WO2015120045A1

WO2015120045A1 - Forced air smart windows

Info

Publication number: WO2015120045A1
Application number: PCT/US2015/014453
Authority: WO
Inventors: Dhairya Shrivastava; Trevor Frank
Original assignee: View, Inc.
Priority date: 2014-02-04
Filing date: 2015-02-04
Publication date: 2015-08-13

Abstract

Certain embodiments pertain to forced air windows and methods of passing air through forced air electrochromic windows. In some cases, a forced air electrochromic window comprises an insulated glass unit comprising a first tinted or tintable lite, a third lite outside the insulated glass unit, a sealing member between the third lite and the first tinted or tintable lite, an interior space formed between the third lite and the insulated glass unit, at least two vent modules configured to control air flow to and from the interior space, and one or more air movement devices. The one or more air movement devices are for actively moving air through the interior space across the first lite to outside the interior space through the at least two vent modules. The air flows between the vent modules and the sealing member through one or more apertures in the sealing member.

Description

FORCED AIR SMART WINDOWS CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims benefit of and priority to U.S. Patent Application No. 61/935,771 titled "FORCED AIR SMART WINDOWS" and filed on February 4, 2014, which is hereby incorporated by reference in its entirety and for all purposes.

FIELD

[0002] Embodiments disclosed herein relate generally to optical devices, and more particularly to windows with one or more electrochromic devices and methods of fabricating thereof. BACKGROUND

[0003] Various optically switchable devices are available for controlling tinting, reflectivity, and other properties window panes. Electrochromic devices are one example of optically switchable devices generally. Electrochromism is a

phenomenon in which a material exhibits a reversible electrochemically-mediated change in an optical property when placed in a different electronic state, typically by being subjected to a voltage change. The optical property being manipulated is typically one or more of color, transmittance, absorbance, and reflectance. One well known electrochromic material is tungsten oxide (WO₃). Tungsten oxide is a cathodic electrochromic material in which a coloration transition, transparent to blue, occurs by electrochemical reduction.

[0004] Electrochromic materials may be incorporated into, for example, windows for home, commercial, and other uses. The color, transmittance, absorbance, and/or reflectance of such windows may be changed by inducing a change in the

electrochromic material, that is, electrochromic windows are windows that can be darkened or lightened electronically. A small voltage applied to an electrochromic device of the window will cause it to darken; reversing the voltage causes it to lighten. This capability allows for control of the amount of light that passes through the window, and presents an enormous opportunity for electrochromic windows to be used not only for aesthetic purposes but also for energy- savings. With energy conservation being foremost in modern energy policy, it is expected that growth of the electrochromic window industry will be robust in the coming years.

SUMMARY

[0005] Certain embodiments described herein generally relate to techniques for passing air over at least one tinted or tintable lite (pane) of a window in order to remove heat and therefore lessen the heat load on the lite. The air, thus heated, may or may not be used as a heat source and/or to generate power.

[0001] Certain embodiments pertain to forced air electrochromic windows. In some cases, a forced air electrochromic window comprises an insulated glass unit comprising a first tinted or tintable lite, a third lite outside the insulated glass unit, a sealing member between the third lite and the first tinted or tintable lite, an interior space formed between the third lite and the insulated glass unit, at least two vent modules configured to control air flow to and from the interior space, and one or more air movement devices. The one or more air movement devices are for actively moving air through the interior space across the first lite to outside the interior space through the at least two vent modules. The air flows between the vent modules and the sealing member through one or more apertures in the sealing member.

[0002] In other cases, a forced air electrochromic window comprises an insulated glass unit comprising a first tinted or tintable lite, a third lite outside the insulated glass unit, a sealing member between the third lite and the first tinted or tintable lite, and an interior space formed between the third lite and the insulated glass unit. The forced air window further comprises at least two vent modules and one or more air movement devices. The at least two vent modules are configured to control air flow to and from the interior space. The one or more air movement devices are configured to actively moving air through the interior space across the first lite to outside the interior space through the at least two vent modules. The air flows between the vent modules and the sealing member through one or more apertures in the sealing member. [0006] Certain embodiments pertain to a method of passing air through a forced air electrochromic window. The forced air electrochromic window comprises an insulated glass unit, a third lite, an interior space between the third lite and a first lite of the insulated glass unit, at least two vent modules, and one or more air movement devices. The method comprises controlling air flow to and from the interior space using the at least two vent modules and actively moving the air through the interior space across the first lite to the outside of the interior space through the at least two vent modules.

[0001] These and other features are described in more detail below with reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS [0007] The following detailed description can be more fully understood when considered in conjunction with the drawings in which:

[0008] Figure 1 is a simplified illustration of fabrication of an insulated glass unit.

[0009] Figure 2 is a drawing of a cross-section view of an insulated glass unit, according to embodiments.

[0010] Figure 3 is a graph of a solar spectrum curve and the portion of the solar spectrum absorbed by an electrochromic coating at four different tint states T_1; T₂, T₃, and T₄, according to an embodiment.

[0011] Figure 4A is a drawing of a cross section view of a forced air

electrochromic window, according to embodiments.

[0012] Figure 4B is simplified illustration of fabrication of a forced air electrochromic window, according to an embodiment.

[0013] Figure 4C is simplified illustration of fabrication of a forced air electrochromic window, 400b, according to an embodiment.

[0014] Figures 5A - 5C are drawings of a cross sectional view of a forced air electrochromic window depicting different modes of operation with a single diverter, according to embodiments. [0015] Figure 6 is a drawing of a cross sectional view of a forced air

electrochromic window depicting a mode of operation with two diverters, according to embodiments.

[0016] Figure 7 is a flowchart of a process flow of a control algorithm for controlling components of a heat management system of forced air electrochromic window, according to embodiments.

DETAILED DESCRIPTION

[0017] It should be understood that while certain embodiments describe windows having one or more electrochromic devices (also called smart windows), the concepts disclosed herein may apply to other types of optically switchable devices, including liquid crystal devices, suspended particle devices, and the like. For example, a liquid crystal device or a suspended particle device, instead of an electrochromic device, could be incorporated in any of the window embodiments. Further, forced air windows described herein may include static (permanent) tinting, e.g., colored glass and/or tinted films glass, that is used as the heat generating component of the forced air window. Certain embodiments are described in terms of electrochromic windows, which have films that can be actively tinted and cleared.

[0018] In the following description, a "window" or "window assembly" comprises one or more lites where at least one of the lites may be tinted. In some cases, the "window" or "window assembly" may comprise an IGU with one or more electrochromic devices, electrical connectors for coupling the one or more

electrochromic devices of the IGU to a window controller, and/or a frame that supports the IGU and related wiring.

[0019] Generally, an insulated glass unit (IGU) comprises two lites (panes) and a spacer registered between the two lites. The spacer may be made of metal or foam and may have a smaller width and length than the two lites. A sealant is applied between the mating surfaces of the two lites and the spacer, and these elements are pressed together such that a hermetic seal is formed between the lites and spacer surfaces. The sealed interior volume of the IGU formed by these mating surfaces is isolated from the ambient environment. Typically, the interior volume of the IGU is filled with a gas such as an inert gas. The seal formed by the sealant applied between the spacer and the lites is called the primary seal. Another sealant is typically applied around the perimeter of the spacer and between the lites to form what is commonly referred to as the secondary seal. Each of the lites in an IGU comprises a

substantially transparent substrate, for example, a glass substrate. Certain

embodiments describe an IGU comprising at least one lite with an optically switchable device (e.g., electrochromic device) disposed on its substantially transparent substrate. In some cases, the IGU comprises one or more additional lites. In some cases, one or more of the lites of an IGU may comprise multiple substrates. While certain embodiments describe IGUs as having one or more of the lites comprising a glass substrate, the lite(s) may comprise a substrate of another substantially transparent material.

[0020] Figure 1 is a simplified illustration of fabrication of an IGU, 100. In this illustration, a first lite, 105, and a second lite, 115, are registered with a spacer, 110, therebeteween. The spacer 110 may be made of metal or foam and may have a smaller width and length than the first and second lites. A sealant is applied so as to lie between the mating surfaces of the lites 105 and 115 and the spacer 110. These components are pressed together such that a hermetic seal is formed between the lites and spacer surfaces for form the IGU, 100. In IGU 100, the seal formed by the sealant applied between the spacer 110 and the glass lites 105 and 115 is called the primary seal. Another sealant is typically applied around the perimeter of the spacer 110 and between the lites 105 and 115 to form what is commonly referred to as the secondary seal. The IGU 100 has a sealed interior volume defined by the inner surfaces of the lites 105 and 115 and the inside perimeter of the spacer 110.

Typically, the interior sealed volume of an IGU is filled with an inert gas rather than air to increase thermal insulation, as an inert gas has lower thermal conductivity and will conduct less heat than air. However, the interior sealed volume of the IGU 100 of this illustrated example and of other IGUs described herein may be filled with another gas such as air.

[0021] Conventional IGUs do not generally have tinted lites, and even when they do, typically the tinting is not dark enough to absorb significant amounts of solar radiation so as to become unduly hot (though some may). That is, their design typically would not be expected to take into account an increased heat load due to absorption of solar radiation due to tinted lites. Certain IGUs described herein, however, comprise one or more lites with an optically switchable device, such as an electrochromic device. These lites can change optical properties (e.g., transmissivity, reflectivity, etc.) by, for example, transitioning to a tinted (e.g., darkened) state or other transitioned state. In many applications, particularly where glare reduction is the goal, electrochromic lites may tint to absorb 95-99% (or more) of the solar spectrum. Thus, these IGUs with these lites may absorb significant solar radiation in these transitioned states and thus, heat load on the IGUs may be considerable. This is especially true for coatings that can change from light to dark states, either passively or actively, e.g., with thermochromic and electrochromic coatings, respectively. For example, Figure 2 depicts a cross-section view of an IGU, 200. The IGU 200 comprises an electrochromic device coating, 210, on an interior surface 212 of a first electrochromic lite, 205. The IGU 200 further comprises a second lite, 215. For simplicity, the spacer, primary seal and secondary seal are depicted as a unitary structure, 225. An interior sealed volume 230 of the IGU 200 is formed by the sealing of the mating surfaces of the spacer and the first and second lites, 205 and 215. The sealed interior volume 230 of the IGU 200 formed by these mating surfaces is isolated from the ambient environment. Although the IGU 200 is shown, for illustration purposes, in a vertical outer wall of a structure (e.g., building) between an occupant of a structure and the Sun radiating solar energy, the IGU 200 could also be in an interior wall and/or may be in other orientations.

[0022] When an electrochromic (EC) device coating (e.g., electrochromic device coating 210) is tinted, particularly in a tint state having a low % transmission (%T), e.g., less than 10% T, less than 5%T, and less than 1%T, the electrochromic (EC) device coating absorbs a large portion of the solar spectrum. For example, Figure 3 shows a graph of a solar spectrum curve and the portion of the solar spectrum absorbed by an electrochromic coating at four different tint states (T_1; T₂, T₃, and T₄) having four levels of %T respectively, as shown by the four dotted curves. The tint states T_1; T₂, T₃, and T₄ correspond to different transmission levels that range from a highest level at transmission (lightest tint state) at T_\ to a highest level of transmission (darkest tint state) at T₄. When the electrochromic coating absorbs all this energy, it gets hot. [0023] In one example, on a hot summer day, a fully tinted (darkest tint state) electrochromic window's outer lite may reach temperatures as high as 90°C and up to and exceeding 100°C. Although certain electrochromic coatings (e.g., inorganic ceramic coatings) can be designed to withstand such temperatures, some applications may be benefit from removing at least some of this heat load, for example, to improve the service life of the electrochromic window and/or provide benefits such as reduced glare and heat intake into the space occupied by an end user. Also, although the electrochromic coating may be able to withstand these heat extremes, sudden changes in temperature may result in the glass substrate breaking due to the extreme stresses imparted by the large temperature gradient across the glass. Thus there are sufficient reasons to actively cool the electrochromic coated glass in certain circumstances. In addition, there are switching algorithms that may be used to mitigate thermal heat load, and thus thermal stress, as part of a comprehensive heat management system. In certain embodiments, the tinting and/or cooling of forced air electrochromic windows may be controlled by electrical communications from a controller, which implements instructions according to a comfort management algorithm such as, for example, the algorithm described with reference to Figure 7 below. A thermal stress management algorithm and associated systems that can be used to control the tinting and/or cooling of forced air electrochromic windows are described in Patent Application No.

14/352,973, titled "MITIGATING THERMAL SHOCK IN TINTABLE

WINDOWS," filed on April 18, 2014, which is hereby incorporated by reference in its entirety.

[0024] Certain embodiments described herein address this heat load problem and others by actively cooling an insulated glass unit, particularly an insulated glass unit comprising one or more thermochromic lites, electrochromic lites, and/or other lites that can have a dark tint to them, and thus, a high heat load.

[0025] Certain apparatus and methods described herein comprise techniques that pass air over at least one lite of an insulated glass unit, e.g., a tinted electrochromic coated lite of an IGU, in order to remove heat and therefore, lessen the heat load on the lite, and any optically switchable device (e.g., electrochromic coating) on the substrate of the lite, and/or other components of the IGU. In certain embodiments, air that has been heated by the IGU lite is passed such as by pumping to the exterior of the structure (e.g., building) having the IGU lite, or is used to warm the interior of the structure. In certain embodiments, the heated air is used to drive a turbine to generate electricity. The electricity thus generated may be stored in a battery on the forced air window assembly. Embodiments are further described below with reference to

Figures 4A-5C.

[0026] Figure 4A depicts a cross section view of a forced air electrochromic window, 400, according to embodiments. The forced air electrochromic window 400 comprises an IGU subassembly having components of the IGU 200 shown in Figure 2. That is, the IGU subassembly comprises an electrochromic device coating 210 on an interior surface 212 of a first electrochromic lite 205, and a second lite 215. For simplicity, the spacer, primary seal and secondary seal of the IGU subassembly are depicted as a unitary structure, 225. An interior sealed volume 230 of the IGU subassembly is formed by the sealing of the mating surfaces of the spacer and the first and second lites, 205 and 215. At least the sealed interior volume 230 is isolated from the ambient environment. In addition to the IGU subassembly, the forced air electrochromic window 400 further comprises a third lite, 405, comprising a substrate made of a substantially transparent material, e.g., glass, plastic, plexiglass or the like. The third lite 405 is spaced substantially parallel to, and registered with the IGU subassembly, and affixed or adhered with sealant, and/or a sealing member, 410a. Any or all of the lites may be laminate structures themselves, but in this depiction each is a single lite.

[0027] Although the forced air electrochromic windows of certain embodiments are shown in a vertical outer wall of a structure with the third lite facing toward the Sun, these forced air electrochromic windows could also be in other orientations (e.g., vertical in a skylight) and/or may be in an interior wall.

[0028] In certain embodiments, a forced air electrochromic window comprises two or more vent modules in communication with an interior space between an electrochromic lite of an IGU subassembly and a third lite. In some cases, one or more of these vent modules may comprise one or more air movement devices, e.g., one or more fans, for actively moving the air through the interior space between an electrochromic lite and a third lite. In one case, the one or more air movement devices comprise one of a blade fan, a bladeless fan, and an air pump. In some cases, one or more air movement devices from the structure and outside the forced air electrochromic window can be configured to feed air into one or more of the vent modules or output air from one or more of the vent modules. In certain embodiments, the vented air may be used to generate electricity by turning a turbine connected to a generator. The generated electricity may be stored in a battery, e.g. in one of the venting modules.

[0029] In Figure 4A, for example, the forced air electrochromic window 400 comprises two vent modules, 415a and 415b. The two vent modules, 415a and 415b, are in cooperation with components of the window 400 with sealant, and/or the sealing member 410a. Although the vent modules 415a and 415b are shown configured at the top and bottom of the window 400, these modules could also be configured at either side, for example. The vent modules 415a and 415b allow forced air to be passed through the interior volume between electrochromic lite 205 of the IGU subassembly and the third lite 405. The forced air can be introduced into the interior volume either from the exterior or the interior of the structure (e.g., building) in which window 400 is installed. In certain embodiments, one or both of the vent modules, 415a and 415b, may comprise an air movement device (e.g., a fan) for actively moving air through the interior space between an electrochromic lite 205 and a third lite 405. For example, both of the vent modules 415a and 415b in Figure 4A comprises air movement devices 445 and 450, depicted as fans, for moving air through the interior space between electrochromic lite 205 and the additional third lite 405. Other forms of air movement devices may be used. In certain cases, the structure outside of the forced air electrochromic window 400 may comprise air movement device(s) that can be configured to feed air into one or both of the vent modules 415a and 415b and/or air movement device(s) that can output air from one or both of the vent modules 415a and 415b. For example, a fan in the frame surrounding the window 400 can direct air into one of the vent modules.

[0030] In the example illustrated in Figure 4A, the vent module 415a comprises first and second apertures, 420 and 425 respectively, which allow air to pass through the vent module 415a, e.g., from the exterior and into the interior space or from the interior space to the exterior. Similarly, vent module 415b comprises first, second, and third apertures, 430, 435 and 440 respectively. Aperture 440 allows air to pass, to or from the interior of the structure. Vent module 415b also includes a diverter, 455, which swivels on a pivot as depicted. Diverter 455 allows air movement through 435 and 430 (in first position), or through 430 and 440 (in second position), depending upon the position of the diverter 455. In the illustration, the diverter 455 is in the first position.

[0031] In the example illustrated in Figure 4A, the vent module 415a further comprises a controller, 460, for controlling air movement devices 445 and 450, and for controlling one or more actuators (not shown) configured to move diverter 455 into the aforementioned venting positions. Controller 460 may be configured to control only vent modules 415a and 415b, or may also be configured to control tint levels of the electrochromic device coating 210. One embodiment of a forced air electrochromic window comprises an EC window controller that is configured to control tint levels of one or more electrochromic lites and also configured to control one or more vent modules of the forced air electrochromic window. The EC window controller may be programmed with instructions to tint the one or more

electrochromic lites based on user input or preferences, and/or to ameliorate thermal stress on the one or more electrochromic lites.

[0032] Figure 4B is simplified illustration depicting fabrication of a forced air electrochromic window 400a, according to an embodiment. The dotted arrows denote the assembly of components/subassemblies that form (denoted by large solid arrow) the forced air electrochromic window 400a. Forced air electrochromic window 400a comprises similar components to those in forced air electrochromic window 400 described with respect to Figure 4A. Forced air electrochromic window 400a comprises an IGU subassembly 401, wherein the IGU subassembly 401 comprises components of the IGU 200 described with respect to Figure 2. Forced air electrochromic window 400a further comprises a third lite 405, vent modules 415a and 415b, and a sealing member 410b. Vent modules 415a and 415b are individual components that cooperate with the IGU subassembly 401, sealing member 410b, and third lite 405. Once assembled, sealing member 410b is registered between the third lite 405 and the first lite of the IGU subassembly 401. The sealing member 410b may be made of metal or foam and may have a smaller width and length than the third lite 405 and the first lite of the IGU subassembly 401. [0033] In some embodiments, the sealing member may comprise protrusions configured to engage with the vent modules, the IGU subassembly and/or the third lite so that the components may be assembled to form the forced air electrochromic window. In the illustrated example shown in Figure 4A, sealing member 410a comprises four vertical protrusions 412 configured to engage with vent modules 415a and 415b. In the illustrated example shown in Figure 4B, sealing member 410b comprises both horizontal and vertical protrusions where the horizontal protrusions are configured to engage with the IGU subassembly and the third lite. In this example, a sealing adhesive such as, for example, polyvinylbutryal (PVB), polyisobutylene (PIB), or other adhesive used in primary seals of conventional IGUs may be used to seal the mating surfaces of the sealing member 410b, the third lite 405, and the IGU assembly.

[0034] In some embodiments, the sealing member may also comprise intake and/or exhaust apertures in one or more sections mating with the vent module(s). These apertures are configured to pass air between the interior space created by the inner perimeter of the sealing member and the third lite and the first lite of the IGU assembly. For example, in Figure 4B, sealing member 410b comprises eight apertures 414 in each of its horizontal sections for venting or otherwise passing air between the interior volume created by the inner perimeter of sealing member 410b, and lites 205 and 405, and the vent modules 415a and 415b. As another example, sealing member 410a in Figure 4A comprises aperture 430.

[0035] In certain embodiments, the vent module(s) of the forced air

electrochromic window comprise one or more intake and/or exhaust apertures. In some cases, the apertures may comprise structures such as louvers, screens, flaps and the like to prevent entry of rain, noise, or foreign objects such as insects, birds etc., and/or to direct the flow of air entering or exiting the apertures. As depicted in

Figure 4A, for example, intake and/or exhaust apertures 420 and 435 comprise louvers. Flaps or other structures may also aid in venting the interior space between lites 205 and 405 to prevent fogging. The vent module(s) and/or sealing member (e.g., in the apertures in the horizontal sections which allow flow) may include desiccant to prevent moisture from accumulating in the aforementioned interior volume. Generally, the interior volume of the IGU subassembly of the forced air electrochromic window is unaffected by moisture because it is hermetically sealed and/or provided with desiccant protection. As discussed in further detail below, condensed moisture in the interior volume between the third lite 405 and the first lite 205 of the IGU subassembly may also be removed by forced air circulation through the interior space. Also, forced air through this interior space may prevent moisture condensation.

[0036] Although certain embodiments describe a forced air electrochromic window with a third lite having dimensions, e.g., length and width, that are substantially the same as the dimensions of the lites of the IGU subassembly, other embodiments may have a third lite with larger or smaller dimensions. In the illustrated example shown in Figure 5B, third lite 405 has a length and width that are substantially the same as the length and width of the lites of IGU subassembly 401. In another embodiment, the third lite 405 may be smaller in length and width than the first lite 205 of the IGU subassembly. In such an embodiment, additional framing or other structure may surround third lite 405 and be part of, or be in cooperation with sealing member 410b. In another embodiment, third lite 405 may be larger in length and width than first lite 205 of the IGU assembly401. In such an embodiment, sealing member 410b may serve the sealing function between third lite 405 and first lite 205 and may also serve a framing function, e.g., where portions of sealing member 410b lie outside the outer edges of (and optionally encompassing) the IGU subassembly 401.

[0037] In the embodiment depicted in Figure 4B, there is nothing visible on the sides of the window; that is, extending past the glass edges on either side. The sealing member 410b structure allows a parallel spaced and registered relationship between pane 405 and IGU pane 205. In this example, the vertical components of sealing member 410b do not extend beyond the vertical edges of panes of the IGU

subassembly or the third pane 405. In a sense, forced air electrochromic window 400a can be thought of as a triple paned IGU, where one of the two interior volumes is hermetically sealed (or at least fully desiccated) and the other of the two interior volumes is vented and allows active airflow therethrough in order to cool at least the (interior) IGU pane 205 of the three panes. In certain embodiments the vented interior volume is actively vented, that is, air is forced through the interior volume to remove heat therefrom.

[0038] Figure 4C depicts another embodiment of a simplified fabrication of a forced air electrochromic window, 400b, comprising an IGU subassembly, 402, and a frame subassembly, 465. The dotted arrow denotes the assembly of IGU subassembly 402 with frame subassembly 465 to form (denoted by large arrow) the forced air electrochromic window 400b. Forced air electrochromic window 400b comprises some of the components in forced air electrochromic window 400 described with respect to Figure 4A. IGU subassembly 402 comprises components of IGU 200 described with respect to Figure 2. Forced air electrochromic window 400b further comprises a third lite and vent modules 415a and 415b.

[0039] In Figure 4C, frame subassembly 465 forms a frame comprising the third lite and vent modules 415a and 415b. In this example, the sealing member (not shown) is part of frame subassembly 465. During assembly, IGU subassembly 402 is inserted into the frame subassembly 465, which is configured to receive the IGU subassembly 402. This embodiment may provide a technical advantage of convenience by providing a convergent fabrication technique where two components, IGU subassembly 402 and frame subassembly 465, are combined in a single step to form the forced air electrochromic window 400b. In addition, this embodiment may provide additional convenience of customizability in having a pre-fabricated frame subassembly 465 comprising vent modules that can be fitted with electrochromic, thermochromic or other optically switchable glass, including in IGU form, at the discretion of the end user. Moreover, in certain embodiments, the frame subassembly 465 may not have a third pane pre-installed. These embodiments may provide the technical advantage of allowing high customizability to end user. In these cases, the end user can select an IGU subassembly with a particular combination of optically switchable components and/or a third lite to be assembled into the forced air electrochromic window. In these cases, the end user can select different combinations of optically tinting components, e.g., electrochromic or thermochromic, along with the mate lite that best compliments the tinting glass component, e.g., in color, material, thickness, coated or not, and the like. Pre-fabricated frame subassemblies, such as 465, may also be prefabricated in a variety of sizes. [0040] As mentioned above, forced air electrochromic windows of embodiments optionally comprise a controller. Figures 4A and Figures 5A-5C depict forced air electrochromic windows that comprise a controller 460. Although not depicted as components of the forced air electrochromic windows 400a and 400b in Figures 4B and 4C, controllers may optionally be included as components of these windows 400a and 400b. In some cases, the controller of the forced air electrochromic window may be located in a venting module, in the frame, in the sealing member, in the spacer, or other components internal to the forced air electrochromic window. Alternatively, a controller may be located external to the forced air electrochromic window. A controller, whether external to the venting modules or not, may be configured to control the venting functions as well as one or more electrochromic device coatings' switching functions.

[0041] In certain embodiments, a forced air electrochromic window may comprise wiring to provide electrical communication for powering and control of the electrochromic device coating. In some cases, this wiring may be combined with wiring for one or more air movement devices (e.g., fans) of the vent modules, if such air movement devices are included in the vent modules. In other embodiments, the controller and/or the electrochromic device coating may be wirelessly powered and/or controlled. In these cases, the forced air electrochromic window may be a standalone unit without needing wiring to the unit.

[0042] In certain embodiments, a forced air electrochromic window may comprise one or more photovoltaic cells, for example, as components of the vent modules. These photovoltaic cells may be used to power and control, for example, the one or more air movement devices and/or the electrochromic coating of the IGU

subassembly (e.g., 200).

[0043] Although certain examples comprise an IGU subassembly comprising an electrochromic device coating on a single EC lite (e.g., lite 205), the IGU

subassembly may be a "dual EC lite" unit comprising an electrochromic device coating on two substrates of the IGU subassembly. For example, a forced air electrochromic window may comprise IGU 200 that is a "dual EC lite" unit, where each of IGU lites 205 and 215 have an electrochromic device coating. [0044] In certain embodiments, the third lite (e.g., 405) of the forced air electrochromic window may comprise an infrared (IR) blocking coating or a hermetically sealed electrochromic coating. For example, the third lite may be a laminated electrochromic pane, or a single pane with an electrochromic coating that is hermetically sealed with an encapsulant or other protective layer that blocks moisture. In some embodiments, one or more lites of the forced air electrochromic window may comprise a thin flexible glass substrate. An example of a thin flexible glass substrate is Gorilla Glass^® or Willow^® Glass made by Corning, Inc. of Corning, New York. In some embodiments, one or more of the lites of the forced air electrochromic window (e.g., 405, 205 and 215) may be laminated lites.

[0045] Figures 5A - 5C are drawings of a cross section view of a forced air electrochromic window, 500, operating under different modes of operation with a single diverter, according to embodiments. Figure 6A is a drawing of a cross section view of a forced air electrochromic window, 600, operating under a mode of operation with two diverters, one in each vent module, according to embodiments.

[0046] Forced air electrochromic window 500, depicted in Figures 5A-5C, comprises components similar to those in forced air electrochromic window 400 described with reference to Figure 4A. Forced air electrochromic window 500 comprises an IGU subassembly with components of the IGU 200 described with reference to Figure 2. The IGU subassembly comprises an electrochromic device coating 210 on a surface of a first lite 205, a second lite 215, and a unitary structure, 225, comprising the spacer, primary seal and secondary seal of the IGU subassembly. An interior sealed volume 230 of the IGU subassembly is formed by the sealing of the mating surfaces of the spacer and the first and second lites, 205 and 215, respectively. Forced air electrochromic window 500 further comprises a third lite, 405, spaced substantially parallel to, and registered with the IGU subassembly, and affixed or adhered with sealant, and/or a sealing member, 410a. Forced air electrochromic window 500 further comprises two vent modules, 415a and 415b, comprising air movement devices 445 and 450 respectively, depicted in the form of rotary fans. Vent module 415a comprises first and second apertures, 420 and 425, respectively, which allow air to pass through the vent module 415a. Vent module 415a further comprises a controller 460. Vent module 415b comprises first, second, and third apertures, 430, 435 and 440 respectively. Vent module 415b also includes a diverter, 455b, which swivels on a pivot as depicted. Diverter 455b allows air movement through 435 and 430 (in first position), or through 430 and 440 (in second position), depending upon the position of the diverter 455. In the illustration, the diverter 455b is in the first position.

[0047] In the mode of operation depicted in Figure 5A, exterior air is pulled into venting module 415a with air movement device 445 and/or air movement device 450 and the diverter 455b is in the first position to allow air to exhaust through 430 and 435 to the exterior of the structure. As shown, air is pulled in from an exterior intake of the structure (e.g., building) as depicted by the dotted arrowed line. The air passes through first and second apertures, 420 and 425, and then through the interior space between first lite 205 (EC lite) and third lite 405 and then exits through first and second apertures, 430 and 435, in vent module 415b to the exterior of the structure. The heated air is exhausted to the exterior of the structure at the exterior exhaust as depicted by the dotted arrowed line. In one case, this air flow may be substantially laminar flow across substantially the entire first EC lite 205, which may allow it to cool evenly.

[0048] The mode of operation depicted in Figure 5A may be useful, e.g., on a warm sunny day. That is, when the EC coating 210 of the first lite 205 is tinted to block the Sun's energy, the coating 210 absorbs solar energy and becomes heated. Cooler air from the exterior of the structure can be pulled into the interior space between the first EC lite 205 and the third lite 405 to cool the first EC lite 205 and then the heated air can be exhausted to the exterior of the structure. That is, on a warm sunny day, it may not be desirable to exhaust heated air into the interior of the structure which could increase the heat load in the interior.

[0049] Referring to Figure 5B, in another mode of operation, interior air is pulled into vent module 415b with air movement device 445 and/or air movement device 450 and the diverter 455b is in the second position to allow air to exhaust through apertures 425 and 420 to the exterior of the structure. In this mode operation, air is pulled in from an interior intake of the structure as depicted by the dotted arrowed line. Air passes through second aperture 440 and first aperture 430 of vent module 415b, through the interior space between first lite 205 (EC lite) and third lite 405, and then exits through the second aperture 425 and first aperture 420 of vent module 415a to the exterior of the structure at the exterior exhaust as depicted by the dotted arrowed line. In this mode of operation, the heated air is again exhausted to the exterior of the structure, but in this embodiment interior air is used to cool the first EC lite 205.

[0050] The mode of operation depicted in Figure 5B may be useful, e.g., on a very hot sunny day, where the interior air is at lower temperature than the exterior air and thus, the interior air would cool the EC devices more efficiently than the exterior air. Also, forced air electrochromic window 500 provides extra air movement in the interior of the structure by sucking air out through vent module 415b. When the EC coating is tinted to block the sun's energy it becomes heated. Cooler air from the inside is used to cool the EC lite 205, and is exhausted to the exterior of the structure. The change of flow path from the example in Figure 5A is achieved by rotating the diverter 455b to establish an interior to exterior air flow path at the intake. In addition, the air movement devices 450 and 445 are adjusted to reverse the flow direction so that the air is pulled into vent module 415b.

[0051] Referring to Figure 5C, in another mode of operation, exterior air is pulled into vent module 415a with air movement device 445 and/or air movement device 450 and the diverter 455b is in the second position to allow air to exhaust through apertures 425 and 420 to the interior of the structure. In this mode of operation, air is pulled in from an exterior intake of the structure as depicted by the dotted arrowed line. Air passes through first aperture 420 and second aperture 425 of vent module 415a, through the interior space between first lite 205 (EC lite) and third lite 405, and then exits through the second aperture 430 and third aperture 440 of vent module 415b to the interior of the structure at the interior exhaust as depicted by the dotted arrowed line. In this mode of operation, the heated air is exhausted to the interior of the structure.

[0052] This mode of operation depicted in Figure 5C may be useful, e.g., on a sunny winter day, where exterior air would efficiently cool the EC device, and the warm air produced would be beneficial to help warm the interior of the structure. When the EC coating is tinted to block the sun's energy, it becomes heated. Cooler air from the exterior of the structure is used to cool the EC lite, and this heated air is exhausted to the interior of the structure. This change of flow path from the example shown in Figure 5A is achieved by rotating diverter 455b to establish an exterior to interior air flow path.

[0053] Figure 6 is a drawing of a cross sectional view of a forced air

electrochromic window, 600. Forced air electrochromic window 600 comprises an extra second diverter, 455a, in vent module 415a, thus both vent modules, 415a and 415b, have the capability to vent air flow to and from the exterior and interior of the structure and through the interior space between third lite 405 and EC lite 205.

[0054] Forced air electrochromic window 600, comprises components similar to those in forced air electrochromic window 400 described with reference to Figure 4A. Forced air electrochromic window 600 comprises an IGU subassembly with components of the IGU 200 described with reference to Figure 2. The IGU subassembly comprises an electrochromic device coating 210 on a surface of a first lite 205, a second lite 215, and a unitary structure, 225, comprising the spacer, primary seal and secondary seal of the IGU subassembly. An interior sealed volume 230 of the IGU subassembly is formed by the sealing of the mating surfaces of the spacer and the first and second lites, 205 and 215, respectively. Forced air electrochromic window 500 further comprises a third lite, 405, spaced substantially parallel to, and registered with the IGU subassembly, and affixed or adhered with sealant, and/or a sealing member, 410a. Forced air electrochromic window 500 further comprises two vent modules, 415a and 415b, comprising air movement devices 445 and 450 respectively, depicted in the form of fans. Vent module 415a comprises first, second, and third second apertures, 420, 425, and 427, respectively, which allow air to pass through the vent module 415a. Vent module 415a further comprises a controller 460 and a first diverter 455a, which swivels on a pivot as depicted. Vent module 415b comprises first, second, and third apertures, 430, 435 and 440, respectively. Vent module 415b further comprises a second diverter, 455b, which swivels on a pivot as depicted. First diverter 455a allows air movement through apertures 425 and 427 when the diverter 455a is in a second position (depicted in Figure 6), or through 420 and 425 when the diverter 455a is in a first position. Second diverter 455b allows air movement through apertures 435 and 430 when the diverter 455b is in a first position or through apertures 430 and 440 when the diverter 455b is in a second position. In Figure 6, the second diverter 455b is in a second position.

[0055] The forced air electrochromic window 600 in Figure 6 is depicted in the interior intake-interior exhaust mode of operation, which is one of at least four modes of operation of the forced air electrochromic window 600. To configure the forced air electrochromic window 600 in this interior intake-interior exhaust mode, the first diverter 445a is moved into a second position and the second diverter 445b is moved into a second position. To configure the forced air electrochromic window 600 in an exterior intake-exterior exhaust mode, the first diverter 445a is moved into the first position and the second diverter 445b is moved into the first position. To configure the forced air electrochromic window 600 in an interior intake-exterior exhaust mode, the first diverter 445a is moved into the second position and the second diverter 445b is moved into the first position. To configure the forced air electrochromic window 600 in an exterior intake-interior exhaust mode, the first diverter 445a is moved into the first position and the second diverter 445b is moved into the second position.

[0056] Referring back to Figure 6, in another mode of operation, interior air is pulled into vent module 415a with air movement device 445 and/or air movement device 450 and the diverter 455b is in the second position to allow air to exhaust through apertures 430 and 440 to the interior of the structure. In this mode of operation, air is pulled in from an interior intake as depicted by the dotted arrowed line. Air passes through third aperture 427 and second aperture 425 of vent module 415a, through the interior space between first lite 205 (EC lite) and third lite 405, and then exits through the first aperture 430 and third aperture 440 of vent module 415b to the interior of the structure at the interior exhaust as depicted by the dotted arrowed line.

[0057] This mode of operation depicted in Figure 6 may be useful, e.g., on a sunny but very cold winter day, where interior air would efficiently cool the EC device (once warm), and the warm air produced would be beneficial to help warm the interior of the structure. Also, this configuration has the added benefit of using interior air to initially warm first lite 205 which may aid in faster tinting of the EC device. Once tinted to block the Sun's energy, first lite 205 may become very warm or hot, and thus the interior air may be further used to cool the EC lite 205, and then the warmed air may be exhausted to the interior to help warm the interior of the structure.

[0058] In certain embodiments, a forced air electrochromic window includes at least one electrical energy generator. The electrical energy generator may be a typical electrical generator which is driven by a turbine. The turbine may be one of the air movement devices. For example, referring to Figure 6, air movement device 445 may be an electric fan, while air movement device 450 is a turbine connected to the shaft of an electrical generator (not shown). Air movement device is actively powered to force air through the vented volume and the air thus heated after traversing the interior volume spins the turbine 450 in order to generate electricity. The electricity may be stored in a battery (not shown) e.g. in one of the venting modules. In this way the removal of heat from the electrochromic assembly may be used not only, e.g., for heating the interior of the building but also to generate (and store) a supply of electricity to aid in, e.g., switching the electrochromic device film and/or powering the (active) air movement device 445. One embodiment is an apparatus as described herein, further including an electrical generator and optionally a storage battery to store the electricity generated by the generator. In certain embodiments, the electricity generated is used to power the EC controller and/or air movement devices of the apparatus. The electricity may be used directly or stored in a battery before being used.

[0059] One of ordinary skill in the art would appreciate that the various modes of forced air movement with windows described herein do not have to be, e.g., in the precise flow paths outlined. For example, using window 600, the four modes of circulation described, exterior intake-exterior exhaust, interior intake-exterior exhaust, exterior intake-interior exhaust and interior intake-interior exhaust, may be

implemented in a number of ways and combinations. For example, in one

embodiment, e.g., on a very cold sunny day where the EC lite 205 is not yet tinted, interior air may be forced through the interior space between lites 405 and 205 in order to warm EC lite 205 to make switching more facile than it otherwise would be. In this embodiment, the interior air used to warm EC lite 205 is vented either to the exterior for a period of time. The EC device coating, 210, is tinted to absorb the solar radiation. A sensor measures the temperature of the exhaust air. When the temperature of the exhaust air reaches a pre-determined level, e.g. warmer than the interior air, then the exhaust air is diverted into the interior to warm the interior. Another temperature sensor, inside the structure, e.g., a thermostat, may reach a level that is higher than the comfort level set by an occupant. This may trigger the window's diverter to again direct the exhaust flow to the exterior of the building.

Thus, e.g., controller 460 may have logic to automatically carry out the commands to the appropriate diverter(s) of the window based on temperature inputs and/or user settings.

[0060] Control Algorithms for forced air electrochromic windows [0061] Figure 7 is a flowchart depicting aspects of a process flow 800, in accord with a control algorithm for controlling components of a heat management system of forced air electrochromic windows described herein. For example, the control algorithm may be used to control heat management system components such as air movement devices (e.g., fans), diverters, and tint levels in one or more optically switchable devices of the window. The heat management system may also comprise one or more sensors, one or more controllers, and/or one or more computer readable medium.

[0062] At decision block 815, a determination is made as to whether the window is "Too hot" at a particular time. The particular time could be at the time of the determination, the time that a sensor determined the window is "Too hot," or at a predicted time of high thermal gradient (e.g., at or about sunrise or sunset, at a time at or near a predicted change in weather conditions), etc. The window may be in a first tint state before this determination. This determination may be made on a periodic basis (e.g., every 60 minutes, 15 minutes, 5 minutes, etc.) in some cases. "Too hot" may mean in this context that the temperature is above a certain predetermined value such as, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, etc.

[0063] If the answer at decision block 815 is "YES," then the window

temperature, particularly the EC lite temperature, must be lowered. In this case, the algorithm determines whether the current tint level needs to be held or not (step 820). For example, if the window is currently at a tint state that is desired to reduce glare in a room, then raising the %T may be unacceptable. If the answer to decision block 820 is "NO," then the window may be actively cooled (step 830) by turning on an air movement device and/or changing positions of diverters to change direction of air flow. If the answer to decision block 820 is "YES," for example, where increasing %T is acceptable, then the optically switchable device is transitioned to a higher %T (step 825) and/or the window is actively cooled (step 830). For example, the window may be actively cooled by turning on an air movement device and/or changing positions of diverters to change direction of air flow. Upon changing the %T to a higher value at 825 and/or active cooling of the window at 830, the method returns to determine the temperature of the window is "Too hot" at 815. [0064] At decision block 815, if the answer is "NO," then a determination is made as to whether the window is "Too Cold" at decision block 817. If the answer is "NO" the algorithm returns to decision block 815, but if the answer is "YES", the algorithm makes a decision as to whether to change %T, see 840. If the answer is "YES," then the EC device is transitioned to a lower %T so as to increase the amount of solar radiation absorbed by the EC device, and thus heat the device. And/or the device and/or room may be actively heated, see 850. For example, the one of the transparent conductive layers of an EC device or a separate resistive heating element may be used to heat the EC device. As another example, an air movement device may be configured to pass warm air over the glass via a heater fan, infrared irradiation, and the like. Additionally or alternatively, the diverters may be positioned to change flow through the interior space of the IGU in order to move warm air from the room or another heated area over the glass via the interior volume. This warm air may be used alone or in conjunction with tinting the glass to absorb more solar energy.

[0065] In certain instances, it will be desirable to keep the window tinted such as, for example, an occupant does not want the intense morning sun entering the room. In such instances, the answer to decision block 840 may be "NO." In this case, the window is actively heated only, see 850. As in the scenario where the window is too hot, there are instances where the decision of "NO" at block 840 is overridden in favor of increasing %T, with or without also actively heating the window. Upon changing the %T to a higher value at 845 and/or actively heating, the method returns to determine whether the temperature of the window is "Too hot" at 815. [0066] In certain cases, the forced air windows may include a controller comprising, for example, one or more microprocessors that control and manage one or more components of the heat management system of the window. The controller is designed or configured (e.g., programmed) to implement instructions from a control algorithm, for example, the control algorithms described above. In various embodiments, the controller receives detected information about a window's condition including, for example, illumination level, temperature, temperature gradient (spatial and/or temporal), transmissivity, and/or state of tint, as appropriate. Further, the controller may have various additional features such as timers, charge detectors (e.g., coulomb counters), oscillators, and the like.

[0067] In one embodiment, the window controller is a multipurpose controller, that is, it can control and/or monitor a number of functions and/or characteristics of one or more tintable windows. Various arrangements of multipurpose controllers are presented in U.S. Patent Application Serial No. 13/049,756, filed March 16, 2011, naming Brown et al. as inventors, titled "MULTIPURPOSE CONTROLLER FOR MULTISTATE WINDOWS," which is hereby incorporated by reference in its entirety. In certain embodiments, the controller controls one or more of the following functions: (1) determining the temperature of the window, (2) providing power to the EC device to control its level of tint in the window, (3) control components that actively cool and/or heat the window, and (4) controlling components that actively cool and/or heat a room with heated air from the window, and (5) controlling components (e.g., one or more diverters) that control the direction of air flow in the window. For example, the controller may also control venting and air movement mechanisms to actively heat or cool the window. [0068] In some embodiments, the controller is located external to the device and communicates with the device via a network. The communication can be direct or indirect (e.g., via an intermediate node between a master controller and the device). The communication may be made via a wired or wireless connection.

[0069] In some embodiments, the controller is integrated with the optical device or housing. In a specific embodiment, the controller is integrated in the housing or a seal of an insulated glass unit (IGU) containing a switchable optical device. Various arrangements of integrated controllers are presented in U.S. Patent No. 8,213,074, filed March 16, 2011, naming Shrivastava et al. as inventors, titled "ONBOARD CONTROLLER FOR MULTISTATE WINDOWS," which is hereby incorporated by reference in its entirety.

[0070] In one embodiment, the controller includes a chip, a card or a board which includes logic for performing one or more control functions. Power and

communication functions of controller 201 may be combined in a single chip, for example, a programmable logic device (PLD) chip, field programmable gate array (FPGA) and the like. Such integrated circuits can combine logic, control and power functions in a single programmable chip. In one embodiment, where the

electrochromic window (or IGU) has two electrochromic panes, the logic is configured to independently control each of the two electrochromic panes. In one embodiment, the function of each of the two electrochromic panes is controlled in a synergistic fashion, that is, so that each device is controlled in order to complement the other. For example, the desired level of light transmission, thermal insulative effect, and/or other property are controlled via combination of states for each of the individual devices. For example, one electrochromic device may be placed in a colored state while the other is used for resistive heating, for example, via a transparent electrode of the device. In another example, the optical states of the two electrochromic devices are controlled so that the combined transmissivity is a desired outcome.

[0071] In some cases, the Controller may also have wireless capabilities, such as control and powering functions. For example, wireless controls, such as RF and/or IR can be used as well as wireless communication such as Bluetooth, WiFi, Zigbee, EnOcean and the like to send instructions to the microcontroller and for the microcontroller to send data out to, for example, other window controllers and/or a building management system (BMS). Wireless communication can be used in the window controller for at least one of programming and/or operating the

electrochromic window, collecting data from the electrochromic window from sensors as well as using the electrochromic window as a relay point for wireless

communication. Data collected from electrochromic windows also may include count data such as number of times an electrochromic device has been activated (cycled), efficiency of the electrochromic device over time, and the like. [0072] Although the foregoing embodiments have been described in some detail to facilitate understanding, the described embodiments are to be considered illustrative and not limiting. It will be apparent to one of ordinary skill in the art that certain changes and modifications can be practiced within the scope of the appended claims.

Claims

CLAIMS What is claimed is:

1. A forced air electrochromic window comprising:

an insulated glass unit comprising a first lite with an electrochromic device, a second lite, and a spacer between the first and second lites;

a third lite outside the insulated glass unit;

an interior space between the third lite and the first lite of the insulated glass unit;

at least two vent modules configured to control air flow to and from the interior space; and

one or more air movement devices for actively moving air through the interior space across the first lite to outside the interior space through the at least two vent modules.

2. The forced air electrochromic window of Claim 1, further comprising a sealing member between the third lite and the insulated glass unit, wherein the interior space is formed between the sealing member, the first lite, and the third lite.

3. The forced air electrochromic window of Claim 1, wherein the one or more air movement devices is configured externally to each of the vent modules.

4. The forced air electrochromic window of Claim 1, wherein the one or more air movement devices is configured in at least one of the vent modules.

5. The forced air electrochromic window of Claim 1, wherein the one or more air movement devices comprises one of a blade fan, a bladeless fan and an air pump.

6. The forced air electrochromic window of Claim 1, wherein the one or more air movement devices are configured to actively move air through the interior space across the first lite to exterior a building in which the forced air electrochromic window is installed.

7. The forced air electrochromic window of Claim 6, wherein the one or more air movement devices are further configured to modify the direction of the air flow.

8. The forced air electrochromic window of Claim 1, wherein at least one of the at least two vent modules comprises a diverter configured to move to change direction of the air flow between the interior space and multiple locations outside the interior space.

9. The forced air electrochromic window of Claim 1, further comprising one or more diverters in the at least two vent modules, wherein the one or more diverters are configured to move to configure the forced air electrochromic window in four modes of circulation comprising exterior intake-exterior exhaust mode, interior intake-exterior exhaust mode, exterior intake-interior exhaust mode, and interior intake-interior exhaust mode.

10. The forced air electrochromic window of Claim 1, further comprising a first diverter in one of the at least two vent modules and a second diverter in another one of the at least two vent modules, wherein the first diverter is configured to pivot to change direction of the air flow between the interior space and multiple locations outside the interior space and wherein the second diverter is configured to pivot to change direction of the air flow between the interior space and multiple locations outside the interior space.

11. The forced air electrochromic window of Claim 9, further comprising an actuator coupled to the diverter, the actuator configured to pivot the diverter to change direction of the air flow between the interior space and multiple locations outside the interior space.

12. The forced air electrochromic window of Claim 11, wherein the multiple locations include exterior of a building in which the forced air

electrochromic window is installed and into an interior room of the building.

13. The forced air electrochromic window of Claim 1, wherein at least one of the vent modules comprises a controller for controlling one or more air movement devices.

14. The forced air electrochromic window of Claim 1, wherein the at least one of the vent modules includes one or more apertures to outside the forced air electrochromic window.

15. The forced air electrochromic window of Claim 1, wherein the at least one of the vent modules comprises one of an intake aperture and an exhaust aperture.

16. The forced air electrochromic window of Claim 1, wherein the third lite is substantially the same width and length as the lites of the insulated glass unit and the third lite is registered with the insulated glass unit.

17. The forced air electrochromic window of Claim 1, wherein the third lite comprises a larger width and/or length than the lites of the insulated glass unit.

18. The forced air electrochromic window of Claim 17, wherein the insulated glass unit is registered within the perimeter of the third lite.

19. The forced air electrochromic window of Claim 1, wherein the third lite comprises a smaller width and/or length than the lites of the insulated glass unit.

20. The forced air electrochromic window of Claim 1, further comprising an electrical generator and/or a battery.

21. The forced air electrochromic window of claim 20, wherein the electrical generator is configured to be driven by a turbine, the turbine is configured to be driven by exhaust gas from the forced air electrochromic window.

22. A forced air window comprising:

an insulated glass unit comprising a first tinted or tintable lite;

a third lite outside the insulated glass unit; a sealing member between the third lite and the first tinted or tintable lite; an interior space formed between the third lite and the insulated glass unit; at least two vent modules configured to control air flow to and from the interior space;

wherein air flows between the vent modules and the sealing member through one or more apertures in the sealing member; and

one or more air movement devices configured for actively moving air through the interior space across the first lite to outside the interior space through the at least two vent modules.

23. The forced air window of Claim 22, wherein the first tinted or tintable lite comprises an optically switchable device.

24. The forced air window of Claim 23, wherein the optically switchable device is an electrochromic device.

25. A method of passing air through a forced air electrochromic window comprising an insulated glass unit, a third lite, an interior space between the third lite and a first lite of the insulated glass unit, at least two vent modules, and one or more air movement devices:

controlling air flow to and from the interior space using the at least two vent modules; and

actively moving the air through the interior space across the first lite to the outside of the interior space through the at least two vent modules.

26. The method of claim 25, moving the one or more diverters to change the direction of the air flow between the interior space and multiple locations outside the interior space.

27. The method of claim 26, further comprising reversing the direction of using the air movement devices.

28. The method of claim 25, further comprising, after actively moving theh the interior space across the first lite, passing the air past a turbine in ordere electricity.