Retrofit window energy management system for dynamic control of energy flow through building windows

Abstract

We provide a retrofit window insulation system that achieves an extremely low solar heat gain coefficient (SHGC) of 0.10 or less. [Solution] The retrofit window insulation system of the present invention is an ultralight, ultratransparent low-e polymer window cover (e.g., a Mackinac WEMS unit) combined with a mechanically deployable solar screen and / or louvers to provide optional shading for adjustable control of daylight illumination and solar heating. A spectrally selective coating on the louvers containing a phase change material (PCM) for storing daytime heat is particularly efficient. Placing a reflective film on the outward-facing surface of the louvers reflects sunlight while simultaneously emitting thermal radiation through the Earth's atmosphere to the cold regions of space. When the louvers are placed between the retrofit window insulation system and the existing window glass, the air gap between the window and the retrofit window insulation system warms up, and thermal energy is stored in the PCM. As sunlight weakens in the evening, the thermal energy stored in the PCM is transferred into the building interior.

Description

Technical Field

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 468,743, filed May 24, 2023. The disclosure of the provisional patent application is hereby incorporated by reference in its entirety for all purposes.

[0002] The present invention generally relates to highly energy-efficient windows and retrofit fixtures, and more particularly to a dynamic shading system for adjustably controlling daylighting and solar heating.

Background Art

[0003] Secondary window fixtures are a cost-effective and efficient way to improve the thermal performance and occupant comfort of a building without replacing the building's windows. Secondary windows are attached to the inside or outside of an existing window frame or building wall and function by creating an insulating air pocket between the existing window and the new secondary window, thereby significantly reducing air leakage and heat transfer, resulting in significant energy savings.

[0004] Secondary window fixtures are available in various forms, such as storm windows, double and triple-pane IGU-like units, rigid or suspended polymer films within the frame, all of which provide varying degrees of insulation value and heat loss reduction.

[0005] The addition of a low-emissivity (low-e) coating to secondary window fixtures is known to improve their performance by minimizing the amount of ultraviolet and infrared light that can pass through the glass without sacrificing the amount of visible light that passes through.

[0006] In the ongoing efforts to find ways to reduce greenhouse gas (GHG) emissions to mitigate global warming, energy efficiency has become a critically important concern in the construction industry. To optimize the energy efficiency of window systems, it is becoming increasingly important to operate these systems dynamically to cope with the constantly changing environmental conditions outside the building, including but not limited to daily temperature variations and hourly variations in solar exposure due to the Earth's rotation, cloud cover, etc.

[0007] In this regard, solar exposure results in solar heating (SH) inside the building. During the winter heating season, this SH functions as another source of internal energy (IE), similar to human presence, lighting energy, plug load energy, etc., providing heat to the building interior that the building's heating, ventilation, and air conditioning (HVAC) system does not need to supply. This is beneficial for reducing the heating costs of operating the HVAC system during the winter heating season. However, during the summer cooling season, the IE (IE solar ) created by the sun adds heat to the building interior, and the HVAC system needs to discharge this heat to the external environment, resulting in increased heating costs.

[0008] When it comes to how windows should function, energy cost is not the only consideration; the comfort and well-being of the occupants are also important. Excessive natural light, such as when sunlight shines directly through the window, can cause uncomfortable glare. Such glare must be controlled in all seasons. Traditionally, excessive solar exposure has been controlled by internal window treatment devices such as curtains, shades, Venetian blinds, louvers, etc. Window treatment devices also provide some insulation from external weather conditions.

[0009] When it comes to controlling energy use, the problem isn't simply controlling the amount of energy flowing into a building, but controlling when that energy is used. In modern utility-scale grid delivery systems, a major concern is controlling "peak loads"—situations where demand is extremely high at specific times of the day, requiring utility companies to bring other assets (e.g., their "peak-load power plants") into operation to meet that demand. These other assets often have high operating costs, lower inherent thermodynamic efficiencies than "base plants," resulting in proportionally higher greenhouse gas (GHG) emissions, and they must respond quickly to minute-by-minute changes in load. If these peak-demand loads can be "shifted" to off-peak hours, the overall grid efficiency improves, and GHG emissions decrease.

[0010] Incorporating phase-change materials (PCMs) into building materials for energy management is being actively explored as a method of storing heat and releasing it during the latter half of the day or at night after the peak demand period has passed. Some conventional secondary window fixtures incorporate PCM-filled louvers in an attempt to further improve their function. Louvers heat up when exposed to solar radiation. While louvers can block direct solar heating through transmission, heat generated by absorption can easily flow into the building's interior. This is a fundamental limitation that prevents a decrease in the solar heat gain coefficient (SHGC). The solar heat gain coefficient (SHGC) is the percentage of solar radiation entering a building through a transparent window or door, ranging from 0 to 1. A lower SHGC results in less heat transfer and better insulation. This is an important factor in a building's overall energy efficiency and thermal performance.

[0011] In addition to "load shifting" from peak to off-peak periods, "load shedding," which simply reduces the load, is another strategy to improve grid energy efficiency. By reducing the overall load during peak demand periods, utilities can rely on base plants for longer periods, and as a result, they can delay the start of operation of peak-load plants for longer. Base plants have higher inherent thermodynamic efficiency than peak-load plants, so they emit less GHG for the same amount of electricity supplied. Furthermore, reducing the base load automatically leads to a reduction in GHG emissions because base / peak plants simply reduce their output.

[0012] Regarding the reduction of window loads, the concepts of light shelves and solar shading have been proposed in the field. A light shelf is a horizontal surface that reflects daylight into the ceiling or deeper into the interior space, reducing power consumption by supplementing electric lighting. However, light shelves must be positioned above eye level. Other known concepts, such as PCM-filled louvers and solar shading, are not optimal in their existing forms because their implementations are not designed at a system-wide level to maximize their capabilities across a wide range of climate zones, or even within specific climate zones, across hourly variations in weather and sunlight conditions.

[0013] The Mackinac Technology Company ("Mackinac"), based in Grand Rapids, Michigan, has developed an energy-efficient retrofit window fitting capable of providing thermal insulation performance exceeding R-6, and plans to commercialize it under its Window Energy Management Systems (WEMS) ("WEMS Unit") (WEMS is a trademark, hereinafter the same). The thermal insulation performance of the WEMS Unit can be improved to exceed R-7 when the unit has double-pane glazing.

[0014] To achieve this high level of thermal insulation, each WEMS unit features a flexible low-e coated polymer pane held taut by a rigid frame. The polymer pane is coated on at least one side, preferably both sides, so that a double-pane embodiment has four coated surfaces. The low-e coating used by Mackinaw has high transparency to visible light due to its anti-reflective design, so the unit still maintains a visible light transmittance of over 80%. Advantageously, this low-e coating blocks almost all ultraviolet and infrared thermal energy while being color-neutral, transparent, and anti-reflective to visible light.

[0015] While basic WEMS units are efficient, it is still advantageous to be able to dynamically control the energy flow from windows into the building, thereby influencing both load shifting and load shedding components. This is particularly important in the summer cooling season and in southern climates, where sensible heating is high, cloud cover is low, and solar heating is high, all of which place a heavy burden on HVAC systems. [Overview of the project] [Problems that the invention aims to solve]

[0016] The present invention aims to solve the problems associated with the background technology. [Means for solving the problem]

[0017] Mackinaw has found that integrating solar shade (SS) fabrics in the form of roller shades or screens, and / or louvers, with Mackinaw's low-e radiation (low-e) WEMS units, as detailed below, results in a far greater overall improvement in energy efficiency than operating the louvers and / or shades alone or using the WEMS units alone. In this specification, this combination is referred to as the “Energy Positive WEMS Unit.” With only minor modifications to accommodate different climate zones, the Energy Positive WEMS Unit of the present invention can be adapted to control energy flow into and out of a building, simultaneously influencing both load shedding and load shifting.

[0018] According to the present invention, low-e WEMS units, such as shades and louvers, preferably PCM-containing louvers, more preferably PCM-containing louvers with the light redirecting coating described herein, are superior in performance and function to any known prior art primary and / or secondary window fixture combinations incorporating or using louvers, PCM-containing louvers, shades, blinds, or light shelves. The superior results achievable by the energy-positive WEMS units of the present invention are shown in Table 4 below, comparing their efficiency to several known prior art secondary fixtures or retrofit window insulation systems.

[0019] A basic retrofit window insulation system, referred to herein as a WEMS unit, has two main components: a pane and a casing structure. The pane typically consists of glass, a polymer film, or a combination of one or more layers of glass and / or polymer, with one or more of the glass or polymer films having a low-e emission (low-e) coating on at least one side, preferably both sides, and is bonded or adhered to a rigid frame. In some cases, the rigid frame is installed within a casing structure, such as a stainless steel frame with grooves for supporting the pane. Gaskets can be used to create a porous seal around the unit. As a retrofit system, the entire unit is installed in or near existing window frames or walls, either inside or outside a building.

[0020] To achieve high thermal insulation performance, the WEMS unit utilizes the fundamental principles of multi-layer insulation used in protecting spacecraft. Low-e radiation surfaces on both sides of each polymer pane reflect infrared thermal energy in stages, limiting heat transfer to conduction and convection through the air, giving each air gap within the unit an R-value per inch of thickness approximately the same as that of 1-inch thick foam insulation. The gap spacing between panes in the WEMS unit is carefully selected to optimize the minimum combined transport of radiation, conduction, and convection.

[0021] The double-pane WEMS unit adds R-5 to the thermal insulation value of any existing glass window. Integrating solar shade fabric into the WEMS unit provides dynamically adjustable control of the solar heat gain coefficient (SHGC) from SHGC 0.65 to SHGC 0.10. However, during testing, it was discovered that absorbed solar energy generates heat within the air gap between the glazing and the WEMS unit. To control the heat generated within the air gap between the glazing and the WEMS unit, coatings or fabrics in different shades ranging from white to dark charcoal can be applied to one or both sides of the shade or louver panel. In this example, the louver can be rotated to expose either the dark or light side, or angled so that only a portion of the sunlight is exposed to the desired side. In this way, the temperature of the air gap can be effectively controlled.

[0022] In one specific example, reflective tape or film is placed on the outward-facing surface of a louver panel positioned between the WEMS unit and the existing window glass. This film can be a reflective tape or film such as metallized tape (aluminum tape, for example).

[0023] Another advantageous example is the dual-mode reflective film developed by SkyCool Systems, Inc. of Mountain View, California, and sold under the registered trademark Skycool. Skycool® film not only exhibits high reflectivity to sunlight but also emits heat radiation very well into the cold space through the Earth's atmosphere.

[0024] Advantageously, this dual-mode film not only reflects sunlight during the day, preventing the lower surface from overheating, but also emits infrared heat towards the cooler air. This keeps the panel and the fluids flowing through it, such as PCM, at a low temperature. This technology is further described in the following patent publications owned by Skycool Systems, Inc.: U.S. Patent Application Publication 2021 / 0219463, U.S. Patent Application Publication 2020 / 0333047, U.S. Patent Application Publication 2020 / 0208854, U.S. Patent Application Publication 2019 / 0375946, and U.S. Patent No. 7,503,971.

[0025] Retrofit window units incorporating reflective tape or film on the outward-facing surface of the louvers may not comply with building codes if the tape or film is too glossy. Applying a thin, example less than 5 mil thick, spectrally selective coating to the glossy surface of the tape or film solves this problem. For example, a diffuse spectrally selective coating could be made of TiO x A transparent polymer incorporating this material can be used, and in preferred embodiments, other fillers such as microbubbles or glass spheres may be further incorporated to achieve a matte finish. The coating is preferably applied by electrostatic spraying or air spraying.

[0026] Experiments were conducted to confirm that applying a diffusion coating to reflective tape or film does not interfere with the reflective properties of aluminum tape or Skycool® film.

[0027] For example, further efficiency can be achieved through dynamic shading using the thermal storage technology disclosed herein, which in some embodiments incorporates an adjustable louver shade filled with a phase-change material (PCM) between the existing glass and the installed WEMS unit. In embodiments incorporating the PCM, the PCM adds thermal mass, making the unit more effective in both cold and warm conditions. This novel system improves daylighting, reduces solar heating, improves glare control, enhances insulation in cold conditions, reduces sensible heat gain in warm conditions, manages heat gain due to absorbed solar radiation, and enables load shifting and load shedding.

[0028] The use of louvers to redirect light and PCM-filled louvers for heat storage is well known in the art. The use of dynamic glazing to manage solar heat acquisition is also known. However, Mackinaw has found that the use of phase-change materials in louvers, either alone or in combination with the light redirection coatings disclosed herein, particularly in combination with low-e coated WEMS units, is novel. [Effects of the Invention]

[0029] According to the present invention, the effects of improving daylighting, reducing solar heating, improving glare control, enhancing thermal insulation in cold weather, reducing sensible heat gain in warm weather, managing heat gain due to absorbed solar radiation, and further enabling load shifting and load shedding are achieved.

[0030] Furthermore, the low-e emission coating used in the WEMS unit blocks almost all ultraviolet and infrared thermal energy while maintaining high transparency to visible light (transmittance of over 80%). This allows for extremely high energy efficiency improvements without compromising the building's design or visibility. [Brief explanation of the drawing]

[0031] [Figure 1] This is a perspective view showing a pane assembly for a retrofit window insulation system, i.e., a WEMS unit, according to the present invention. [Figure 2] This is an exploded view showing a casing adapted to hold two pane assemblies. [Figure 3] This is a perspective view showing a dual-pane WEMS unit of the type shown in Figure 2, installed within an existing window frame. [Figure 4A] This is a perspective end view showing an energy-positive WEMS unit installed in an existing window and incorporating a PCM-containing plate. [Figure 4B] This is a perspective end view showing another configuration of an energy-positive WEMS unit installed in an existing window and incorporating a PCM-containing plate. [Figure 4C] This is a perspective end view showing yet another configuration of an energy-positive WEMS unit installed in an existing window and incorporating a PCM-containing plate. [Figure 5] This is a perspective end view showing an energy-positive WEMS unit incorporating multiple optional functions such as solar cells and batteries for controlling shading, illumination, and the angle of the PCM-filled plate. [Figure 6] This is a photographic cross-section showing an energy-positive WEMS unit incorporating a roller shade. [Figure 7] This is a graphical representation of passive heat generation and heat storage, showing the temperature rise in °C as a function of time for energy-positive WEMS units with PCM-filled louvers and basic WEMS units. [Figure 8] This is a cross-sectional view showing a hollow louver plate filled with PCM. [Figure 9]This graph shows the measured reflectance and transmittance [Rss, Tss] of white solar shades with aperture ratios ranging from 1% to 10% as a function of wavelength (nm) measured by a spectrophotometer in the range of UV (190nm) to NIR (2500nm). [Figure 10] Figure 9 is a graph showing the effective [n,k] of the solar shade fabric. [Figure 11] This graph plots the temperature (°F) of the components of various window system configurations (see configurations B-E in Table 1) as a function of the component's position within the window system, assuming the solar shade ( / SS / ) component is a Mermet White solar shade with a 1% aperture ratio. [Figure 12] This graph plots the temperature (°F) of the components for various configurations of the window system (see configurations D and E in Table 1) as a function of the component's position within the window system, assuming the solar shade ( / SS / ) component is a Mermet-colored solar shade with a 5% aperture ratio. [Modes for carrying out the invention]

[0032] Basic WEMS unit The two main components of a basic retrofit window insulation system are a pane assembly 20 (Figure 1) and a casing structure 30 (Figure 2) configured to hold one or more pane assemblies. In the case of the energy-positive WEMS unit of the present invention, the casing structure 30 is configured to hold one or more auxiliary and optional fixtures, such as louvers or shades.

[0033] Referring to Figure 1, each pane assembly 20 consists of at least one polymer film 11 bonded to the front 13 of a rigid frame 12. The rigid frame 12 can be formed from a high-strength polymer (exemplarily pultruded fiberglass). The frame 12 can also be made from a metal such as lightweight stainless steel.

[0034] While the frames and casings are custom-made for retrofit window insulation system applications, the rigid frame 12 is typically rectangular in shape, meaning that the rigid frame 12 has two sets of frame profile sections 15, 15' of different lengths that form a rectangle. The frame profile sections have a thickness (t) measured in the front 13, back 14, and front-to-back directions. The rigid frame 12 is sized to fit within the casing structure 30 (see Figure 2) or is mounted directly to an existing window frame or surrounding wall by any method known to those skilled in the art, such as press-fitting, or preferably with removable or permanent fasteners.

[0035] A second polymer film (not shown in Figure 1) can be bonded to the back surface 14 of the rigid frame 12. The thickness (t) of the rigid frame 12 is advantageous in separating the two films and forming an air gap. If three or more films are desired, multiple pane assemblies 20 can be stacked and secured. In this case as well, the thickness of the rigid frame forms an air gap between the films in adjacent pane assemblies. For optimal thermal performance, a preferred air gap width is between approximately 19 mm and 23 mm, most preferably about 21 mm.

[0036] Figure 2 is a complete exploded view of an add-on window insulation system 10' showing two pane assemblies 20, 20' installed in a casing structure 30. The casing structure 30 comprises a horizontal header 31 (upper), two vertical supports 32 and 33, and a horizontal support 34 (lower), which in this embodiment form a rectangular structure supporting the pane assemblies 20, 20'. The inner surfaces of the aforementioned elements constituting the casing structure 30 have grooves 37 and 38 configured to receive the two pane assemblies.

[0037] Naturally, the casing can be configured to hold three or more pane assemblies by adding grooves. Alternatively, a single groove can be wide enough to accommodate multiple pane assemblies by using spacers (not shown) to separate the pane assemblies and form an air gap. As shown in Figures 5 and 6, the casing can be configured to accommodate one or more auxiliary fixtures in addition to the pane assemblies, resulting in an energy-positive WEMS unit according to the principles of the present invention.

[0038] Further details of exemplary pane assemblies and casings of a basic WEMS unit can be found in jointly pending U.S. Patent Application No. 17 / 876,999, assigned to the present applicant, filed on 29 July 2022, and published on 16 March 2023 under publication number US-2023-0084137, the disclosures of which are incorporated herein by reference.

[0039] Figure 3 is a cutaway perspective view of a double-pane WEMS unit of the type shown in Figure 2, installed within the frame of an existing window. Referring to Figure 3, the pane assembly 200 includes two low-e coated polymer films 201, 201 within a rigid frame 202, which is in the form of a U-shaped casing structure 203u. A gasket 204 seals the perimeter of the assembly. In this example, the pane assembly 200 is installed in the frame 101 of an existing window 100, which is a single glass pane 102. An air gap 207 is formed between the outer surface 206 of the polymer film 201 and the inner surface 106 of the window pane glass 102.

[0040] The following are examples of polymers suitable for constructing panes of the type of WEMS unit used in the implementation of the present invention. The polymer film provides a substrate for depositing a low-e emission coating required to achieve the desired energy performance. In this specification, the term “low-e emission polymer film” refers to the coated polymer.

[0041] The polymer substrate film should have a thickness ranging from 5 mil to over 20 mil and have low haze (less than 1%). In a preferred embodiment, the polymer is flame-retardant.

[0042] Low-e emission polymer films have a low-e emission coating, which may be a laminated layer of metal oxide or silver, as is known in the art. As used in the examples herein, a low-e emission coating that is color-neutral and achieves a visible light transmittance of more than 90% with good low-emission performance in the long-wave infrared (thermal) region has been developed by Mackinaw.

[0043] TPU In one example, the polymer film 11 (Figure 1) is a thermoplastic polyurethane (TPU) with a low-e emission coating that exhibits high reflectivity to infrared thermal energy but is transparent to visible light. TPU is available from commercial suppliers, one specific example being Huntsman Corporation's KRYSTALGRAN® PE501-200 DP TPU. Naturally, other polymers such as polycarbonate or polyesters such as PET can also be used as the base film.

[0044] ETFE Another polymer film that can be used for pane assemblies is ETFE, a copolymer of ethylene and tetrafluoroethylene, which is commonly used in building applications and is commercially available. As a specific exemplary example, this fluoropolymer film is available from Saint-Gobain Performance Plastics under its trademark Chemfilm® ETFE-E2. Saint-Gobain also supplies ETFE films with a proprietary "C-treatment" on one side to facilitate adhesion of the film to rigid frames.

[0045] Another example of an ETFE film suitable for use in the implementation of the present invention is disclosed in jointly pending international patent application PCT / US21 / 43343, which has been assigned to the present applicant and published as International Publication No. 2021 / 258083 on 23 December 2022, and which disclosure is incorporated herein by reference. This unique ETFE film, developed by Mackinaw, has a haze of less than 1%, which is lower than that of standard ETFE having a haze of more than 10%.

[0046] Silicone rubber A recent discovery is that panes can be fabricated from silicone rubber by applying a low-e emission coating to commercially available transparent calendered silicone sheets. The low-e emission coating can be achieved, as is known to those skilled in the art, using a batch-type vacuum deposition machine or, preferably, a semi-continuous high-volume coating machine.

[0047] Low-e emission (low-e) coatings using metal oxides require high-temperature annealing. However, annealing damages silicone rubber films. We have found that a fiber laser can concentrate energy pulses onto individual nanolayers of the coated coating, generating enough oxide to anneal the coating without damaging the silicone substrate.

[0048] Example of an energy-positive WEMS unit louver Using the WEMS unit of the type described above, an energy-positive WEMS unit can be fabricated in accordance with the principle of the invention described herein.

[0049] Figures 4A to 4C show a cutaway perspective end view of the energy-positive WEMS unit 400, more specifically, a double-pane assembly 200 (see Figure 3) incorporating two low-e emission (low-e) coated silicone rubber panes 201, 201' within a rigid frame 202, installed within a window frame 100. In some embodiments, louvers 300, which may be filled with PCM (not shown in this figure), are positioned between the existing glass 101 and the installed WEMS unit 200. In this example, the energy-positive WEMS unit 400 is positioned on the inside of the existing window. As will become apparent from the discussion herein relating to Figures 11 and 12, there are advantages to positioning the energy-positive WEMS unit on the outside of the existing window.

[0050] In this example, the louvers 300 are "bi-tinted," meaning that, for example, the outward-facing side 301 is white or light-colored, while the opposite side of the louvers, i.e., the inward-facing side 302, is dark-colored. In operation, the louvers can be tilted by a well-known mechanism. Like Venetian blinds, the louvers can be fully retracted to minimize their visual or energetic impact on the window, or they can be pulled down and opened to various angles.

[0051] Solar heating and daylighting can be controlled by adjusting the louver pitch. By angling the louvers as shown in Figures 4A and 4B, glare is reduced, and the light-colored reflective surfaces of the louvers act like mini light shelves, allowing sunlight to be redirected upwards towards the ceiling for daylighting, as shown in Mode 400A, which is flat, i.e., fully open. In Mode 400B, the louvers are angled to reflect or absorb a controlled proportion of the solar energy that strikes the white outward-facing surface 301. In Mode 400C, the louvers are completely closed to prevent light from entering the interior of the building. This creates an additional pane for maximum insulation, while the window becomes opaque for privacy and provides darkness for sleep.

[0052] In an advantageous embodiment, the light-colored surface 301 is reflective and, exemplary, is created by placing a metal film or tape, such as aluminum tape or Skycool® film, on at least the outward-facing surface. The inward-facing surface 302 may be covered with the same material, or preferably with an absorbent material. Details of the spectrally selective surface coating will be described later.

[0053] In another advantageous embodiment, the louvers are hollow and filled with PCM. Referring to Figure 8, a cross-section of a hollow louver plate 305 shows an elliptical opening 307 into which PCM 309 can be filled. Long hollow louver plates are commercially available. These plates are extruded polycarbonate profiles that are lightweight for compatibility with mechanical systems, yet rigid enough to withstand deflection when suspended across the width of a window. The hollow louver plates are sealed to prevent leakage.

[0054] Ideally, the PCM filling the louver panels should melt at 27-29°C and have a thermal capacity of 75 kWh / m³. 3It should have an energy density and supercooling of 2°C. Examples of PCMs suitable for use in the implementation of the present invention include paraffin waxes or organic hydrated salts known in the art. PCM products are commercially available, for example, from Rubizerm GmbH in Berlin, Germany.

[0055] Makinnaugh has developed a proprietary inorganic hydrated salt composite PCM that meets these standards and possesses superior thermal reliability. 75 kWh / m 3 The proprietary Mackinac® PCM, with its high energy density, is well-suited for the proposed application. Measurement data from solar simulation experiments shows that a Mackinac PCM-filled louver, approximately 5 mm thick, reflects a significant portion (at least 80%) of solar radiation, even on the hottest days in Phoenix, Arizona, and absorbs all of the residual solar heat gain and sensible heat.

[0056] Figure 7 is a graphical representation of passive heat generation and heat storage in °C over time, measured in the air gap between the existing window glass and the WEMS pane (see, e.g., Figure 3). An energy-positive WEMS unit with PCM-filled louvers and a basic WEMS unit without PCM or louvers were heated with a solar lamp for 5 hours to simulate daytime, and then the lamp was turned off to simulate nighttime. Trace (1) shows the data for the energy-positive WEMS unit. As shown in Trace (1), the temperature of the air gap rose to a maximum of 41°C and dropped sharply when the heat lamp was turned off at the 5-hour mark. The energy-positive WEMS unit then slowly released the stored heat over the next 10 hours. Trace (2) shows the results for the basic WEMS unit. In this case, the maximum rise in the gap temperature was only 5°C above the ambient temperature (approximately 23°C). Three hours after the lamp was turned off, the gap temperature returned to the ambient temperature.

[0057] Spectroselective surface PCM-filled louvers used in conjunction with WEMS units yield excellent results, as shown in Figure 8. However, even better results can be obtained by applying a spectrally selective coating to one or both flat, planar surfaces of the louvers.

[0058] Referring, for example, to Figure 4B, the elongated hollow plates 41, 41' have upper surfaces 51, 51' and lower surfaces 52, 52', which are clearly shown in Figure 4D. The upper surfaces 51, 51' have a specular reflective coating 53 on the outward-facing side of the louver plate. The lower surface (not clearly shown in this figure), which faces inward, is also coated or covered with a reflective or diffuse reflective material 54 in some exemplary embodiments.

[0059] For the present invention to be useful, the diffuse specular reflecting material must reflect 80% of both visible light and near-infrared energy (wavelength 350-2,500 nm). Naturally, these materials must be aesthetically pleasing when applied to louvers and not cause discomfort to occupants.

[0060] Diffused mirror coating materials are liquid polymers, and their optical properties can be adjusted by changing the ratio and particle size distribution of fillers such as titanium dioxide (TiO2), calcium carbonate (CaCO3), and various other fillers, pigments, and glass or polymer microbubbles. For optimal energy performance, different levels of absorption and thermal gain are required for different climate zones.

[0061] Examples of diffusion spectroscopically selective reflective materials useful in implementing the present invention are shown below.

[0062] Coating for louvers / shades The reflective coating for the louvers (or shades) used to control the heating of those elements is low [A sol It should have ].

[0063] As an example of a coating, the following materials are low enough to be suitable as a reflective coating [A sol It has ]. Naturally, other commercially available or future-developed coatings with the necessary properties are also within the scope of this invention. These exemplary coatings were developed primarily for daytime sky-cooling applications. However, their very high [R sol ] is our low [A sol Suitable for solar shading applications.

[0064] 1) 3M products that use hollow glass microbubbles as additives to standard paint formulations (see Kevin Rink et al., "Evaluation of glass bubbles for solar heat reflection in waterborne acrylic elastomeric roof coatings," Coatings Tech, p. 40 (September 2016)).

[0065] 2) A polymer-based hybrid metamaterial with randomly distributed SiO2 microsphere inclusions, developed by researchers at the University of Colorado (see Yao Zhai et al., "Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling," Science, Vol. 355, Pages 1062–1066 (2017)).

[0066] 3) Hierarchical porous poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-HFP)HP) coatings (referred to herein as "F polymers") developed by researchers at Columbia University (see J. Mandal et al., "Hierarchically porous polymer coatings for highly efficient passive daytime radiative cooling", Science, 10.1126 / science.aat9513 (2018). See also Supplementary Material 10.1126 / science.aat9513 (2018), U.S. Patent No. 10,386,097 issued on August 20, 2019, and U.S. Patent Application Publication No. 2018 / 0180331 published on June 28, 2018).

[0067] 4) Surface coatings developed by SkyCool Pty Ltd. (see, for example, U.S. Patent No. 7,503,972 issued on March 17, 2009 in the name of Wojtyslak et al.).

[0068] All of these coatings are designed to function in the following ways. 1) Reject incident solar radiation at UV-VIS and NIR wavelengths as much as possible, thereby achieving a high "solar reflectance" [R sol and, conversely, a low solar absorptance [A sol . 2) Maximize the thermal emissivity [e th at infrared (IR) wavelengths (approximately 7 - 14 μm) where air is nearly transparent to this infrared energy.

[0069] By achieving a high [R sol , the coating prevents the louver / shade from being heated by midday solar exposure due to its low [A sol performance. A high [e thBy achieving this, the temperature of the thermal radiation from the sky at these infrared (IR) wavelengths is significantly lower than the ambient temperature, allowing the coating to be effectively cooled to below ambient temperature. Therefore, the coating emits a lot of energy but receives very little from the sky. Thus, by receiving less heat from the sun and more thermal radiation than they receive from the sky, these coatings achieve passive cooling of the surface even when exposed to solar radiation during the day.

[0070] Solar shading fabric In addition to louvers, another option that can be incorporated into an energy-positive WEMS unit is solar shading fabric, which in a typical implementation is a roller blind. Solar shading fabric is a commercially available sheer fabric offered in a wide range of colors and open weaves to enhance outdoor visibility. Open weaves have what is referred to herein as an "opening ratio," ranging, for example, from 1% to 10%. Typical solar shading fabrics are available in colors that can vary, for example, from pure white to very dark charcoal, intended to accommodate the aesthetic preferences of the customer. In most configurations, the roller blind or shade is pulled down from top to bottom using a roller shading mechanism, which is well known in the art.

[0071] Examples of solar shading fabrics that can be used in the implementation of the present invention are glass / vinyl composites, and specifically include solar shading fabrics sold by Phifer Incorporated in Tuscaloosa, Alabama, Mermet USA in Cowpens, South Carolina, and Rollease Acmeda / USA Division in Stamford, Connecticut. Extensive measurements, tests, and modeling of these fabrics have been carried out with the aim of integrating these solar shading fabrics into the energy-positive WEMS unit of the present invention in order to achieve desired energy-related objectives of the final product.

[0072] The examples described above are illustrative, and any SS fabric having these characteristics can be used in carrying out the present invention.

[0073] The solar heat gain coefficient (SHGC) is an index that quantifies how much of the solar radiation from the sun entering outside a window is transported through the window into the interior space of a building. SHGC is defined by total solar heating (SH t ) is the sum of the following two components: SH t = SH1 + SH2(1) Here, SH1 represents solar energy that indirectly enters the interior space of a building through the absorption of solar energy by all envelope components (e.g., walls, roof, etc.), while SH2 represents the direct transmission of solar energy through transparent envelope components, specifically windows.

[0074] Different solar shading materials have different dependencies on the indirect and direct components of solar heating, meaning the dominant component can change depending on the material's absorption properties. While it may seem obvious that darker materials or fabrics will heat up more than lighter ones, the real question is whether that heat reaches the interior space of the room. This counterintuitive aspect depends on the specific design of the window or shading system. The solar shading strategies and designs of the present invention allow for dynamic control of when and where thermal energy is directed. Even with the use of existing commercially available shading fabrics, the systems of the present invention achieve unprecedentedly low SHGC values, enabling a significant reduction in air conditioning energy to reduce demand load.

[0075] To quantify these solar heating (SH) processes, we first focus on the solar shading fabric itself. We have conducted extensive testing on Mermet's fabrics. These fabrics have a wide range of colors from white to very dark charcoal, and aperture ratios ranging from 1% to 10%. We have found that these fabrics have extremely high solar reflectance and extremely low solar absorptive coefficients [R], similar to the daytime cooling materials or reflective coatings mentioned earlier. sol , A sol This indicates that it does not have [ ].

[0076] To evaluate the suitability of the solar shading fabric for use in the present invention, first the reflectance and transmittance [R SS , T SS The measurement of [ ] is performed. David V. Two's "Obtaining optical constants of thin Ge x S y Te zUsing the method established in "films from measurements of reflection and transmission" (J. Vac. Sci. Technol. A, Vol. 17, No. 4, p. 1854 (1999), its disclosure incorporated herein by reference), the effective optical constants, expressed by refractive index (n) and extinction coefficient (k), are numerically solved. These [n, k] values ​​allow the solar shade to be modeled similarly to any other optical panel, enabling the insertion of the shade at various positions within a wider window system to determine the [RW, TW, AW] of the window system. A wider window system is defined as an existing window with an energy-positive WEMStm unit added.

[0077] This allows us to obtain the visible "VIS" reflectance and transmittance [Rvis, Tvis], which are [RW, TW] weighted by the human visual response, and the aforementioned [R], which incorporates [RW, TW] and is weighted by the 1.5-air mass (AM1.5) solar spectrum. sol , T sol , A sol This will make it possible to calculate various indicators that are important to the window industry, such as quantity.

[0078] Figure 9 shows the [R] of Mermet "White" solar shading fabric for aperture ratios ranging from 1% (trace 1) to 10% (trace 4) (aperture ratios of 3% and 5% are located in between). SS , T SS The measurements are shown. As the aperture ratio increases, [R] decreases and [T] increases. In these white fabrics, the total [R+T] signals are all substantially the same and close to 0.80. Here, since the absorption rate [A] is defined as follows, A = 1 - (R + T) (2) When the total [R+T] = 0.80, the absorption rate is 0.20. This absorption rate is not particularly low compared to the daytime cooling materials and coatings mentioned above.

[0079] Figure 10 shows the effective [n,k] of Mermet's solar shading fabric, and the high [R] of white (1%). SS A value greater than 0.70 is converted to a very high effective [n] of over 11.0. As the opening ratio increases, [n] decreases, and in trace (4) showing white with an opening ratio of 10%, [n] exceeds 7.0. As the tinting of the fabric becomes darker, [n] decreases further. In trace (5) showing linen-colored fabric (e.g., buff or off-white) with an opening ratio of 5%, [n] is around 5.0, and in the very dark charcoal with an opening ratio of 5% shown in trace (6), [n] is below 2.0. Regarding the extinction coefficient, in white fabric, a slight increase in [k] is observed with increasing opening ratio, but in linen (5%), [k] increases significantly, and in charcoal (5%), [k] increases strongly.

[0080] Since the effective [n,k] of the solar shading fabric being evaluated was obtained, the solar shading can be assembled into various complete window configurations, with existing glass panels designated as / G / , WEMS unit panels as / W / , and solar shades as / SS / . We examined various configurations A through E listed in Table 1.

[0081] [Table 1]

[0082] As is evident from the data shown below, these solar fabrics have a high A sol Regardless of their characteristics, they can be used within the energy-positive WEMS system of the present invention.

[0083] All properties [R t , T t , A t , A (j) ](Here A (j)Once the absorptivity of each (j)-th panel is obtained, a complete thermal-optical energy calculation is performed to first determine how much heating each panel experiences, and then to determine whether this heat is transferred to the external or internal environment.

[0084] The table below shows the calculated [R sol , T sol , A sol ] indicates the value, where [A sol ] represents the total absorption rate of all panels, i.e., the value from [At].

[0085] Referring to Table 2, the flow inside [A sol The percentage of ] is "fA sol It is specified as "_IN". SH_1 is equal to the absorbed solar energy that actually enters the building, and in this specification it is referred to as "A sol It is specified as "_IN". The SH_2 component is simply [T sol It is equal to ], and the sum of the SH_x component and SH_t represents SHGC.

[0086] [Table 2]

[0087] Table 2 shows the solar radiation performance of Mermet White fabric with an aperture ratio of 1% for configurations A to E, which are described in more detail in Table 1A. For reference, in a standard double-glazed window (configuration A), absorbed solar radiation flowing into the interior (A sol ) ratio (fA sol _IN) is only 0.356, which is about one-third of the total absorbed solar energy. The reason this ratio is less than half (0.50) is that there is forced convection (i.e., wind) in the external environment, while there is only natural convection in the internal environment. If forced convection is present, fA sol A value of _IN being approximately one-third represents a symmetrical or balanced "thermal stack." In this configuration, A solBecause it is relatively small (0.130), the actual absorbed energy component SH1 that flows into the internal air is only 0.046, while the direct component SH2 is T sol The ratio is 0.734, and direct components overwhelmingly dominate, accounting for 94% of the total SHGC.

[0088] Standard shade implementations, i.e., standard double-pane windows with fabric shades on the front (configuration B, / G / G / SS / ), slow down the flow of heat to the outside, fA sol _IN becomes a more balanced 0.495. In other words, this configuration has a high A sol Where absorption is directly adjacent to the internal environment, it creates an unbalanced thermal stack that cancels out the effects of forced convection from the external environment. As a result, SH1 is now dominant over SH2, with SH1 accounting for 73% of SHGC(SHt). 0.391 A sol Although it is much larger than configuration A, R sol The increase to 0.537 is the main reason why SHt of 0.265, which is lower than that of configuration A, is achieved.

[0089] In configuration C, a known but non-standard configuration in which a solar shade is inserted between two glass plates, R sol , T sol , A sol The value of is almost the same as in configuration B. However, in configuration C, the thermal stack becomes symmetrical again, so the ratio fA sol _IN becomes 0.326, returning to approximately one-third of the value in configuration A. This explains why SHt decreases to 0.186 in this embodiment.

[0090] Configurations D and E are illustrative of the present invention and, in some cases, are characterized by the use of one or more low-e radiation WEMS panels to create a highly asymmetrical thermal environment by utilizing low-e radiation surface properties to act as a shield that prevents heat generated within the solar shading fabric from flowing back into the internal environment. As can be seen from the data presented herein, for example, a high A of 0.20. sol Even when using very sub-optical (below optimal) solar shading materials to achieve this, configuration E can achieve a low SHGC value of 0.117.

[0091] The WEMS panel incorporated into configurations D and E allows R sol , T sol , A sol The value of will be almost the same as in configurations B and C, but the thermal stack imbalance will be even more pronounced. As a result, for example in configuration E, fA sol _IN is only 0.169. Here, the final A sol _IN (SH1 in Table 1B) is T sol Similar to the extremely low value of 0.057 for SH2 (Table 1B), the value for SHGC(SHt) is 0.060, resulting in a very low value of only 0.117. The SH1 and SH2 components contribute almost equal amounts (51% vs. 49%) to the total SHGC.

[0092] The data in Table 2 demonstrates the advantageous protective effect against high solar absorptivity. Referring to Table 2, solar shading fabrics in shades other than white, provided by Mermet, are used in configurations D and E of the present invention. Comparing white (1%) and white (5%), the main reason for the slight increase in SHt is the naturally occurring higher T when there are more voids (i.e., aperture ratio) through which light can pass unobstructed. sol It is related to this.

[0093] As shown in Table 3, SH1 increases as the tinting level increases, but this is because SH2(T solThe final SHt only increases slightly because it is effectively offset by the decrease in ). In configuration E, for charcoal shades, A sol White (both with an aperture ratio of 5%) A sol It increases significantly, by more than 2.3 times (or 230%), but the increase in SHt of charcoal is A sol This represents only a 1.24-fold (or 24%) increase compared to the overall increase.

[0094] [Table 3]

[0095] The data in Table 3 shows that the configuration devised according to the present invention can contain the heat generated by absorptive solar shading using low-emissivity WEMS panels, thereby confining most of the solar heat to the external environment. This naturally reduces the load on the building's HVAC system by enhancing load reduction.

[0096] In addition to solar shading fabrics that can be incorporated into window systems, such as roller shades or honeycomb shades, other examples of energy-positive WEMS units can be devised within the principles of the present invention. Naturally, the use of louvers, particularly louvers incorporating PCM, is advantageous for shading control. Louvers can be installed horizontally, like Venetian blinds, or vertically, as is known in the art. Energy efficiency can be further enhanced by providing the louvers with coatings and shades that may differ on each side in some examples, as described herein, thereby influencing the heat storage and release operation and function of the PCM.

[0097] Figure 5 is a perspective end view of an energy-positive WEMS unit 500 incorporating several optional functions, such as a solar cell 502 that charges a battery 503 used to power a control device for shading, lighting, and tilting the PCM-filled louver panel 303. In Figure 5, the energy-positive WEMS unit 500 is installed on the exterior of the building, in front of an existing windowpane 101. The casing 30 supports the elements of the energy-positive WEMS unit 500, specifically the solar cell 502, the LED 501, and a mechanism (not shown) for raising and lowering the louver and tilting it at an angle so that the outward-facing surface 301 of the louver can guide sunlight as desired. The casing 30 also holds a first pane assembly 200, which comprises a low-emissivity polymer film 201 within a rigid frame 203, between the existing windowpane 101 and the PCM-filled louver 303. The second external pane (EP) assembly, which includes a polymer film 205 within a rigid frame 203EP, is located on the outer surface of the unit and serves to protect the internal elements from wind and weather.

[0098] Another advantageous option for the energy-positive WEMS unit of the present invention is the addition of sound-absorbing material. Examples include rock wool or other fibrous insulation materials, such as commercially available products sold under the registered trademark Sonozorb by GDC Corporation in Goshen, Indiana. Sonozorb® insulation is a lightweight, durable, high-loft polypropylene acoustic insulation material that creates complex pathways for sound waves. It can be used in a casing (e.g., casing 30 in Figure 2) that holds the WEMS pane assembly (e.g., pane assembly 20 in Figure 1) in place to attenuate sound. Naturally, other products are also available and, in some cases, suitable for use as a film on the inward-facing surface of the louvers (e.g., inward-facing surface 302 in Figure 4C).

[0099] Figure 6 is a photographic cross-sectional representation of an energy-positive WEMS unit 600 incorporating a roller shade. In this figure, the energy-positive WEMS unit 600 is installed in the exterior window frame 101 of an existing window 100, which is a single glass pane 102. Referring to Figure 6, the roller shade comprises a cover (or header) 601 for the roller mechanism 602 and a shading fabric 603, which is a colored shading fabric with some aperture ratio in this example. The pane assembly 200 comprises a first pane assembly of a low-emissivity polymer film 201 within a rigid frame 203, located between the existing window glass 102 and the roller shade fabric 603. A second exterior pane (EP) assembly holds a polymer film 205 within the rigid frame 203EP to protect the interior elements from wind and weather.

[0100] Naturally, an air gap is formed between all elements of the energy-positive WEMS unit 600 and the outer surface 108 of the window glass 102.

[0101] The mechanism for retracting and lowering the slats is located within the header of the WEMS unit and can be any manual mechanism known in the art. For example, a manual mechanism for raising and lowering a Venetian blind in which long slats are bundled together by a cord and raised and lowered by pulling another cord, and opened and closed by rotating a rod or pulling another cord. Similarly, a mechanism for retracting and lowering a fabric solar shade, such as a roller shade mechanism (e.g., 602), is located within the header of the WEMS unit. Naturally, all of these mechanisms can be electrically controlled as known in the art.

[0102] The energy-positive WEMS unit of the present invention can be installed adjacent to an existing window (i.e., inside the window frame) or on a wall, such that an air gap exists between the WEMS unit and the window. Naturally, the WEMS unit can also be installed on the exterior of the building. In the case of casement windows or tilt-and-turn windows, the WEMS unit can be attached to the window frame and move with the window. In the case of double-hung or single-hung windows, a vertical lift mechanism can allow the lower WEMS unit to be stacked on top of the upper WEMS unit. Naturally, the WEMS unit can also be adapted for sliding doors. From the above, it is clear that the energy-positive WEMS unit of the present invention can be adapted to any existing window / door configuration that is currently known or may become known in the future.

[0103] The excellent results achievable with the energy-positive WEMS unit of the present invention are shown in Table 4 below, comparing its efficiency with several known prior art secondary mounting devices or retrofit window insulation systems.

[0104] [Table 4] Winsert Lite and Winsert Plus are high-performance secondary interior window inserts available from Alpen High Performance Products in Louisville, Colorado. Cardinal LoE glass is available from Climate Guard Windows & Doors in Chicago, Illinois.

[0105] Energy-positive WEMS units are part of what is described herein as an "energy-positive window system." The arrangement of glass, solar shading, and WEMS units in this system allows for temperature control of internal components within the system, such as phase-change materials (PCMs), enabling them to function more reliably for storing and releasing thermal energy.

[0106] This energy-positive window system consists of a combination of uncoated panels (typically existing glass panes ( / G / )), solar shade panels ( / SS / ) or louvers (likewise / SS / ) with different shades and aperture ratios, and low-e coated panels ( / W / ) within the WEMS unit. According to this invention, even with very dark-colored (e.g., charcoal) roller shade fabrics, the solar heating effect is substantially decoupled from the solar heat gain coefficient (SHGC). For example, with white solar shade fabric, the effect is 500 W / m 2 Under the same amount of solar radiation, the measured temperature of the / SS / panel is 83°F, while the temperature of the dark charcoal solar shade fabric is 150°F. Nevertheless, the difference in their respective SHGC values ​​is only a slight increase from 0.11 to 0.17.

[0107] By controlling the temperature distribution within the components of an energy-positive window system, it becomes possible to perform work in a general sense within a region of the system. This work can include mechanical, electrical, or chemical actions. The key to enabling such actions is controlling the temperature distribution within the system to create specific or selected regions of controllable high-temperature states. For example, a working material such as a PCM placed within a selected region undergoes a chemical phase change reaction to absorb thermal energy under sunlight irradiation, and then releases that heat as the temperature drops. Without establishing specific temperature conditions within this selected region, the control of the PCM would be left to chance.

[0108] Figure 11 is a graphical representation of the temperature distribution of the configuration shown in Table 1. In Figure 11, the solar shading ( / SS / ) is Mermet White with an aperture ratio of 1%. The environmental conditions for these calculations are indoor / outdoor temperature (T0 / T3) = 70°F / 30°F, wind speed = 10 Mph, and solar radiation incident on the outer surface of the window (#1) = 500 W / m². 2 The component temperatures (°F) are plotted relative to the position (inches) from the outer surface #1 of the first / G / panel, which defines the origin at position 0.0 inch. Position T3 is set to -1.0 inch, and position T0 is set to +1.0 inch beyond the final window surface. The gap temperature is the average of the temperatures of two adjacent components.

[0109] Referring to Figure 11, Configuration B ( / G / G / SS / ), a standard shade implementation where / SS / is the most indoor element, is shown in orange. Configuration B has the highest temperature at 83°F. Generally speaking, the temperature decreases monotonically towards T3 and has a similar gradient when decreasing towards T0. This means that, according to this visual depiction, about half of the absorbed solar energy that heats the / SS / panel flows into the outdoor / indoor environment.

[0110] Configuration C ( / G / SS / G / ), shown in blue, has a solar shade between two glass panes, and the temperature is 75°F. This is somewhat lower than the temperature of the solar shade in Configuration B because there is only one glass pane blocking the flow of heat to the outside. The second glass pane also blocks the flow of heat from the solar shade into the room. In Figure 11, the gradient is virtually flattened, and currently 32% of that heat flows into the indoor environment.

[0111] Configurations D and E represent energy-positive WEMS units according to the present invention. In Configuration D, a single low-emissivity (low-e) panel ( / W / ) is more effective at trapping heat in the solar shade compared to the two glass panels in Configuration C. The temperature of the solar shade in Configuration D reaches 78.2°F, and 22% of its absorbed heat flows into the indoor environment.

[0112] In configuration E, adding a second low-e emission panel raises the solar shade temperature to a further 80.5°F, but only 16% of the absorbed energy reaches the indoor environment.

[0113] Figure 12 is a graphical representation of the temperature (°F) for configurations D and E in Table 1, where the solar shade ( / SS / ) component is a Mermet tinted solar shade with a 5% aperture ratio, plotted as a function of the component's position in the window system. Various tinting options are listed in Table 2. Generally, as the tint of the solar shade darkens, the temperature of the solar shade rises because more heat is absorbed. This is shown in Figure 12, where in configuration D, which has only one WEMS unit panel ( / W / ) to trap heat from flowing into the indoor environment, the white solar shade rises to 80.0°F, while the charcoal shade rises to 140°F. In this comparison, the total solar radiation absorptivity [A] using the white panel is shown. sol ] is 36.2%, of which 22.8% reaches the indoor environment, and the total percentage of absorbed incident solar radiation is 8.2%, i.e., SH1 = 0.082. In the case of charcoal color, [A sol The ratio is a much higher 86.2%, of which only a slightly higher 26.0% reaches the indoor environment, and the total percentage of absorbed incident solar radiation is 22.4%, i.e., SH1 = 0.224.

[0114] Configuration E has two WEMS unit panels to block heat from flowing into the indoor environment. The temperature of the white solar shade rises to 83.0°F and the charcoal shade rises to 149.5°F, but the SH1 decreases to 0.061 and 0.144, respectively.

[0115] The temperature plots shown in Figures 11 and 12 convey only the effect of Type 1 SH1 indirect solar heating. SH1 increases as the shade of the solar shade darkens, but the direct SH2 component decreases as the darkness increases. Therefore, even at the darkest charcoal shade, the total SHt can still be kept below 0.17. Thus, the shade shade can be effectively isolated from the SHGC problem. This demonstrates that when the energy-positive WEMS unit of the present invention is incorporated into a window system, the temperature in a selected area of ​​the window system can be controlled.

[0116] While the present invention has been described in terms of specific embodiments and uses, those skilled in the art can, in light of this teaching, generate additional embodiments without exceeding the scope or departing from the spirit of the claimed invention. Therefore, it should be understood that the drawings and descriptions in this disclosure are provided for the convenience of understanding the invention and should not be construed as limiting its scope. Furthermore, the technical effects and problems described in the specification are illustrative and not limiting. The embodiments described in the specification may have other technical effects and solve other technical problems.

Claims

1. A retrofit window insulation system for an existing window frame or surrounding wall structure, comprising at least one pane assembly, the at least one pane assembly comprising: a rigid frame structure having a front and a back, and a thickness (t) measured from the front to the back; and at least one low-e emission (low-e) coated polymer film bonded to the front of the rigid frame structure.

2. The retrofit window insulation system according to claim 1, further comprising a casing structure that holds one or more pane assemblies and is configured to be attachable to the existing window frame or surrounding wall.

3. The retrofit window insulation system according to claim 2, wherein two low-emissivity coated polymer films are bonded to the rigid frame structure, the second low-emissivity coated polymer film is bonded to the back surface of the rigid frame structure, and the thickness (t) defines an air gap between the two low-emissivity coated polymer films.

4. The retrofit window insulation system according to claim 2 or 3, wherein the low-emissivity polymer film has a low-emissivity coating on both sides.

5. The retrofit window insulation system according to claim 2, wherein the casing structure is further adapted to support elements of a decorative and / or functional nature.

6. The retrofit window insulation system according to claim 5, wherein the decorative and / or functional elements are selected from the group consisting of louvers, solar shades, blinds, or light shelves.

7. The retrofit window insulation system according to claim 6, wherein the decorative and / or functional element is a louver having a profile with a cavity filled with a phase change material, and the profile of the louver has an outward-facing surface and an inward-facing surface.

8. The retrofit window insulation system according to claim 7, wherein at least one of the outward-facing surface and the inward-facing surface has a reflective coating or covering.

9. The retrofit window insulation system according to claim 8, wherein the reflective coating is on the outward-facing surface, and the coating or covering is a metallized tape further comprising a diffusion coating or covering.

10. The retrofit window insulation system according to claim 9, wherein the diffusion coating or covering is a polymer composite that can be adjusted by changing the ratio and particle size distribution of fillers such as titanium dioxide (TiO2), calcium carbonate (CaCO3), pigments, and glass or polymer microbubbles.

11. The retrofit window insulation system according to claim 8, wherein the inward-facing surface is coated or covered with an absorbent material to generate solar heat that can be stored in the PCM.

12. The retrofit window insulation system according to claim 11, wherein the absorbent material is a fabric, wood veneer, or a darker colored coating.

13. A retrofit window insulation system for an existing window frame or surrounding wall structure, comprising at least one pane assembly, the at least one pane assembly having a rigid frame structure having a front and a back and a thickness (t) measured from the front to the back, and at least one low-emissivity coating polymer film bonded to the front of the rigid frame structure, the retrofit window insulation system further comprising a casing structure configured to hold one or more pane assemblies and solar shading components, the casing structure being attached to the window frame such that at least one pane assembly is present between the solar shading components and the indoor air,

Images