ZEMCH 2019 International Conference Proceedings April.2020 | Page 13
1. Introduction
With the recent increase in the number of buildings with high window area ratios, these buildings
have advantages in terms of viewing from occupants, securing large amounts of natural light, saving
energy in lighting, and ventilation. However, there is a disadvantage in that the cooling and heating
load is increased due to excessive heat gain in summer season and heat conduction in winter season.
Since windows are a major part of the buildingʹs enclosure that cause heat loss, it is essential to install
high‐performance windows for the energy‐efficient buildings. Although many technologies have been
developed for the high‐efficiency windows, there is a shortage of studies of retrofit technology for
developing the performance of windows installed in existing buildings.
In this paper, we proposed techniques to improve the airtightness and thermal performance of
sliding windows mostly used in Korea and the technologies were applied to windows installed in
existing buildings. Mock‐up experiments were conducted to verify the effectiveness of each technique.
In particular, the effectiveness was evaluated using various standards from domestic as well as
international standards.
2. Materials and Methods
2.1. Improving technolgy of thermal and airtightness performances of windows installed in existing buildings
2.1.1. Windbeak
The windbreak is a technology designed to enhance the airtightness performance that prevents
infiltration of outside air through a window. It can be applied to sliding windows mainly used in
residential buildings in Korea. The principle is not complicated. It prevents leakage by installing
windbreak on the junction of windows and window frames. In spite of the installation, windows can
be opened and closed. The construction of windbreak can be done regardless of window size. Also, it
can be installed directly by anyone without specific equipment, and it can be used semi‐permanently
because of its high durability. Appearances of the windbreak are shown in figure 1. The placement of
windbreak is shown in figure 2.
Figure 2. The placement of windbreak
Figure 1. Appearances of the windbreak
2.1.2. Attached glazing
The Attached Glazing is a technology designed to improve the thermal performance of windows
without removing existing windows. The principle is not complicated. The attached glazing is installed
in a space of about 10 mm between a window glass and its frame. The attached glazing and the air layer
created between them generate a heat insulating effect. The ch11aracteristic of windows such as the
view, the solar radiation and light can be maintained regardless of if the attached glazing is installed.
As solar heat can be acquired, the glazing surface temperature on the inside glass is increased, and the
energy loss is minimized.
Imroving thermal and airtightness performance of windows installed in existing buildings
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