• Journal of the Korean Solar Energy Society
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• v.38 no.5
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• pp.75-84
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• 2018

The most crucial point of reducing building energy is application of high performance envelope. The amount of heat exchange through window is highest in comparison of other envelopes so that heat exchange through window influence directly with building energy consumption. The window energy performance can be define with thermal, leakage and optical performance. In previous study we can confirmed that not only thermal performance but also optical performance are considered, 11% to 15% of building energy consumption can be reduced. Smart window system has potential of energy saving so that many industry field use smart window system including architectural area and these aspect causes smart window market continuous growth year by year. In this study, building energy consumption has been analyzed which consist of smart window that dynamically control optical states. The consideration of standard commercial building model for research, the reference medium size commercial building model of DOE (Department Of Energy, USA) has been used. The building energy simulation result of 4 axis in 8 regions in Korea shows 8% to 22% reduction of building energy consumption by application of smart window system.

• Journal of the Korean Solar Energy Society
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• v.30 no.2
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• pp.33-38
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• 2010

The perimeter zone is space which receives a significant effect of ambient condition, it is necessary to improve the thermal performance in order to building energy saving. For this reason, a lot of study about the active approach is being performed, such as perimeter-less air conditioning system. But the performance of the perimeter zone is necessary to improve, through the passive approach. Therefore, the purpose of this study is to provide basic materials of energy-saving design of perimeter zone, based of the PAL that simulation changing the thickness of insulation and the rate of windows.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.10
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• pp.515-529
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• 2017

EnergyPlus, which is widely used in various fields, provides Simple Window Model, a window model that can be used practically. However, the results of building load using the model are different from those of the standard model. The main cause of the deviation by Simple Window Model was analyzed to be due to the assumption that all windows were considered as single layer. The purpose of this study is to propose a window model that improves the cause of deviation by Simple Window Model and can be easily calculated from the algebraic relations. The proposed window model solved the heat balance equation algebraically by using seven window characteristic coefficients. The coefficient relationships consisted of the heat transmission coefficient and solar heat gain coefficient as input parameters make practical use and calculation possible. As a result of comparing the deviation between each window model by implementing the dynamic analysis method, the proposed window model showed that the deviation of the total heating/cooling energy consumption was reduced to 1/3 compared to Simple Window Model for one year. Although the maximum energy consumption did not show any significant improvement, the indoor temperature evaluation showed significantly reduced deviation.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.109-115
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• 2011

It can gain both the electric energy production and disperse of light at the same time if DSSC is applied in the building as window system. It means to help facade design and to be used in lighting, heating, cooling energy directly by applicating DSSC BIPV window that is possible to daylighting and materialization of color. For this, optical characteristics analysis that is basic step must take precedence. So, basic databases of DSSC are builded and optical performances according to the double and triple glazing are evaluated by analyzing spectral data of various colored DSSC. As a result, Green(4) has the highest visible transmittance that is 28.8%, and Blue(3) has the lowest that is 0.3%. And, in case of optical performance of Green(4) depending on the incidence angle, SHGC and Tsol are decreased sharply from more than $60^{\circ}C$. Finally, It is judged that Red(4), Green(1), (4), Blue(4) are suitable for application in office building because visible transmittance is high and solar heat gain coefficient is low relatively in spite of composing to double and triple glazing.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.12
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• pp.753-764
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• 2015

Among several types of energy saving smart window technologies, the leader, the dynamic EC (electrochromic) window one needs integrated PV (photovoltaics), to minimize expensive electrical wiring as well as to obviate the need for external energy. Self-powered smart windows were reviewed according to PV types used. DSSCs (dye sensitized solar cells) were found to be compatible with EC cells, to have several categories of next generation smart windows such as PECCs (photoelectrochromic cells), PVCCs (photovoltachromic cells), EC polymer PECCs. In addition silicon solar cells and third generation solar cells were investigated. They are summarized in a table showing their advantages and disadvantages respectively for a fast comparison. The strategy to expedite the commercialization of these next generation smart windows includes developing retrofit smart window coverings for use on flexible polymer substrates adhered to the inside surface of a window and easily replaced after use for upto 10 years.

• Solar Energy
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• v.10 no.2
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• pp.10-17
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• 1990

Short-term tests were conducted on a house at KIER, Daejon for its thermal performance evaluation. The test procedure and data analysis were made according to the PSTAR method. Each test period was 3 days during which the building was unoccupied. The data measured with 8 channels were used to renormalize an audit based simulation model of the house. The following are the key parameters obtained in the present analysis: 1) the building loss coefficient(skin conductance plus infiltration conductance during coheating period); 2) the effective building heat capacity; and 3) the effective solar gain. An estimation of total heat required to maintain a standard level of comfort during a typical winter season is also calculated on the basis of the renormalized simulation model and typical long term weather data.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.165-170
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• 2012

This study aims to analyze the characteristics of temperature variation of Spandrels. According to the change of SHGC of Window system, air space, insulation performance and absorption factor of inner surface at the Spandrels, It was firstly estimated by using simulation. Secondly, measured to minimize the temperature-rise of inner surface temperature and the intermediate air temperature by using Full-scale Mock-up based on the result of simulation analysis. As a result, it turns out that low SHGC window system such as BIPV system had an advantage of reducing the window surface temperature, and the surface temperature of clear window system was all higher than BIPV system on simulation results. In the experiment results, it had some advantages of increasing the Spandrels volume, decreasing insulation performance and lower absorption factor.

• Journal of the Korean Solar Energy Society
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• v.40 no.1
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• pp.49-60
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• 2020

This study reviewed selected specific windows and reviewed the window performance certification criteria including KS F 2278 and KS L 9107 and analyzed the change in performance based on the change of area. This study also compared the heating and cooling loads of an apartment house applied with window performance reviewed in consideration of insulation and SHGC performance and actual size based on KS F 2278. The analyzed window was a double window composed of aluminum and PVC and the building was the apartment house model of 141 ㎡. The analysis results were as follows. First, as the window glass's thermal performance is superior to frame, the performance degraded in reduced area. In case of selected window, the 1 m × 1m window's thermal performance and SHGC decreased by 35% and 37% respectively compared to 2 m × 2 m window. Secondly, in the comparison of performance for increasing area with 2 m × 2 m and 3 m × 3 m windows, the 3 m × 3 m window's thermal performance and SHCG increased about 14%. Third, in the comparison of heating and cooling loads of the analyzed model considering the apartment house model applied with window performance derived from KS F 2278 and actual figures, the model's total heating and cooling loads increased by 33% with cooling decreasing by 36% and heating increasing by 77%. Above analysis results show that evaluation of window performance based on criteria such as KS F 2278 and KS L 9107 may lead to distortion of performances different from actual products. Thus, it is necessary to suggest new evaluation criteria.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.95-102
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• 2011

The purpose of study is to estimate heating, cooling load performance and economic efficiency in office building with applied the functional paint. this paint can reduced SHGC(Solar Heat Gain Coefficient) on the glazing surface by coating. In this study, estimated to compared with double glazing, low-e glazing, IP(Insulation Paint) and IPu(Insulation UV-Cut Paint) coating glazing. As a result of this study, 1)heating & cooling load Analysis, SHGC value and U-factor of double glazing is about 0.70 and 3.29($W/m^2K$). low-E glazing is about 0.65 and 2.70($W/m^2K$). Two-side it is about 0.27 and 3.25($W/m^2K$). When compared to double glazing, annual heating & cooling load of low-E glazing, Two-side IPu and IP paint coating glazing is 3,012MWh($124kWh/m^2$), 2,910MWh($120kWh/m^2$), 2,867MWh($118.4kWh/m^2$) and 2,867MWh($118.4kWh/m^2$). It i sreduced to 2.0%, 5.2%, 6.7%, and 6.7% respectively. 2)the estimation of economic efficiency, low-e glazing installed in office building can not recover the investment within a lifetime 40years. but IPu and IP paint, two-side coating in glazing, have a payback period of 13 years respectively.

• Land and Housing Review
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• v.13 no.1
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• pp.131-140
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• 2022

A smart window is a new building material that can realize energy savings in a building. Smart windows can freely adjust Visible Light Transmittance (VLT) and solar gain coefficient (g-value) according to the situation. Smart windows include such technologies as Electrochromic (EC), Suspended Particle Device (SPD), and Polymer Dispersed Liquid Crystal (PDLC). Recent research on building energy savings through the VLT and g-value control functions of smart windows is being actively conducted and meaningful results are being drawn. However, since most of the research is focused on energy savings, research on the indoor environment is somewhat lacking. A building is a space where people live and the comfort of life should be prioritized before energy savings. Therefore, in this study, analysis on the daylight performance of an office space was carried out. Through green building standards such as LEED, BREEAM, CASBEE, and G-SEED, the daylight performance was reviewed according to VLT value changes of the smart window. In addition, a study was conducted on the VLT range of the electrochromic façade that can maintain a comfortable indoor environment. The smart window used electrochromic control with a wide range of VLT. The study showed that the minimum VLT of a smart window that can satisfy G-SEED is 25% or more. In addition, it was found that the VLT change of the electrochromic smart window did not significantly affect the uniformity of the room. When the LEED standard was applied, the minimum VLT value of the electrochromic smart window that must be maintained according to each orientation of the building was derived.