Experimental Investigation of Thermal Behaviors in Window Systems by Monitoring of Surface Condensation Using Full-Scale Measurements and Simulation Tools

Hong, Goopyo; Kim, Daeung Danny; Kim, Byungseon Sean

doi:10.3390/en9110979

Cited by 6 publications

(11 citation statements)

References 27 publications

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“…However, at b > 12 mm, neglecting the convective component can lead to significant errors. For such cases, in the formula for thermal resistance, the authors of [20,21] propose that the convection in the vertical gap between the panes can be taken into account by replacing the value of the gas thermal conductivity by λ eqv :…”

Section: Evaluation Of Heat Transfer Rates Through Window Structuresmentioning

confidence: 99%

Evaluation of Heat Transfer Rates through Transparent Dividing Structures

et al. 2022

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In this paper, heat transfer and airflow in the gap between the panes of a central part of a double-glazed window were investigated using mathematical modeling. It has been shown that the cyclical airflow regime, in the form of ascending and descending boundary layers, loses stability and changes to a vortex regime under certain conditions depending on the gap width, transverse temperature gradient, inclination angle and window height, as in Rayleigh–Bernard convection cells. The study made it possible to determine the critical values of the Rayleigh number (Ra) at which the air flow regime in the gap between the panes of a window changes (in the range of values 6.07 × 103 < Ra < 6.7 × 103). As a result of the modeling, the values of the thermal resistance of a central part of double-glazed window were determined as a function of the width of the gap between the panes, the angle of inclination and the transverse temperature gradient.

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Section: Evaluation Of Heat Transfer Rates Through Window Structuresmentioning

confidence: 99%

Evaluation of Heat Transfer Rates through Transparent Dividing Structures

et al. 2022

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“…Windows in apartment buildings have relatively low thermal resistance compared to opaque, insulated building components; thus, condensation easily occurs on their indoor surfaces. For condensation on the indoor surfaces of large windows, there are many adverse effects that can induce secondary damage to floor covering materials (e.g., the generation of mildew) [1][2][3][4][5][6][7][8]. To resolve frequent condensation problems in winter, the Korean government enacted the Design Standard for Preventing Condensation in Apartment Buildings [9], which came into effect in May 2014.…”

Section: Introductionmentioning

confidence: 99%

“…Multistory apartment buildings account for more than 58% of all residential buildings in Korea [6], with most having additional windows on the outdoor side of the balcony to create an unheated indoor space. In many cases, the balcony, which can act as a thermal buffer zone between outdoor and heated indoor spaces, is eliminated to increase the effective floor area indoors (as allowed by law; Figure 1); thus, condensation often occurs on the indoor faces of windows during winter.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Alternatives for Improving the Thermal Resistance of Window Glazing Edges

Park¹,

Song²

2019

Energies

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To reduce condensation and ensure occupant comfort, the Korean Design Standard for Preventing Condensation in Apartment Buildings was enacted in 2014. However, glazing edges remain vulnerable to condensation. Because this design standard is recent, few window products satisfy the condensation resistance requirement for glazing edges, especially in the coldest region, and there have been limited investigations on improvement measures. This study evaluates and verifies various treatments for improving the glazing edge thermal resistance of double-glazed four-track horizontal sliding windows to reduce condensation risk and satisfy the design standard. Three-dimensional heat transfer simulations are performed for each alternative to obtain the surface temperature and temperature difference ratio (TDR) for the bottom edge of the glazing. The U-factors of the alternatives satisfying the required TDR for the coldest region are simulated, and the effects of increased local thermal resistance in the glazing edge on the U-factor of the window are analyzed. Mock-up tests are performed on the most economical and best-performing alternatives satisfying the coldest region TDR, and the TDRs and U-factors from the simulations and mock-up tests are compared to verify the performance of the most economical alternative. Insulating spacers, frame extensions, and low-emissivity coatings are effective in various cases.

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“…Insulating spacers have been introduced to reduce heat loss caused by the thermal bridge in the edge-of-glazing. Previous research has shown that improving spacers could significantly reduce the energy lost through multi-pane windows [11][12][13]. In high-performance windows, such as triple-glazed windows, insulating spacers can reduce window U-value by 12% compared to the U-value with aluminum spacers [11].…”

Section: Introductionmentioning

confidence: 99%

“…Energies 2018, 11, 382 11 of 13 for the edge-of-glazing, corresponding to a temperature difference of approximately 1 • C. As in Case 4, the accuracy of predicting the condensation risk at the edge-of-glazing could be improved most effectively by using the increased local surface thermal resistance at the edges. For example, relative to the measurement of f Rsi at Point E-1, the simulation of Case 2 produces an error of approximately 10%, while the simulation of Case 4 reduces the error to less than 3%, as shown in Table 4.…”

mentioning

confidence: 99%

Effect of Surface Thermal Resistance on the Simulation Accuracy of the Condensation Risk Assessment for a High-Performance Window

et al. 2018

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Abstract:The accuracy of condensation risk assessment depends on the accuracy of the measured or calculated temperatures. The existing 2D simulation method provides sufficiently accurate results for evaluating average performance values, such as U-values. However, the accuracy of predicting the temperatures in the local areas such as the edge-of-glazing and the frame has been questioned. This study analyzes the effect of the surface thermal resistance on the accuracy of the condensation risk assessment for high-performance windows. Experiments and three-dimensional simulations were performed for a triple-glazed window. The differences in results between the basic experimental test and the simulations with several different applied boundary conditions were analyzed. The results show that, in the simulations, a small change in the surface thermal resistance has no significant effect on the accuracy of the condensation risk assessment of the center-of-glazing or the frame. However, for the edge-of-glazing, the accuracy of predicting the condensation risk was significantly improved by using the increased local surface thermal resistance with the simulation. By employing the reduced radiation and convection at the edges or junctions between two surfaces, the error between the measured and calculated temperature factors can be reduced to less than 3%.

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Experimental Investigation of Thermal Behaviors in Window Systems by Monitoring of Surface Condensation Using Full-Scale Measurements and Simulation Tools

Cited by 6 publications

References 27 publications

Evaluation of Heat Transfer Rates through Transparent Dividing Structures

Evaluation of Heat Transfer Rates through Transparent Dividing Structures

Evaluation of Alternatives for Improving the Thermal Resistance of Window Glazing Edges

Effect of Surface Thermal Resistance on the Simulation Accuracy of the Condensation Risk Assessment for a High-Performance Window

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