Patent Application
20200271336
The present invention relates generally to a thermoelectric dehumidifying device, and more particularly to a slim type thermoelectric dehumidifying device which has higher dehumidifying efficiency compared to conventional thermoelectric dehumidifying devices.
A conventional dehumidifier typically uses a gas compressor to circulate refrigerant in tube passes involving a condenser and an evaporator. Due to the change in pressure, the refrigerant circulating in tube passes undergoes phase transitions between a liquid state and a gaseous state. Specifically, at the evaporator section, the refrigerant changes from a liquid state to a gaseous state through evaporation. By absorbing the heat contained within, the evaporation of the refrigerant cools the surrounding air which is drawn into the dehumidifier and flows by the outside of the tube passes. As the air temperature decreases, the moisture in the air is removed in the form of condensed water droplets. On the other hand at the condenser section, the dehumidified air, in turn, cools the compressed high-temperature refrigerant which is sent out by the gas compressor, so as to heat the dehumidified air before venting it to the outside. The moisture contained in indoor air can be removed in this way. However, this kind of dehumidifiers is usually bulky since it has to accommodate at least a gas compressor, a condenser, and an evaporator within, and therefore is not suitable for cramped usage environments such as in wardrobes, closets, or shoe cabinets.
In order to reduce the size of dehumidifiers, some manufacturers replace gas compressors with thermoelectric cooling modules, as disclosed in the published Japanese patent application No. JPH06-163997, which can be referred to in
When the thermoelectric cooling module is not supplied with electricity, its two end surfaces would naturally have equal temperatures. After being provided with electric current, the energy on one end surface is gradually transferred to the other one end surface by the energy carriers in the electric current, whereby the end surfaces respectively become a cold surface and a hot surface as described above. Along with the process that the temperature at the cold surface approaches the temperature suitable for condensing moisture, there is more and more energy being reduced from the cold surface side and accumulated at the hot surface, only cooled and dehumidified air has a smaller volume, and therefore can only take away limited heat energy with it. Due to this reason, when the cold surface and the hot surface have a great temperature difference in between, the cold surface may not be able to be further cooled since only limited heat energy can be transferred to the hot surface. As a result, the cold surface naturally has a poorer performance in condensing moisture. To solve this problem, said published patent application discloses a design that introduces an airflow into the dehumidifier from outside before the cooled and dehumidified air reaches the hot surface. The combined airflow formed by mixing the cooled airflow and the outside airflow has a larger volume, so that the airflow utilized to bring away the heat energy at the hot surface can have a larger volume as well. More details about the design of said published patent application: an opening 31 is provided where the airflow has yet to reach the hot surface, and a cross-flow fan 29 is provided at an air outlet, through which the airflow is vented after passing through the hot surface. The cross-flow fan 29 provides an air-drawing effect, whereby the outside air can be pulled into the dehumidifier through the opening 31 to become a second airflow, which can be mixed with the cooled and dehumidified air before passing through the hot surface, whereby to bring away more heat energy at the hot surface. The air-drawing effect of the cross-flow fan 29 can create smooth and steady airflow, which has roughly constant cross-sectional shape and area. Hence, the mixed airflow which is formed by mixing the second airflow and the cooled airflow by the drawing of the cross-flow fan 29 is smooth and steady. However, when such mixed airflow passes by the hot surface, only the heat energy at locations on the hot surface having contact with the cross-section of the mixed airflow can be taken away, so that the heat dissipation effect of the hot surface is still rather limited. If the heat dissipation effect of the hot surface is limited, so is the cooling effect of the cold surface of the thermoelectric cooling module, leading to a poor moisture-condensing performance on the cold surface, which hinders the dehumidifying efficiency.
In order to increase the areas on the cold surface and on the hot surface contacting with the airflow, the above-mentioned published patent application further provides multiple fins 23 connected to the cold surface of the thermoelectric cooling module. A top of each fin 23 is connected to the cold surface, while a bottom thereof is a free side extending downward. The hot surface of the thermoelectric cooling module also has multiple fins 23 connected thereto. When the airflow drawn into the dehumidifier passes by the fins connected to the cold surface, the air temperature will be decreased through the abundant contact with the fins 23, so that the moisture in the airflow will condense on the fins 23 into water droplets. These droplets will slide down along the fins 23 toward the free side due to their own weight, and eventually fall off from the fins. However, a water droplet would not slide too quickly on the fin 23 where it condenses onto, especially when it is light in weight and located near the top side of the fin 23. Being light in weight, such a water droplet can only slide slowly. It is only until the water droplet, in its slow-paced sliding movement, happens to bump into another water droplet which is also condensed on the same fin and merge into a heavier water droplet, the sliding movement can be quickened. During the slow-paced sliding movement of the water droplets, the airflow keeps passing by the fins 23. However, those water droplets prevent the airflow from contacting the portions of the fins which are directly covered by the droplets, which hinders the cooling of the airflow, and therefore interferes with the water droplet from further condensing on the fins 23. As a result, the dehumidifying efficiency of the airflow drawn into the dehumidifier is still not satisfying.
In view of the above, one aspect of the present invention is to provide a thermoelectric dehumidifying device, which is a slim cuboid with the air inlet/outlet provided on the short lateral surface of the case, and therefore is adapted to be placed in a cramped space for dehumidification. By providing the fan at a right position, the heat dissipation effect of the hot surface of the thermoelectric element could be improved, so that the temperature at the cold surface could be well-maintained to provide a better dehumidifying capability. Furthermore, the bottom of each condensing fin is inclined downward in line with the flowing direction of the airflow, and the bottoms of any two adjacent condensing fins are not at the same height, so that the sliding and dropping of the water droplets condensed on the condensing fins could be accelerated, which could improve the efficiency for the water droplets on the condensing fins to fall off. As a result, the overall dehumidifying efficiency of the thermoelectric dehumidifying device could be further enhanced.
The present invention provides a thermoelectric dehumidifying device, which includes a case, a thermoelectric element, a first air inlet, a second air inlet, an air outlet, a condenser, a heatsink, and a fan. The case has a first lateral surface and a second lateral surface, wherein the first lateral surface and the second lateral surface are separated by a first spacing. A horizontal length of the first lateral surface and a horizontal length of the second lateral surface are both greater than the first spacing. The thermoelectric element is provided between the first lateral surface and the second lateral surface, and divides a space between the first lateral surface and the second lateral surface into an upper air passage and a lower air passage, wherein an end of the upper air passage communicates with an end of the lower air passage. The thermoelectric element has a cold surface and a hot surface, wherein the cold surface is located in the lower air passage, and the hot surface is located in the upper air passage. The first air inlet is provided on the case, and communicates with another end of the lower air passage. The second air inlet is provided on the case, and communicates with the end of the upper air passage. The air outlet is provided on the case, and communicates with another end of the upper air passage. The condenser includes a plurality of condensing fins, which are provided in the lower air passage, and are arranged substantially parallel to the first lateral surface in a spaced manner, wherein each of the condensing fins has a top side connected to the cold surface, and a bottom side far away from the cold surface. The bottom side of each of the condensing fins is a free side, and is inclined downward in a direction away from the first air inlet. The heatsink includes a plurality of heat dissipation fins, which are provided in the upper air passage, and are arranged substantially parallel to the first lateral surface in a spaced manner; wherein a bottom side of each of the heat dissipation fins is connected to the hot surface. The fan is fixedly provided in the upper air passage, and is located between the second air inlet and the heatsink.
By utilizing the difference between the horizontal lengths of the opposite lateral surfaces of the case and the first spacing between the opposite lateral surfaces, and by providing the air outlet and inlets between the first spacing, the thermoelectric dehumidifying device could be a slim cuboid, and therefore is adapted to be placed in a cramped space for dehumidification. Furthermore, the fan provided between the second air inlet and the heatsink could push the turbulent airflow, which is mixed by the outside airflow and the dehumidified cold airflow, to flow between the heat dissipation fins, which could effectively bring away the heat energy on the heat dissipation fins and the hot surface of the thermoelectric cooling module, whereby to maintain the low temperature at the condensing fins and to ensure the dehumidifying capability achieved by condensing water droplets. In addition, the bottom side of each of the condensing fins is designed to be inclined downward in line with the flowing direction of the airflow, which could urge the water droplets condensed on each of the condensing fins to slide in the downwardly inclined direction. Moreover, a droplet could easily contact and combine with another droplet condensed on the same or the adjacent condensing fin to form a more massive droplet, whereby the dropping of water droplets could be sped up. Therefore, the dehumidifying effect for the airflow which enters the dehumidifying device could be improved.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
As shown in
The case 10 includes a first lateral surface 101, a second lateral surface 102, a third lateral surface 103, and a fourth lateral surface 104, wherein the first lateral surface 101 and the second lateral surface 102 are separated by a first spacing d1. A horizontal length 1011 of the first lateral surface 101 and a horizontal length 1021 of the second lateral surface 102 are both greater than the first spacing d1. The third lateral surface 103 and the fourth lateral surface 104 are provided between the first lateral surface 101 and the second lateral surface 102, and are respectively connected to the first lateral surface 101 and the second lateral surface 102. In the current embodiment, the ratio of the horizontal length 1011 (1021) to the first spacing d1 is 3:1 to 4:1, so that the case 10 is a slightly slim cuboid as a whole, which is adapted to be placed in cramped spaces such as in wardrobes, closets, or shoe cabinets. The air outlet 50 and the first air inlet 30 are vertically provided on the third lateral surface 103, while the second air inlet 40 is provided on the fourth lateral surface 104.
As shown in
A second deflector 109 is provided between the first air inlet 30 on the third lateral surface 103 and another end of the lower air passage 106, whereby to communicate the first air inlet 30 and the lower air passage 106, so that airflow can be guided to flow to the lower air passage 106 from the first air inlet 30. A third deflector 110 is provided between the air outlet 50 on the third lateral surface 103 and another end of the upper air passage 105, whereby to communicate the air outlet 50 and the upper air passage 105, so that airflow can be guided to flow to the air outlet 50 from the upper air passage 105.
The thermoelectric element 20 has a cold surface 201 and a hot surface 202, wherein the cold surface 201 is located in the lower air passage 106, and the hot surface 202 is located in the upper air passage 105. As shown in
As both shown in
In the current embodiment, as shown in
In the current embodiment, the bottom side 601b of each of the long condensing fins 601 and the bottom side 602b of each of the short condensing fins 602 are both gradually inclined in a direction away from the first air inlet 30, as shown in
As shown in
In the current embodiment, the bottom side 601b of each of the long condensing fins 601 and the bottom side 602b of each of the short condensing fins 602 are inclined downward in the direction away from the first air inlet 30, as shown in
It is worth mentioning that, during the sliding of a water droplet, it could also combine with another water droplet on the adjacent condensing fin to form a larger water droplet when it is possible, even if it is yet to arrive at the corresponding bottom side 601b, 602b. The subsequent sliding movement could be therefore accelerated, whereby the water droplets could quickly leave the condensing fins 601, 602.
The table below shows the dehumidifying ability for thermoelectric dehumidifying devices implemented based on the present invention, each of which has different condensing fin spacing d2 and different height difference d3 between any two adjacent condensing fins. The results are measured in the same conditions (specifically, the devices are operated in rooms with the same interior space, the same indoor humidity, and the same room temperature), and are expressed by the weight of the extracted water per hour. In these tests, the external volume of the condenser 60 (which is about 40 mm long, 40 mm wide, and 38 mm high) and the thickness of each condensing fin (which is between 1.0 and 1.3 mm) stay unchanged. Hence, with a greater fin spacing d2, there will be fewer condensing fins. As for the height difference d3, which is a shortened amount for the short condensing fins 602 relative to the long condensing fins 601, we take 0 to 5 mm for testing. In addition, the average height of the condensing fins in each test model is all the same (for example, when d3=2 mm, each long condensing fin is 39 mm and each short condensing fin is 37 mm, so the average height is 38 mm; when d3=0, each long condensing fin and each short condensing fin are both 38 mm, which also have a 38 mm average height). With this requirement, the total surface area of the condensing fins in each test model will be equal, which excludes unnecessary variables for our comparison. This table should be able to show how the changes in the fin spacing d2 and the height difference d3 between each two adjacent condensing fins 601, 602 would affect the dehumidifying effect.
In the above experiments, the total number of condensing fins varies due to different fin spacing. Among all test models, those having a nonzero height difference d3 between two adjacent condensing fins are able to extract more water from the ambient air in comparison to the one having condensing fins of the same length. The test models with a height difference d3 of 2 to 4 mm between two adjacent condensing fins particularly have good performance. In other words, the height difference d3 between two adjacent condensing fins is preferably set as 2 to 4 mm for the best moisture condensing efficiency.
Also, in the current embodiment, the fan 80 is provided between the second air inlet 40 and the heatsink 70, as shown in
Another embodiment of the present invention is shown in FIG. 12, which is different from the previous embodiment by the number of the thermoelectric elements 20 provided in the case 10. In other words, there can be more than one thermoelectric element 20 connected in series or in parallel. In the current embodiment, there are two thermoelectric elements 20 connected in series, wherein the two cold surfaces 201 of the thermoelectric elements 20 are connected to the condenser 60, and the two hot surfaces 202 of the thermoelectric elements 20 are connected to the heatsink 70. With such design, there can be two thermoelectric elements 20 used for dehumidification. Needless to say, there also can be more than one condenser 60 and more than one heatsink 70. Furthermore, their fins can be appropriately staggered in the flowing direction of the airflow, whereby to facilitate a good heat dissipation effect for the airflow which passes through.
With the structures described above, the benefits provided by the present invention would include:
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
