• International Journal of High-Rise Buildings
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• v.6 no.2
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• pp.177-185
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• 2017

This research suggests the most effective way for improving energy efficiency in tall buildings is a "fabric-first" approach. This involves optimizing the performance of the building form and envelope as a first priority, with additional technologies a secondary consideration. The paper explores a specific fabric-first energy standard known as "Passivhaus". Buildings that meet this standard typically use 75% less heating and cooling. The results show tall buildings have an intrinsic advantage in achieving Passivhaus performance, as compared to low-rise buildings, due to their compact form, minimizing heat loss. This means high-rises can meet Passivhaus energy standards with double-glazing and moderate levels of insulation, as compared to other typologies where triple-glazing and super-insulation are commonplace. However, the author also suggests that designers need to develop strategies to minimize overheating in Passivhaus high-rises, and reduce the quantity of glazing typical in high-rise residential buildings, to improve their energy efficiency.

• KIEAE Journal
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• v.17 no.3
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• pp.15-21
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• 2017

Purpose: "Building energy design standard" is used to limit the thermal transmittance of building in Korea. However, it only covers the insulation standard for each appropriate elements of a building, not the thermal performance of Junction thermal bridge of windows and doors installed in wall. Therefore in this study, we have evaluated the thermal performance of Junction thermal bridge depending on installation method and position of windows and provide it as design data. Method: We analyzed heat transfer of 4-Track sliding window and tilt & turn triple glazed window that are placed in the first class category on window energy efficiency rating using Window 7.4 and Therm 7.4. Result : First, linear thermal transmittance of 4-Track sliding window differs by 2.2 times or more depending of installation method and location. It is higher than the linear thermal transmittance, 0.01W/mK, proposed by Passivhaus. Second, linear thermal transmittance of Tilt & turn triple glazed window differs by 7.7 times or more depending of installation method and location. The average linear thermal transmittance was less than 0.01W /mK when windows were installed on the internal wall insulation by the fixed hardware attachment method. Third, the thermal losses of a window caused by a junction thermal bridge are inversely proportional to the window area and converge gradually as the area increased.