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This research investigates the energy efficiency of a novel double-glazing system incorporating solid–solid phase change materials (SSPCMs), which offer significant advantages over traditional liquid–solid phase change materials. The primary objective of this study is to develop a 3D numerical model using the finite volume method, which will be followed by a parametric study under real climatic boundary conditions. A proposed double-glazing setup featuring a 2 mm layer of SSPCM applied on the inner glass pane within the air gap is modeled and analyzed. The simulations consider various transient temperatures and ranges of the SSPCM to evaluate the energy performance of the system under different weather conditions of Miami, FL during the coldest and hottest days of the year, both in sunny and cloudy conditions. The results demonstrate a notable improvement in energy performance compared to standard double-glazing windows (DGWs), with the most efficient SSPCM configuration exhibiting a phase transition temperature and range of 25 °C and 1 °C, respectively. This configuration achieved energy savings of 24%, 26%, and 23% during summer sunny, winter sunny, and winter cloudy days, respectively, relative to DGWs during cooling and heating degree hours. However, a 3% energy loss was observed during summer cloudy days. Overall, the findings of this study have shown the potential for energy savings by incorporating SSPCM with suitable thermophysical properties into double-glazing systems.

The building envelope provides thermal comfort, an excellent visual view, and sunlight for the occupants. It consists of two parts: (i) an opaque (non-transparent) part (e.g., walls and roofs) and (ii) a transparent part (e.g., windows, curtain walls, and skylight devices). Recently, the use of fully-glazed facades, especially in large cities, has increased due to their aesthetical and structural advantages. This has led this study to review the performance of the currently passive smart glazing technologies. Phase Change Materials (PCMs) as latent energy storage material is the focus of this review, as well as other individual and combined techniques, including shading systems, solar cells (photovoltaic), and chromogenic (thermotropic and thermochromic) materials. PCM-integrated glazing systems have been extensively studied and rapidly developed over the past several decades from the standpoint of unique system designs, such as passive, active, and passive/active mixed designs, intelligent management, and sophisticated controls. In the academic literature, numerous studies on PCM-integrated building envelopes have been conducted, but a comprehensive review of PCM-integrated GUs combined with other passive and active techniques using dialectical analysis and comparing the climatic conditions of each study using Köppen-Geiger climate classification climate classification has been performed only rarely. Consequently, the primary objective of this study is to reduce this discrepancy for all types of glazing, excluding glazed roofs. This review article also contains literature tables as well as highlights, limitations, and further research suggestions at the end of each subsection.

Enclosed airspaces to reduce heat flow have been recognized for well over 100 years. Airspaces with one or more reflective surfaces define reflective insulation (RI) assemblies, a product type used in walls, roofs, windows with multiple panes, curtain walls and skylights. The thermal resistance (R value) of airspaces depends on the emittance of all surfaces, airspace dimensions and orientation, heat flow direction and surfaces temperatures. The modeling of RI now includes CFD coupled with radiation to quantify the total heat transfer. This study compares a validated model for airspace R values with existing methods such as ISO 6946 and hot-box results that provide the R values in the ASHRAE Handbook of Fundamentals. The existing methods do not include an airspace aspect ratio. This study showed that the aspect ratio can impact the R value by a factor of two. The impact of aspect ratio was calculated for double airspaces variation such as that for single airspaces. The present calculations are two-dimensional and also consider all the bounding airspace surfaces, while previous methods are one-dimensional and do not include surface temperature variations or detailed radiative transport.

The overall building performance depends mainly on the energy performance, indoor air quality, and moisture performance. In order to accurately calculate the building performance, the development of a model with the ability to integrate all three performances is required. In this research, a combination of three models namely EnergyPlus for energy, CONTAM for indoor air quality, and WUFI for moisture transport are used to develop an integrated model. The mechanism of this combination is based on the exchange of temperatures, airflows, and heating-cooling flows control variables between all three sub-models. By using the paired sample t-test, an integrated model is verified and its accuracy is validated. The accuracy of the integrated model is verified by the paired sample t-test. In order to analyze the accuracy of the integrated model in comparison with single models, four scenarios of airtight fan off, airtight fan on, leaky fan off, and leaky fan on are defined for a three-story-house subjected to three different climate cities of Montreal, Vancouver, and Miami. Percentage differences of simulated measures with the ASHRAE Standard are considered as the performance criteria. The simulated results by single and integrated models are compared and analyzed. Finally, the scenarios with the high performances are evaluated in terms of energy efficiency, indoor air quality, and moisture for Montreal, Vancouver, and Miami. Overall, it can be concluded that an integrated model should be developed.

In this paper, an integrated model that coupled CONTAM and WUFI was developed to assess the indoor air quality (IAQ), moisture, and thermal comfort performance. The coupling method of CONTAM and WUFI is described based on the exchange of airflow rate control variables as infiltration, natural and mechanical ventilation parameters between heat and moisture flow balance equations in WUFI and contaminant flow balances equations in CONTAM. To evaluate the predictions of the integrated model compared to single models of CONTAM and WUFI, four scenarios were used. These scenarios are airtight-fan off, airtight-fan on, leaky-fan off, and leaky-fan on, and were defined for a three-story house subjected to three different climate conditions of Montreal, Vancouver, and Miami. The measures of the simulated indoor CO2, PM2.5, and VOCs obtained by CONTAM; the simulated indoor relative humidity (RH), predicted percentage of dissatisfied (PPD), and predicted mean vote (PMV) obtained by WUFI; and those obtained by the integrated model are compared separately for all scenarios in Montreal, Vancouver, and Miami. Finally, the optimal scenarios are selected. The simulated results of the optimal scenarios with the integrated model method (−28.88% to 46.39%) are different from those obtained with the single models. This is due to the inability of the single models to correct the airflow variables.

Cool roofs use reflective materials or coatings to reflect a portion of the incident solar radiation. This results in a lowering the surface temperature of the cool roof compared to black roofs, and thus helps reduce the cooling energy loads during the summer season. The research reported in this paper was conducted to assess experimentally and numerically the performance of cool and black roofs that were subjected to the hot, humid and dusty climate of Jubail Industrial City (JIC). This paper focused on characterizing one of the important properties of reflective coating material (RCM), which is its solar reflectivity. In this study, the effect of dust/dirt accumulation on the solar reflectivity of the RCM was investigated at different exposure times to the natural weathering conditions of JIC. The test results showed that dust and dirt can significantly contribute in reducing the solar reflectivity of the RCM. As such, a number of cleaning processes were conducted on the surface of the RCM so as to increase its solar reflectivity. The effect of each cleaning process on the solar reflectivity of the RCM was investigated. Finally, this paper provides a test protocol and procedure for characterizing the dust concentration/intensity on the surfaces of the RCM and cleaning this material after different exposure times to a natural and polluted climate.