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This article discusses the problem of Hermitian interpolation, which involves constructing a function that matches the values and derivatives of a given function at specific points. The authors focus on interpolation formulas based on window systems of functions generated by translates of the Gaussian function. They propose a method that does not require integration and reduces computational requirements. The article presents the construction of Hermitian cardinal functions and provides simple formulas for them in certain cases. The approach described is applicable to other window systems as well. [Extracted from the article]

• The study clarifies the impacts of various transparent envelope thermal parameters on glazing surface temperature. • It provides optimum condition design guidelines for EAW in hot climates by investigating the thermal performance of DGEW and TGEW with different parameters. • The study examined EAW's thermal performance with varying air gaps, air velocity, return air temperature, and pressure values. • The outcomes add another level of validation to the experimental model by using the same CFD simulation to validate the experimental and mathematical models. Window systems, particularly in hot climates, are the source of considerable heat transfer that affects the buildings' indoor environment and energy consumption. Proper design and optimization of its thermal performance significantly contribute to the overall envelope energy performance. Using a multi-layer glazing system, Energy Active Window (EAW) adapts window insulation technology to reuse low-grade air from the HVAC system, keeping the temperature at the internal surface of the window close to the indoor air temperature, minimizing heat exchange between indoor and outdoor. This study aims to reduce energy consumption by optimizing EAW to increase its thermal resistance by channeling the return air (RA) from the HVAC system into the curtain frame, thereby lowering the temperature of the air gap and air film layer. The study examined the window system's exhaust/return air behavior using the Computational Fluid Dynamics (CFD) tool (Fluent) to simulate the heat exchange between outdoor and indoor building environments. The CFD simulation was validated using experimental measurements. Results show a surface temperature decrease of 4 to 7 °C based on the inner and outer pane airflow conditions when the outdoor temperature is 45 °C with an 8 % margin of error. Various EAW components were tested, including air velocity, air–gap width, volume, and outdoor temperatures, examining both triple and double-glazing layers. [ABSTRACT FROM AUTHOR]

Utilization of high temperature cooling sources or natural energy sources can potentially contribute to improving energy efficiency in buildings. In this study, a dual-cavity window with gravity-driven cooling mechanism (GDC window) was proposed to integrate the low-grade cooling sources into the glazing system for improving the thermal performance of the window. The embedded pipes circulated with low-grade cooling water are the key component of GDC window, which can remove the absorbed solar heat and reduce the heat gain through the window. A numerical model based on CFD simulation was developed to analyze the flow characteristic and heat transfer within the GDC window. Model validation was conducted by comparing the simulation results with measurement data obtained from previous study. Numerical simulations were carried out to compare the thermal performance of GDC window with that of conventional blinds window. Sensitivity analysis was performed to evaluate the influence of some design parameters on the flow characteristic and thermal performance of GDC window. The simulated results show that compared with the blinds window, the GDC window reduces 57.4% and 40.4% of heat gain in summer for the low-grade cooling water of 18 °C and 25 °C, respectively. Reducing the flow resistance within the GDC window is significant for improving the heat removal performance of the embedded pipes. This study provides an alternative solution to integrate the low-grade cooling sources into the glazing system for enhancing the energy-efficiency and decreasing the building energy demand in cooling-dominated buildings. [ABSTRACT FROM AUTHOR]

The exhaust air glass unit (EAGU) can be treated as an integration of multilayer glazing unit and heat recovery device to utilize the exhaust air from conditioned space with a fresh air ventilation system to improve the thermal performance of window system. However, compared with the conventionally used mechanical ventilation with a heat recovery (MVHR) system, whether the use of EAGU is energy-efficient or not has not been estimated. In this paper, a numerical model, validated by experimental measurement, was used to calculate the hourly cooling and heating loads and annual energy demand of EAGU. This study compared the annual energy performance of EAGU and MVHR under various conditions, and further discusses the applicability of EAGU for different climates. The results indicate that the energy saving potential of EAGU ranges from 26.8% to 38.2% for different climate conditions. In the cooling season, the energy saving potential of EAGU performed much better than that of the commonly used MVHR. However, the EAGU was inferior to the MVHR in the heating season. Moreover, the EAGU is more suitable for application in warm climates, rather than cold climates. This study can provide some application guidelines about the selection of exhaust air heat recovery devices for maximizing the energy saving potential. [ABSTRACT FROM AUTHOR]

The exhaust air glass unit (EAGU) can be treated as an integration of multilayer glazing unit and heat recovery device to utilize the exhaust air from conditioned space with a fresh air ventilation system to improve the thermal performance of window system. However, compared with the conventionally used mechanical ventilation with a heat recovery (MVHR) system, whether the use of EAGU is energy-efficient or not has not been estimated. In this paper, a numerical model, validated by experimental measurement, was used to calculate the hourly cooling and heating loads and annual energy demand of EAGU. This study compared the annual energy performance of EAGU and MVHR under various conditions, and further discusses the applicability of EAGU for different climates. The results indicate that the energy saving potential of EAGU ranges from 26.8% to 38.2% for different climate conditions. In the cooling season, the energy saving potential of EAGU performed much better than that of the commonly used MVHR. However, the EAGU was inferior to the MVHR in the heating season. Moreover, the EAGU is more suitable for application in warm climates, rather than cold climates. This study can provide some application guidelines about the selection of exhaust air heat recovery devices for maximizing the energy saving potential.

The presence of daylight reflections on blackboards in classrooms can be disruptive to students and negatively impact their visual comfort and learning efficiency. A novel window system with switchable blinds has been specifically designed to balance daylight availability, visual comfort, and adequate window view in classrooms. This study aims to develop a validated simulation method to assess the daylighting performance of the novel window system in these three domains. Radiance -based simulation using bidirectional scattering distribution function (BSDF) data was developed and validated against experimental measurements in a test room. Daylight autonomy (DA) was used as the criterion for daylight availability, while the contrast ratio on the board was used to evaluate the disturbing light reflections on it. The simulation results show that, regardless of the classroom orientation (south/east/west), the novel window system with switchable blinds can: a) successfully meet the LEED requirements for spatial daylight autonomy (sDA) > 55%; b) reduce the low-contrast areas on the blackboard by adaptively switching the blinds , and c) maintain a satisfactory openness of the window with a clear image of the exterior. The studied window system with switchable blinds can provide a sensible balance between daylight availability, visual comfort, and view. The method of rating visual comfort in classrooms using contrast ratio on the blackboard was demonstrated to be feasible and applicable. • RADIANCE simulation method to conduct contrast-based evaluation has been validated. • The switchable glazing system with blinds could balance daylight availability, visual comfort and view in classrooms. • Contrast-based metric is highly recommended to be used in classroom daylight design. [ABSTRACT FROM AUTHOR]