Patent Application
20140045419
This invention relates generally to the problem of moisture vapor in the air in a building, and wherein the moisture vapor condenses on the building windows when the temperature outside the building is substantially colder than the temperature inside the building. It is important to maintain a certain level of humidity in the air in a so-warmed building thus to avoid drying out of sinuses and other internal and external body surfaces of people who occupy the building. For example, a relative humidity of about 30% is typically desired during winter weather in the northern part of the temperate zone.
Absolute capacity for air to hold water vapor as humidity is directly related to, among other factors, the temperature of the air. Thus, all other factors being equal, relatively cooler air cannot hold as much moisture as relatively warmer air.
The relatively warmer air inside the building and the relatively cooler air outside an intervening window set up a heat gradient which drives heat through the window by a heat transfer process commonly known as conduction. As a result of the conduction process, the outside surface of the window is relatively warmer than the outside air and the inside surface of the window is relatively cooler than the ambient air inside the building.
Absent treatment as in the invention, heat energy passes from the air inside the building and adjacent the window to the relatively cooler inside surface of the window, whereby the air adjacent the window is cooled. As the air adjacent the window is cooled, its capacity to hold water vapor diminishes, whereby the relative humidity in that air rises. If the air is cooled sufficiently, the air becomes supersaturated, and the excess water condenses as tiny droplets, commonly known as condensation, on the window glass. Such condition is sometimes known as “fog” on the window.
This relatively cooler air is also denser than the air farther from the window, and at the base of the window, whereby the cooled air falls downwardly along the surface of the window, setting up a downwardly flowing curtain of air adjacent the inside surface of the window, which decreases in temperature as the air progresses down the height of the window. As the cooled air falls, the space vacated by the falling air draws replacement room air toward the top of the window, setting up a relatively continuous flow of air which can be described as a falling curtain of air adjacent the window surface. As the replacement room air comes into proximity with the cooler window surface, the replacement air is cooled. As the replacement air is cooled, its capacity to hold water vapor diminishes. If the temperature of the replacement air drops low enough that the water holding capacity drops below the quantity of water which is already entrained in the replacement air, water vapor in the replacement air condenses on the window glass. As additional room air is drawn into the falling curtain, water vapor can continue to condense on the window glass. Condensation thus creates a first problem of obscuring, or partially obscuring, visibility through the window.
As a given mass of air traverses in a downward direction along the inside surface of the window, that mass of air transfers heat to the surface of the window whereby the temperature of the air continues to fall as that mass of air traverses down along the inside surface of the window.
As the relatively continuous flow of cool air downwardly along the inside surface of the window continues, the quantity of water condensed on the window glass increases, and eventually becomes great enough that the tiny droplets coalesce into relatively larger droplets or drops. The relatively larger droplets or drops continue to coalesce with each other and with additional ones of the tiny droplets until the growing drops become large enough to be drawn by gravity downwardly along the inside surface of the window. These coalesced drops move by gravity to the bottom of the window, where they typically stop and gather, first on an underlying portion of the frame of the sash. As the quantity of water on the underlying portion of the frame of the sash increases, the drops, themselves, coalesce with each other and an overflow quantity of water runs down the inside surface of the frame of the sash to the window sill.
The condensed water typically remains on the window sill and sash frame for extended periods of time until the condensation process stops when the temperature gradient is less, or the humidity in the air inside the building is less, and the condensed water is absorbed back into the air in the room. As the water remains on the sill and sash for extended periods of time, the water penetrates the finish coating on the wood and deteriorates the wood substrate of the window sash frame and the window sill thus creating a second problem of causing deterioration of the wood which serves as the substrate for the sash and/or the window frame.
In addition, the falling curtain of cooler air creates a third problem in that the cool air falls close to the floor and creates a cold draft close to the floor, which can result in thermal discomfort to people in the room as they experience “cold feet”.
Given the above scenario, water may remain on part of the sash frame and the sill of the window frame for prolonged periods of time. While the occupants of the building can remove the condensed water by e.g. wiping up the water with absorbent cloths or paper towels, such removal requires continued vigilance and action by the occupants, which may not occur. Rather, the condensed water typically remains in pools, puddles, and/or coalesced drops on the window sill and sash frame, and the like for prolonged periods of time.
As indicated above, as the water sits on the sash and sill, the water works its way through the protective coatings on the e.g. wood substrate, which protective coatings are commonly used to protect the wood substrates from which the sash and sill are commonly made. Commonly-used protective coatings are effective to prevent penetration to the underlying wood substrate for short periods of time, but are not effective to prevent penetration to the underlying wood when the water is present on the coated surface for prolonged periods of time. Typically, the first evidence of damage by the water remaining on the sill and sash for prolonged periods of time is the development of what is commonly known as “water spots” on the sill and sash.
As water continues to stand on the coated wood surfaces, or as water repeatedly stands on the coated wood surfaces, the water eventually penetrates the coating enough to wet the underlying wood. The wetted underlying wood is then vulnerable to attack by the various organisms which feed on wetted cellulose in the wood, causing deterioration of the structural capacity of the wood. Over time, the structural integrity of the wood is sufficiently degraded by such attack that the barrier function of the window is compromised such that the window must be replaced. In addition, water penetration and persistent residence of water in/on the wood can and may support growth of mold and/or mildew in the wood and in the wall structure surrounding the window installation site.
The purpose of this invention is to solve the above four problems of (i) visibility caused by fog, (ii) deterioration of the window framing caused by standing water, (iii) cold drafts caused by the movement of the chilled air along the floor of the room, and (iv) mold/mildew. The condensation gets under the sill and into the wall. The insulation becomes wet and mold begins to grow (unseen). This also ruins the wall and causes serious health issues to occupants of the building.
Condensed water on windows has long been recognized as a problem, both in terms of obscuring visibility through the window and in terms of deterioration of the window sill and the sash frame.
For example, U.S. Pat. No. 5,844,202 Alverson teaches a portable device which mounts temporarily on the dash of a vehicle. The device plugs into an outlet in the vehicle for power and blows warmed air onto the inside surface of the windshield to clear away fog and ice. Alverson thus addresses fog removal but not fog prevention.
U.S. Pat. No. 3,064,110 Vogler teaches an electrical heater inside a metal window frame. When switched on, the heater heats the metal frame, thus to vicariously heat the associated glazing by heat conducted through the frame, sufficiently to prevent water from condensing on the glass. Vogler heats the frame directly by conduction, and thus the window glazing indirectly by conduction.
U.S. Pat. No. 2,888,943 Steele teaches a window heater at the bottom of the window, which receives the falling curtain of cool air, heats that air and directs that heated air away from the window and into the room. Steele thus addresses the cold draft, but not condensation or water standing on a window frame or window sill.
U.S. Pat. No. 3,762,118 Sanders teaches a thermal insulator mounted to the outer surface of the glass at the bottom of the window, thus to maintain the bottom portion of the window at a somewhat warmer temperature, while apparently obscuring visibility through the lower portion of the window.
U.S. Pat. Nos. 4,064,666 Kinlaw, 4,408,425 Torme, and 4,966,129 Curtis teach respective methods of capturing and handling the moisture which does condense, and run down the window, but do not teach any way to avoid the condensation.
There remains a need for methods and apparatus which effectively prevent the formation of condensation on the window glazing.
There is additionally a need for methods and apparatus which avoid the need to deal with water collecting on the sash and sill.
There is further a need for methods and apparatus which address the combination of problems related to visibility through the window, cold draft close to the floor, and damage to window framing caused by standing condensed water.
The invention comprises an air handler, mounted to a surface of a window frame or a trim piece. The air handier admits a supply of air from inside the building at the top of the window and blows that air along a downwardly-depending air path and onto the inner surface of the window. The air handler has one or more legs depending downwardly from an air inlet, to air outlet apertures which express the air in a direction which is generally transverse to the height of the window. The air can be expressed onto the window at ambient temperature or, in some embodiments, supplemental heat is added to the air such as from an electric heater.
Thus, the invention provides a convection curtain of air, from inside the building, adjacent the inside surface of the window/glazing, which curtain of air warms the inside surface of the glass enough that condensation does not form on the glass, or the curtain of air removes and absorbs condensation which has already formed on the glass.
In some embodiments, the air handler comprises a leg which extends down along the side of the window. An air inlet is proximate the top of the window. The air outlets are below the inlet. First and second legs may extend down along opposing sides of the window, thus to project air onto the window glazing from both the left and right sides of the window.
In a first family of embodiments, the invention comprehends a window air handler adapted to attenuate moisture condensation on a glazing of an installed window in a building, the window including a glazing, and having a top and a bottom, a left side and a right side, a height between the top and the bottom, a width between the left side and the right side, and an inside glazing surface facing an interior of the building. The window air handler is external to, and separate and distinct from, the window, and comprises a header: a first leg extending down from the header and alongside more than half the height of the window glazing; an air inlet adapted to admit air from an ambient environment inside the building proximate the top of the window when at least one of the header and the first leg is mounted to one of the window or the building such that the header is proximate the top of the window; an air outlet structure comprising a first set of two or more air outlet apertures in the first leg, below the air inlet; an air flow path between the air inlet and the air outlet apertures whereby air enters the air handler proximate the top of the window and flows downwardly to the air outlet apertures, below the air inlet; and a blower in the airflow path between the air inlet and at least one of the air outlet apertures, the blower blowing air out of the air handler at the at least two air outlet apertures.
In some embodiments, when the air handler is installed at the window, the header extends across at least a portion of the width of the window, and the air outlet apertures are spaced along a length of the first leg, with a distal such aperture being proximate a remote bottom end of the first leg.
In some embodiments, the blower is inside the header, above the window glazing, and above the first leg.
In some embodiments, the blower is inside the first leg.
In some embodiments, the first leg extends alongside the window for substantially the full height of the window.
In some embodiments, a relatively smaller cross-section remote portion of the first leg is slidably and telescopically received into a relatively larger cross-section proximal portion of the first leg, the remote portion of the first leg having a first length and the proximal portion of the first leg having a second length, whereby the remote portion of the first leg can be extended from, and retracted into, the proximal portion of the first leg, and wherein at least one of the outlet apertures is disposed in each of the remote portion of the first leg and the proximal portion of the first leg.
In some embodiments, the header has a useful width sufficient to extend across the width of the window, and wherein the header extends along the top of the window, from a left side of the window to a right side of the window, and wherein a relatively smaller cross-section first portion of the header is slidably and telescopically received into a relatively larger cross-section second portion of the header, whereby the first portion of the header can be extended from, and retracted into, the second portion of the header, whereby the header can be telescopically adjusted in width across the width of the window, and the first leg an be telescopically adjusted in height along the height of the window.
In some embodiments, the window air handler further comprises a heater in the downwardly-extending first leg.
In some embodiments, the first leg has a useful length sufficient to extend substantially the full height of the window, down along the right side of the window, the air handler further comprising a second telescoping leg, in gaseous communication with the header and extending down along the left side of the window, the second leg having a second set of air outlet apertures expressing air onto the window glazing from the left side of the window.
In some embodiments, the air inlet comprises a first air inlet between a relatively central portion of the width of the header and an uppermost one of the air outlet apertures in the first leg, and thus provides for air flowing through the first leg, the air handler further comprising a second air inlet between the central portion of the width of the header and an uppermost one of the air outlet apertures in the second leg, and thus providing for air flowing through the second leg.
In some embodiments, the blower is disposed between the first air inlet and the first set of outlet apertures in the first leg, the air handler further comprising a second blower between the second air inlet and the second set of outlet apertures in the second leg, an air flow barrier being disposed in the header between the first and second blowers such that air flowing between the first air inlet and the outlet apertures in the first leg is segregated from the air flowing between the second air inlet and the outlet apertures in the second leg.
In some embodiments, the air handler further comprises first and second sensors sensing condensation conditions at first and second spaced locations on the glazing of the given window in association with respective air flows being expressed from the air outlet apertures in the first and second legs, and a controller receiving condensation condition information from the first and second sensors, and controlling operation of the first blower according to the information received from the first sensor, and separately controlling operation of the second blower according to the information received from the second sensor.
In some embodiments, the heater in the first leg comprises a first heater, and the air handler further comprises a second heater in the second leg, the controller separately controlling output of the first heater and output of the second heater according to the information received from the first and second sensors, respectively.
In some embodiments, the header has a useful width sufficient to extend across the width of the window, and wherein the header extends along the top of the window, from the left side of the window to the right side of the window, further comprising a first heater between the air inlet and the blower, and a second heater between the blower and a remote end of the first leg.
In some embodiments, the second heater extends generally continuously between a location proximate the blower and a location proximate the outlet aperture which is most remote from the blower.
In some embodiments, the second heater extends intermittently between the location proximate the blower and the location proximate the outlet aperture which is most remote from the blower.
In a second family of embodiments, the invention comprehends a window for use in a building, the window having a top and a bottom, a left side and a right side, a height between the top and the bottom, a width between the left side and the right side, and an inside glazing surface facing an interior of the building. The window comprises a window frame; a window sash; and a window air handler mounted to at least one of the window frame and the window sash, the window air handler comprising a first telescoping leg extending down along either the left side or the right side of the window, a relatively smaller cross-section lower portion of the first leg being slidably and telescopically received into a relatively larger cross-section upper portion of the first leg, whereby the first lower portion of the first leg can be extended from, and retracted into, the upper portion of the first leg, a first air inlet proximate the top of the first leg, as a first air outlet structure, a first set of two or more air outlet apertures in the first leg, below the first air inlet, and a first blower in the first leg, the first blower blowing air out of the first leg at the first set of two or more air outlet apertures and onto and across the inside glazing surface of the window, whereby air enters the air handler at the first air inlet and travels downwardly inside the first leg along the respective side of the window and is expressed from the first leg and onto and across the inside glazing surface of the window at locations below the first air inlet.
In some embodiments, the window further comprises a first heater between the first air inlet and the first blower, and a second heater between the first blower and a remote end of the first leg.
In some embodiments, the window air handler further comprises a second telescoping leg separate and distinct from the first telescoping leg and mounted to one of the window frame and the window sash at the other of the left side or the right side of the window, the second telescoping leg having a second upper end proximate the top of the window and a second lower end displaced from the top of the window, a relatively smaller cross-section lower portion of the second leg being slidably and telescopically received into a relatively larger cross-section upper portion of the second leg, whereby the second lower portion of the second leg can be extended from, and retracted into, the upper portion of the second leg, the second leg having a second air inlet proximate the top of the second leg and an air outlet structure comprising a second set of two or more air outlet apertures in the second leg, below the second air inlet.
In some embodiments, the window further comprises a third heater between the second air inlet and the second blower, and a fourth heater between the second blower and a remote end of the second leg.
In some embodiments, the window further comprises a first condensation sensor sensing condensation on the window proximate the first leg and a second condensation sensor sensing condensation on the window proximate the second leg, and a controller receiving input from both of the first and second sensors, the controller sending a first set of control signals to the first blower and the first heater in the first leg in response to input from the first sensor, and sending a second set of control signals to the second blower and the second heater in the second leg in response to input from the second sensor.
FIG. 8E1 shows a cross-section of a leg, and mounting structure mounting the leg to the window.
The invention is not limited in its application to the details of construction, or to the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various other ways. Also, it is to be understood that the terminology and phraseology employed herein is for purpose of description and illustration and should not be regarded as limiting. Like reference numerals are used to indicate like components.
Air handler 2 includes a housing 8, relative humidity sensor 10 mounted on the housing, and condensation controller 12 mounted on the housing. Housing 8 has a top wall 14, a bottom wall 16, a front wall 18, a back wail 20, and left and right ends 22, 24. In use, the back wall 20 of air handler 2 is generally in contact with, or closely adjacent, the inner surface 26 of the bottom of the lower sash 28 of the window.
If desired, a quick-release attachment system such as a small amount of hook and loop fastener material can be attached to the facing surfaces of the window sill and the bottom wall of the housing, thus to temporarily mechanically restrain the air handler, beyond the restraints of gravity, while effecting an automatic release when lifting force is applied to housing 8 e.g. at an end of the housing displaced from such temporary restraint.
Referring now to
In the embodiment illustrated in
One or more small, low volume, driven blowers 36 are mounted in the chamber 37 inside housing 8 and draw air in through inlet grill 30, along an air path such as that illustrated by arrows 38, between the air inlet and the air outlet, and express the air upwardly and out through the top of the air handler housing at air outlet grill 32 and alongside, optionally against, the bottom of the adjacent lower sash of the window, as illustrated by arrows 34 coming from the top of the air handler.
As illustrated in
Thus, air enters housing 8 at inlet grill 30 and is drawn along a generally straight-through path by, and to, blower 36. Blower 36 then pushes the air along the path defined by baffles 42, 44 and arrows 38 in the generally straight-through path, illustrated in
Similarly, air entering the air handler through the center, or through the right side, of the air handler at grill 30, exits the air handler through exit grill 32 at the respective center, or right, side of the air handler. Thus, the interior of the air handler housing 8 provides a relatively straight-through path of travel, unrestricted by cross-section changes except as the air moves past blower 36. Thus, the left-to-right dimension (
Such upward expression of the air along the glass, which air is overall warmer than the air in the naturally-occurring down-flow of cold air at the inner surface of the window, generally prevents the naturally-occurring down-flow of cold air along the inner surface of the window.
Sensor 10, as illustrated in
Sensor 10 feeds its sensed humidity to controller 12 by a connecting wire, not shown. Controller 12 is a variable humidistat which can activate an electrical circuit when the relative humidity sensed by sensor 10 reaches a predetermined/pre-set level. Condensation controller 12 is electrically connected to blower 36, illustrated in
Controller 12 can, in the alternative, be a digital touch pad or other digital user interface which enables the user to specify the triggering relative humidity and/or the time over which air is to be expressed along the window glazing.
When the set relative humidity is reached, controller 12 activates the electrical circuit, turning on the blower. Once the blower is turned on, timer 48 begins counting down the set time until the timer shuts the blower off unless sensor 10 senses relative humidity greater than the set relative humidity. If the sensed relative humidity corresponds to the set relative humidity, or is greater, blower 36 continues to operate until the sensed relative humidity has fallen enough to no longer correspond to the set relative humidity, whereupon the blower then turns off.
With the blower off, the relatively cooler window glass again cools the air in its vicinity, again setting up the natural downward flow of cooler air near the window and passing close enough to sensor 10 that sensor 10 can sense the general humidity level in the falling curtain of cooled air. As the thus-cooled air moves past sensor 10 as the blower is in the “off” setting, the sensor monitors the changing relative humidity of the falling curtain of air coming off the window, and sends its sensed values to controller 12. When the sensed values again reach the relative humidity setting at controller 12, the controller again turns on blower 36.
A master on/off switch 49 (
In some embodiments, the sensor and controller are eliminated whereby blower 36 is controlled directly by the master switch. In such embodiments, once activated, the blower runs continuously until the user turns the switch off.
In especially adaptable air handlers of the invention, blower 36 has a variable speed motor, and controller 12 has a third variable speed control feature whereby the user can set and vary the speed of blower 36 so as to control the rate at which air is expressed from housing 8 at outlet grill 32. In the alternative, conventional circuitry in controller 12 can increase or decrease blower speed according to the extent by which air temperature and/or relative humidity, as sensed by sensor 10, deviates from a pre-set temperature and/or humidity.
It is typically desirable to provide relatively uniform rates of outflow of air across substantially the full width of the air handler, in order to effectively treat the full width of the window illustrated in
In the alternative, air inlet grill 30 can have a reduced width between ends 22, 24 and the air flow path can define a reduced-cross-section throat, relative to the width of the housing, and containing a reduced-size/shorter blower: whereupon the air is thence channeled along one or more expanding air flow paths to outlet grill 32.
In yet another alternative, the air flow path can include a pressurized, low pressure, chamber wherein the rate at which air is expressed from the outlet grill is controlled by the sizes of the air outlet openings 50 in outlet grill 32.
Returning to
Application of the invention disclosed herein is a compromise between heat loss and prevention of condensation. Condensation is prevented by warming the inner surface of the window using e.g. ambient air from the room to heat the surface of the glass enough that the humidity in the ambient room air does not condense. However, such warming of the inside surface of the window glass does extract an incremental amount of heat from the ambient air and transfer that heat to the glass. Such heat loss is automatically and generally made up by the building central heating system in the normal course of heating the building through conventional registers or radiators according to a thermostat setting used by the central heating system to heat the building. The amount of heat used in incrementally heating the window is related to the rate at which the air flows over the inner surface of the glass, and the temperature of that air. Accordingly, the rate of air flow and/or the heat applied to the air is controlled so as to apply, with suitable margin for fluctuating conditions, just the right amount of heat to the glass to prevent condensation. The lower corners of the glass are the areas most prone to condensation, and so enough air is applied, optionally including at or proximate the lower corners, to prevent condensation in the lower corners.
By contrast, the invention does not contemplate applying a normal full register output of heated air, from the building central heating system, onto/along the window; as such quantity of heat transfer is normally excess to the amount needed by the window for preventing condensation, and wastes heat by transferring, to the glass, more heat than is needed to avoid condensation forming on the window. Rather, the amount of air and heat needed to avoid condensation is typically far less than the amount of heat produced by the building heating system. Accordingly, such centrally-heated air, where used, is only a small fraction, substantially less than half, the amount of air normally expressed through a zone-sized air diffuser.
By zone-sized air diffuser is meant an air diffuser adapted to convey space heating heat for a medium size room of about 1000 cubic feet to about 2000 cubic feet.
In some embodiments, the air handier includes a heater 52 (
The aftermarket air handler 2 shown in
In some implementations, rear wall 20 is displaced from the inner surface of the sash whereby air outlet grill 32 can be located in the rear wall 20 of the housing of the air handler. However, the direction of flow of a substantial portion of the air, generally all of the air, relative to window 6 is still upwardly.
Power to run the blower(s), sensor 10, control 12, where used, and optionally heater 52, can be provided from a conventional outlet connected to the national electric grid, from photovoltaic cells, from a battery charged by photovoltaic cells, or from other desired power source.
The embodiment shown in
Sensor 10 is mounted on air outlet grill 32. Controller 12 is mounted on window side trim element 56. Wiring connecting controller 12, sensor 10, and blower 36 are contained internally within the window structure. Wire connectors releasably connect the wiring between controller 12 and the sensor and blower. Air inlet grill 30 and air outlet grill 32 are removable from the window structure to enable cleaning the air path and servicing blower 36 and the electrical connectors.
The principles of operation of the air handler illustrated in
The embodiments illustrated in
As illustrated in
One or more third air outlet grills 68 in the upper surface of upper element 64 is in fluid communication with third chamber 66 and directs air from the third chamber upwardly along the inside surface of the upper sash, as indicated by arrows 70 in
A fourth air chamber 72 is in fluid communication with second air chamber 58 and extends upwardly along the right side of the window frame adjacent the right side of upper sash 73. A fourth air outlet grill 74 is in fluid communication with fourth chamber 72 and expresses a gentle flow of air onto the upper sash from the right side of the window frame as illustrated by arrows 76.
A fifth air chamber is in fluid communication with the first bottom air chamber 37 and extends upwardly from the first bottom air chamber 37 inside the left side of the window frame, generally to the top of the lower sash. A fifth air outlet grill is in fluid communication with the fifth chamber and expresses a gentle flow of air onto the lower sash from the left side of the window frame.
A sixth air chamber is in fluid communication with the fifth chamber and extends upwardly from the fifth air chamber along the left side of the window frame adjacent the left side of upper sash 73. A sixth air outlet grill is in fluid communication with the sixth air chamber and expresses a gentle flow of air onto the upper sash from the left side of the window frame.
While the fifth and sixth chambers and the fifth and sixth air outlet grills are not shown, these elements are generally mirror images, in structure, in location, and in function to the respective air chambers and air outlet grills on the right side of the window, with the exception of air chamber feed opening 62. While feed opening 62 is illustrated on the right side of the window frame, the third chamber can as well be fed from the left side of the window frame, or from both sides of the window frame, by fabricating such feed opening in the left side of the window frame, fed from the fifth air chamber, and communicating with a corresponding intake opening on the left side of the third air chamber.
Referring now to
A positive displacement blower 36 in tap duct 80 meters the air to air chamber 37. Air chamber 37 feeds a gentle flow of a first portion of the air in an upwardly direction as indicated by arrows 40 along the inside surface of the window through an air outlet grill 32 at the bottom of the window, and feeds second and third portions of the air into an upwardly extending second chamber 58 and an upwardly extending fifth chamber 84. The second and fifth chambers communicate with respective air outlet grills in generally horizontally expressing respective gentle air flows along the inside surface of the window as indicated by arrows 76 and 82. The user controls operation of the positive displacement blower 36 in the embodiments which employ such blowers, using controller 12, including dial 46 and timer 48.
While a positive displacement blower has been illustrated in
A master control valve, such as a damper 85, is located in tap duct 80. Damper 85 provides an overall open-closed capability to the flow of air in tap duct 80. Damper 85 is opened during the winter heating season to allow passage of warmed air and is closed during the summer air conditioning season to generally prevent passage, onto the window glazing, of air cooled by the air conditioning system.
In some embodiments, the building central heating system blower is set up to run constantly as a way of maintaining constant air circulation and thus good mixing of the air throughout the building space controlled by the space heating system. Where the blower is so set up to run constantly, a portion of that constant air supply is constantly fed to tap duct 80. Given such constant air flow supply, blower 36 can be deleted and the air flow rate is controlled by damper 85 in combination with sensor 10 and the corresponding condensation controller 12 or computer controller 88 discussed following with respect to
The above description has focused on a single window. And one or more individual windows can be so controlled to eliminate the formation of condensation on the respective window. An alternative is to control multiple windows, optionally all the windows on a floor of a building, or all the windows in the building, using a computer controller, such as a digital computer.
A block diagram representation of such system is shown in
Computer 88 is shown connected by dashed communication link 100 to building central heating unit 90. Central heating unit 90 is connected by dashed lines 104A, 104B, 104C representing heating air conduits connecting to respective windows 6A, 6B, 6C.
Referring to
As used herein, a central heating unit is a heating device which provides general ambient air heating to a substantial portion of a building such as to multiple rooms, to a heating zone, or to the entire building. The heat output from such heating unit may be controlled by multiple spaced thermostats, all feeding to one or more space heating units which generate the heat, whether from combustion, heat pump, or non-conventional e.g. renewable heat source, for generally heating the space, the furniture, and the fixtures housed inside the building. Temperature of heated air outputted from such heating unit at steady-state operation is typically at least about 120 degrees F. or greater, though lower temperatures are contemplated as the industry strives to capture greater efficiency from such heating systems. Especially in residential heating systems, the heated air is commonly expressed into the heated air space of the building ate temperature which feels warm to a person who samples or senses the air flow at the diffuser.
Where a central heating system is used as the source of air for air handlers 2, throttling down the air flow can be an important feature of the air handling system of the invention in order to not be expressing an unnecessary amount of warmed air along the relatively cooler surface of the glass; thus to limit the amount of heat which is lost through the glass and which heat loss is associated with air handling as taught herein, while effectively controlling the formation of condensation on the respective window. In such instance, the air can be throttled by e.g. damper 85, or positive displacement blower 36, or both.
It will also be recognized that closing off tap duct 80 during the air conditioning season, to avoid blowing cold air onto the window glass, is an important feature of those embodiments which use air from, and/or air ducting connected to, the building central heating system. Thus, some structure must be provided to close off tap duct 80 as seasonally needed. Damper 85, or other effective closure structure, can serve such purpose.
Recognizing the compressibility of air, the phrase “positive displacement blower” is a relative term, and refers to blowers which can be used to generally meter a flow of air including throttling down an incoming air pressure to provide a lower-pressure, more gentle, output at a relatively predictable and consistent air flow rate.
Still referring to the embodiments which use input air from the central heating system, computer 88 continuously monitors both the sensors 10 and the central heating unit. When a sensor triggers a computer command for air to be blown along a window, computer 88 queries the central heating unit. If the central heating unit is producing and supplying a warm air flow, the computer calculates and sets a suitable opening on the respective damper 85 accordingly, and starts the respective blower 36.
If, on the other hand, the central heating unit is not supplying an air flow, computer 88 sets a suitable opening on damper 85 for blower-only air draw, and starts blower 36, which thus draws air from inside the heating system air ducting. In the latter scenario, the damper is typically wider open in order to pass sufficient air mass under the influence of a less aggressive air output from blower 36, and at a relatively lower temperature, than is typically received from the blower on the central heating unit.
Where the condensation control system is not integrated into the building heating system, computer 88 monitors the sensors 10 and activates a respective blower, on a given window, when the sensor at that window reaches the triggering humidity value.
Blowers 36 can be single speed blowers, or alternatively variable-speed blowers. Input platform 96 can be used to set certain parameters, where different settings can be used at different windows, and under different weather conditions. Typical parameters which can be set for a given window are, without limitation,
(i) the humidity level which triggers activating the respective blower,
(ii) the time the blower runs before it is shut off,
(iii) blower speed/output, and
(iv) whether a heater is activated or left turned off.
The air handlers at any number of windows can be controlled by computer 88. Computer 88 can be integrated into the control system for central heating unit 90, or any other climate control computer in the building, or can be a stand-alone, separate computer, or can have advisory/information exchange communications capability with any climate control computer associated with the building central heating system.
In general, grills 30 and 32 can be similar to removable air diffuser grills commonly used in conventional forced air central heating systems, adapted to the size requirements of the air handlers employed herein. Grills 30 and 32 are typically removable from the window structure to enable cleaning the structure inside housing 8 and along the air path and for servicing blower 36 and the electrical connectors.
Grill 30, or grill 32, or both, are optionally configured to have e.g. closure louvers which can close off the air flow path at the grills and to limit the chance of items being accidentally dropped through e.g. an outlet grill. Such louvers can be controlled manually or electrically such as by activation of a two-position actuator, for example and without limitation a solenoid actuator. For example, baffle 44 can have an upper segment and a lower segment as shown in
The humidity sensor illustrated in
In other embodiments, sensor 10 can be a light-based sensor which is sensitive to prismatic effects or other light scattering as is common when condensation forms on the window glass. Such light-based sensor can be set to directly detect the presence, or absence, of such light-scattering affect at the surface of the glass. When the sensor senses a light scattering which is representative of condensation, the sensor sends a signal to that affect to computer 88, and the computer turns on the respective blower 36 and/or heating unit, depending on default input in computer 88, or overriding input from input platform 96.
Sensor 10 can alternatively sense other proxies for condensation and/or humidity in order to determine the probability that condensation has already formed on the window or that formation of condensation on the window is imminent or likely, thereby triggering the activation of blower 36 or other means to initiate flow of air along the inner surface of the window glass.
The air being moved through air handler 2 is at a relatively lower humidity, such as about 30 percent relative humidity, whereby such air can and does absorb moisture from the condensation on the glass/window. In addition to the condensation moisture being absorbed into the air moving past the glass, the warmer-temperature moving air also imparts some of its heat to the glass, whereby the temperature of the glass rises. The combined effect of the warmer air absorbing moisture and the warmer glass having less capability to attract condensation results in a decrease in moisture condensation on the glass. As the amount of condensation on the glass decreases, the light-scattering affect of the condensation decreases.
As the light scattering affect decreases, sensor 10 senses the reduced light scatter and reports such change to computer 88. As a result, computer 88 either turns the blower off or progressively incrementally reduces the speed of the variable speed blower until either the blower is turned off or initial elements of condensation light scatter again are sensed by the sensor. in the situation where the degree of condensation light scatter changes, as sensed by the sensor, the computer increments the speed of the blower up or down as needed to maintain a minimum indication of condensation light scatter from the sensor. Where a heater 52, or otherwise-heated air, is also available, computer 88 can also control heat flow relative to condensation amount, as part of the control system.
As humidity and temperature conditions at the window change, to the effect that condensation will not form with the blower off, the computer's constant monitoring of sensor input and incrementing of blower speed and optionally heat input, results in turning the blower off when no air is needed at the window surface. Thus, the combination of variable speed blower, variable heat input, light scatter-sensitive sensor, and computer control, provide the option of relatively close control of system operation to provide, on the glass surface, that minimum rate of airflow, and only as actually needed, which is the minimum required to prevent significant condensation on the window.
The benefit of such careful control of air flow and heat input is that condensation is controlled while limiting, optimizing, largely minimizing the amount of added heat lost through the window as a result of blowing the air along the surface of the window in order to heat the window surface enough that substantial quantities of condensation do not form on the window, and limiting the energy consumed by running the blower, optionally the heater in controlling formation of condensation on the window.
The invention has been presented here in the context of the four-fold objectives of
(i) preventing cold air flow proximate the floor,
(ii) preventing fogging which obscures visibility through the window,
(iii) preventing damage to window frame elements from standing water on such frame elements, and
(iv) preventing mold and mildew.
The first two objectives represent comfort and convenience factors which have different values to different people, whereby these objectives may not need to be achieved in all instances. The primary objective is to prevent damage to window frame elements and the associated wall structure such that the windows need not be replaced before they serve their expected use life and the wall structure is not damaged.
Since the first and second stated objectives are less important, and can be compromised as desired, the air flow rate and frequency can be set to ignore these factors if and as desired by a given user, though such objectives typically are pursued. Where light-sensitive sensors are used, the invention is permissive of some condensation forming on the windows, so long as the amount of condensation is not so great that droplets coalesce and flow to the bottom of the glass and onto the sash or window frame, thus achieving the primary objective of preventing rotting of the wood. Overall, typically all four objectives are pursued, and can be achieved.
A first critical feature distinguishing this invention from general space heating, using e.g. a central heating system, is that air handling, and air handlers, of the invention express their air flow only onto/along the inner surfaces of the windows and only within the confines of the heights and widths of the windows, and only at heat exchange rates which are generally insufficient to meet the space heating needs of the adjacent areas inside the building.
A second critical feature distinguishing this invention from general hot-air space heating, using e.g a central heating system, is that the rate of air flow expressed onto the window glazing by air systems of the invention is substantially lower than the rates of air flow from air diffusers used in conventional central hot-air central building heating systems.
The following are exemplary, and not limiting, parameters representative of how an air handler of the invention can service a window which fits a nominal 10 square foot opening in a building, and expressing the air onto the window glazing, and across substantially the full length and width of the window glazing:
The above-recited air flow rates are considered “gentle” air flow rates within the scope of the invention. Such air flow rates, passing through conventional air diffusers, are generally not distracting to people in the same room. The volumetric and linear rates of gentle air flow, of course, depend on the assumed parameters, whereby air flow rates and/or heat input are adjusted accordingly within the capabilities of the air handler and/or the air handling system.
Housing 8 contains a first air chamber 37 which extends the full length of the housing between the left and right sides of the window. Inside chamber 37, housing 8 has one or more fans, and one or more baffles, generally as illustrated in
A left leg 110 depends downwardly from the left end of housing 8. Leg 110 extends frontwardly over the front surface of the lower sash and extends thence downwardly along the left side of the lower sash generally adjacent the front of the lower sash, to the vicinity of window sill 4.
In the illustrated embodiment, left leg 110 is made of the same PVC tubing material as housing 8, and the air chamber 112 inside left leg 110 connects with, communicates freely with, chamber 37 in housing 8 at the left end of housing 8. Air outlet openings, corresponding to the air outlet openings in housing 8, are arrayed along the length of left leg 110 adjacent the glazing in lower sash 28, and are adapted to direct an outlet air flow in a rightward direction onto and across the glazing. Structure and sizing of the air outlet openings in the left leg are generally the same as the structure and sizing of the air outlet openings in housing 8.
A right leg 114 depends downwardly from the right end of housing 8. Right leg 114 extends frontwardly over the front surface of the lower sash and extends thence downwardly along the right side of the lower sash generally adjacent the front of the lower sash, to the vicinity of window sill 4.
In the illustrated embodiment, right leg 114 is made of the same PVC tubing material as housing 8, and the air chamber 116 inside right leg 114 connects with, communicates freely with, chamber 37 in housing 8 at the left end of housing 8. Air outlet openings, corresponding to the air outlet openings in housing 8, are arrayed along the length of right leg 114 adjacent the glazing in lower sash 28, and are adapted to direct an outlet air flow in a leftward direction onto and across the glazing. Structure and sizing of the air outlet openings in the right leg are generally the same as the structure and sizing of the air outlet openings in housing 8.
In consonance with the operation of the one or more blowers, the one or more baffles, and the optional one or more heating units, ambient-temperature room air is drawn into chamber 37 at air inlet openings 106 in housing 8. The one or more blowers, in combination with the chambers 37, 108 and 116, are sized and configured such that, when the blowers are running at steady state condition, a generally uniform air pressure is set up inside all three of air chambers 37, 108, and 116, whereby a generally equal quantity of air is expressed onto both of the respective upper and lower sashes. The air is heated as necessary to achieve the desired relief from fogging of the window glazings.
In the embodiment illustrated in
Thus, the air handling unit of
On the rear of the window structure is mounted a rear closure panel 118 which closes off the rear of the window from the ambient environment, thus creating a chilling cavity 120.
The window unit as tested was 2 feet wide by 3 feet tall. U-values for the upper and lower glazings 122, 124 were 0.35W/m*K.
Before start of the tests, the rear surface of the window frame was covered by four layers of standard e.g. d-flute 3-layer corrugated cardboard 125 such that the cardboard was about 0.25 inch to about 0.5 inch from the rear of the glass. The overall thickness of the cardboard was about 0.38 inch. Pellets of dry ice 126, shown in dashed outline in
An air handler 2 was mounted to the front of the window, Air handler 2 had a header housing 8 mounted to the sash at the top of the sash. Left and right legs 110 and 114 extended from header housing 8, downwardly along the left and right edges of the window, in front of, and adjacent, the sash framing. Legs 110 and 114 extended generally straight down from housing 8 at the top of the window to terminal ends adjacent the bottom of the glazing. Thus, the legs were generally tight against the lower sash and spaced from the upper sash by a distance which corresponded to the front-to-back thickness of the lower sash.
Housing 8 had an air chamber 37. Left and right legs had air chambers 112 and 116, both connected to air chamber 37 for passage of air from chamber 37 to chambers 112 and 116.
Air outlet openings 108 as in
An input T-adapter 130 was assembled to housing 8 at the left side of the top of the window. Flexible tubing 132 was connected to adapter 130. Tubing 132 was connected to the outlet of a commonly-available personal-care hair dryer such that the air and heat output of the hair dryer was fed into chamber 37 when the hair dryer was turned on. The purpose of the test was to demonstrate that low velocity air, with optional use of heat, can be used to control fog on a window under even very adverse outside weather conditions.
At the start of the test, dry ice was loaded into chilling cavity 120 and was positioned against the glazings. The dry ice was maintained in constant contact with the glazings throughout all testing. The following Table 1 shows the conditions of the test, and the resulting control of fog on the window glass.
As shown in Table 1, as the test started, the test bed was stabilized at room temperature of about 75 degrees for 10 minutes. Then the dry ice was added to cavity 120. At that point, relative humidity was 25%, air velocity from the outlet slots was “0”, room temperature was 75F, slot temperature air was 75F, temperature on the inside surface of the upper window glass immediately dropped to 43F, temperature on the inside surface of the lower window glass immediately dropped to 16F, and temperature on the outside surfaces of the glass, indicated in the data as screen temperature, immediately dropped to −48F. Within 2 minutes after loading the dry ice into cavity 120, condensation began forming on the glass, with temperatures on the glass surfaces having generally not changed. Within 5 minutes after loading the dry ice into the cavity, frost was present on the glass, and glass temperatures had dropped modestly.
The test system was then held constant for 24 minutes whereupon the dryer was turned on with high heat. Table 1 shows that air velocity at the slots was 767 feet/minute, and temperature leaving the air slots was 75 degrees but had risen to 92 degrees six minutes later. Also six minutes later, concurrent with the rise in the slot temperature, the frost had disappeared from the glass such that there was no condensation, no frost on the window. The window had been freed from condensation in six minutes.
The same condition of high heat, and the same air velocity, was held for about 1 hour, with no change in condition of the glass. Then room relative humidity was raised to about 45% and the heater on the hair dryer was switched to low heat, maintaining the same air velocity. In ten minutes, a low level of condensation appeared on the glass. Then the hair dryer was turned off and within 5 minutes the glass showed a medium level of condensation. While maintaining the higher room humidity, the hair dryer was again turned on with high heat. Over a period of 44 minutes, the extent of the condensation gradually diminished until the glass was again clear of all condensation, in the presence of about 45% relative humidity.
Table 1 gives the data collected, as well as representing the levels of condensation and the hair dryer settings at the respective times.
The data collected during the above test was then analyzed to project the combination of a slot air temperature, linear air velocity needed at that air temperature to prevent condensation, inside duct diameter to maintain specified linear air velocity with 0.08 inch water pressure drop, and heater output required to maintain the specified temperature at the specified linear air velocity, all for a series of double-hung windows under the following conditions:
As illustrated in
air temperature at the outlet slots, about 65 degrees F.
air velocity, about 200 ft/min,
air volume, about 10 CFM,
duct diameter, about 2 inches,
heater output, about 70 watts.
The parameters shown in
While the rate of flow of air fro the outlet grill is relatively modest, the rate is sufficiently great as to affect the temperature of the window along substantially the full dimension of the window from the outlet grill to the distal side of the glazing. Thus, where the outlet grill is at the bottom of the glazing, the air expressed from the outlet grill affects the full height of that glazing. Where the outlet grill extends along a single side of the window, the air expressed from the outlet grill affects the full width of the respective glazing. Where there are outlet grills on opposing sides of a given glazing, the air expressed from the outlet grills, collectively, affects the full width of the respective glazing. Wherever the outlet grill, whether there is one outlet grill or more than one outlet grill, the outlet grill design and configuration collectively enable the air handler to provide functional air flow to all areas of the window which are susceptible of experiencing condensation under the operating conditions to which the window is expected to be exposed in routine use in the anticipated environment.
As can be seen from the various embodiments illustrated in the drawings, air handlers of the invention are designed differently for specific classes of windows, such classes as double hung windows, fixed-pane windows, casement windows, awning windows, and the like. The air handlers are also designed differently where the air handler is incorporated into the window structure, itself, as opposed to stand alone air handlers which can be mounted on an exposed surface of the window structure.
Air chambers extend substantially the full telescoped lengths of legs 110, 114, and have gaseous communication with chamber 37 in header 8. First and second blowers 36 are disposed inside the air chambers in legs 110, 114. In the alternative, the blowers could be located in the left and right portions of chamber 37 in header 8.
First heaters 52 are disposed in each of the air paths between the respective air inlets 30 and the uppermost ones of the air outlet apertures in legs 110, 114. A second supplementary heater 53 is disposed in each of legs 110, 114 between the respective blower 36 and the most remote one of the air outlet apertures in the respective leg.
As in the earlier examples of the invention, operation of the air handler can be controlled by manually operated switches, or can be controlled by e.g. a computer chip 140. In any event, the blowers 36, the first heaters 52, and the second heaters 53 can each be individually controlled so as to maintain the window with little or no condensation on the glass while limiting the amount of energy used.
Thus, a given window may be adequately protected from condensation by mounting a single one of legs 110 or 114 to either side of the window. Where the temperature gradient between inside and outside is especially harsh, or for relatively wider windows, legs on both sides of the window can advantageously be used. Thus, by providing air inlet, heater, and blower in each leg, the user can simplify the need for servicing a variety of window sizes, in a variety of use conditions, by applying either one or two of the air handlers of
Advantageously, such legs are installed with the air inlets disposed upwardly. Heaters 53 are optional, and are controlled separate from the control of heaters 52 whereby heaters 53 can be used to provide supplementary heat when suggested by adverse temperature/weather conditions.
FIG. 8E1 shows a cross-section of one of the legs 110, 114, and mounting structure mounting the leg to the window frame 39. A mounting element 148, such as double-sided tape, hook and loop fasteners, or the like, is interposed between a mounting foot 158 on the leg and the window frame 39. While it is contemplated that the air handler, once mounted to a window, will not be moved, use of a releasable such mounting structure such as hook and loop fasteners can accommodate a temporary such mounting as desired.
While the air handlers illustrated herein have illustrated air being expressed onto the glass from both left and right sides of the glass, it is contemplated that relatively narrower windows can be kept free of condensation by air expressed from only the left side, or from only the right side, and that with relatively wider windows, the air should be expressed from both sides in order to ensure that the windows remain fog-free. The actual requirements for a given window include considerations of window structure as well as the expected operating environment within which the window will be functioning, and generally represent a balancing of structure, air flow parameters, and heat applied to the outlet air. Greeter linear footage of air outlet grill and/or air temperature typically accommodate relatively lower air flow rate. Greater air flow rates generally accommodate relatively lower temperature and/or relatively smaller air outlet linear footage.
Where the air handler is not incorporated into the window, but rather is mounted to an external surface of the window, the header and any leg or legs can be telescoped as illustrated in e.g.
Accordingly, now that the invention has been described for various of such embodiments, those skilled in the art can now readily design air handlers of the invention, and methods for use of such air handlers, for any desired window class, or for custom window structures, without departing from the spirit of the instant invention. And while the invention has been described above with respect to the preferred embodiments, it will be understood that the invention is adapted to numerous other rearrangements, modifications, and alterations, and all such arrangements, modifications, and alterations are intended to be within the scope of the appended claims.
To the extent the following claims use means plus function language, it is not meant to include there, or in the instant specification, anything not structurally equivalent to what is shown in the embodiments disclosed in the specification.
This application is a Continuation-In-Part of U.S. Non-Provisional Application 12/386,700, filed Apr. 21, 2009, which is a Non-Provisional Patent Application of Provisional Application 61/124,938, filed Apr. 21, 2008, the complete disclosures of all of which are incorporated herein by reference, in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 61124938 | Apr 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12386700 | Apr 2009 | US |
| Child | 14058472 | US |
