Patent Application
20090113898
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.
The aforesaid appliance is illustrated in
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.
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.
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.
In
Referring to
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.
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.
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.
In the design of the improved appliance of the invention, the boiler comprises a single extrusion contacting all three thermoelectric modules. In
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.
By way of example only, nominal specifications of an apparatus as described above may include the following:
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.
