1. A thermoelectric refrigerator with an evaporative cooling system, the device comprising:
a. a roll bond evaporator (101) for cooling the refrigerator;
b. a thermoelectric engine connected to the roll bond evaporator (101), wherein the thermoelectric engine has plurality of heat exchangers;
c. a cold side thermoelectric engine enclosure (102) for cooling the cold side;
d. a hot side thermoelectric engine enclosure (106) for maintaining the generated heat to the ambient temperature of the hot side;
e. a thermoelectric chip array (108) for heating and cooling the liquid electrically;
f. a micro channel plate heat exchanger (103) and an evaporative pad (104) used for hot side liquid heat exchanger;
g. a fan (107) for cooling the hot side of said micro channel plate heat exchanger (103) and said evaporative pad (104);
h. a first tank (105)for holding the ambient liquid; and
i. a mechanism adjacent to the hot side for maintaining the first temperature of the hot side below the ambient temperature which is almost equal to the wet bulb temperature of the surrounding ambient air,
wherein said mechanism adjacent to the hot side includes option to have open loop cooling during the availability of continuous water supply and in non-air-conditioned environment,
wherein in sequence, the water from the first tank (105) which is filled continuously through external source of water supply (201) is pumped to the thermoelectric chip array (108) and the outlet of the thermoelectric chip array (108) is connected to the micro channel plate heat exchanger (103), the outlet of the micro channel plate heat exchanger (103) is connected to the evaporative pad (104) and outlet of the evaporative pad (104) is connected to the first water tank (105).
2. The device as claimed in claim 1, wherein said device has a float switch (202) integrated with the external source of water supply (201) to maintain the automatic flow of water in the first tank (105) by opening and closing the float valve (203).
3. The device as claimed in claim 1, wherein said cooling liquid used may be any cooling agent but not limited to water, wherein said device has a provision to add anti-freeze agent such that the freezing point of the liquid is maintained to predefined value using a thermostat.
4. The device as claimed in claim 1, wherein said evaporator pad is made of any metallic or non-metallic material but not limited to cellulosic material based evaporative pad.
5. The device as claimed in claim 1, wherein the arrangement of said device enables the flexibility to carry the device in any tilted position but not limited to horizontal, vertical, on wheels etc.
6. The device as claimed in claim 1, wherein said device may be powered ON using Alternating Current (AC), Direct Current (DC) and solar energy installed at user (s) location.
7. A thermoelectric refrigerator with an evaporative cooling system, the device comprising
a. a mechanism adjacent to the hot side for maintaining the first temperature of the hot side below the ambient temperature, wherein said mechanism adjacent to the hot side includes option to have closed loop cooling in air-conditioned environment, where the outside ambient is less than 30 Degree Celsius,
wherein in sequence, the onetime manually filled water in the first tank is pumped to the thermoelectric chip array (108) and the outlet of the thermoelectric chip array (108) is connected to the micro channel plate heat exchanger (103), the outlet of the micro channel plate heat exchanger (103) is connected to first water tank (105).
8. The device as claimed in claim 3, wherein said device has an inverted container (301) fastened to first water tank, wherein the inverted container is used to fill the water and indicate the water level in the tank.
9. A thermoelectric refrigerator with an evaporative cooling system, the device comprising:
a. the first tank (105) and a second tank (105a);
b. a mechanism adjacent to the hot side for maintaining the first temperature of the hot side below the ambient temperature, wherein said mechanism adjacent to the hot side includes option to have combination of an open loop and closed loop cooling during the unavailability of continuous water supply and in non-air conditioned environment;
c. the closed loop cooling is carried out when the second tank (105 a) is drained out, wherein in sequence, the manually filled water from the first tank (105) is pumped to the thermoelectric chip array (108) and the outlet of the thermoelectric chip array (108) is connected to the micro channel plate heat exchanger (103), the outlet of micro channel plate heat exchanger (103) is connected to the first tank (105).
d. combination of the open loop and the closed loop cooling is carried out when the float switch (404) senses an availability of adequate level of water in second tank (105a), wherein the float switch (404) operates a solenoid (402) and energizes the pump (404),
wherein in sequence, the manually filled water from the first tank (105) and the second tank (105a) is pumped to the thermoelectric chip array (108) and the outlet of the thermoelectric chip array (108) is connected to the micro channel plate heat exchanger (103), the outlet of micro channel plate heat exchanger is connected to the evaporative pad (104) and first tank (105), and outlet of the evaporative pad (104) is connected to second water tank (105a).
10. The device as claimed in claim 5, wherein said connection between second tank (105a) and thermoelectric chip array (108) has a shuttle valve (401) which allows water to flow in one direction from second tank (105a) to thermoelectric chip array (108), and the said solenoid valve (402) is connected between the micro channel plate heat exchanger (103) and evaporative pad (104) through the first tank (105).
, Description:[001] Description of the invention
[002] The following specification particularly describes the invention and the manner in which it is to be performed:
[003] Technical field of the invention
[004] The present invention relates to thermoelectric refrigerators. More particularly, the invention relates to thermoelectric refrigerator with an evaporative cooling system.
[005] Background of the invention
[006] Refrigeration is the process of driving heat energy out of an insulated chamber in order to reduce the temperature of the chamber below that of the surrounding air. Thermoelectric refrigeration uses a principle called the "PELTIER" effect to pump heat electronically. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current. Such an instrument is also called a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC). It can be used either for heating or for cooling, although in practice the main application is cooling.
[007] Various types of conventional thermal electric refrigerator are known in the prior art, wherein most of them use air cooling to reduce the temperature of the chamber below that of the surrounding air. The air cooling fails to ensure the efficient cooling process in these devices.
[008] The United States patent number 2278242, discloses about evaporative cooler. The invention provides an evaporative cooler having an improved arrangement for controlling the effective capacity thereof and for minimizing the accumulation of deposits caused by the complete evaporation of water on portions of the surface of the cooler.
[009] The United States patent number 5605052, provides a mist spray system for refrigeration condensers and includes a water spray nozzle centrally affixed to the condenser grill for spraying a circular pattern of water on the condenser while operating. A paddle pivotally suspended over the condenser exhaust is connected to a control arm that functions as a pinch valve controlling the flow of water to the nozzles when the paddle is activated by the flow of exhaust air. Water into the system is pressure controlled, and travels through 1/4 inch plastic tubing to the nozzles which are adjustable.
[0010] The United States patent number 6003319, discloses about thermoelectric refrigerator with evaporating/condensing heat exchanger. The thermoelectric refrigerator comprises a heat transfer system along with a thermoelectric device and, a heat exchanger along with an evaporating surface and a condensing surface. A working fluid is sealed within the heat exchanger. The thermoelectric device includes a thermally conductive hot plate and a thermally conductive cold plate with thermoelectric elements disposed there between. The thermoelectric elements are preferably electrically coupled in series and thermally coupled in parallel. The evaporating surface of the heat exchanger is thermally coupled with the hot plate. A fluid flow path is provided to allow working fluid in its vapor phase to flow from the evaporating surface to the condensing surface and working fluid in its liquid phase to flow from the condensing surface to the evaporating surface. The configuration of the heat exchanger will optimize heat transfer by the working fluid from the thermoelectric device.
[0011] Further, in the existing devices, the cooling sequence is an open loop, in which the cooling liquid is not fed back to start the cooling process again. Therefore, there is a possibility of the t ank getting dried due to evaporative process where the water used for cooling gets evaporated.
[0012] Hence, looking at the problems in the prior art, there is a need of a thermoelectric refrigerator which enables a more efficient cooling process. The device should also have continuous cooling process, such that the liquid tank doesn’t become dry during the evaporation process.

[0013] Summary of the invention:
[0014] The present invention overcomes the drawbacks in the prior art and provides a thermoelectric refrigerator with an evaporative cooling system. The present invention comprises a roll bond evaporator for cooling the inner part of the refrigerator. A thermoelectric engine is connected to the roll bond evaporator, wherein the thermoelectric engine has plurality of heat exchangers. A cold side thermoelectric engine enclosure is used for cooling the cold side. A hot side thermoelectric engine enclosure is used to maintain the generated heat to ambient temperature of the hot side. A thermoelectric chip array is used to heat and cool the liquid electrically. A micro channel plate heat exchanger and an evaporative pad are used for the hot side liquid heat exchanger. A fan is used for cooling the hot side of the micro channel plate heat exchanger and the evaporative pad. A tank is used for holding the ambient liquid.
[0015] In the preferred embodiment of the invention, said device has a mechanism adjacent to the hot side for maintaining the first temperature of the hot side below the ambient temperature. The maintained temperature is almost equal to the wet bulb temperature of the surrounding ambient air. The mechanism adjacent to the hot side includes option to have open loop cooling in the device, during the availability of continuous water supply and in non-air conditioned environment. In sequence, the water from the first tank, which is filled continuously through external source of water supply, is pumped to the thermoelectric chip array. The outlet of the thermoelectric chip array is connected to micro channel plate heat exchanger. The outlet of micro channel plate heat exchanger is connected to the evaporative pad and outlet of the evaporative pad is connected to the first water tank.
[0016] In the preferred embodiment of the invention, said device has a float switch integrated with the external source of water supply to maintain the automatic flow of water in the first tank.
[0017] In the another embodiment of the invention, a mechanism adjacent to the hot side includes option to have closed cooling in the device, during the unavailability of continuous water supply and in air-conditioned environment. In sequence, the onetime manually filled water in the first tank is pumped to the thermoelectric chip array and the outlet of the thermoelectric chip array is connected to micro channel plate heat exchanger, the outlet of micro channel plate heat exchanger is connected to the first water tank.
[0018] In the preferred embodiment of the invention, said device has an inverted container fastened to the first water tank, wherein the inverted container is use to fill the water and indicate the water level in the tank.
[0019] In another embodiment of the invention, said device has a mechanism adjacent to the hot side, which is used for maintaining the first temperature of the hot side below the ambient temperature. The mechanism includes an option to have combination of an open loop and closed loop cooling in the device, during the unavailability of continuous water supply and in non-air conditioned environment.
[0020] The closed loop cooling is carried out when the second tank is drained out, wherein in sequence, the manually filled water from the first tank is pumped to the thermoelectric chip array and the outlet of the thermoelectric chip array is connected to the micro channel plate heat exchanger. The outlet of micro channel plate heat exchanger is connected to the first tank.
[0021] The combination of the open loop and the closed loop cooling is carried out when the float switch senses availability of adequate level of water in second tank. The float switch operates a solenoid and energizes the pump. In sequence, the manually filled water from the first tank and the second tank is pumped to the thermoelectric chip array and the outlet of the thermoelectric chip array is connected to the micro channel plate heat exchanger. The outlet of micro channel plate heat exchanger is connected to the evaporative pad and the first tank. Further, the outlet of the evaporative pad is connected to second water tank.
[0022] In the preferred embodiment of the invention, wherein said connection between second tank and thermoelectric chip array has a shuttle valve in which water flows only in the one direction, and the connection between the second tank and the thermoelectric chip array has a solenoid valve to control the flow of water.
[0023] In the preferred embodiment of the invention, said evaporator pad is made of any metallic or non-metallic material but not limited to cellulosic material based evaporative pad.
[0024] In the preferred embodiment of the invention, wherein the arrangement of said device enables the flexibility to carry the device in any tilted position but not limited to horizontal, vertical, on wheels etc.
[0025] In the preferred embodiment of the invention, wherein said device may be powered ON using Alternating Current (AC), Direct Current (DC) and solar energy installed at user (s) location.
[0026] Brief description of the drawings:
[0027] The foregoing and other features of embodiments will become more apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like elements.
[0028] Figure 1 illustrates a block diagram of the thermoelectric refrigerator, in accordance with an embodiment of the invention.
[0029] Figure 2illustrates a block diagram of the open loop cooling in the thermoelectric refrigerator during the availability of continuous water supply and in non-air-conditioned environment, in accordance with an embodiment of the invention.
[0030] Figure 3 illustrates a block diagram of the closed loop cooling in the thermoelectric refrigerator during the unavailability of continuous water supply and in an air-conditioned environment, in accordance with an embodiment of the invention.
[0031] Figure 4 (a) and Figure 4 (b) illustrates a block diagram of the combination of open loop and closed loop cooling in the thermoelectric refrigerator during the unavailability of continuous water supply and in non-air conditioned environment, in accordance with an embodiment of the invention.
[0032] Figure 5 illustrates a circuit diagram of the open loop cooling in the thermoelectric refrigerator during the availability of continuous water supply and in air-conditioned environment, in accordance with an embodiment of the invention.
[0033] Figure 6 illustrates a circuit diagram of the closed loop cooling in the thermoelectric refrigerator during the unavailability of continuous water supply and in air-conditioned environment, in accordance with an embodiment of the invention.
[0034] Figure 7 illustrates a circuit diagram of the open loop cooling in the thermoelectric refrigerator during the unavailability of continuous water supply and in non-air conditioned environment, in accordance with an embodiment of the invention.
[0035] Figure 8 illustrates a block diagram showing the usage of the Alternating Current (AC)/Direct Current (DC)/solar source to switch ON the device.
[0036] Detailed description of the invention:
[0037] Reference will now be made in detail to the description of the present subject matter, one or more examples of which are shown in figures. Each embodiment is provided to explain the subject matter and not a limitation. These embodiments are described in sufficient detail to enable a person skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, physical, and other changes may be made within the scope of the embodiments. The following detailed description is, therefore, not be taken as limiting the scope of the invention, but instead the invention is to be defined by the appended claims.
[0038] The present invention provides a thermoelectric refrigerator with an evaporative cooling system. The thermoelectric refrigerator comprises a roll bond evaporator for cooling the inner part of the refrigerator. A thermoelectric engine is connected to the roll bond evaporator, wherein the thermoelectric engine has a plurality of heat exchangers. A cold side thermoelectric engine enclosure is used for cooling the cold side. Ahot side thermoelectric engine enclosure is usedfor heating the hot side. A thermoelectric chip array is used to heat or cool the liquid electrically, as needed. A micro channel plate heat exchanger and an evaporative pad are used for the hot side liquid heat exchanger. A fan is used for cooling the hot side of the micro channel plate heat exchanger and the evaporative pad. A tank is used for holding the ambient liquid.
[0039] Figure 1 illustrates a block diagram of the thermoelectric refrigerator, in accordance with an embodiment of the invention. The thermoelectric refrigerator comprises a roll bond evaporator (101) for cooling the inner part of the refrigerator. A thermoelectric engine is connected to the roll bond evaporator (101), wherein the thermoelectric engine has plurality of heat exchangers. A cold side thermoelectric engine enclosure (102) is used for cooling the cold side. Ahot side thermoelectric engine enclosure (106) is usedfor maintaining the generated heat to the ambient temperature of the hot side. A thermoelectric chip array (108)is used to heat and cool the liquid electrically. A micro channel plate heat exchangers (103) and an evaporative pad (104) are used for the hot side liquid heat exchanger, wherein the evaporator pad may preferably be made of any metallic or non-metallic material but not limited to cellulosic material based evaporative pad. A fan (107) is used for cooling the hot side of the micro channel plate heat exchanger (103) and the evaporative pad (104). A tank (105) is used for holding ambient liquid, wherein water is used as refrigerant for cooling the refrigerator.
[0040] The mechanism adjacent to the hot side includes an option to have a closed loop cooling and open loop cooling in the device, wherein the hot side outlet is divided into two types of cooling circuits.
[0041] In the preferred embodiment of the invention, water can be filled by connecting the tap connection directly to the tank during the availability of continuous water supply and in air-conditioned environment, wherein the water is replenished when the cooling water gets evaporated.
[0042] During the unavailability of continuous water supply, and in non-air conditioned and air-conditioned environment the water is filled using an inverted container, wherein the inverted bottle is fastened to the tank as per the requirement. The inverted container also indicates the water level as shown in FIGURE 3.
[0043] In the preferred embodiment of the invention, wherein said device further has an automated float valve and a relay/switch controls to allow the pump to fill the tank automatically from the tap or the bottle when the cooling water gets evaporated from the tank.
[0044] In the preferred embodiment of the invention, the arrangement of said device enables the flexibility to carry the device in any tilted position but not limited to horizontal, vertical, or on wheels etc. In the cited prior arts the refrigerator has to be transported in vertical direction but in the present invention the refrigerant used is water, hence the device can be transported in any position and provides flexibility to logistics and E-commerce crews to transport the refrigerator easily.
[0045] In the preferred embodiment, said cooling liquid used may be any cooling agent but not limited to water, wherein said device has a provision to add anti-freeze agent such that the freezing point of the liquid is maintained to predefined value using a thermostat. The thermostat senses the liquid temperature and based on the liquid temperature it limits the temperature to the predefined temperature.
[0046] Figure 2 illustrates a block diagram of the open loop cooling in the thermoelectric refrigerator during the availability of continuous water supply and in non-air-conditioned environment, in accordance with an embodiment of the invention. The mechanism adjacent to the hot side is employed for maintaining the first temperature of the hot side below the ambient temperature. The maintained temperature is almost equal to the wet bulb temperature of the surrounding ambient air. The said mechanism adjacent to the hot side includes option to have open loop cooling in the device, during the availability of continuous water supply and in non-air-conditioned environment. For example, in kitchens where the refrigerator has got utility to connect to water tap connection and under non- air conditioned environment.
[0047] In sequence, the water from the first tank (105) which is filled continuously through the external source of water supply(201) is pumped to the thermoelectric chip array (108) and the outlet of the thermoelectric chip array (108) is connected to micro channel plate heat exchanger (103), the outlet of micro channel plate heat exchanger (103) is connected to the evaporative pad (104) and the outlet of the evaporative pad (104) is connected to the first water tank (105). The device has a float switch (202) integrated with the external source of water supply (201) to maintain the automatic flow of water in the first tank (105). A fan (107) is mounted to cool the temperature around micro channel plate heat exchanger (103) and evaporative pad (104).
[0048] Figure 3 illustrates a block diagram of the closed loop cooling in the thermoelectric refrigerator in air-conditioned environment, in accordance with an embodiment of the invention. A mechanism adjacent to the hot side is employed for maintaining the first temperature of the hot side below the ambient temperature. The said mechanism adjacent to the hot side includes option to have closed cooling in the device, during the unavailability of continuous water supply and in air-conditioned environment. This mechanism is suitable where there is unavailability of utility to connect to water tap connection and for air conditioned rooms or environment where ambient temperature is around 25-30 Degree Celsius for whole year. Here, one-time water is filled in the tank for closed loop operation.
[0049] An inverted container is fastened to the first water tank to fill the water in the tank, wherein the inverted container is used to indicate the water level in the tank. The inverted container may be a transparent container or an opaque container with transparent opening to indicate the level of the water in the tank.
[0050] Figure 4 (a) and Figure 4 (b) illustrates a block diagram for the combination open loop and closed loop cooling in the thermoelectric refrigerator during the unavailability of continuous water supply and in non-air conditioned environment, in accordance with an embodiment of the invention. A mechanism adjacent to the hot side is employed for maintaining the first temperature of the hot side below the ambient temperature. The said mechanism adjacent to the hot side includes option to have combination of an open loop and closed loop cooling in the device, during the unavailability of continuous water supply and in non-air conditioned environment.
[0051] This mechanism is suitable where the tap water connection is unavailable and for non-air conditioned environments. This ensures the thermoelectric protection for the device, in case the water is completely drained out from the tank.
[0052] Figure 4 (a) shows the mechanism involved in the closed loop cooling. The closed loop cooling is carried out when the second tank is completely drained out. In sequence, the manually filled water from the first tank (105) is pumped to the thermoelectric chip array(108).The outlet of the thermoelectric chip array (108) is connected to the micro channel plate heat exchanger (103) and the outlet of micro channel plate heat exchanger (103) is connected to the first tank (105).
[0053] Figure 4 (b) shows the mechanism involved in combination of the open loop and the closed loop cooling. The combination of the open loop and the closed loop cooling is carried out, when the float switch (403) senses an availability of adequate level of water in second tank (105a). The float switch (403) operates a solenoid (402) and energizes the pump (404) in the second tank (105 a). In sequence, the manually filled water from the first tank (105) and the second tank (105a) is pumped to the thermoelectric chip array (108) through a shuttle valve (401). The outlet of the thermoelectric chip array (108) is connected to micro channel plate heat exchanger (103). The outlet of micro channel plate heat exchanger (103) is connected to the evaporative pad (104) and first tank (105), wherein the remaining water from the micro channel plate heat exchanger (103) is fed to first tank (105).Further, the outlet of the evaporative pad (104) is connected to second water tank (105a) as shown in Figure 4 (b).
[0054] In the preferred embodiment of the present invention, an inverted container (301) is fastened onto the water tank (105), wherein the water tank is provided with the threads to fit the container as shown in Figure 3.
[0055] Figure 5 illustrates a circuit diagram of the open loop cooling in the thermoelectric refrigerator during the availability of continuous water supply and in non-air-conditioned environment, in accordance with an embodiment of the invention.
[0056] Figure 6 illustrates a circuit diagram of the closed loop cooling in the thermoelectric refrigerator during the unavailability of continuous water supply and in air-conditioned environment, in accordance with an embodiment of the invention.
[0057] Figure 7 illustrates a circuit diagram of the open loop cooling in the thermoelectric refrigerator during the unavailability of continuous water supply and in non-air conditioned environment, in accordance with an embodiment of the invention.
[0058] Figure 8 illustrates a block diagram showing the usage of the Alternating Current (AC)/Direct Current (DC)/solar source to switch ON the device. In the preferred embodiment of the present invention, the device may be powered ON using AC or DC or solar energy installed at user (s) location. The device has a utility to connect to any source such as AC or DC or solar energy to switch ON the device.
[0059] In the preferred embodiment of the present invention, the evaporative cooling padis made up of cellulosic material which provides effective cooling. Considering the plurality of evaporating cooling pad designs. For example, in one embodiment the evaporating cooling pad has pad height ranging from 1200-2000 millimetres, width ranging from 600-900 millimetres, depth ranging from 100-300 millimetres, flute height of 7 millimetres and flute angle of 45 degrees.
[0060] In another embodiment of the invention, the evaporating cooling pad has pad height and pad width as per user’s requirement. In a preferable embodiment, the pad depth may range from 50-150 millimetres, flute height may be 5 millimetres and flute angle may be kept at 45 degrees. As the outside temperature decreases and the outside relative humidity of the pad increases, the temperature in the pad decreases.
[0061] Hence, the present invention provides a system, which is cost effective and provides more efficient cooling process. The invented device produces low noise as it does not have a compressor and employs minimum number of moving parts and hence the maintenance required is also very less. The present invention enables the thermoelectric protection for the device all the time.
[0062] The present invention does not use refrigerant which pollutes the environment, but uses water as refrigerant. Hence the device is green and eco-friendly.
[0063] The present invention has continuous cooling process, such that the liquid tank is not dried during the evaporation process.
[0064] It is to be understood, however, that even though several characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.