Focused on Window to Wall Ratio and Window Performances and shgc

지역에 따른 공동주택 에너지 절약형 창호선정에 관한 연구

- U-value, SHGC 및 창면적비를 중심으로 -

Simulation Analysis for The Optimal Window System of Apartment Building by Region

- Focused on Window to Wall Ratio and Window Performances and SHGC -

박 승 수^* 이 동 현^*

Pa, Seung Su Lee, Dong Hyeon
Abstract
As energy issues become reality, the government is strengthening its annual energy consumption standards by building type.

It is mandatory to make zero energy housing in 2025 by 2010. Domestic apartment houses use mostly top-type for securing open feeling and increasing floor space ratio. It generates more heat loss and energy consumption of the building than the south-facing flat-type apartment house. It is important to establish an efficient energy saving plan from the initial stage of design. Considering architectural characteristics such as window to wall ratio. This study compares the U-value, SHGC, window to wall ratio, and building heating / cooling energy load according to the climate of each area. After comprehensive analysis, we would like to present appropriate windows for each region. Using the Design Builder simulator, determine the effect of window to wall ratio, window performances, SHGC on the building's cooling / heating energy consumption by climate.

The target building is a flat type apartment house, and the window area ratio is classified into 5 cases as 30 ~ 70%.

We analyzed load according to window performance and SHGC. and divided into five regions to analyze energy consumption by climate. According to glass performance and SHGC window area ratio, heating and cooling energy consumption showed different results in different regions. The increase in insulation performance was expected to reduce energy consumption, but in some areas increased energy consumption.

키워드 : 열 관류율, 태양열취득계수, 창면적비, 디자인 빌더, 유리성능

Keywords: U-value, SHGC, Window to wall ratio, Design Builder, glass performance

1. Introduction
1.1 Background and purpose of the study
As the energy problem becomes a reality, the government is strengthening the annual energy consumption standards for each building type under the goal of 'low carbon green growth'. As of 2010, the national roadmap was established to reduce the annual energy consumption of residential buildings by 30% in 2012, to 60%, which is the level of passive housing in 2017, and to mandate zero energy housing in 2025.1)

If you look at the shape plan of domestic multi-family house, it is in the form of plate and tower.

 

However, in the 1990s, most apartments in Korea were built in a flat plate shape. Since then, most of the tower-shaped multi-family houses are used to secure occupants' openness and increase the floor area ratio, and the exterior area and window area are increased compared to the existing south-facing apartment houses, resulting in more heat loss and energy consumption of buildings. Will be generated. 2)

Therefore, in order to reduce energy consumption, it is important to establish an efficient energy saving plan in consideration of architectural characteristics such as window and wall insulation and window area ratio from the early stage of design. It is used a lot. One of the important properties for glass is SHGC (Solar Heat Acquisition Coefficient).

SHGC indicates the degree to which radiant heat is transmitted to the room by the solar heat transmitted directly to the glass and the solar heat absorbed therein.

* 동아대학교 건축공학과

** 지도교수 이정재

¹⁾ 이명주, 김원석, 이우주, 이원택, 건축물에너지절약요소기술 적용에 따른 단독주택 에너지 요구량 절감률 변화에 관한 연구, 대한건축학 회논문집, 2012

²⁾ 정승민, 이정재, 창호 성능 및 창면적비에 따른 난방에너지 저감율 예측에 관한 연구, 2016

³⁾ 노은아, 임재한, 송승영, 공동주택 외피의 창면적비에 따른 에너지 성능 평가, 한국건축 친환경 설비학회, 2011

Therefore, if the SHGC is to be lowered to reduce the insolation load, it not only affects the heating and cooling load, but also affects the view and lighting required to secure the occupant's openness, which affects residents' satisfaction. Therefore, it is necessary to apply an appropriate SHGC to reduce the cooling load.4)

This study aims to select energy-saving windows for multi-unit apartments by region and to use them as basic data bases. Buildings based on the heat transfer rate and SHGC, window area ratio by window characteristics based on legal design criteria, and climate by region The cooling and heating energy loads were compared.

1.2 Current research trends
Lee Yong-jun (2009) compared and analyzed the energy-saving effect of buildings according to the improvement of the glass performance of the envelope in the 'Study on the Energy-Saving Effect of Curtain Wall Buildings by Glass Performance'. In this study, there is a limit to accommodate design diversity due to the same window area ratio.

Noah Eun-ah (2011) used DesignBuilder v.2.4 program in 'Evaluation of energy performance according to the window area ratio of the apartment complex' to analyze the changes in the heating and cooling load according to the window area ratio of the apartment complex. In this study, the effects of low-e glass and high-functional glass due to the same glass performance are excluded.

In addition, Kim Ki-han (2014) explained the effect of the solar radiation value on the building energy performance in the 'Influence of the horizontal total solar radiation calculation model on the building energy performance analysis considering the solar radiation coefficient and window area ratio'. The analysis was focused on the effect of changing the window area ratio. However, this study overlooks a comprehensive analysis of various regional characteristics and climates.

Therefore, this study intends to suggest appropriate windows for each region after conducting a comprehensive analysis considering not only the glass performance and window area ratio, but also SHGC and different climates for each region.

1.3 Research scope and method

Using the Design Builder simulation program, we investigated the effect of window area, glass performance, and solar heat gain coefficient on the cooling and heating energy consumption of buildings by region. The target building was a flat-type apartment house, and a general apartment house of 85 square meters or less was selected based on the national housing specified in Article 2 of the Housing Act. Among them, the domestic top-shaped multi-family house was selected as the main type of the double-wing type of the 4th generation combination, and the load characteristics by continuous operation conditions were analyzed.

⁴⁾ 서혜수, 강은율, 김병선, 태양열취득계수(SHGC)에 의한 가시성 및 에너지 성능에 따른 거주자 선호도 상관관계 분석, 대한건축학회논 문집, 2011

The window area ratio of the target building was divided into 30 cases by 30% to 70%, and classified into a total of 5 cases. Divided into Gwangju and analyzed energy consumption by climate. The heat transmission rate for each type of window was referred to the energy saving design standard of buildings proposed by the Ministry of Land, Infrastructure and Transport.

flow chart

2. Roy Glass and Solar Heat Gain Coefficient (SHGC) Overview

2.1 Low Emissivity Glass
It is a thin coating of metal or metal oxide on the glass surface. It is an energy-saving glass that minimizes heat transfer, and is called low-emission glass or low-emission glass. Most of the visible light coming through the window can be transmitted to keep the room bright and effectively block radiation in the infrared area. Although there are some differences depending on the conditions of use, it is known to have an energy saving effect of about 50% compared to single-pane glass and about 25% compared to ordinary double-layer glass.

Soft-coated Roy glass is manufactured by using a metal target plate in a separate vacuum chamber for the float plate glass that has been produced, using the MSVD (Magnetron Sputtering Vacuum Depositon) method. It is produced by coating a multi-layer thin film of metal, and because of the metallic properties of Ag (silver), oxidation in the air is likely to occur, and immediately after production, through the processing of multilayers, bonding, etc., air must be prevented. It can prevent damage to the coating due to oxidation. Due to these features, the ease of processing and use is hard.

Compared to this, however, it is possible to obtain a lower thermal conductivity through secondary coating and tertiary coating, which is advantageous for use in commercial buildings and high-rise curtain wall buildings that require low thermal conductivity.

Conceptual diagram of Roy Glass