Abstract:
The appliance provides chilled water, heated water, or both chilled and heated water simultaneously. The primary intended use is in military vehicles, but the appliance may be used in any environment where heated and/or chilled liquid is desired.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Rocky Research, of Boulder City, Nev., has developed a prototype thermoelectric water chiller and heater appliance for the U.S. Army. The appliance provides chilled water, heated water, or both chilled and heated water simultaneously. The primary intended use is in military vehicles, but the appliance may be used in any environment where heated and/or chilled liquid is desired. 
         [0002]    The aforesaid appliance is illustrated in  FIG. 1  as prior art. The apparatus includes a hot bottle receiver  10  and a cold bottle receiver  20 . Liquid to be heated or cooled is placed in tapered aluminum bottles and inserted into bottle receivers of the appliance. Liquid to be heated is always placed in a top bottle receiver, and liquid to be cooled in a lower receiver. Three thermoelectric modules  21 ,  22  and  23  provide heating and cooling. Phase-change refrigerant is heated in boilers  11 ,  12  and  13  in which the refrigerant is vaporized by heat from the hot side of the thermoelectric module. Each of the three boilers cooperates with a thermosyphon loop comprising a first pipe ( 18 ) for directing vaporized refrigerant to the hot bottle receiver  10  and a return pipe ( 17 ) for directing refrigerant to a separate auxiliary condenser and back to the boiler. Thus, three different hot side thermosyphon loops and piping are required as are three separate auxiliary condensers  27 ,  28  and  29 . An equalization or liquid equilibration pipe  14  is also required and extends and communicates between the three boilers for liquid flow to maintain equal levels of refrigerant. The thermosyphon loops communicate with each other at the bottle receiver. 
         [0003]    On the cold side of the appliance, three condensers  24 ,  25  and  26  are in thermal communication with the cold side of the three thermoelectric modules, respectively. Each of the condensers also cooperates with a separate phase-change thermosyphon loop for directing condensed refrigerant from a condenser via a pipe ( 15 ) to the cold bottle receiver  20  and a return pipe ( 16 ) for directing vaporized refrigerant back to the condenser. Like the hot side, the cold side thermosyphon loops communicate at the bottle receiver. 
         [0004]    Removable aluminum bottles are used and received in the respective hot and cold bottle receivers which are tapered to match the taper of the aluminum bottles and provide good thermal contact. Auxiliary fans, not shown, provide heat rejection for the auxiliary condensers. 
       SUMMARY OF THE INVENTION 
       [0005]    The apparatus of the present invention simplifies the design by utilizing counter-flow liquid and vapor ducts between the boiler and hot bottle receiver and between the condenser and cold bottle receiver, respectively. In the apparatus, a single boiler is used, and in a preferred embodiment, a single condenser is also used. These improvements will be further described in the detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    In  FIG. 1 , a perspective view of the prior art design, previously described, is shown; 
           [0007]      FIG. 2  is a schematic view of components of the improved apparatus design; 
           [0008]      FIG. 3  is a perspective view showing the components of the improved apparatus; and 
           [0009]      FIG. 4  is a perspective view of a preferred thermosyphon boiler and condenser design. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0010]    Referring to  FIGS. 2 and 3 , the apparatus includes a hot bottle receiver  30  comprising a tapered cylindrical jacket having an annular space in which heated refrigerant vapor from boiler  31  provides heat to the receiver for heating a bottle  41  inserted into the bottle receiver. An auxiliary condenser  36  is positioned along the counter-flow thermosyphon ducts  38  which communicates the boiler  31  with the hot bottle receiver  30 . Each thermosyphon duct  38  provides counter-flow of liquid and vapor simultaneously between the bottle receiver and boiler in each tube. 
         [0011]    An auxiliary condenser  36  is cooled by a fan  37 . The auxiliary condenser design is modular, incorporating a plurality of flat, planar fins each of which physically contacts and substantially envelops the thermosyphon ducts or tubes. The modular auxiliary condenser is a fintube assembly replacing the individual finned tube auxiliary condensers used in the prior art appliance. Such a modular auxiliary condenser design simplifies the assembly, provides better air flow without complicated fan or ducting arrangements, and also provides improved heat rejection. The auxiliary condensers are used to reject heat after the hot water has reached target temperature, e.g., 140° F. Normally, target hot water temperature will be reached before the cold water target temperature, e.g., 60° F. Such continued heat rejection permits continued cooling of water in the cold bottle receiver after the hot water target temperature is reached. Such hot-side heat rejection provides for maintenance of a heat balance around the thermoelectric module independent of heat flow to or from the fluid containing bottles. 
         [0012]    On the cold side, a cold bottle receiver  32 , always the lower receiver, is tapered in a manner as previously described regarding the hot bottle receiver. A condenser  33  communicates with the cold bottle receiver  32  via counter-flow liquid and vapor thermosyphon ducts  39  in which liquid and vapor flow simultaneously during operation of the appliance apparatus. Typically, a plurality of counter-flow ducts are used on the hot and/or the cold sides of the apparatus. 
         [0013]    The condenser is sized so that in most ambient temperature conditions, hot-side temperature drops when fans are operated. The apparatus includes a plurality of thermoelectric (TE) modules  35  positioned end-to-end. Such thermoelectric modules typically comprise two ceramic plates with bismuth telluride pellets between the ceramic plates. A direct electrical current flows through the device moving heat from one side to the other, one side becoming cool, the other side hot. Such thermoelectric modules are well known to those skilled in the art and are not described further in this specification. The ceramic plates on each side of the thermoelectric device have a substantially flat, planar surface against which the respective condenser and boiler are juxtapositioned. Each condenser and boiler is provided with a substantially flat, planar surface portion which is juxtapositioned against the respective hot and cold side of the thermoelectric modules. 
         [0014]    In the design of the improved appliance of the invention, the boiler comprises a single extrusion contacting all three thermoelectric modules. In  FIG. 4 , such a single extrusion design  40  is illustrated having a substantially flat, planar exterior surface portion  45 , and a plurality of heat exchange surfaces  46  formed on the interior of the component. In a preferred embodiment of the appliance of the invention, the condenser is of the single extrusion design illustrated, similar to the boiler extrusion. Alternatively, the condenser and/or the boiler may be divided into three separate extrusions of the same design which are aligned end-to-end. Using separate extrusions for each TE module on at least one side will provide good thermal contact with all TE modules without imposing excessively restrictive thickness tolerances on the modules. 
         [0015]    The design improvements of the appliance described hereinabove reduce manufacturing cost and provide a more compact package. The use of a modular auxiliary condenser also provides improved performance and operating efficiency. 
         [0016]    By way of example only, nominal specifications of an apparatus as described above may include the following:
       Cool 16 oz. water to 60° F. and heat 16 oz. water to 140° F. in 20 min. or less from 76° F. ambient.   Size: 12″×7¾″×6¾   Weight: 8.3 lbs.   Power consumption: 250 W max.   R134a refrigerant       
 
         [0022]    In operation of the above-described apparatus, heating and cooling may be carried out irrespective of starting water temperatures or the mass of liquid (water) in either bottle. Moreover, heating or cooling may be accomplished independently, with only one bottle positioned in a bottle receiver, hot or cold. Operation of the appliance will continue after target temperatures are reached. Preferably, the apparatus will be configured to stop heating at a maximum 170° F. hot bottle temperature. Chilled water cooling may be continued with freeze protection shut down configuration preferred.