Abstract:
An apparatus is configured to receive an incoming air stream from within an enclosure and to exhaust an outgoing air stream into the enclosure, the incoming and outgoing air streams flowing in a flow direction. The apparatus comprises an evaporator, a compressor, a condenser, and a heat exchanger. The heat exchanger has a heat extraction portion and a heat depositing portion, wherein the heat extraction portion is disposed in an air stream outside of the enclosure and wherein the heat depositing portion is disposed downstream of the evaporator with respect to the flow direction. A method includes receiving an incoming air stream from within an enclosure in a dryer apparatus, the apparatus including an evaporator, a compressor, and a condenser. A heat exchanger is operably connected to the dryer apparatus to transfer sensible heat from an air stream outside of the enclosure to a location downstream of the evaporator.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority from, and hereby incorporates by reference, U.S. Provisional Patent Application Ser. No. 61/535,011, filed Sep. 15, 2011, by Khanh Dinh. 
     
    
     BACKGROUND 
       [0002]    Dehumidifier dryers have been used for applications such as water damage remediation for the drying of flooded houses and other buildings. However, all of the state-of-the-art dryers provide heat energy obtained only from the energy from electric consumption and the latent energy resulting from condensing of water vapors. 
       SUMMARY 
       [0003]    In one aspect, the disclosure is directed to an apparatus configured to receive an incoming air stream from within an enclosure and to exhaust an outgoing air stream into the enclosure, the incoming and outgoing air streams flowing in a flow direction. The apparatus comprises an evaporator, a compressor, a condenser, and a heat exchanger. The heat exchanger has a heat extraction portion and a heat depositing portion, wherein the heat extraction portion is disposed in an air stream outside of the enclosure and wherein the heat depositing portion is disposed downstream of the evaporator with respect to the flow direction. 
         [0004]    In another aspect, the disclosure describes a method comprising receiving an incoming air stream from within an enclosure in a dryer apparatus, the apparatus comprising a first evaporator, a compressor, and a condenser, the incoming air stream flowing in a flow direction. A heat exchanger is operably connected to the dryer apparatus to transfer sensible heat from an air stream outside of the enclosure to a location downstream of the evaporator with respect to the flow direction. An outgoing air stream is exhausted into the enclosure, the outgoing air stream flowing in the flow direction. 
         [0005]    This summary is provided to introduce concepts in simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the disclosed or claimed subject matter and is not intended to describe each disclosed embodiment or every implementation of the disclosed or claimed subject matter. Specifically, features disclosed herein with respect to one embodiment may be equally applicable to another. Further, this summary is not intended to be used as an aid in determining the scope of the claimed subject matter. Many other novel advantages, features, and relationships will become apparent as this description proceeds. The figures and the description that follow more particularly exemplify illustrative embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The disclosed subject matter will be further explained with reference to the attached figures, wherein like structure or system elements are referred to by like reference numerals throughout the several views. 
           [0007]      FIG. 1  is a schematic elevation view of a prior art refrigeration-based dehumidifier dryer installed in an enclosure. 
           [0008]      FIG. 2  is a schematic elevation view of a first exemplary embodiment of a refrigeration-based dehumidifier dryer installed in an enclosure. 
           [0009]      FIG. 3  is a schematic elevation view of a second exemplary embodiment of a refrigeration-based dehumidifier dryer installed in an enclosure. 
       
    
    
       [0010]    While the above-identified figures set forth one or more embodiments of the disclosed subject matter, other embodiments are also contemplated, as noted in the disclosure. In all cases, this disclosure presents the disclosed subject matter by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this disclosure. 
         [0011]    The figures may not be drawn to scale. In particular, some features may be enlarged relative to other features for clarity. Moreover, where terms such as above, below, over, under, top, bottom, side, right, left, etc., are used, it is to be understood that they are used only for ease of understanding the description. It is contemplated that structures may be oriented otherwise. 
       DETAILED DESCRIPTION 
       [0012]    The present disclosure is directed to a dehumidifier dryer using ambient heat enhancement. A particularly suitable application for such a dryer is for use in drying out an enclosure such as a flooded building, for example. 
         [0013]      FIG. 1  is a schematic elevation view of a prior art refrigeration-based dehumidifier dryer  10  installed in an enclosure  12 , which in the illustrated example is a building with an interior that needs to be dried. Latent heat energy in the building air, available in the form of water vapor, is transformed into sensible heat energy by cooling the building air below its dew point to condense the water vapor into liquid water that is then removed. The heat of condensation is released in the dehumidification process; additional heat also comes from electricity used to power the compressor and blower. The warmer, dryer air is used for drying the building  12 . 
         [0014]    In the illustrated embodiment, dryer  10  includes a housing  14  that contains evaporator or cooling coil  16 , compressor  18 , condenser  20 , and blower  22 , as is known in the art. In an exemplary embodiment, enclosure  12  is a building in which the air is more moist than desired. In an extreme case, the building may have been flooded or otherwise water-damaged. Thus, dryer  10  is used to dry out the building structure and the air within the building. In an exemplary application, the air in the building need not be controlled for human comfort; rather, the air is warmer than typical for enhanced drying effectiveness. 
         [0015]    In a first example, incoming air stream  24  enters dryer  10  at 80 degrees Fahrenheit (F.). Evaporator  16  reduces the air temperature of air exiting the evaporator  38  to 55 F, thereby condensing water vapor from incoming air stream  24 . This liquid water condensate  26  is removed from enclosure  12 , such as through drain line  28 . A 1,000-watt compressor  18  produces 12,000 British Thermal Units per hour (BTUh). A 300-watt blower  22  moves air through dryer  10  at a rate of 1,000 cubic feet per minute (cfm). The outgoing air stream  30  exits dryer  10  at 100 F. A typical dehumidifier dryer  10  can condense water vapor and release latent heat of condensation at a rate of 5,000 BTUh. Additionally, the heat resulting from consumption of 1,300 watt.hour of electricity adds 4,434 BTUh. Thus, a total useable heat amount of 9,434 BTUh is available for drying the enclosure  12 . 
         [0016]      FIG. 2  shows an exemplary embodiment of the present disclosure, which is a refrigeration-based dehumidifier dryer apparatus  32  that uses a heat exchanger  34  to extract heat from the ambient outdoor air stream  36 . Dryer  32  is configured to receive incoming air stream  24  from within enclosure  12  and to exhaust outgoing air stream  30 ′ into enclosure  12 . The incoming and outgoing air streams  24 ,  30 ′ flow in a flow direction indicated by the arrows in the  FIG. 2 . As illustrated in  FIG. 2 , ambient outdoor air stream  36  flows counter-current to incoming and outgoing air streams  24 ,  30 ′. However, it is contemplated that ambient outdoor air stream  36  may flow in the same direction as incoming and outgoing air streams  24 ,  30 ′ or in another direction, as directed by blower  40 . 
         [0017]    Compressor  18  delivers hot compressed refrigerant gas to condenser  20  via line  19 . Condenser  20  receives the refrigerant gas and condenses it to produce hot refrigerant liquid. The hot refrigerant liquid travels via line  21  to expansion device  23 . Expansion device  23  receives the refrigerant liquid from condenser  20  and expands the refrigerant liquid to reduce the temperature and pressure of the liquid. Evaporator  16  receives the cool liquid refrigerant from expansion device  23  and evaporates the liquid refrigerant to produce cold gas refrigerant, which is returned to compressor  18  via line  25  to complete the refrigeration cycle. Incoming air stream  24  is directed across the evaporator  16  to cool the air below the dew point such that water vapor in the air is condensed to liquid condensate  26  to dehumidify the air. The dehumidified air exiting the evaporator  38 ′ is then directed across condenser  20  to rewarm the air. 
         [0018]    In the embodiment of dryer  32  illustrated in  FIG. 2 , the extracted heat from the outdoor air stream  36  is used to supplementally heat the air exiting the evaporator  38 ′. The reheated air exiting the evaporator  38 ′ continues to the condenser  20  to get further heated. As a result, the air coming out of dryer  32  will include three sources of heat: latent heat from condensing water vapors in the air, heat resulting from the use of electricity by the compressor and blower, and also the heat energy transferred into the cold air stream exiting the evaporator  38  via the outdoor air heat exchanger  34 . Thus, outgoing air stream  30 ′ discharged into an interior of the enclosure  12  is warmer than in  FIG. 1  because of the added sensible heat from outdoors. Because this additional heat is free, it increases the efficiency of the whole system. 
         [0019]    In a second example, the same entering air conditions, compressor, and blower are used as in the first example. Thus, ambient air enters the dryer at 80 degrees Fahrenheit (F.). The evaporator  16  reduces the air temperature to 55 F, thereby condensing water vapor from the air, which is thereby removed through drain line  28  as condensate  26 . A 1,000-watt compressor  18  produces 12,000 British Thermal Units per hour (BTUh). A first 300-watt blower  22  moves the air at a rate of 1,000 cubic feet per minute (cfm). A second 1,000 cfm blower  40  pulls outdoor air stream  36  (at 80 F) through heat exchanger  34  via a coupling  42  that maximizes air flow from blower  40  to heat exchanger  34 . 
         [0020]    In an exemplary embodiment, heat exchanger  34  has a heat extraction portion  46  and a heat depositing portion  48 . Heat extraction portion  46  is disposed in outdoor air stream  36 . In this case, “outdoor” refers to an area outside of enclosure  12 . Heat depositing portion  48  is disposed downstream of evaporator  48  with respect to the flow direction of outdoor air stream  36 . Thus, sensible heat is extracted from outdoor air stream  36  at heat extraction portion  46 , moves through heat exchanger  34  in direction  44 , and is picked up by air exiting the evaporator  38 ′ as that air stream flows through heat depositing portion  48 . In one embodiment, heat exchanger  34  transfers sensible heat in direction  44  from outdoor air stream  36  to the air leaving the evaporator  38 ′, thereby warming the air by 10 F. Thus, air leaving the coiling coil  38 ′ that has passed through heat exchanger  34  has a temperature of 65 F. The gain of 10 F of heat from heat exchanger  34  results in outgoing air stream  30 ′ exiting dryer  32  at 110 F. Moreover, because 10 F of heat is transferred by heat exchanger  34 , outgoing air stream  46  exiting heat exchanger  34  is cooled to 70 F. 
         [0021]    Suitable types of known heat exchangers  34  include, for example, heat pipes, tube heat exchangers, heat wheels, liquid loops, plate type, and thermosiphon heat exchangers. The manner of connecting the heat exchanger  34  to the dryer  32  to transfer sensible heat from the outdoor air stream  36  to the air leaving the evaporator  38 ′ will depend on the type of heat exchanger  34  chosen. Such manners of connection are known in the art. U.S. Pat. No. 5,921,315 to Dinh, incorporated herein by reference, discloses a suitable three-dimensional heat pipe heat exchanger. U.S. Pat. No. 5,845,702 to Dinh, incorporated herein by reference, discloses a suitable serpentine heat pipe heat exchanger. U.S. Pat. No. 5,582,246 to Dinh, incorporated herein by reference, discloses a suitable finned tube heat exchanger. U.S. Pat. No. 4,960,166 to Hirt, incorporated herein by reference, discloses a suitable rotary heat wheel. U.S. Pat. No. 6,959,492 to Matsumoto, incorporated herein by reference, discloses a suitable plate type heat exchanger. U.S. Pat. No. 8,262,263 to Dinh, incorporated herein by reference, discloses suitable liquid loop and thermosiphon heat exchangers. 
         [0022]    An exemplary calculation follows: with a reasonable effectiveness of 50%, the amount of heat that can be captured from ambient outdoor air stream  36  by heat exchanger  34  will be about 1,000 cfm×10 F×1.08=10,800 BTUh. This calculation is based on a “quick formula” known in the trade of air conditioning: 1,000 cfm is the air volume through heat exchanger  34 ; 10 F is the sensible heat gain; the factor of 1.08 reflects the conversion of cfm into flow mass in pounds of air per hour times the specific heat of air at standard conditions. Thus, the total amount of heat delivered will be 9,434 (from the first example)+10,800 (from the quick formula)=20,234 BTUh, which is more than double the amount of heat from the conventional dehumidifier dryer  10  of  FIG. 1 . Moreover, heat exchangers  34  with even higher effectiveness levels may be used to yield even more usable heat. Since only sensible heat is transferred from the outdoor air stream  36  to the process air stream  24 ,  38 ′, no humidity is added to the outgoing air stream  30 . Therefore the hotter, dry outgoing air stream  30  will be able to provide more drying capacity as compared to the first example. Considering that a second blower  40  is typically used to draw outdoor air stream  36  through heat exchanger  34 , some extra energy will be needed, but that amount of energy will be small compared to the heat energy extracted as above explained. 
         [0023]      FIG. 3  shows the addition of a second evaporator  48  placed after the heat exchanger  34  discharge to further extract heat from the outdoor air stream  36  as it reduces the temperature of the outgoing air stream  46 ′. This extracted heat can be directed back into the building as shown by recycle heat stream  50 , thereby contributing to warming air exiting the evaporator  38 ″ and outgoing air stream  30 ″ even further. This is especially desirable for cold climates. In other respects, machine  52  works similarly to dryer  32 , shown in  FIG. 2 . When the configuration of  FIG. 3  is used, the machine  52  becomes a combined dehumidifier and heat pump. U.S. Pat. No. 7,350,366 to Yakumaru, incorporated herein by reference, discloses a heat pump. 
         [0024]    Compressor  18  delivers hot compressed refrigerant gas to condenser  20  via line  19 . Condenser  20  receives the refrigerant gas and condenses it to produce hot refrigerant liquid. The hot refrigerant liquid travels via line  21  to juncture  54 , at which line  21  branches to segment  56  leading to evaporator  16  and segment  58  leading to evaporator  48 . The operation of one or both evaporators  16 ,  48  is controlled by valves  60 ,  62 , respectively. In an exemplary embodiment, valves  60 ,  62  are solenoid valves, as are known in the art. When valve  60  is open, the refrigerant travels to expansion device  23  of evaporator  16 ; when valve  60  is closed, evaporator  16  does not run. When valve  62  is open, the refrigerant travels to expansion device  64  of evaporator  48 ; when valve  62  is closed, evaporator  48  does not run. Thus, valves  60 ,  62  are controllable so that just evaporator  16  can run, so that machine  52  operates as a dehumidifier (primarily remove moisture from enclosure  12 ); just evaporator  48  can run, so that machine  52  operates as a heat pump (primarily add heat to enclosure  12 ); and both evaporators  16 ,  48  can run simultaneously, so that machine  52  operates as a combined dehumidifier and heat pump (remove moisture from and add heat to enclosure  12 ). 
         [0025]    When valve  60  is open, expansion device  23  receives the refrigerant liquid from condenser  20  and expands the refrigerant liquid to reduce the temperature and pressure of the liquid. Evaporator  16  receives the cool liquid refrigerant from expansion device  23  and evaporates the liquid refrigerant to produce cold gas refrigerant, which is returned to compressor  18  via line  25  to complete the refrigeration cycle. When valve  62  is open, expansion device  64  receives the refrigerant liquid from condenser  20  and expands the refrigerant liquid to reduce the temperature and pressure of the liquid. Evaporator  48  receives the cool liquid refrigerant from expansion device  64  and evaporates the liquid refrigerant to produce cold gas refrigerant, which is returned to compressor  18  via a line (not shown) to complete the refrigeration cycle. Incoming air stream  24  is directed across the evaporator  16  to cool the air below the dew point such that water vapor in the air is condensed to liquid condensate  26  to dehumidify the air. The dehumidified air exiting the evaporator  38 ′ is then directed across condenser  20  to rewarm the air. Outdoor air stream  36  is directed across evaporator  48  to extract heat therefrom so that recycle heat stream  50  can be directed back into enclosure  12 . 
         [0026]    Although the subject of this disclosure has been described with reference to several embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the disclosure. In addition, any feature disclosed with respect to one embodiment may be incorporated in another embodiment, and vice-versa. Moreover, all patents and publications mentioned in this disclosure are fully incorporated by reference.