Conventional Windows Research Articles

A liquid crystal smart window for energy saving and harvesting

Energy conservation, particularly in buildings, has become a critical focus area. Among the various components of a building, windows play a significant role in the exchange of heat and light. Electrochromic systems, known for their ability to switch between transparent and opaque states with the aid of external energy, have served as the basis for conventional smart windows. This research introduces a novel approach to smart window technology by incorporating a luminescent solar concentrator (LSC) that incorporates thin photovoltaic cells at the window's edges, coupled with a thermally and optically adjustable liquid crystal cell. The device intelligently transitions between an energy-saving, opaque mode (day mode) and a transparent, idle mode (night mode), based on ambient temperature and incident light levels. Through this innovative design, the proposed smart window offers enhanced energy efficiency and harvesting capabilities, promising significant benefits for sustainable building practices.

Investigating Neurologic Improvement After IV Thrombolysis: The Effect of Time From Stroke Onset vs Imaging-Based Tissue Clock.

Time from stroke onset is associated with clinical response to intravenous thrombolysis (IVT) with alteplase and is therefore used to select patients for treatment. Alternatively, neuroimaging may be used for treatment in the uncertain or extended time window. We hypothesized that the patient-specific imaging indicator of ischemic lesion progression ("tissue clock") using CT perfusion (CTP) or quantitative net water uptake (NWU) is a predictor of early neurologic improvement (ENI) independent of time. Observational study of anterior circulation ischemic stroke patients with proximal vessel occlusion and known time from symptom onset triaged by multimodal CT undergoing endovascular treatment. Quantitative NWU using an established threshold (11.5%) or CTP lesion core mismatch (EXTEND criteria) was used to estimate ischemic lesion progression. The treatment effect of IVT depending on lesion progression defined by tissue clock vs time clock was assessed by inverse probability weighting (IPW). End points were binarized ENI and functional independence at day 90. Four hundred nine patients were included, of which 223 (54.5%) received IVT. The proportion of patients within an early time window (<4.5hours), low NWU, and CTP mismatch were 45.0%, 86.5%, and 80.3%. In IPW, IVT was associated with higher rates of ENI (%-difference: 7.3%, p = 0.02). For patients with CTP mismatch or low NWU, IVT was associated with a 9.6% or 7.2% higher rate of ENI, which was different than the effect of IVT in patients without CTP mismatch or high NWU (-9.3%/-7.3%; p = 0.004/p = 0.03), whereas early treatment window did not modify the effect of IVT. CT-based measures of the "tissue clock" might identify patients who benefit from IVT more accurately than conventional time windows. Considering the high number of patients with early "tissue clock" (low NWU/CTP mismatch) within an extended time window, considerable benefit from IVT using imaging indicators of the "tissue clock" may be achieved.

Freezing-resistant poly(N-isopropylacrylamide)-based hydrogel for thermochromic smart window with solar and thermal radiation regulation

Adaptive regulation of solar and thermal radiation by windows in diverse (hot and cold) climates is essential to reduce building energy consumption. However, conventional hydrogel-based thermochromic smart windows lack thermal radiation regulation, and have difficulty to combine high solar regulation with excellent freezing resistance. It is challenging to integrate the above performance into one hydrogel-based thermochromic window. Here, we firstly prepared poly(N-isopropylacrylamide-co-N, N-dimethylacrylamide)/ethylene glycol (PNDE) hydrogels with tunable and excellent freezing resistance (below −100 °C) by adding the anti-freezing agent ethylene glycol, and assembled PNDE hydrogels, polyvinylidene fluoride and polymethyl methacrylate-silver nanowires panels into a freezing-resistant smart window with solar and thermal radiation regulation (STR). PNDE hydrogels had an excellent thermochromic performance with luminous transmittance (Tlum) of 89.3 %, solar regulation performance (ΔTsol) of 80.7 % and tunable phase change temperature (τc, 22–44 °C). The assembled STR window showed high Tlum of 68.2 %, high ΔTsol of 62.6 %, suitable τc of ∼30 °C and freezing resistance to low temperature of −27 °C. Moreover, the different thermal emissivity (0.94 and 0.68) of the two sides of the STR window gave it the ability of radiative cooling in hot climates and warm-keeping in cold climates. Compared to the conventional thermochromic windows, the STR window promotes heat dissipation in hot conditions while reduces heat loss in cold conditions and is applicable to diverse climates, which is a promising energy-saving device for reducing building energy consumption.

Advanced Imaging in the Current Era of Acute Reperfusion Therapies

Reperfusion of the ischemic brain parenchyma with intravenous thrombolysis and/or mechanical thrombectomy is the cornerstone of acute ischemic stroke treatment. A paradigm shift from “time is brain” to a more precision medicine approach now called “imaging is brain”, has taken place during the last decade. This transformation has been fueled by the progress in neuroimaging. Advanced Neuroimaging incorporates perfusion imaging in order to depict real-time cerebral perfusion disturbances and provide maps of the penumbra and ischemic core that will inform individualized clinical decisions. Advance neuroimaging has now a fundamental role in triaging patients that will receive reperfusion treatments beyond the conventional time windows of 4.5 hours for intravenous thrombolysis and 6 hours for mechanical thrombectomy. We provide a narrative review of all the pivotal observational studies and randomized-controlled clinical trials that supported the use of advance neuroimaging, as well as technical issues and pitfalls that may be useful for its implementation in routine clinical practice.

Effect of paper filter windows on indoor exposure to particles of outdoor origin

Buildings are often located near ambient air pollution sources such as wildfire or heavy traffic areas. While windows in buildings are intermittently open for free cooling or natural ventilation, increased leakage area can lead to elevated human exposure to air pollutants of outdoor origin. The objective of this study is to investigate the effectiveness of paper filter windows in reducing exposure to outdoor air pollution and improving indoor air quality. The physical properties of paper windows as filtration media were experimentally determined, based on which multi-zone indoor air quality and ventilation analysis (CONTAM) simulations were performed for a full-scale building. The results show that the outdoor-indoor air exchange rate of a building can increase about 100% when conventional windows are replaced with paper filter windows. Even with the increased air exchange rate, the infiltration of outdoor particles into the building was reduced about 57–77% for the particle size range of 7–300 nm. These findings imply that paper windows have potential benefits for controlling both outdoor originated pollutants and indoor-generated pollutants with minimal energy inputs, especially in cities and communities impacted by urban air pollution and wildfires.

Assessing the Energy-Saving Potential and Visual Comfort of Electrochromic Smart Windows in Office Buildings: A Case Study in Dhahran, Saudi Arabia

This study comprehensively evaluates the energy-saving potential and visual comfort aspects of electrochromic (EC) smart windows in a hot-humid climate office building. Using an advanced building simulation tool, EC windows are compared to conventional low-E glazed windows, considering two control triggers: daylighting level and glare control. The primary objective is to determine energy savings achievable with EC windows while addressing visual comfort. Detailed analysis of the building’s energy performance and indoor environment is conducted. Results show significant energy savings of 23% with EC windows using daylighting control but limited visual comfort in some zones. Conversely, EC windows with glare control achieve 17% energy savings while maintaining visual comfort throughout the building. These findings highlight the potential of EC windows with glare control in saving energy and maintaining visual comfort in hot-humid office buildings. Further research is needed to optimize performance for different building types and climates. In conclusion, this study provides insights into energy-saving capabilities and visual comfort considerations with EC smart windows, emphasizing the importance of appropriate control triggers for maximizing energy savings and occupant comfort. Future investigations should explore EC window performance across diverse building typologies and climates to enhance the benefits of this innovative technology.

Intelligent optical management for energy-efficient windows driven by mechano-thermochromism

The thermochromic windows based on vanadium dioxide (VO2) can intelligently modulate the transmittance of indoor solar radiation, which is significant for reducing building energy consumption. However, conventional thermochromic windows only have the ability of single spectral modulation, continuously switching the solar spectral transmittance in response to varying ambient temperature on a window is challenging. In this work, a SiO2-VO2-PDMS-driven by mechano-thermochromism intelligent optical management system was proposed for automatic switching and continuous adjustment of the solar spectral transmittance. Compared with the single-layer VO2 film, the SiO2-VO2 double-layer thermochromic window provides a gradual refractive index change from the top with nair = 1 to the middle with around 1.5, and then to the bottom with a higher refractive index, which suppresses reflections over a wider wavelength range. The results show that the SiO2-VO2 double-layer coating with a refractive index buffer layer exhibits improved optical performance with a solar modulation ability (ΔTsol) of 18.4% and an average luminous transmittance (Tlum,avg) of 49.1%. Furthermore, the design can achieve increases in the stretch-related solar modulation ability (ΔTsol,stretch) and the stretch-related luminous transmittance (Tlum,stretch) from 18.4% to 43.8% and 49.1% to 60.5%, respectively, which is realized by the deformation of polydimethylsiloxane (PDMS). Combining elastic stretching with thermochromic windows can dynamically modulate the solar spectral transmittance to improve thermal comfort. This work provides a promising approach to improve the industrial application of VO2 thermochromic windows, contributing to the advancement of research in green buildings, window design, and automotive energy efficiency.

A Novel Sensing Feature Extraction Based on Mold Temperature and Melt Pressure for Plastic Injection Molding Quality Assessment

Injection molding is one of the polymer molding methods. Product quality mainly can be affected by temperature and pressure. To observe the process of the melt forming in the mold, it is required to monitor the signal with the sensor. To achieve the purpose of robust molding, this research provides a new design-process window architecture based on machine learning of the injection product quality assessment. The process window is also known as the forming area map. The monitored value for defective products will be above or below the variable limit. The process is set to the center of this window so that any variation within the window will still result in an acceptable product. There are some potential problems in the current process. First, the conventional process window uses a small number of process variables as monitoring indicators, and it cannot provide stronger monitoring indicators. Second, most of the conventional process windows are 2-D and there are many monitoring windows, so the information that can be monitored is limited. Therefore, product quality cannot be effectively monitored without proper selection of important factors. Finally, the current process window can only provide information in the process and cannot make product quality prediction. In order to solve the above problems, a machine learning method is proposed to design the process window. The random forest classifier and regressor are used to predict the product quality. In order to improve the usability of the factor, the design of the proposed new variable is derived from the classical formula of thermodynamics (heat conduction). Using existing factors and proposing time-based feature changes can better represent the molding process as a whole. Based on the experimental results, the proposed variables can effectively increase the predictive performance of random forest model for quality assessment. The research results make a satisfactory result to the quality assessment of industrial injection molding. The accuracy of the prediction results is 100%. Moreover, it can be found from the 3-D process window that the data are very concentrated and can be clearly classified by the hyperplane, which is defined as the shortest distance between two clusters, and this space is the boundary of the process window. Therefore, compared with the past, the judgment boundary based on the random forest process window is no longer a simple boundary. Random forests can provide more accurate visualization boundaries.

Thermochromic Ni(II) Organometallics With High Optical Transparency and Low Phase-Transition Temperature for Energy-Saving Smart Windows.

Thermochromic smart windows with rational modulation in indoor temperature and brightness draw considerable interest in reducing building energy consumption, which remains a huge challenge to meet the comfortable responsive temperature and the wide transmittance modulation range from visible to near-infrared (NIR) light for their practical application. Herein, a novel thermochromic Ni(II) organometallic of [(C2 H5 )2 NH2 ]2 NiCl4 for smart windows is rationally designed and synthesized via an inexpensive mechanochemistry method, which processes a low phase-transition temperature of 46.3 °C for the reversible color evolution from transparent to blue with a tunable visible transmittance from 90.5% to 72.1%. Furthermore, cesium tungsten bronze (CWO) and antimony tin oxide (ATO) with excellent NIR absorption in 750-1500 and 1500-2600nm are introduced in the [(C2 H5 )2 NH2 ]2 NiCl4 -based smart windows, realizing a broadband sunlight modulation of a 27% visible light modulation and more than 90% of NIR shielding ability. Impressively, these smart windows demonstrate stable and reversible thermochromic cycles at room temperature. Compared with the conventional windows in the field tests, these smart windows can significantly reduce the indoor temperature by 16.1 °C, which is promising for next-generation energy-saving buildings.

Kinetics of postoperative circulating cell-free DNA and impact on minimal residual disease detection rates in patients with resected stage I-III colorectal cancer.

5 Background: A growing body of evidence supports the utility of circulating tumor DNA (ctDNA) as a useful biomarker for detecting molecular residual disease (MRD) in colorectal cancer (CRC). Immediately after surgery or during adjuvant therapy, high levels of cell-free DNA (cfDNA) from normal tissue may limit the detection of tumor-derived ctDNA. The optimal timing of blood collection for reliable MRD detection after surgery or adjuvant therapy remains unclear. Methods: In this retrospective, U.S.-based, multi-institutional study, data from commercial ctDNA testing in 16,347 patients with stage I-III CRC were analyzed. Complete clinical data were available for 417 patients with 2,538 plasma samples collected between 6/2019 and 4/2022. The median follow-up for relapsed and non-relapsed patients was 730 and 615 days, respectively. A personalized, tumor-informed multiplex PCR-based next-generation sequencing assay (Signatera) was used to quantify ctDNA prior to surgery and postoperatively in a longitudinal manner. We analyzed the kinetics of total cfDNA and compared it with the ctDNA MRD positivity rates at various time points after surgery. Results: Among all patients, cfDNA levels were higher immediately after surgery (0-2 weeks) and gradually declined during the subsequent 2-8 weeks (p&lt;0.0001). Despite the higher cfDNA levels, among patients with immediate post-operative draws (0-2 weeks) 30.6% (113/369) of patients were ctDNA positive. Similar ctDNA detection rates were observed with conventional MRD windows after resection, whether the window was defined as 2-6 weeks (20.8%; 957/4605) or 2-8 weeks (20.9%; 1155/5534). In the clinically annotated cohort, ctDNA-positivity during the MRD time window of 2-8 weeks and during surveillance (&gt;6 months post-operatively and subsequent to any adjuvant therapy) was significantly associated with worse recurrence-free survival as compared to ctDNA negative patients (MRD: HR 14.1, 95% CI: 5.8-34; p&lt;0.0001; and surveillance HR 20.6, 95% CI: 10.6-37.6; p&lt;0.0001), respectively. On analyzing cfDNA dynamics during adjuvant therapy, cfDNA levels gradually increased between 8 weeks and 8 months after surgery (p=0.0001), suggesting a potential impact of treatment on cell death and cfDNA shed. Conclusions: This is one of the first, large-scale in-depth studies evaluating treatment-based fluctuations in post-operative cfDNA and its correlation with ctDNA-positivity. Our analyses demonstrated no significant impact of plasma cfDNA levels on ctDNA detection rates across different MRD windows using a tumor-informed approach. This may affect real-world application of personalized ctDNA testing by allowing earlier testing windows, as well as guide clinical trial designs using ctDNA as an integral biomarker.

Daylighting and energy performance of the combination of optical fiber based translucent concrete walls and windows

Optical fiber based translucent concrete (OFTC) is a kind of innovative building envelope for building energy efficiency. Prior studies indicated that both optical fibers and OFTC have angular transmittance that strongly depends on the angle of incidence, but most research on OFTC at the building level did not take this feature into account. This study focused on the annual daylighting and energy performance of the combination of OFTC walls with windows. The analysis was based on a cellular office room with an external OFTC wall and a window in Beijing, considering the influence of window-to-wall ratios, fiber volumetric ratios, optical fiber numerical aperture, and glazing types on building daylighting and energy performance. The results indicate that the combination of OFTC walls and windows can achieve the least net electricity use, which is about 32.07% and 5.36% lower than the optimal case with only OFTC walls, and that with the combination of conventional concrete walls and windows, respectively. The use of high numerical aperture optical fibers in OFTC can further contribute to building energy efficiency, but might increase the risk of daylight glare. However, the effects of OFTC walls on daylight glare are insignificant especially when the window-to-wall ratio is high.

New Class of Cosine-Sum Windows

Window functions are required to achieve excellent frequency resolution, peak sidelobe ratio, and sidelobe decay. The cosine-sum window function satisfies these requirements. However, conventional cosine-sum windows limit the number of terms and coefficient values. Therefore, this study proposes a new class of cosine-sum windows that has more terms than those in the conventional cosine-sum window and considers positive and negative coefficients. For such windows, we present three design examples. The first is a window function with low sidelobe decay, which reduce the sidelobes by adding correction terms to the conventional windows without damaging the sidelobe decay. The second is a window function that improves the frequency resolution by emphasizing the discontinuities of the extracted signal. The third is a window function that reduces sidelobes further without deteriorating the frequency resolution by adding correction terms to the window functions, which are designed in advance. We confirmed the effectiveness of these examples of the proposed window function.

Ensuring the energy efficiency of heat supply energy systems functioning by justifying the choice of glazing units for the external enclosing structures of buildings

The article is devoted to the further development and implementation of technologies that allow some considerable reducing energy consumption and, as a result, reduce greenhouse gas emissions. In Ukraine and abroad, a huge amount of heat is lost through the external enclosing structures of buildings. The largest specific heat losses occur through translucent enclosures, in particular, windows, the main elements of which are double-glazed windows. Today, manufacturers offer double-glazed windows, which are characterized by different costs and energy efficiency. The buyer does not know which double-glazed window to choose. We have proposed a clear and understandable method of solving this issue. For example, two different double-glazed windows were considered and a comparison was made on their cost, thermal resistance of heat transfer, and the ability to save certain amounts of heat and money for its purchase during operation. A feasibility study of additional capital investments in double-glazed windows with improved characteristics instead of conventional double-glazed ones has been carried out. Its results show that, at the current stage of the society development, the use of double-glazed windows with improved characteristics, despite their higher cost, is economically more appropriate than conventional double-glazed windows. This applies to external translucent fences of buildings of any purpose and form of ownership - both residential and industrial, public, which are on the balance sheets of local and state budgets, etc. The results of all calculations are explained in detail and presented in the form of a table. In addition, a simple and clear scheme of technical and economic substantiation of additional capital investments in a double-glazed window with improved characteristics is presented instead of an ordinary one, which can be used at the design stages of new construction or thermal renovation of existing buildings to ensure the selection of the most rational structural solutions. The materials of the article can be generalized to any other cases of technical and economic substantiation of the choice of options for technical solutions in energy-efficient projects.

A solar/radiative cooling dual-regulation smart window based on shape-morphing kirigami structures.

The energy efficiency of buildings has become a critical issue due to their substantial contribution to global energy consumption. Windows, in particular, are often the least efficient component of the building envelope, and conventional smart windows focus solely on regulating solar transmittance while overlooking radiative cooling. Although several recent designs achieved dual-control of solar and radiative cooling, these windows still face limitations in terms of durability, limited modulation ability and energy-saving performance. To address these challenges, we propose a novel dual-control smart window design consisting of a reconfigurable kirigami structure and polydimethylsiloxane-laminated thermochromic hydrogel coated with silver nanowires. In summer, the thermochromic hydrogel turns translucent to suppress the solar heat gain, while the high emissivity kirigami structure covers the exterior surface of the window, promoting radiative cooling. In winter, the hydrogel becomes transparent to allow for solar transmission. Additionally, the kirigami structure undergoes an out-of-plane structural change, opening towards the outside environment to expose the underlying low-emissivity silver nanowires and suppress heat radiation. Our design achieves a promising solar transmittance modulation ability of ∼24% and a good long-wave infrared emissivity regulation ability of 0.5. Furthermore, it exhibits significantly improved durability, which is nine times longer than the lifespan of conventional smart hydrogels. Our novel approach offers a promising solution for constructing energy-efficient and durable smart windows and outperforms existing state-of-the-art solar/radiative cooling dual-regulation smart windows in the literature.

NUMERICAL INVESTIGATIONS OF THE THERMAL PROPERTIES OF WINDOW SYSTEMS: A REVIEW

Windows are an essential part of building envelopes since they enhance the appearance of the building, allow daylight and solar heat to come in, and allow people to observe outside. However, conventional windows tend to have poor U-values, which cause significant heat losses during the winter season and undesired heat gain in summer. Modern glazing technologies are therefore required to improve thermal resistance and comfort of the occupants, whilst mitigating the energy consumption of buildings. In the present work, a comprehensive review of the numerical investigations of the thermal properties of window systems and glazed buildings partitions is presented. However, the proposed models to predict the thermal performance most often concern only specific cases of window systems related to geometry and used material solutions, focused on specific physical processes, thus they contain a lot of simplifications, such as omitting the influence of radiation, temperature changes or velocity profiles.

Modeling, Simulation, and Performance Analysis of a Liquid-Infill Tunable Window

Solar shading is important in buildings for better indoor thermal/light environment and energy conservation, especially in the tropical region. Compared with conventional windows with additional fixed shading devices, windows with adaptive self-shading functions take up less space and require less management labor. The present investigation focuses on a compact liquid-infill tunable window, which can provide adaptive shading with colored liquid-infill according to the surrounding environment. The numerical model of the liquid-infill tunable window was established on the basis of the law of energy and mass conservation, which enabled prediction of the adaptive response of the window under different boundary conditions. Then the thermal performance of this innovative window was analyzed in comparison with triple-layered clear glass windows. Influences of solar radiation level, incident angle, and ambient temperature were taken into consideration. The window was proven to be efficient in reducing indoor heat gain in the cooling season under strong solar radiation. With an 60° incident angle, the total indoor heat gain through window can be reduced by 1.60–8.33%. In the future, the established numerical model may be inserted into existing building simulation software as an energy-efficient window module to evaluate its energy and economic performance. The present study may inspire architectures and engineers in the design of near-zero energy and/or carbon neutral buildings.

Reconfigurable origami-inspired window for tunable noise reduction and air ventilation

Conventional windows encounter significant challenges in simultaneously achieving noise reduction and ventilation. Recent advent in origami technology offers new possibilities and smart solutions to solve this bottlenecking problem. In this paper, we propose a novel modular-origami-based reconfigurable silencing window that achieves balanced noise mitigation and air ventilation while ensuring flexible tunability. Specifically, the balance between the two competing functions originates from the unique ‘tile—void’ structure of the modular origami, and the tunability is a result of the single-degree-of-freedom folding mechanism. Based on a comprehensive understanding of the correlations between the design variables (including origami geometry, internal partition forms, and folding angles) and the acoustic characteristics of the window, on-demand sound attenuation for a specific target frequency band can be achieved via optimization. Broadband noise reduction can be obtained through cascading multiple origami layers, whose design can be conceived by an intuitive spectral superposition principle. Finally, we demonstrate through numerical simulations that for different working scenarios, balanced sound attenuation and air ventilation can be achieved by simply folding the origami window. This conceptual design, alongside the reported findings, provides new ideas for the design of modular acoustic devices and contributes to addressing the noise reduction and ventilation needs for urban buildings as well as industrial installations.

Thermochromic Smart Windows Assisted by Photothermal Nanomaterials.

Thermochromic smart windows are optical devices that can regulate their optical properties actively in response to external temperature changes. Due to their simple structures and as they do not require other additional energy supply devices, they have great potential in building energy-saving. However, conventional thermochromic smart windows generally have problems with high response temperatures and low response rates. Owing to their great effect in photothermal conversion, photothermal materials are often used in smart windows to assist phase transition so that they can quickly achieve the dual regulation of light and heat at room temperature. Based on this, research progress on the phase transition of photothermal material-assisted thermochromic smart windows is summarized. In this paper, the phase transition mechanisms of several thermochromic materials (VO2, liquid crystals, and hydrogels) commonly used in the field of smart windows are introduced. Additionally, the applications of carbon-based nanomaterials, noble metal nanoparticles, and semiconductor (metal oxygen/sulfide) nanomaterials in thermochromic smart windows are summarized. The current challenges and solutions are further indicated and future research directions are also proposed.

The incidence of smart windows in building energy saving and future climate projections

The ongoing climate crisis leads to develop smart communities with zero net emissions, and the Responsive Building Envelopes (RBEs) have a crucial role for the goal to be achieved. In this frame the smart windows are promising building envelope solution. With respect to conventional static windows, on one hand they could reduce the building thermal loads and therefore lead to an energy saving and to an improvement of the thermal comfort, on the other hand they could reduce the possible glare, improving the also the visual comfort. There are some smart windows based on widespread technologies and deepen investigated in the scientific literature, such as the electrochromic solution, but there are some others, such as liquid crystal devices, not really investigate, or characterized only by means of simulative analysis, often without calibrated models with experimental data. Thus, the present study aims to investigate, under experimental and numerical point of view, an electric-driven window with liquid crystal technology installed in a full-scale facility located in a Mediterranean climate. A calibrated numerical model is carried out and different windows control logics and future climate projections (to 2050s and 2080s) are analyzed. Among different control logics, the one depending on daylight illuminance level on the work plane shows the best performance, with a total energy saving (lighting and cooling) of -3% with respect a static window in clear state.

Performance evaluation of a novel rotatable dynamic window integrated with a phase change material and a vacuum layer

A glass window filled with a phase change material (PCM) can effectively increase the thermal inertia of a building envelope and achieve peak load transfer. However, conventional PCM windows have low energy efficiency, and the PCM layer has a risk of overheating. To improve the building energy efficiency and avoid the overheating of PCM windows, a new type of rotating dynamic PCM window (DPCMW) was designed in this study. The window comprised a PCM layer and a vacuum glass layer. The DPCMW could adjust the relative position of PCM and vacuum glass layers according to the time; thus, the heat flux direction could be changed to reduce the building load. A theoretical model of the DPCMW was established and verified. The performance of the DPCMW was investigated under the Cfa climate, and the effects of the phase transition temperature, PCM layer thickness, and PCM phase transition temperature range on the performance was discussed. The results indicate that the performance of the DPCMW exceeds that of a static PCM window (SPCMW) in both winter and summer. The DPCMW reduces the heating load relative to the SPCMW by 12.40% in winter and reduces the cooling load relative to the SPCMW by 93.79% in summer. The DPCMW reduces the annual building load by 28.70% relative to the SPCMW. Additionally, the optimal phase transition temperature is 23–25 °C. The thicker the PCM layer, the better the energy-saving effect, and the optimal phase transition temperature range is 19–25 °C. This study provides a theoretical basis for the application of the DPCMW.