, we evaluate the efficiency and the frequency characteristics of the anti-eavesdropping system. The purpose of the study is to provide useful information to prevent the eavesdropping through the window glass.