Beverage dispenser with a dehumidifier utilizing a thermoelectric cooler

A dehumidifier which includes a thermoelectric cooler having first and second ends on opposite sides, with the first end being cooler than the second end during operation; a first plate which is thermally conductive and has first and second surfaces on opposite sides, wherein the first surface is thermally coupled to the first end of the thermoelectric cooler; a second plate spaced from and facing the second surface of the first plate to form a first air passage therebetween; and a fan positioned to cause air to flow through the first air passage, wherein the air flowing through the first air passage is dehumidified as moisture therein condenses on the second surface of the first plate. The invention also relates to a dispensing machine which includes the humidifier and a method for dehumidifying air in the dispensing machine or in other devices.

FIELD OF THE INVENTION 
The present invention generally relates to beverage dispensers that include 
dehumidifiers to lower humidity therein. More specifically, the 
dehumidifiers utilize thermoelectric coolers to condense and remove 
moisture from inside of the dispensers. 
BACKGROUND OF THE INVENTION 
Various automated beverage dispensers for making hot or cold beverage 
products are known in the art. In a conventional beverage dispenser, a 
metered amount of water-soluble beverage powder, stored in a powder 
storage chamber, and a metered amount of hot or cold water, supplied from 
a water source, are conveyed into a mixing chamber to produce a beverage 
product, which is dispensed into a cup. In more sophisticated beverage 
dispensers, a number of different types of beverage making powders are 
stored in a storage chamber to produce different types of beverage 
products, e.g., coffee, tea, hot chocolate or exotic tropical drinks, at a 
user's choice. Because these beverage dispensers conveniently produce 
different types of beverage products with consistently high quality, these 
types of beverage dispensers are finding increasing acceptance with 
households, restaurants and the vending machinery industry. 
In the above described beverage dispensers, the common problem is caking or 
clumping, caused by humidity, of the beverage making powders. When the 
powders are caked or clumped, dispensing the powders in accurate amounts 
becomes difficult, and, in some extreme cases, powders may become 
unsuitable for human consumption. Therefore, dehumidifiers that can 
efficiently control humidity inside the powder storage chambers are highly 
desired. 
SUMMARY OF THE INVENTION 
The present invention relates to a dehumidifier comprising a thermoelectric 
cooler having first and second ends on opposite sides, with the first end 
being cooler than the second end during operation; a first plate which is 
thermally conductive and has first and second surfaces on opposite sides, 
wherein the first surface is thermally coupled to the first end of the 
thermoelectric cooler; a second plate spaced from and facing the second 
surface of the first plate to form a first air passage therebetween; and a 
air circulating means for causing air to flow through the first air 
passage, wherein the air flowing through the first air passage is 
dehumidified as moisture therein condenses on the second surface of the 
first plate. 
Advantageously, a thermally conductive buffer block is disposed between the 
first end of the thermoelectric cooler and the first plate. This block 
preferably is substantially made of copper and imparts a spacing between 
the first end of the thermoelectric cooler and the first plate. 
If desired, the dehumidifier may include a housing having first and second 
surfaces located on opposite sides and defining a first orifice, wherein 
the orifice is configured to receive and hold the thermoelectric cooler; 
and a pair of side panels mounted on the first surface of the housing and 
configured to rigidly hold the second plate thereto. The first plate is 
preferably mounted on the first surface of the housing between the pair of 
side plates, thereby forming an inlet and an outlet at a top side and a 
bottom side of the first air passage, respectively. In this arrangement, 
the inlet of the first air passage is disposed above the outlet of the 
first air passage to cause any moisture condensed on the second surface of 
the first plate to flow to the outlet of the first air passage. Also, the 
air circulating means is a fan that is positioned to draw air from the 
outlet of the first passage during operation of the fan. 
In another arrangement, a back panel is disposed apart from the second 
plate, wherein the fan is mounted on the back panel; a top panel 
configured to connect a top side of the second plate to a top side of the 
back panel; and a bottom panel configured to connect a bottom of the back 
panel to the housing below the first plate; and the two side panels 
further configured to be connected to the back panel, the top panel, and 
the bottom panel, to thereby form an outer air passage and to thereby 
force the air to flow toward the fan in the first and second air passages 
when the fan is in operation. If desired, a third plate may be disposed 
between the back panel and the second plate to create a second air passage 
between the second plate and the third plate. Also, the housing can 
further define a second orifice located between the bottom of the first 
plate and above where the bottom plate is connected to the housing, such 
that the second orifice is filled up with a material that allows water to 
sip therethrough while preventing air from flowing therethrough. This 
material may be a piece of wicking fabric. 
In another arrangement, a movable door is included, and the back panel 
further defines an additional air intake opening configured to mount the 
movable door. Thus, the movable door may be moved to open or close the 
additional air intake opening. Advantageously, the housing includes a 
control device including at least one of a fan control device configured 
to control the speed of the fan, a door control device configured to move 
the movable door, and a TEC power supply control device configured to 
control power supply to the thermoelectric cooler; and a controller 
configured to send controlling signals to the control device for 
controlling the operation of the dehumidifier, to thereby optimally 
control the operation of the dehumidifier. 
Another embodiment of the invention relates to a beverage dispenser that 
includes the previously described dehumidifier. 
Yet another embodiment of the invention relates to a method of 
dehumidifying a chamber that stores beverage making powder. This method 
comprising the steps of drawing air from inside of the chamber; flowing 
the drawn air on a cold surface to cause moisture in the air to condense 
thereon, thereby dehumidifying the air; returning the dehumidified air to 
the chamber; collecting the moisture formed on the cold surface; passing 
the collected moisture to outside of the chamber through a conduit; and 
preventing air from the outside to enter the chamber through the conduit, 
to thereby ensure low humidity within the chamber. 
This method also can include the steps of controlling an air flow speed on 
the cold surface to thereby maintain the humidity inside the chamber 
within a predetermined range. Thus, the predetermined humidity range can 
be maintained between about 28% and 60%. 
If desired, the temperature and humidity of the air inside the chamber can 
be measured; and the airflow speed automatically controlled according to 
the measured temperature and humidity for maintaining the air inside the 
chamber at predetermined ranges of temperature and humidity. It is also 
possible to include the step of cooling a heat sink of the cold surface 
for maintaining the cold surface at a lower temperature than that of the 
air inside the chamber. Further, the temperature inside the chamber can 
also be controlled.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, there is illustrated a portion of a beverage dispenser 
101 with a dehumidifier 103 of the present invention installed thereon. 
More specifically, a wall 105, into which the dehumidifier 103 is 
installed, forms a part of the beverage making powder chamber so that the 
dehumidifier 103 can remove moisture from the air inside of the chamber. 
Referring to FIG. 2, the dehumidifier 103 of the present invention includes 
a thermoelectric cooler (TEC) 201, a housing 203 into which the TEC 201 is 
placed, a cold side structure 205, a heat sink side structure 207 and a 
moisture disposal conduit 209. 
The TEC 201 has a cold side 211 and a heat sink side 213. The TEC is formed 
as a thermopile by connecting in series a plurality of thermocouples 215 
in a known manner: each thermocouple consisting of a p-type semiconductor 
and a n-type semiconductor electrically connected between two poles of a 
direct-current power supply to produce a cool junction and a warm junction 
on the cold side 211 and the heat sink side 213 of the TEC 201, 
respectively. The electrical power, typically 12V, is supplied to the TEC 
201 from a power source by electrical wiring. Thus, in operation the cold 
side 211 is maintained to be colder than the heat sink side 213. The 
dimension of a typical TEC with 30 watts heat load capacity is 
approximately 40.times.40.times.2 mm. The TEC 201 is also known as a 
thermoelectric module, a Peltier cooler or a thermoelectric 
heating/cooling device in the art. 
The housing 203, preferably made of a rigid material with no substantial 
thermal conductivity, has an opening within which to receive the TEC 201. 
The housing 203 is mounted into the wall 105 of the beverage dispenser 
101, as described above, and divides the dehumidifier 103 into the cold 
side structure 205 and the heat sink side structure 207. Once the housing 
203 is mounted into the wall 105, the cold side structure 205 is disposed 
inside of the chamber and the heat sink side structure 207 is disposed 
outside of the chamber. Although the housing 203 is made of the thermally 
non-conductive material, there is some inevitable thermal conductivity 
between the heat sink side structure 207 and the cold side structure 205 
of the dehumidifier 103 when they are located too close together. In order 
to minimize the unwanted thermal conductivity, the thickness of housing 
203 is preferably between 5 mm and 20 mm, which is thicker than that of 
the TEC 201. The difference in the thickness between the TEC 201 and the 
housing 203 is compensated by inserting a buffer block 217 made of 
thermally conductive and rigid material. Preferably, the buffer block 217 
is made of copper, but other thermally conductive material such as 
aluminum provides a good alternative to copper. The buffer block 217 is 
preferably disposed between the TEC 201 and the cold side structure 205 in 
order to transfer the cold temperature generated from the TEC 201 to the 
cold side structure 205. As alternatives, it should be noted that the 
buffer block 217 can be disposed between the heat sink side structure 207 
and the TEC 201 or that two buffer blocks can be provided one on each side 
of the TEC. In the embodiments described above, a thermally conductive 
insert, such as thermally conductive grease, is provided between the 
buffer block(s) and the TEC 201, between the buffer block and the cold 
side structure 205, and between the buffer block and the heat sink side 
structure 207 in order to ensure thermal conductivity among these 
components. Further, applying undue stress, in an attempt to thermally 
connect the components, to the TEC 201 is avoided by providing the 
thermally conductive grease between the components. 
The cold side structure 205 includes an active cold plate 219, a secondary 
plate 221, an outer plate 223, an outer shell 225 and a fan 229 installed 
on the outer shell 225. 
The active cold plate 219 is made of thermally conductive and 
anti-corrosive material, preferably, aluminum. The active cold plate 219 
has a rectangular shape, e.g., 50.times.30 mm to 100.times.80 mm. The 
active cold plate 219 has two surfaces: a TEC-coupled surface, facing the 
cold side 211 of the TEC 201, and a condensation surface 227. The 
TEC-coupled surface of the active cold plate 219 is either directly 
attached to the TEC 201, when no buffer block is inserted therebetween, or 
thermally coupled to the TEC 201 via the buffer block 217. The 
condensation surface 227 is preferably flat and left untreated. In an 
alternative embodiment, the condensation surface 227 has a plurality of 
fins and/or grooves formed thereon in order to increase the surface area. 
In this embodiment, the fins and/or grooves are vertically formed; 
however, they can be in any other shapes such as a winding shape or a 
zigzagging shape. In addition, thermally conductive and hydrophobic 
plastics, e.g., nylon or metalized plastics, can be deposited upon the 
condensation surface 227 to further prevent corrosion thereon. 
The secondary plate 221 is made from substantially the same material and 
shaped as that of the active cold plate 219. It should be noted, however, 
that the secondary plates can be made from any other material that is 
rigid, thermally conductive and anti-corrosive material such as copper. 
Preferably, the secondary plate 221 has flat surfaces. In alternative 
embodiments, the surfaces of the secondary plate 221 may have fins and/or 
grooves, similar to the alternative embodiments of the active cold plate 
219. In addition, thermally conductive hydrophobic plastics can be applied 
to the surfaces of the secondary plate 221 to further protect the surfaces 
from corrosion. The secondary plate 221 is disposed apart from and 
substantially parallel to the active cold plate 219. Two side panels 107 
that are parts of the outer shell 225 are provided to rigidly hold the 
secondary plate 221 in relation to the active cold plate 219. The side 
panels 107 are also rigidly attached to the surface of the housing 302 
placing the active cold plate 219 between the side panels 107. 
A first air passage 231 is formed by the active cold plate 219 on one side, 
the secondary plate 221 on the opposite side and the two side panels 107 
of the outer shell 225. The first air passage 231 has two openings: an 
inlet 233 from which to draw air from the chamber and an outlet 235 to 
which air flows out from the first air passage 231. The gap between the 
active cold plate 219 and the secondary plate 221 is 5-20 mm. With this 
configuration, the size of the inlet 233 of the first air passage 231 is 
between 5.times.50 mm and 20.times.100 mm. 
The outer plate 223, made of rigid and thermally non-conductive material 
such as Teflon, is disposed apart from and substantially parallel to the 
secondary plate 221. This arrangement, along with extensions of the two 
side panels 107 of the outer shell 225, forms a second air passage 237. 
Preferably, the outlet 235 of the first air passage 231 connects to an 
inlet 239 of the second air passage 237, to thereby allow the air from the 
first air passage 231 to flow to the inlet 239 of the second air passage 
237. It should be noted that additional secondary plates can be provided 
between the active cold plate 219 and the outer plate 223 in alternative 
embodiments. In these alternative embodiments, additional air passages are 
formed by the additional secondary plates, and the additional air passages 
are connected similar to the connection between the first and the second 
air passages 231, 237. 
The outer shell 225 is made of rigid and thermally non-conductive material, 
e.g., Teflon, and shaped to rigidly hold the secondary cold plate 221 and 
the outer plate 223 with the two side panels 107 as described above. The 
outer shell 225 also forms an outer wall 241, which is shaped as a panel 
and disposed apart from and substantially parallel to the outer plate 223, 
thereby forming an outer air passage 243. It should be noted that the 
components described above that form the cold side structure are made of 
materials safe for food processing. 
The fan 229 is mounted on the outer wall 241. When the fan 229 is in 
operation, it draws air from the outer air passage 243, which in turn 
draws air from the second air passage 237, which in turn draws air from 
the first air passage 231 and which in turn draws air from the chamber 
through the inlet 233 of the first air passage 231. In other words, the 
fan 229 is provided to forcibly flow the air through the air passages 231, 
237, 243. It should be noted that fan 229 can be a blower or any other 
means to circulate the air through the air passages. 
More specifically, in operation of the cold side structure 205, the air 
from the inside of the chamber, presumably humid, is drawn into the first 
air passage 231 via its inlet 233. The humid air flows down through the 
first air passage 231 to its outlet 235. While the humid air is flowing 
from the inlet 233 to the outlet 235 of the first air passage 231, it 
comes in contact with the condensation surface 227 of the active cold 
plate 219. Because the air from the chamber is warmer than the 
condensation surface 227, the moisture in the air drawn in from the 
chamber is condensed thereon, thereby removing the moisture from the air 
and making it less humid. Furthermore, because the condensation surface 
227 cools the air that comes in contact with it, the air exiting at the 
outlet 235 of the first air passage 231 is colder than the air entering 
the inlet 233 of the first air passage 231. This also causes the upper 
portion of the secondary plate 221 near the inlet 233 of the first air 
passage 231 to be warmer than the lower portion of the secondary plate 221 
near the outlet 235 of the first air passage 231. Therefore, as the cold 
air flows from the inlet 239 of the second air passage 237 to its outlet, 
some heat exchange takes place between the cold air in the second air 
passage 237 and the upper portion of the secondary cold plate 221. This 
heat exchange serves to cool the upper portion of the secondary plate 221, 
warms up the air temperature as it flows through the second air passage 
237. This results in an efficient dehumidifier configuration because the 
cooled upper portion of the secondary plate 221 assists in cooling down 
the air temperature near the inlet 233 of the first air passage 231. 
TABLE 1 
______________________________________ 
Environment 23.degree. C./45% 
33.degree. C./85% 
33.degree. C./80% 
Chamber initial 
23.degree. C./87% 
33.degree. C./85% 
33.degree. C./80% 
Time Down to 60% 
12 min. 10 min. 9 min. 
Time Down to 50% 
22 min. 20 min. 19 min. 
Time Down to 40% 
46 min. 60 min. 65 min. 
Final RH 28% 36% 38% 
______________________________________ 
TABLE 2 
______________________________________ 
Environment 
32.degree. C./88% 
34.degree. C./88% 
33.degree. C./85% 
33.degree. C./81% 
Chamber initial 
32.degree. C./89% 
34.degree. C./81% 
33.degree. C./77% 
33.degree. C./81% 
1" opening 
3" opening 
4.5" opening 
Time Down to 
40 min. 35 min. 20 min. 40 min. 
60% 
Time Down to 
70 min. 65 min. 80 min. 
50% 
Final RH 41% 45% 48% 58% 
______________________________________ 
Table 1 and 2 illustrate performance characteristics of preferred 
embodiments where a 150-liter chamber and a 280-liter chamber, 
respectively, are dehumidified using the dehumidifier of the present 
invention. Each table shows the initial temperature and relative humidity 
(RH) of the environment and respective chambers. The final relative 
humidities (RHs) and the lengths of time the dehumidifier operated to 
achieve the final RHs are also shown. With respect to Table 2, an opening 
is bored into the 280-liter chamber in order to determine the operational 
capability of the dehumidifier of the present invention when the chamber 
is not completely sealed air tight. The diameters of the openings are 
noted in the second row of Table 2. 
Notwithstanding the efficient dehumidifier configurations described above, 
in an alternative embodiment, the outer plate 223 is removed. In this 
embodiment, the cold air exiting from the outlet 235 of the first air 
passage 231 is drawn out to the chamber via the fan 229, thereby lowering 
the temperature as well as the humidity inside the chamber. Moreover, a 
rate of dehumidification, defined herein as the amount of humidity removed 
from the air by the dehumidifier within a unit time period, can be further 
adjusted. In particular, the lengths of the air passages, the speed of the 
air flowing through the air passages, the temperature difference between 
the active cold plate 219 and the air at the inlet 233 of the first air 
passage 231 and other similar variables all contribute in controlling the 
rate of dehumidification. The lengths of the air passages and the speed of 
the air flowing through the air passages are related to a dwell time of 
the air on the condensation surface. In principle, as the dwell time 
increases, more condensation takes place on the condensation surface 227. 
Therefore, in order to increase or decrease the rate of dehumidification, 
various structural components can be modified and/or some aspects of the 
operations of the dehumidifier can be controlled. 
With respect to modifying the structural components, in an alternative 
embodiment a more powerful TEC can be provided to increase the temperature 
difference between the active cold plate 219 and the air inside the 
chamber causing more moisture to condense on the condensation surface 227, 
to thereby lower the humidity at a faster rate. In another alternative 
embodiment, the sizes of the TEC, the active cold plate 219 and the 
secondary plate 241 are increased to provide a larger area of the 
condensation surface, to thereby increase the dwell time. In yet another 
alternative embodiment, the inlet 233 of the first air passage 231 is 
configured to be wider than the outlet 235 by slanting the secondary plate 
221 so that the upper portion of the secondary plate 221 is further away 
from the active cold plate 219 than that of the lower portion of the 
secondary plate 221. As more air can be drawn through the inlet 233 of the 
first air passage 231 than flowing out of its outlet 235, the air flowing 
through the first air passage 231 would be slower, thereby increasing the 
dwell time. In another embodiment, a pair of intake openings 247 is 
provided on the outer shell 225 near the fan 229. These openings reduce 
the air drawing power of the fan 229 through the air passages, thereby, 
again, lengthening the dwelling time. 
With respect to operationally controlling the rate of the dehumidification, 
in one embodiment, the air flow speed can be controlled by changing 
various aspects of the operation of the dehumidifier such as changing the 
fan speed or controlling the electrical power applied to the TEC. 
Furthermore, in the alternative embodiment described above that has a pair 
of intake openings 247, when a movable door 109 is provided for each of 
the pair of intake openings 247, the doors can be moved to adjust to 
increase or decrease the size of openings. These various aspects of the 
operation can be manipulated by an automated control system. 
Referring to FIG. 3, there is shown a schematic block diagram of the 
automated control system 301 for the dehumidifier of the present 
invention. The control system 301 includes a plurality of sensors 305, 
307, 309 to determine the conditions inside the chamber and a control 
circuit 303 to receive corresponding measurements from the sensors 305, 
307, 309. The control system 301 also includes control devices 331, 335, 
337 to control the various aspects of the operation. 
The plurality of sensors includes a first temperature sensor 305 configured 
to measure the temperature of the active cold plate 219, a second 
temperature sensor 307 configured to measure the temperature of the air 
inside the chamber, and a humidity sensor 309 to measure the humidity of 
inside the chamber. The measurements made by the sensors are sent to the 
control circuit 303. The control devices include a TEC power control 
device 331, configured to shut off or turn on the power supply to the TEC 
201, a fan speed control device 335, configured to control the speed of 
the fan 229, and a door control device 337, configured to move the movable 
doors 109. 
The control circuit 303 includes a processor 311, a set of input interface 
devices 313, 315, 317 to receive the measurements from the sensors 305, 
307, 309, respectively, and a set of output interface devices 319, 321, 
323 to send control signals to the control devices 331, 335, 337, 
respectively. The processor 311 preferably includes a microprocessor 325 
and a memory device 327 coupled thereto. 
The input interface devices 313, 315, 317 between the control circuit 303 
and the sensors 305, 307, 309 allow the control circuit 303 to receive the 
measured data from the sensors. Base on the received measured data, the 
processor 311 makes decisions as to how to control the control devices 
331, 335, 337. The output interface devices 319, 321, 323 allow the 
control circuit 311 to send signals to the control devices 331, 335, 337 
based on the decisions made by the processor 311. 
For example, if the temperature measured by the temperature sensor 305 
coupled to the active cold plate 219 falls below a certain temperature, 
e.g., -4.degree. C., then controller 303 would send a signal to the TEC 
power control device 331 to turn off the power supply to the TEC 201. In 
other words, when the moisture condensed on the condensation surface 227 
freezes because the condensation surface 227 temperature is below the 
freezing point for water, then the power to the TEC 201 is shut off in 
order to raise the temperature of the condensation surface 227, to thereby 
melt the ice formed on the condensation surface 227. When the temperature 
rises above a certain temperature, e.g., the freezing point, the power 
would be turned on again. 
In another example, if the humidity inside the chamber is to be maintained 
at a certain range, e.g., see Tables 1 and 2 above, then depending upon 
the humidity measurements from the humidity sensor 309, the control 
circuit 303 may open or close the movable door 109 and/or adjust the speed 
of the fan 229. 
The above described example schemes and other similar schemes are stored in 
the memory device 327 in the form of the processor 325 executable 
instructions. The stored executable instructions, when loaded and executed 
by the processor 325, monitor the variations and interrelationship among 
the measurements received from the sensors 305, 307, 309 and predetermined 
conditions, e.g., optimal range of humidity and/or temperature inside the 
chamber, and the status of the control devices 331, 335, 337. Based on the 
monitoring mentioned above, the stored executable instructions cause the 
control circuit 331 to issue appropriate control signals to the control 
devices 331, 335, 337. 
It should also be noted that, for the proper control of the dehumidifier, 
none, only one or any combination of the sensors 305, 307, 309 and the 
control devices 331, 335, 337 is required. As described above, in some 
instances, the length, the shape and the number of air passages are 
properly designed so that no control system 301 is required in maintaining 
the desired humidity level in the chamber. In other instances, only the 
temperature sensor 305 on the active cold plate 219 and the TEC power 
control device 331 are all that is required. In yet other instances, all 
of the sensors 305, 307, 309 and control devices 331, 335, 337 may be 
required to properly maintain the humidity and temperature inside the 
chamber. 
Referring back to FIG. 2, the moisture disposal conduit 209 preferably 
includes a side orifice 251 formed in the housing 203, having a length 
that is coextensive as that of the active cold plate 219 and open to the 
heat sink side structure 207. The side orifice 251 is then plugged with a 
piece of wicking fabric 253 that starts near the inlet 239 of the second 
air passage 237 to the heat sink side structure 207. A fastener 257, e.g., 
a nail, screw or wire, is provided to removably fasten the wicking fabric 
253 to a base plate 259 of the heat sink side structure 207. Further, the 
bottom of the outer shell 225 is slanted so that any moisture dripping 
down on the wicking fabric 253 would be urged to slip down and flow to the 
heat sink side structure 207. In other words, in operation of the 
dehumidifier 103, moisture drips down from the condensation surface 227 of 
the active cold plate 219 and from the two surfaces of the secondary plate 
221. The moisture collected, water at this point, is passed through the 
wicking fabric 253 to the heat sink side structure 207 and evaporated. Any 
excess water not evaporated at the heat sink side structure 207 is dripped 
down and collected into a water collector (not shown). 
The wicking fabric 253 allows the water to pass but prevents air from 
passing therethrough. This configuration is desired to achieve a thermal 
separation between the cold side, located in the inside the chamber, and 
the heat sink side, located in the outside of the chamber. If the conduit 
209 allows the air to pass therethrough freely, the humidity and 
temperature control inside the chamber becomes more difficult and 
inefficient due to the outside air coming in and the inside air going out 
though the conduit 209. The wicking fabric is a commercially available 
humidifier filter material. Exemplary wicking fabric is available from RPS 
Products located in Hampshire, Ill. or The Barker Company located in 
Seattle, Wash. It should be noted that other similar material possessing 
the similar characteristics with that of the wicking fabric described 
above can be used. Another desirable characteristic of the wicking fabric 
is that it can be replaced periodically. 
FIG. 4 illustrates an alternative embodiment of the moisture disposal 
conduit that includes a cold side opening 401 and a heat sink side opening 
403, and a middle portion 405. The cold side opening 401 is configured to 
collect moisture dripping down from the condensation surface 227 of the 
active cold plate 219 and from the two surfaces of the secondary plate 
221. The collected water is passed through the middle portion 405 of the 
conduit to the heat sink side opening 403. Preferably, the middle portion 
405 is configured to allow the water to pass but prevent air from passing 
therethrough. This is achieved by inserting the wicking fabric in the 
middle portion 405 of the conduit. 
Referring back to FIG. 2, the heat sink side structure 207 includes the 
base plate 259 and a large fan 261 mounted thereto. The base plate 259 is 
thermally connected to the heat sink side of the TEC 201 either directly 
or via a buffer block. The base plate 259 is preferably made of same 
material as that of the active cold plate 219, but it can be made of any 
other material that is rigid, thermally conductive and anti-corrosive. The 
base plate 259 also includes a plurality of fins 263 that are made of the 
substantially same material as that of the base plate and formed thereon. 
It should be noted that the large fan 261 can be a blower or any other 
means to blow air onto the base plate 259. 
The fan 261 blows air onto the fins 263 and the base plate 259 to cause 
efficient dissipation of the heat generated at the heat sink side of the 
TEC 201. It should be noted that there is a direct relationship between 
the amount of the heat dissipated at the heat sink side and the lowering 
of the temperature on the cold side of the TEC 201. It should also be 
noted that the fins 263 are formed vertically so that the air blown in by 
the fan 261 is blown to the wicking fabric 253 to increase the evaporation 
rate of the water therefrom. It should be noted that in alternative 
embodiments, the fins can be formed in any direction as long as the heat 
can be efficiently dissipated from the heat sink side of the TEC 201. 
While various descriptions of the present invention are described above, it 
should be understood that the various features can be used singly or in 
any combination thereof. Therefore, this invention is not to be limited to 
only the specifically preferred embodiments depicted herein. Further, it 
should be understood that variations and modifications within the spirit 
and scope of the invention may occur to those skilled in the art to which 
the invention pertains. For instance, the dehumidifier of the present 
invention can be scaled up, made much larger than the preferred 
embodiment, to be a dehumidifier for large grain storage rooms in tropical 
areas. In another instance, the dehumidifier of the present invention can 
be used in chambers that store food stuff such as liquid cheese and 
sauces. 
Accordingly, all expedient modifications readily attainable by one versed 
in the art from the disclosure set forth herein that are within the scope 
and spirit of the present invention are to be included as further 
embodiments of the present invention. The scope of the present invention 
is accordingly defined as set forth in the appended claims.