Abstract:
An improved HVAC system is provided for the delivery of a temperature controlled air supply via one or more air curtains provided at windows, doors and walls. The air curtains create a double layer of insulation over the surface of a window, door or wall. The invention provides for the use of the temperature controlled air flow from the air curtain to directly affect the interior room temperature. The invention provides an improved system for continuous cleaning the recycled air through the use of a wet electrostatic precipitator in the HVAC air flow, as well as providing a higher speed mode for the air curtain to prevent the inflow of particles and contaminants from outside of the building, when windows or doors are open. The invention may be installed on existing construction, or incorporated as part of new construction.

Description:
FIELD OF INVENTION 
       [0001]    A system is proposed for a central heating, ventilation and air conditioning (HVAC) system for residential and commercial buildings that will save energy for ventilation, heating or cooling by changing the thermal resistance R-value of the structural elements of the building, and also deliver clean air to the interior room environment. The proposed system will allow windows to be kept open, if desired, while preventing contaminants, dust and insects from entering the interior environment. 
       BACKGROUND 
       [0002]    Contemporary HVAC systems are based on a combination of recycled air as well as the intake of ambient “clean and fresh” air that in reality may contain a variety of impurities and particulate matter, including pollutants, carcinogenic compounds, volatile organic compounds from vehicle exhaust, and a long list of toxic chemicals from any number of industrial sources. These impurities and particulate matter may be delivered by wind and precipitation, traveling from far distances, and contaminate the air and exterior spaces around the buildings. After airborne impurities and particulate matter enter a building, the concentration of such pollutants increases and may only be alleviated currently by the use of filters and similar devices. Recent data demonstrates that indoor contamination of pollutants can be up to seven times higher than outdoors. 
         [0003]    Even such perceived “harmless” exhaust from a laundry dryer may contain up to 600 toxic chemicals, many and of them being carcinogenic coming from chemicals in detergents. 
         [0004]    Conventional HVAC systems employ air cleaning devices such as dry electrostatic precipitators and filters that at best remove only dust particles, but do not remove or isolate the long list of pollutants identified above. Such conventional systems also require manual cleaning and periodic replacement of filter media. Such extensive maintenance makes the use of conventional systems impractical. Failure to clean these systems and/or to replace the filter media can drastically reduce the efficiency of these systems due to high pressure drop on the filters. 
         [0005]    Existing HVAC systems circulate heated or cooled air from the air handling unit and return it back to the air handling unit, in both cases via registers located on the floors and walls. The current locations of such registers is not the optimum place for proper temperature control, as most energy losses take place at the windows and doors, where registers are not able to be located. 
         [0006]    Further, temperature exchanges often occur along exterior facing walls, windows and doors, bringing interior temperatures closer to the temperatures outside of a building. These temperature exchanges or thermal energy losses increase the cost of operating HVAC systems in a building. As is known in the field of building construction, the use of insulating materials can decrease such temperature exchanges, but for existing structures, it may not be cost-effective to replace existing materials or add insulation within walls. 
         [0007]    The thermal energy losses, both heat and cold, can be very substantial through windows in a building. The level of energy loss depends on several factors, including the quality of manufacture, materials used, and design. Windows can account for approximately 30% of the total thermal energy loss of a building. As the latest architectural practice calls for allocating at least 40% of exterior walls for windows, the potential for thermal energy loss can only increase. 
         [0008]    The energy losses are inversely proportional to the thermal resistance R, meaning that the larger the value of R, the less energy will be lost. 
         [0009]    The thermal energy losses for a particular material are directly proportional to the heat transfer coefficient K. For a single pane glass window K=0.96, but for double paned glass conventional windows K=0.27 for the windows, with the layer of air between the window panes having a K=0.024. It is evident from these numbers that adding an air blanket above the glass window will further reduce the energy losses by 0.27/0.024 or 11.25 times. 
         [0010]    Conventional air curtains are commonly used in industrial applications where there is a need or desire to have open doors, while maintaining thermally distinct areas on each side of the door. An example of such use appears in at building entrances or cold storage rooms, where there is heavy truck or fork lift traffic in and out of the buildings or cold storage rooms. 
         [0011]    Existing air curtains are high velocity blowers located in a large housing above the door producing substantial noise and requiring frequent cleaning and maintenance. Conventional air curtains are based on traditional electrically driven blowers located in the housing placed above the desired location. In addition to their bulk and being esthetically undesirable in the residential interior setting, these blowers are also noisy, require frequent cleaning and other routine maintenance as is usually required for high speed rotating machinery. Even a small amount of dirt on the surface of the high speed rotating rotor creates dynamic misbalance leading to high noise and eventual damage to or destruction of the unit. Existing air curtain systems are not feasible for use in residential or commercial office buildings. The proposed invention eliminates the problems of existing air curtain systems. 
         [0012]    According to the present invention, the air circulated through the HVAC system is delivered into the interior of a building as an air curtain to prevent thermal energy exchanges between the interior and exterior of a building, and at the same time also uses the air curtain as a pollutant and insect barrier for open windows and/or doors. 
       SUMMARY OF THE INVENTION 
       [0013]    The invention relates to the improvements in the field of HVAC and indoor air pollution control, specifically providing a new and improved system for the delivery of a temperature controlled air supply via air curtains located at windows, doors and walls. The present invention also provides an improved system for cleaning the recycled air through the use of a wet electrostatic precipitator in the HVAC air flow, providing continuous air cleaning, without the problems of down time or labor for cleaning and replacement, and providing close to 100% efficiency in cleaning pollutants, particulate matter as small as 0.01 micron, bacteria and viruses from the air flow. 
         [0014]    The invention creates a double air blanket, preferably on the interior of a window, door or wall, where one air blanket is an air stream of an air curtain and the other air blanket is an air gap between the surface of the window, door or wall and the air curtain stream. 
         [0015]    According to the invention, the air supply operates in two modes, one for creating a slow moving air curtain blanket in front of a closed window or door or a wall, and a second mode to create much faster air curtain in front of an open window or door. An alternate embodiment of the invention provides for an air curtain along a window or paned door, the air curtain being encapsulated by an additional pane of glass. 
         [0016]    The basic climate control technology for a building using the proposed invention is similar to the conventional HVAC systems using thermostats to control heating and cooling units. As conventional HVAC systems utilize low velocity air flow delivery, the present invention provides for greater energy efficiency over existing air curtain systems. 
         [0017]    The present invention provides energy savings directly attributed to the diminished amount of thermal energy exchange between the exterior and interior of the building. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is an elevation view, with cut outs, of a single window equipped with the invention. 
           [0019]      FIG. 2A  is cross-sectional view along line A-A of  FIG. 1 , showing the upper window frame and upper nozzle. 
           [0020]      FIG. 2B  is cross-sectional view along line B-B of  FIG. 1 , showing the lower window frame and lower nozzle. 
           [0021]      FIG. 3  is block diagram of the invention. 
           [0022]      FIG. 4  is a plan view of the invention showing the conversion of small high pressure air flow to a large volume of the air flow at lower pressure based on an air-ejector design. 
           [0023]      FIG. 5  is a cross-sectional view along line C-C of  FIG. 4 , showing an air manifold mounted in front of a window. 
           [0024]      FIG. 6  is a cross-sectional view of an air delivery manifold on top at the ceiling which is constructed in the shape of the crown molding. 
           [0025]      FIG. 7  is a cross-sectional view of a window constructed with an additional glass pane installed to create the dedicated channel for the air curtain. 
           [0026]      FIG. 8  is a plan view of the invention showing the high velocity delivery of air to a window using a local blower booster and nozzle with multiplying effect. 
           [0027]      FIG. 9  is a cross-sectional view of the invention in a two story building, showing air curtains on walls, windows and the second floor ceiling. 
           [0028]      FIG. 10  is a cross-sectional view of the invention in a two story building, showing an alternate embodiment 
           [0029]      FIG. 11  is a cross-sectional view of the invention in a two story building, showing another alternate embodiment, with the invention installed within walls and ceiling. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]      FIG. 1  depicts a single window frame  1  window pane  6 . First chamber  400  and second chamber  420  are mounted on opposite sides of window frame  1 , preferably above and below window pane  6 . First chamber  400  is connected at one end to first duct  13  and has perforations  410  along wall  4 . Air distribution manifold  500  is preferably located in first chamber  400 . Vanes  5  are strategically located within air distribution manifold  500  and direct air flow toward perforations  410 , preferably for equal air distribution of the air curtain stream along the surface of window pane  6 . 
         [0031]    Second chamber  420  may be of identical construction as first chamber  400 , but is connected to second duct  14  instead of first duct  13 . Second chamber  420  has perforations  430  along wall  440 . As shown in  FIG. 1 , while first chamber  400  contains air distribution manifold  500 , second chamber is depicted without optional feature air distribution manifold  500 . 
         [0032]    In one mode of operation, an air flow enters first chamber  400  from first duct  13 , and the air flow exits first chamber  400  through perforations  410 , forming an air curtain stream across the surface of window pane  6 . The air curtain stream enters second chamber  420  through perforations  430  and exits second chamber  420  through second duct  14 . 
         [0033]    In an alternate embodiment, instead of being above and below the window pane  6 , first chamber  400  and second chamber  420  may be mounted on opposite sides of window pane  6 . 
         [0034]    While the window pane  6  shown in  FIG. 1  is a double paned window, a common type of window, window pane  6  could be a single pane of glass or multiple panes. Further, the invention may be implemented on a door, wall or ceiling, creating an air curtain stream across any of these. 
         [0035]    According to the invention when a thermal energy difference attempts to penetrate from the exterior of the building in to the interior, the thermal energy would have to overcome the insulating resistance of window pane  6  and also two layers of air, namely the layer of the air curtain and an additional layer of air between the air curtain and window pane  6 . 
         [0036]    Since the layer of air is at least 10 times less conductive then the glass the energy savings on heating or cooling can be substantial. 
         [0037]      FIG. 3  shows a plan layout of the invention. Blower  12  of air handling unit  7  sends a forced air stream into duct selector  600 . In a preferred embodiment, duct selector  600  allows the system to use first duct  13  and second duct  14  as alternating supply and return ducts for the air stream. One selection for duct selector  600  would direct the air stream from blower  12  into first duct  13 , while second duct  14  would be connected to return intake  610  of air handling unit  7 . Another selection for duct selector  600  would direct the air stream from blower  12  into second duct  14 , and first duct  13  would be connected to return intake  610 . 
         [0038]    Sensors  16  determine whether windows  6  or doors  2  are open or closed and provide the information to the programmable logic controller (PLC)  19  that operates variable frequency drive  17 , controlling the speed of blower  12 . When the windows  6  are closed, a lower air volume is needed to provide the air curtain stream over the surface of window pane  6 . 
         [0039]    After the air stream enters return intake  610  of air handling unit, the air stream enters wet electrostatic precipitator (WESP)  8 . WESP  8  is a down-flow continuously self-cleaning precipitator with at least one ionizing electrode and collecting surface within a chamber. High voltage transformer  15  provides the current for WESP  8 . As is known in the art, the ionizing electrode of WESP  8  will apply a charge to dust particles and other particles in the air stream, including particles as small as 0.01 micron size, bacteria, and viruses. The charged particles are attracted to the collecting surface of WESP  8 . Preferably, WESP  8  is continuously cleaned by a fine water mist injected into the WESP chamber by spray manifold  18 . The particles are washed off of the collecting surface by collected water droplets and as a slurry by gravity, are collected in bottom sump  30  and drained out through air lock  9  for disposal. 
         [0040]    Clean air leaves the WESP chamber through exhaust  550  and, depending upon thermostat setting as in any conventional air handling unit, may passed directly into blower  12 , or may first be heated in heater  10  or cooled in air conditioning unit  11 , after which the clean air would then pass into blower  12 . 
         [0041]    External air may be introduced into the system via intake duct  20 , as controlled by damper  21 . Damper  21  is controlled by signals from programmable logic circuit  19 , which receives data from CO 2  sensor  22 , volatile organic compound sensor  23 , or other sensors as may be desired. CO 2  sensor  22 , volatile organic compound sensor  23 , and other sensors each monitor the internal air quality and external air quality. 
         [0042]      FIG. 4  depicts an alternate embodiment of the invention in the form of an air curtain system that converts a small, high pressure air flow to a large volume air flow at lower pressure based on an air-ejector design. This embodiment comprises of filter  100 , high pressure blower  120 , connecting duct  130  and nozzle manifold  140 . 
         [0043]    As shown in  FIG. 5 , nozzle manifold  140  comprises of housing  150  located above the window, preferably along its entire width, and the internal surface is shaped as the classical Venturi throat  190 . The top wall of housing  150  has two longitudinal openings  160 , high pressure air nozzle  170 , and at the bottom of housing  150  there is a low pressure longitudinal exhaust  180  for the delivery of the air stream downwards along the surface of the window glass. Longitudinal openings  160  allow the entry of ambient air. 
         [0044]    During operation, air enters high pressure blower  120  via disposable filter  100  and delivered under high pressure via connecting duct  130  to the air nozzle  170  and is directed into the Venturi throat  190  where the air flow is accelerated, creating negative pressure and promoting the influx of extra air from the room via openings  160 , thus multiplying the original air volume delivered by the blower  120 . The larger air volume provides much better air mixing in the room when it is used as a part of the improved HVAC system. 
         [0045]    Another embodiment of the invention is depicted on the  FIG. 7 , where in order to deliver air flow to the window with low velocity while at the same time ensuring equal flow distribution of air along the glass window  6 , and to prevent any cross flow disturbance of the air curtain, an additional glass pane  200  is installed thus creating the dedicated channel  210  for the air curtain. 
         [0046]    In this embodiment, first chamber  400  is located at the top of channel  210  and second chamber  420  is located at the bottom of channel  210 . Air flow enters first chamber  400  from first duct  13  and exits second chamber  420  through second duct  14 , as described above. This embodiment provides a damper  240  between second chamber  420  and second duct  14 , where the return air flow may be blocked from entering second duct  14 . Glass pane  200  is equipped with flexible cover  230  acting as a release valve that opens under air pressure to direct the air flow into the room when damper  240  is closed preventing air from entering second duct  14 . Return air flow can then follow traditional HVAC direction via return registers located in the room. 
         [0047]    As an additional feature, this embodiment assists in providing forced air temperature adjustment to the location. When the temperature in a room is at a desired level, damper  240  will remain open and air will go into second duct  14  for return to the air handling unit  7 . When the thermostat determines a need for heated or cooled air, such temperature controlled air will be circulating through the system from the blower into the first duct. Damper  240  will close and under positive pressure flexible cover  230  will open to let the conditioned air enter the room to satisfy the desired temperature. Once the desired temperature is reached, damper  240  will open again allowing the air flow to return to the air handling unit  7 . 
         [0048]    As depicted in  FIG. 8 , for further improvement and energy savings, the originally proposed high velocity delivery of the air to the windows can be modified whereas the air would be delivered via larger duct  280  with a lower pressure drop along the way but can be connected to high pressure blower  120  as show in  FIG. 4 . 
         [0049]    As depicted on  FIG. 6 , for further energy savings, the air curtain may be delivered along the interior walls of a building by placing an air delivery manifold  300  in a corner of ceiling  301  and wall  302 . Air delivery manifold  300  may be in the shape of crown molding or other architecturally similar component, to disguise its functional nature. The interior of air delivery manifold  300  has the same internal design as nozzle manifold  140 , with openings  360 , high pressure air nozzle  370  and low pressure exhaust  380  corresponding to the functions of longitudinal openings  160 , high pressure air nozzle  170  and low pressure exhaust  180 . 
         [0050]      FIGS. 9 ,  10  and  11  show the air curtain technology used for the reduction of energy loses via walls and ceilings of a building, adding flexibility to a designer by allowing the location of the air curtain not only in open areas, but also in cavities  710  within walls and/or ceilings. The air curtain cavities  710  could be constructed as part of new construction, from the same materials as in use for the structure. Manifold units  700 , similar in construction to air delivery manifold  300  and nozzle manifold  140 , can be located as desired inside interior walls or on the surface of interior walls, as well as on the surface of a ceiling, or in an attic space. 
         [0051]    While certain novel features of the present invention have been shown and described, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing from the spirit of the invention.