Abstract:
A closed air handling system for heating and/or cooling has an integrated damper mechanism for diverting discharge air into the attic or crawl space of a house, apartment, or other building, and for facilitating the introduction of fresh air into such building. Optionally, the damper has integrated louvers for use during an open position such that a venturi effect increases airflow by creating a vacuum between the louvers and the ducts connected to the discharge plenum.

Description:
CROSS REFERENCES  
       [0001]     Applicant claims priority to U.S. patent application Ser. No. 11/224,764, filed Sep. 13, 2005. 
     
    
     GOVERNMENTAL RIGHTS  
       [0002]     None.  
       BACKGROUND OF THE INVENTION  
       [0003]     Before the advent of evaporative air cooling systems, now commonly known as air conditioning, many homes were cooled by the movement of air via fans. Even today, the high cost of heating and cooling indoor living spaces makes moderating indoor air temperatures using fresh air highly desirable when outdoor temperatures allow. Not only can fresh air be used to moderate temperature, the simple movement of air can create a cooling sensation on the human skin.  
         [0004]     Attic fans are capable of both creating air movement and bringing fresh air into a dwelling. Attic ventilations systems date back to at least 1938, when U.S. Pat. No. 2,130,660 issued on such a system. However, the prior art relating to attic ventilation systems is deficient as applied to contemporary dwellings for several reasons. Many structures may not be designed such that installation of an attic fan is feasible. Attic fans may not be aesthetically pleasing to builders, owners, and potential purchasers of modern homes as such devices require a large opening inside the dwelling. Attic fans are typically very noisy. Finally, when not in use, an attic fan usually does not form a sufficient protective barrier between the hot, cold, or dusty attic and the living spaces of the dwelling in which the fan is installed.  
         [0005]     Other attempts to improve the attic fan have not remedied the above-listed deficiencies of the prior art. U.S. Pat. No. 2,337,382 (the &#39;382 patent) issued on an attic fan that contains auxiliary ducts to transmit air not only into the attic, but also into other rooms of the dwelling. Because this design necessarily includes an attic fan, it is deficient for the similar reasons as an attic fan, including unsuitability for installation in modern dwellings, noise, and unpleasing aesthetics. The &#39;382 patent relies solely upon ambient temperatures outdoor for cooling and separate sources (such as fireplaces or wood-burning stoves) for heating.  
         [0006]     Central heating and/or air conditioning systems are ubiquitous for most new construction of dwelling houses in the continental United States. These systems rely upon a closed system of ducts to transfer heated or cooled air from a central location to all rooms within a dwelling. However, central heating and/or air conditioning systems have one major deficiency in that such systems merely circulate air already inside the dwelling. That is, central heating and/or air conditioning systems have no means by which to facilitate the introduction fresh air to the dwelling. Certainly an inhabitant can open the windows to a home to allow entry of fresh air, but the central heating and/or air conditioning system of such a home does nothing to speed such entry. There exists a clear need to unify the old technology of attic fan units with current closed system central heating and/or air conditioning systems. Indeed, many scientific studies demonstrate that indoor air is more polluted than outdoor air even in the most heavily populated and industrialized cities. These studies conclude that the poor ventilation rates provided by central heating and/or air conditioning systems are unsatisfactory. High moisture and dust content of air continually recycled by central heating and/or air conditioning systems may be a contributing factor to indoor air pollution.  
         [0007]     One invention of the prior art purports to solve the problem of utilizing both ambient air and air conditioning to cool the interior of a building. U.S. Pat. No. 5,065,585 (the “&#39;585 patent”) discloses a central air handling unit mounted in the attic of a building. The air handler has a return air vent, a blower, an evaporator coil, a discharge plenum, and a plurality of ducts coupled to the discharge plenum. The discharge plenum is connected via additional ducts to a stand-alone damper, which has a damper blade that may be selectively positioned in two arrangements. In a first closed arrangement, the damper blade is positioned such that the system acts as a normal air handling system; that is, when the blower is activated air flows into the system through the return air duct, past the stand-alone damper, through the central air handling unit, and out the ducts into the building. In a second closed configuration, the damper blade of &#39;585 patent is secured in a position such that when the blower is activated, an air duct connected to the outside of the building allows outside air to flow through the duct, past the stand-alone damper, into the central air handler, and out the ducts into the building. The inventive step is that the damper also opens a port to the attic, and air flowing through the return air duct is blown into the attic. This design suffers from four known flaws. First, in many applications, the blower cannot draw sufficient air from outside the building through the ducts to positively pressurize the interior of the building, so very little air actually moves through the port into the attic; such a deficiency defeats the purpose of the invention. Second, the utility of the invention is wholly compromised if the interior of the building is not a closed system; for instance, if someone were to open a window, the port would be rendered useless. Third, the &#39;585 patent requires a stand-alone damper that, due to the outside port, can be expensive to purchase and install. Fourth, the invention disclosed in the &#39;585 patent will allow heat to be transmitted from the interior air through the damper to the fresh air coming in, unless the damper is insulated or made from an insulating material and the damper and damper enclosure create a tight seal. It is thus an object of the present invention to provide a damper that can be retrofitted to existing installations and works well in an open system.  
         [0008]     Bearing in mind the deficiencies of the prior art, it is an object of the present invention to provide a semi-closed central heating and/or air conditioning system that facilitates the entry of fresh air into a dwelling.  
         [0009]     It is a further object of the present invention to provide a central heating and/or air conditioning system that increases the ventilation rate for dwellings in which it is installed.  
         [0010]     It is a further object of the present invention to provide ventilation for the removal of smoke or other undesirable odors wherein the semi-closed system pulls fresh air from outside the system to refresh ambient room conditions.  
         [0011]     It is a further object of the present invention to provide a semi-closed system for introducing fresh air into a dwelling that is quiet and substantially hidden, with the exception of the grilles and diffusers typical of a central heating and/or air conditioning system of the prior art.  
         [0012]     It is a further object of the present invention to provide a semi-closed system that operates similarly to an attic fan but requires a much smaller area of exposure to the attic that is necessary to seal and insulate.  
         [0013]     It is a further object of the present invention to provide an automated semi-closed system for introducing a predetermined amount of fresh air into a dwelling&#39;s central heating and/or air conditioning system.  
         [0014]     The apparatus in accordance with the present invention provides a substantially quiet, hidden, and automatic semi-closed system that is integrated with a central heating and/or air conditioning system and facilitates the entry of fresh air into a dwelling.  
       BRIEF SUMMARY OF THE INVENTION  
       [0015]     A semi-closed central heating and/or air conditioning system is provided in which the system further facilitates the entry of fresh air into a dwelling. A typical central heating and/or air conditioning system has a central air handler that is comprised of a return air vent, a discharge plenum, and a plurality of ducts coupled to the plenum for distributing air to a plurality of areas in the building. For heating, the system has a blower and a heat exchanger for heating interior air. For cooling, the system has an inside evaporator coil coupled to the air handler and an outside condenser unit for cooling interior air.  
         [0016]     In the present invention, the discharge plenum contains an integrated damper mechanism. The damper, when closed, allows the system to operate as a normal central heating and/or air conditioning system. When opened, the damper allows the air to be discharged into the attic or crawl space, and further discharged through attic or crawl space vents into the atmosphere. The discharge of air from the system blower through the damper creates suction by which the central air system pulls air from outside the dwelling via windows or door, which increases the ventilation rate for the dwelling.  
         [0017]     The present invention is designed to complement pre-existing central heating and/or air conditioning systems. The circuitry for controlling the present invention simply connects into the unit board of a pre-existing central heating and/or air conditioning system of the prior art. The circuitry of the present invention turns on power to the central heating/cooling system blower, and locks out the thermostat signals, so no air is conditioned with heating or cooling during operation as an attic fan system. Further, when the invention is installed in an attic, the discharge of air from the damper into the attic serves to carry away the solar heating load of the roof, which keeps such load from reaching the living quarters without the necessity of operating the high-energy cooling system.  
         [0018]     These and other advantages will become apparent from the following detailed description which, when viewed in light of the accompanying drawings, disclose the embodiments of the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  is a depiction of a dwelling with an up-flow central heating and/or air conditioning system that operates in the mode of the prior art. Air is drawn into the blower through a return air duct/vent, forced through the heat exchanger and/or air-cooling coils and into the discharge plenum, and ultimately diverted into the duct system servicing the various rooms in the dwelling.  
         [0020]      FIG. 2  is a depiction of the same system as in  FIG. 1  where the discharge plenum is open to the attic space. Air is drawn into the return air duct/vent and forced through the heat exchanger and/or air-cooling coils and into the discharge plenum. Instead of being circulated back into the rooms of the dwelling as is done with the closed heating and/or air conditioning systems of the prior art, the new system exhausts air into the attic and outside through the attic vents.  
         [0021]      FIG. 3  is a depiction of a dwelling with a down-flow central heating and/or air conditioning system that operates in the mode of the prior art. Air is drawn into the blower through a return air duct/vent, forced through the heat exchanger and/or air-cooling coils and into the discharge plenum, and diverted into the duct system servicing the various rooms in the dwelling.  
         [0022]      FIG. 4  is a depiction of the same system as in  FIG. 3  where the discharge plenum is open to the crawl space. Air is drawn into the return air duct/vent and forced through the heat exchanger and/or air-cooling coils and into the discharge plenum. Instead of being circulated back into the rooms of the dwelling as is done with the closed heating and/or air conditioning systems of the prior art, the new system exhausts air into the crawl space and outside through wall vents.  
         [0023]      FIG. 5  is a depiction of a dwelling with a central heating and/or air conditioning system situated in an attic space that operates in the mode of the prior art. Air is drawn into the blower through a return air duct/vent, forced through the heat exchanger and/or air-cooling coils and into the discharge plenum, and diverted into the duct system servicing the various rooms in the dwelling.  
         [0024]      FIG. 6  is a depiction of the same system as in  FIG. 5  where the discharge plenum is open to the attic space. Air is drawn into the return air duct/vent and forced through the heat exchanger and/or air-cooling coils and into the discharge plenum. Instead of being circulated back into the rooms of the dwelling as is done with the closed heating and/or air conditioning systems of the prior art, the new system exhausts air into the attic and outside through attic vents.  
         [0025]      FIG. 7  is a depiction of a dwelling with a central heating and/or air conditioning system situated in a floor crawl space that operates in the mode of the prior art. Air is drawn into the blower through a return air duct/vent, forced through the heat exchanger and/or air-cooling coils and into the discharge plenum, and diverted into the duct system servicing the various rooms in the dwelling.  
         [0026]      FIG. 8  is a depiction of the same system shown in  FIG. 7  where the discharge plenum is open to the crawl space. Air is drawn into the return air duct/vent and forced through the heat exchanger and/or air-cooling coils and into the discharge plenum. Instead of being circulated back into the rooms of the dwelling as is done with the closed heating and/or air conditioning systems of the prior art, the new system exhausts air into the crawl space and outside through wall vents.  
         [0027]      FIG. 9  is a front view of the optional damper of the present invention in an open position.  
         [0028]      FIG. 10  is a side view of the optional damper of the present invention in an open position.  
         [0029]      FIG. 11  is a front view of the optional damper of the present invention in a closed position.  
         [0030]      FIG. 12  is a side view of the optional damper of the present invention in a closed position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]     Referring to  FIGS. 1 through 8  of the drawings, a central heating and/or air conditioning system for a dwelling is disclosed that additionally provides a ventilation mode. The modified central heating and/or air conditioning system has a central air handler  11  which is positioned within a building and includes a heat exchanger  13  and/or evaporator cooling coils  15  and blower  17  for transferring air from a return air duct/vent  19  through heat exchanger  13  and/or evaporator cooling coils  15  and into the discharge plenum  21 . Discharge plenum  21  then delivers the air through a plurality of ducts  23  to vent the air into different areas of a dwelling. As shown by the arrows, the air normally passes directly from the interior air space  25  through the return air duct/vent  19  into the central air handler  11 . The system in accordance with the present invention adds an integrated damper  27  to discharge plenum  21  for air discharge into an attic space  29  or crawl space  39 .  
         [0032]     As seen in  FIG. 1 , the invention in the previously-known operating mode has discharge plenum damper  27  closed so that central air handler  11  acts as a conventional up-flowing heating and/or air conditioning system by taking return air via return air duct/vent  19  from interior air space  25  and forcing return air with blower  17  through the heat exchanger  13  and/or evaporator cooling coils  15  for distribution throughout the dwelling via ducts  23  in the ceiling.  
         [0033]     As shown in  FIG. 2 , the invention provides that fresh air is drawn into interior air space  25  through a window  31  or door (not shown). Stale air is drawn into return air duct/vent  19  and forced with blower  17  through central air handler  11  and into discharge plenum  21 . Discharge plenum damper  27  is open to allow the free-flow of stale air into the attic space  29 . Blower  17  forces stale air from interior air space  25  into attic space  29 , and the stale air is expelled through soffit vents  33 , roof vents  35 , ridge vents  37 , or gable openings (not shown).  
         [0034]     As seen in  FIG. 3 , the invention in the previously-known operating mode has discharge plenum damper  27  closed so that central air handler  11  acts as a conventional down-flowing heating and/or air conditioning system by taking return air via return air duct/vent  19  from interior air space  25  and forcing return air with blower  17  through the heat exchanger  13  and/or evaporator cooling coils  15  for distribution throughout the dwelling via ducts  23  in the floor.  
         [0035]     As shown in  FIG. 4 , the invention provides that fresh air is drawn into interior air space  25  through a window  31  or door (not shown). Stale air is drawn into return air duct/vent  19  and forced with blower  17  through central air handler  11  and into discharge plenum  21 . Discharge plenum damper  27  is open to allow the free-flow of stale air into crawl space  39 . Blower  17  forces stale air from interior air space  25  into crawl space  39 , and the stale air is expelled through wall vents  41 .  
         [0036]     As seen in  FIG. 5 , the invention in the previously-known operating mode has discharge plenum damper  27  closed so that central air handler  11  acts as a conventional horizontally-flowing heating and/or air conditioning system by taking return air via return air duct/vent  19  from interior air space  25  and forcing return air with blower  17  through the heat exchanger  13  and/or evaporator cooling coils  15  for distribution throughout the dwelling via ducts  23  in the ceiling. In this case, central air handler  11  resides in attic space  29 .  
         [0037]     As shown in  FIG. 6 , the invention provides that fresh air is drawn into interior air space  25  through a window  31  or door (not shown). Stale air is drawn into return air duct/vent  19  and forced with blower  17  through central air handler  11  and into discharge plenum  21 . Discharge plenum damper  27  is open to allow the free-flow of stale air into attic space  29 . Blower  17  forces stale air from interior air space  25  into attic space  29 , and the stale air is expelled through soffit vents  33 , roof vents  35 , ridge vents  37 , or gable openings (not shown).  
         [0038]     As seen in  FIG. 7 , the invention in the previously-known operating mode has discharge plenum damper  27  closed so that central air handler  11  acts as a conventional horizontally-flowing heating and/or air conditioning system by taking return air via return air duct/vent  19  from interior air space  25  and forcing return air with blower  17  through the heat exchanger  13  and/or evaporator cooling coils  15  for distribution throughout the dwelling via ducts  23  in the ceiling. In this case, central air handler  11  resides in crawl space  39 .  
         [0039]     As shown in  FIG. 8 , the invention provides that fresh air is drawn into interior air space  25  through a window  31  or door (not shown). Stale air is drawn into return air duct/vent  19  and forced with blower  17  through central air handler  11  and into discharge plenum  21 . Discharge plenum damper  27  is open to allow the free-flow of stale air into crawl space  39 . Blower  17  forces stale air from interior air space  25  into crawl space  39 , and the stale air is expelled through wall vents  41 .  
         [0040]     Opening and closing integrated damper  27  may be accomplished with an electric motor and screw drive, as seen in  FIGS. 1-8 . The inventor contemplates other methods of opening and closing integrated damper  27  such as other electro-mechanically driven methods utilizing hydraulic pistons, springs, linkages, or the like. Whatever the drive mechanism, opening and closing integrated damper  27  operates to change the system from normal mode to vent mode. The inventor contemplates both manual and automatic methods of opening and closing integrated damper  27 . As an example of suggested operation, integrated damper  27  can be opened by turning central air handler  11  to the off position, energizing the drive mechanism to open or close integrated damper  27  until integrated damper  27  is fully open, and turning central air handler  11  to a “vent mode” that energizes blower  17  without activating either heat exchanger  13  or evaporator cooling coils  15 .  
         [0041]     Turning now to  FIGS. 9-12 , damper  27  is hingeably connected along one or more sides of the discharge plenum  21 . Damper  27  optionally has one or more louvers  51 . Louvers  51  are flat, rectangular plates having two long sides and two short sides. Louvers  51  are hingeably connected on one long side to discharge plenum  21 . The second long side of louvers  51  is connected to one end of one or more actuating means  53 , preferably where the second long side of louvers  51  joins the two short sides. The other end of actuating means  53  is connected to damper  27  on the side opposite the side to which damper  27  is hingeably connected to discharge plenum  21 . For some types of actuating means  53  such as rope or cable, actuating means  53  optionally pass through guides  55  and tubes  57 , which give rigidity to louvers  51  when damper  27  is placed in the open configuration shown in  FIGS. 9 and 10  and air is blown from discharge plenum  21  out through open damper  27 . Actuating means  53  can be constructed of fiber, rubber, belted rubber, chains, servo motors, or any other means which will operate to move louvers  51  into the desired configuration when damper  27  is opened and closed.  
         [0042]     In the open position, louvers  51  act as venturi that create a partial vacuum between louvers  51  and ducts  23 , which draws air through ducts  23  and increases the total airflow of the present invention. In the closed configuration shown in  FIGS. 11 and 12 , louvers  51  hinge such that louvers  51  fold to the sides of discharge plenum  21  to prevent louvers  51  from impeding airflow from discharge plenum  21  to ducts  23 .  
         [0043]     Referring generally to the drawings, damper  27  is designed to be retrofitted to existing and/or off-the-shelf HVAC or other central heating and/or air conditioning system units. Due to the nature of materials used in traditional HVAC units, care must be taken during the installation of damper  27  to ensure that there is ample space for damper  27  to open. For typical installations, such room must comprise at least 20 inches (20″) from discharge plenum  21 , although this distance may vary for different installations.  
         [0044]     In accordance with the present invention, a central air handling system can be conveniently converted to a central ventilation system using outside fresh air for ventilating an entire dwelling when the outside conditions and temperature are such that the cooling or heating system is not needed. However, it should be clear that the present invention is not to be construed as limited to the forms shown, which are to be considered illustrative rather than restrictive.