CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to US Provisional Patent Application No. 63/182,254, filed on April 30, 2021, incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Conventional air conditioners are an intelligent technology in cooling spaces rapidly; however, they consume a tremendous amount of energy, pollute the environment, and emit GHG emissions. Thermoelectric air conditioners are an alternative cooling method that consumes less energy without emitting GHG emissions. The main problem with the existing thermoelectric air conditioners and patents is that they can only cool small spaces such as cars, computer enclosures and refrigerators.

[0003] Effectiveness may be improved by merging two cooling systems in order to make thermoelectric air conditioners capable of cooling bigger spaces such as residential spaces. For example, a thermoelectric cooling system may be merged with an evaporative cooling system to enable a thermoelectric air conditioner to cool residential spaces.

SUMMARY OF THE INVENTION

[0004] In one aspect, a zero-refrigerant cooling device comprises a device body having an inlet and an outlet, a thermoelectric cooling section positioned at the inlet of the device body comprising at least one thermoelectric cooling module, the thermoelectric cooling module having a hot side and a cold side, the thermoelectric cooling section further comprising a cooling chamber section in which the cold side of the at least one thermoelectric cooling module is positioned, a fan configured to drive air from the cooling chamber section toward the outlet of the device body, and a humidifying section positioned between the fan and the outlet of the device body, the humidifying section comprising an evaporative pad. [0005] In one embodiment, the thermoelectric cooling section further comprises at least one hot side heatsink connected to the hot side of the at least one thermoelectric cooling module, at least one hot side fan connected to the at least one hot side heatsink opposite the hot side of the at least one thermoelectric cooling module, at least one cold side heatsink connected to the cold side of the at least one thermoelectric cooling module, and at least one cold side fan connected to the at least one cold side heatsink opposite the cold side of the at least one thermoelectric cooling module.

[0006] In one embodiment, the thermoelectric cooling section further comprising a first insulating barrier fixedly attached to the at least one thermoelectric cooling module and configured to thermally isolate the hot side of the at least one thermoelectric cooling module from the cold side of the at least one thermoelectric cooling module. In one embodiment, the at least one thermoelectric cooling module is a Peltier module. In one embodiment, the device further comprises at least one spray nozzle positioned on the hot side of the at least one thermoelectric cooling module, configured to spray water on at least one of the hot side heatsink or the hot side fan. In one embodiment, a surface of the device body fluidly connected to the hot side of the at least one thermoelectric cooling module comprises a phase change material positioned on the surface of the device body.

[0007] In one embodiment, the cooling chamber section further comprises a chamber defined by the device body, the first insulating barrier, and a second insulating barrier positioned opposite the first insulating barrier, and the second insulating barrier comprises an aperture facing the fan, wherein the fan is configured to draw air from the aperture.

[0008] In one embodiment, the aperture is a 5 cm square. In one embodiment, the humidifying section further comprises a reservoir positioned beneath the evaporative pad, a tube having a first end positioned at a top end of the evaporative pad, and a water pump having an inlet in the reservoir, and having an outlet connected to a second end of the tube, configured to pump a liquid from the reservoir to the top end of the evaporative pad via the tube.

[0009] In one embodiment, the evaporative pad comprises a curvilinear shape including at least one ventilation void, at least one protrusion configured for temporary liquid storage, and at least one smooth pathway configured to enhance liquid distribution. In one embodiment, the evaporative pad comprises terracotta. In one embodiment, at least a portion of the tube is positioned over at least a portion of a top surface of the evaporative pad, and wherein the tube comprises one or more apertures along a length of the tube configured to deposit water on the top surface of the evaporative pad. In one embodiment, the device is an indoor cooling unit.

[0010] In one aspect, a zero-refrigerant cooling method comprises providing a device as described herein, cooling room temperature air to a first temperature via thermoelectric cooling, storing the first temperature air in the cooling chamber, releasing the first temperature air from the cooling chamber, accelerating the released air via the high-speed fan to a first velocity to further cool the air to a second temperature, passing the air at the second temperature through the biomimetic evaporative pad to humidify the air and to further cool the air to a third temperature, and releasing the humidified air at the third temperature to a room.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing purposes and features, as well as other purposes and features, will become apparent with reference to the description and accompanying figures below, which are included to provide an understanding of the invention and constitute a part of the specification, in which like numerals represent like elements, and in which:

Fig. l is a schematic diagram of a cooling device;

Fig. 2 is a cutaway view of a cooling device;

Fig. 3 is an exemplary cooling device;

Fig. 4 is a photographic representation of an exemplary cooling device in use;

Fig. 5 is a photograph of a thermoelectric cooling stage of an exemplary cooling device;

Fig. 6 is a diagram of a cooling chamber of an exemplary cooling device;

Fig. 7 is a cutaway view of a cooling chamber of an exemplary cooling device; Fig. 8 is a set of images of an evaporative cooling stage of an exemplary cooling device;

Fig. 9 is a graphical representation of the surface of a tongue;

Fig. 10 is an exemplary evaporative pad of an exemplary cooling device;

Fig. 11 is a cutaway view of an exemplary cooling device;

Fig. 12 is a diagram of a method of cooling air;

Fig. 13 is a graph of experimental data;

Fig. 14 is a graph of experimental data;

Fig. 15 is a graph of experimental data;

Fig. 16 is a comparison image of a conventional air conditioning unit and a device of the disclosure; and

Fig. 17 is a power consumption diagram of an exemplary cooling device.

DETAILED DESCRIPTION

[0012] It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for the purpose of clarity, many other elements found in related systems and methods. Those of ordinary skill in the art may recognize that other elements and/or steps are desirable and/or required in implementing the present invention. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements and steps is not provided herein. The disclosure herein is directed to all such variations and modifications to such elements and methods known to those skilled in the art.

[0013] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and materials are described.

[0014] As used herein, each of the following terms has the meaning associated with it in this section.

[0015] The articles “a” and “an” are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

[0016] “About” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1%, and ±0.1% from the specified value, as such variations are appropriate.

[0017] Throughout this disclosure, various aspects of the invention can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, 6 and any whole and partial increments therebetween. This applies regardless of the breadth of the range.

[0018] In one aspect, disclosed herein is a thermoelectric air conditioner using a hybrid cooling system by combining thermoelectric and evaporative cooling. With reference to Fig. 1, a schematic design of an exemplary device 100 includes three cooling phases. In the depicted embodiment, the first phase 101 is a thermoelectric cooling phase, the second phase 102 is a cooling chamber, and the third phase 103 is a humidifying phase. The depicted first phase 101 includes at least one thermoelectric cooler 111 (two are shown in device 100, but more or fewer may be used). The depicted second phase 102 may be separated from first phase 101 for example with a barrier 122, having an aperture 123 to allow air to flow from the first phase 101 into the second phase 102. The depicted second phase cooling chamber 102 comprises at least one fan 121 configured to draw air in through an inlet, for example inlet 105, and move the air move air from the first phase 101 through second phase 102, through third phase 103 and out the system outlet 104. The depicted third phase 103 is a humidifying phase comprising an moisture pad 131 and a quantity of fluid 132, which may for example be water.

[0019] In some embodiments, these three phases may be integrated together into a device 200 shown in Fig. 2 that consumes 230 watts per hour, 72% less than a conventional air conditioner. The depicted hybrid cooling device 200 is an indoor cooling unit with a smooth body shape (see Fig. 3 and Fig. 4) that can be placed on a table, a nightstand, or a wall shelf without heavy installation requirements. This avoids any modifications in building envelopes, which could cause thermal bridging and increases potential heat transfer between inside and outside.

[0020] In some embodiments, the devices and methods disclosed herein are zero-refrigerant cooling devices and methods. This is to say that certain embodiments disclosed herein accomplish cooling and/or conditioning of air while using no refrigerant or coolant chemicals or compositions, for example freon or other phase-change materials used in conventional air conditioners or refrigeration systems which utilize a refrigeration cycle. By contrast, some embodiments disclosed herein accomplish cooling via one or more hybrid methods using combinations of thermoelectric cooling, air acceleration, and evaporative cooling/humidification of air.

[0021] With reference to Fig. 2, a cross-sectional view of an exemplary device 200 is shown enclosed in a device body 206, arranged with first, second, and third phases 101, 102, and 103. The first phase includes thermoelectric coolers, for example Peltier modules 214, each having a hot side and a cold side, and configured in some embodiments with heat sinks 212 and/or fans 213 on the hot side. In some embodiments, the hot side of the device may comprise one or more mist spray nozzles (not shown) configured to spray water, for example water pumped from water tank 211 (see Fig. 8), onto one or more elements positioned on the hot side of the thermoelectric coolers. In some embodiments, the spray nozzles may be positioned on or near the fans 213, on or near the heat sinks 212, on or near an air intake path of the fans 213, or on or near the hot side of the thermoelectric cooler modules 214. In some such embodiments, the device may be configured with a drain or sump (not shown) positioned below the hot side of the device and fluidly connected to the water tank 211, such that at least some of the sprayed water from the mist spray nozzles drains into water tank 211.

[0022] In some embodiments, one or more elements of the hot side of the device may comprise or be coated with one or more phase change materials, configured to absorb heat by changing its form. In one embodiment, any or all of the surfaces of the device on the hot side, for example surface 603 or surface 604, or any other surface of the device body in fluid communication with the hot side of a thermoelectric cooler module of the device, may be coated with a phase change material. In some embodiments, an outer surface of fan 213 or heat sink 212 may comprise or be coated with a phase change material.

[0023] The cold sides of the thermoelectric coolers 214 are positioned in cooling chamber 205, which is fluidly connected to the third phase 103, with air being driven from the cooling chamber 205 into the third phase 103 via fan 209. Third phase 103 in device 200 includes an evaporative pad 208 positioned over a water tank 211, with a water pump 210 positioned in water tank 211 and configured to pump water from water tank 211 to the top of evaporative pad 208. In the depicted embodiment, device body 206 includes louvers 207, which in some embodiments may be adjusted to increase or decrease conditioned air flow.

[0024] Another view of exemplary device 200 is shown in Fig. 3, including a display 301 which may for example be configured to display room temperature or other status information. Fig. 4 shows an exemplary device 200 positioned on a table in a room. Although some embodiments of the disclosed device envision a portable device positioned in a room, it is understood that in some embodiments a device according to the present disclosure may be positioned in a window or embedded in a wall of a building or room, for example such that the hot side(s) of the thermoelectric coolers are thermally isolated from both the cold side and the room being cooled.

[0025] A separate view of a prototype first thermoelectric cooling phase 101 is shown in Fig. 5. The thermoelectric cooling phase 101 may in some embodiments comprise one or more thermoelectric coolers 214, having a hot side heat sink 212 and a cold side heat sink 204, as well as hot side fan 213 and cold side fan 515. Hot side fan 213 is configured with hot side heat sink 212 to dissipate heat from the hot side of thermoelectric cooler 214, while cold side heat sink 204 and cold side fan 515 are configured to absorb heat from the air at the cold side of the thermoelectric cooler 214. In some embodiments, a thermal compound, for example a thermally conductive paste, may be used to create a high thermal conductivity connection between the heat sinks 204, 212, and the opposite surfaces of the thermoelectric cooler 214.

[0026] In the depicted embodiment 101 in Fig. 5, four Peltier coolers 214 are used, for example TECl-12706 Peltier modules, and an insulating material (for example high density foam board 510) is positioned to thermally isolate the hot sides and the cold sides of the Peltier coolers 214. In some embodiments, where multiple Peltier coolers are used, the coolers and in some embodiments the fans may be powered in parallel.

[0027] With reference to Fig. 6, an exemplary view of a second phase 102, and how it relates to a first phase 101, is shown. The second phase 102 of the depicted device comprises a cooling chamber 205 and a fan 209, which may in some embodiments be a high-speed fan, for example having an airflow rate of at least 100 CFM, at least 200 CFM, at least 300 CFM, or at least 400 CFM. In a conventional thermoelectric air conditioner, thermoelectric modules cool the air on the cold side and then release it quickly into the room. Because the thermoelectric modules in such systems are exposed directly to large spaces, conventional thermoelectric air conditioners are incapable of cooling larger spaces. In the depicted device, a cooling chamber 205 is used having an aperture 123, which in the depicted embodiment is a 5x5 cm square aperture in the middle of the volume (see also Fig. 7). In some embodiments, the cooling chamber 205 further comprises a temperature sensor 601 positioned in the cooling chamber 205 and configured to measure the current temperature in the cooling chamber 205. When the disclosed device begins to operate, the thermoelectric modules 114 cool the air, then the cooling chamber 205 stores the cold air inside it and releases it slowly so as not to affect the Peltier modules' efficiency in cooling larger spaces. Then the fan 209 decreases the air's temperature further through increasing velocity. The air velocity phase is located after the thermoelectric cooling to decrease air temperature first, then increase its velocity.

[0028] Another view of a cooling chamber is shown in cutaway view in Fig. 7, which shows barrier 122 between the second and third phases, having aperture 123 which in the depicted embodiment is a square, for example a 5 cm x 5 cm square. It is understood that in some embodiments an aperture 123 may be other shapes, for example a circle, ellipse, or oval, and may in some embodiments be shaped to have approximately the same or similar geometry or shape as fan 209. Also visible in the cutaway view of Fig. 7 are the edges of the device body 206, and the display 717 for a temperature sensor positioned inside the cooling chamber, the display configured to show the current temperature inside the cooling chamber. In some embodiments, the current temperature in the cooling chamber may be used as an input to a control system, for example to modulate the speed of fan 209 in order to, for example, increase the speed of fan 209 when the temperature in cooling chamber 205 is sufficiently cold, or decrease the speed of fan 209 when the temperature in cooling chamber 205 is too warm so as to impact the efficiency of thermoelectric coolers 214.

[0029] With reference to Fig. 8, a third phase 103 of a device is shown comprising an evaporative pad 208, which may in some embodiments be a biomimetic evaporative pad, a water tank 211, and a water pump 210, which pushes water from water tank 211 through water tube 818 to the top of the evaporative pad 208, where the water re-enters the pad and flows down again to water tank 211. In some embodiments, at least a portion of water tube 818 may be positioned over at least a portion of evaporative pad 208. In some embodiments, a portion of water tube 818 may be integrated into or positioned within a portion of evaporative pad 208, or may run along one or more edges of evaporative pad 208. In some embodiments, water tube 818 may include one or more mist spray nozzles or apertures (not shown) positioned along the length of water tube 818 and configured to spray, drip, or otherwise infuse or deposit water directly onto the surface of evaporative pad 208. In some embodiments, water tube 818 may include more than one branch of water tube extending from one or more water pumps 210 positioned in water tank 211. In embodiments where multiple branches of water tube 818 are present, a plurality of the multiple branches of water tube 818 may comprise mist spray nozzles or apertures and may therefore be configured to directly deposit water over a greater surface area of the evaporative pad 208, thereby increasing the cooling efficiency of the system.

[0030] The water pump 210 may in some embodiments have a flow rate of at least 50 GPH, at least 60 GPH, at least 70 GPH, at least 80 GPH, at least 90 GPH, at least 100 GPH, or about 95 GPH. The evaporative cooling phase (third phase 103) creates a transitional stage between the thermoelectric cooling of smaller volumes of air to the cooling of larger ones. The evaporative cooling maintains a low temperature on the cold side of the Peltier modules to enhance their performance. The water or other fluid absorbed into the evaporative cooling pad 208 acts as a barrier between the thermoelectric cooling modules and the high temperature present in the space external to the device, because if the thermoelectric modules are in direct contact with hot air, they quickly warm up, hence decreasing their performance.

[0031] After the air is cooled and its velocity is increased in the first two phases, the evaporative pad 208 humidifies the air and cools it further to increase the cooling efficiency. Peltier modules may in some systems be problematic because they dehumidify the air because when the air comes into contact with the Peltier modules’ cold side, any water vapor present in the air condenses on the cold surface of the cold side of the Peltier module and/or its heat sink. This can cause a problem in hot, dry climates where there is already a lack of humidity. Therefore, a benefit of the third phase 103 of the disclosed device is to humidify dry air and increase the cooling capacity of the device.

[0032] In some embodiments, the evaporative cooling system uses a biomimetic pad design and/or material. An ideal evaporative pad is designed to stay moist longer, which increases the cooling efficiency of the system. Additionally, the distribution of water across the pad is an essential factor, as a uniform distribution of water will further increase the efficiency of the system. The biomimetic evaporative pad design disclosed herein was inspired by the tongue surface. It is understood that tongues play a significant role in the evaporative cooling process in humans and other species. The tongue pattern distributes saliva across the surface of the tongue, allowing hot air to cool down through evaporative cooling (see for example Fig. 9, which is a diagram of the surface of a tongue).

[0033] Therefore, in one embodiment disclosed herein, evaporative pad 208 is formed with a curvy, smooth shape similar to the tongue to enhance water distribution, while also including a plurality of voids to allow air movement through the volume of the pad rather than merely across the surface. The protrusions in front of the voids are meant for temporary water storage to improve the cooling process by adding more water to the air flowing through the voids (see Fig. 10), similar to the tongue. [0034] In some embodiments, the pad is made of terracotta to retain moisture for longer periods of time, but in other embodiments the pad may be constructed from foam, cellulose, or any other suitable material.

[0035] An exemplary evaporative pad 208 is shown in Fig. 10, shown in a first isometric view 1001 and a side view 1002. As can be seen in isometric view 1001, the evaporative pad 208 comprises a plurality of voids 1019 to allow air to flow through. The evaporative pad 208 may further comprise one or more protrusions of material 1021 which may for example be configured to store water or other fluid in a location where air flowing through the voids 1019 will flow past the protrusion 1021. The protrusions 1021 improve the cooling process by adding more water to the air flowing through the voids 1019, similarly to how the tongue works. In one embodiment, the evaporative pad is made of terra cotta to retain moisture for longer periods of time. In one embodiment, multiple pads may be positioned in series to increase the amount of pad surface area air is exposed to before exiting the device.

[0036] In one embodiment, a method of cooling air is disclosed. One embodiment of a method of cooling air comprises the steps of cooling a cooling chamber with one or more thermoelectric coolers, pulling the cold air from the cooling chamber through an aperture in the chamber using a fan, and passing the air to an evaporative cooling pad which may be a biomimetic evaporative cooling pad. The method may further include positioning one or more moist cloths between the cooling chamber’s aperture and the evaporative pad to avoid any undesirable heat transfer between the three phases (see Fig. 11). After the pad cools and humidifies the air, the air then flows out of the device to cool a room. The cycle repeats itself continuously, leading to a decrease in room temperature. In some embodiments, the method further comprises pumping water from a tank or reservoir positioned beneath the evaporative pad and/or moist cloth or cloths up to a top side of the evaporative pad and/or moist cloth or cloths so that the water continuously flows down the pad and/or cloths and both remain saturated.

[0037] The moist cloth positioning is shown in Fig. 11. In the depicted embodiment of device 200, the moist cloth 1223 is positioned between the cooling chamber aperture 123 and the evaporative pad 208. [0038] With regard to Fig. 12, a method 1200 of cooling air is shown. The method 1200 comprises the steps of providing a cooling device in step 1205, cooling room temperature air to a first temperature via thermoelectric cooling in step 1210, storing the first temperature air in a cooling chamber in step 1215, releasing the first temperature air from the cooling chamber in step 1220, accelerating the released air via a high-speed fan to a first velocity to further cool the air to a second temperature in step 1225, passing the air at the second temperature through an evaporative pad to humidify and further cool the air in step 1230, and releasing the cooled, humidified air at a third temperature to a room in step 1235.

EXPERIMENTAL EXAMPLES

[0039] The invention is further described in detail by reference to the following experimental examples. These examples are provided for purposes of illustration only, and are not intended to be limiting unless otherwise specified. Thus, the invention should in no way be construed as being limited to the following examples, but rather, should be construed to encompass any and all variations which become evident as a result of the teaching provided herein.

[0040] Without further description, it is believed that one of ordinary skill in the art can, using the preceding description and the following illustrative examples, make and utilize the system and method of the present invention. The following working examples therefore, specifically point out the exemplary embodiments of the present invention, and are not to be construed as limiting in any way the remainder of the disclosure.

Experiment 1

[0041] A prototype device was constructed with four thermoelectric cooling modules installed; however, for technical reasons, only three were operating. Each phase of the device was tested separately for 30 minutes using a 12V, 5 A adapter under the same conditions with an ambient temperature of 78°F (25.5°C), and then a full operation took place. In phase one, the cooling chamber was tested once while completely closed, and again when the new 5x5 cm void was added. As shown in Fig. 13, the temperature dropped significantly under both conditions, thus meeting the design development primary target. In the second phase, the evaporative cooling recorded a temperature reduction of 5° F. Finally, when the hybrid cooling device was fully operational, it produced cool air that was 12° F lower than room temperature (see Fig. 14) with 0% greenhouse gas (GHG) emissions. Simultaneously, the device maintained its interior temperature at 16° F lower than room temperature, which enhanced its performance to produce cool air. Moreover, the device recorded a relative humidity increase of 30% higher than room temperature (see Fig. 15). Generally, the device produced air with a temperature 7° C (12° F) cooler using three thermoelectric TECl-12706 Peltier modules, while a conventional 900 Watt window air conditioner produces air with a temperature 12° C (20° F) cooler (Wedell, 2020; Hydesac, 2015). The device’s performance could potentially exceed the performance of a conventional 900 Watt air conditioner if larger, more powerful thermoelectric cooling modules, for example TEC 1-12712 modules, were used instead. As one example the TEC 1-12712 Peltier modules have a cooling capacity of 103 W (compared to 52.8 W for the modules used in the disclosed prototype, see Table 1 below), which could lead to a significant increase in cooling capacity.

Table 1

Cost Comparison

[0042] The disclosed hybrid air conditioner consumes 72% less energy than a conventional air conditioner while preventing GHG and CO2 emissions (see Fig. 16). A conventional window air conditioner's operation consumes 900 watts, or 324 KWh/month (Morrison D., 2021; Hanson, 2021). In comparison, a hybrid thermoelectric cooling device consumes 254 watts (see Fig. 17), or 91KWh/month. [0043] The cost of installing a conventional window air conditioner that cools a 130 ft ² (12 m ² ) room is $540 (Life Prices, 2021). By contrast, the cost of the hybrid thermoelectric cooling device is approximately $185, which is 66% less, reducing the initial cost by almost two thirds. Furthermore, no construction costs are required because the device is portable. However, the device needs to be placed in a shaded area, because if exposed to direct sunlight, the Peltier modules’ performance will decrease by rapidly increasing their temperature.

[0044] The disclosures of each and every patent, patent application, and publication cited herein are hereby incorporated herein by reference in their entirety. While this invention has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations of this invention may be devised by others skilled in the art without departing from the true spirit and scope of the invention. The appended claims are intended to be construed to include all such embodiments and equivalent variations.