Patent Application
20250230994
This invention relates to a microchannel heat exchanger that performs heat exchange between two fluids.
Patent reference 1 (JP 2005-83676 A 1) addresses the issue of increasing the cross-partial area of the flow channel and lowering the resistance of the flow channel in a heat exchanger core used in a microchannel heat exchanger, wherein a first plate with a plurality of channels formed on its surface and a flat second plate are superimposed to form a plate part, and wherein the plate parts are stacked in multiple stages so that the longitudinal directions of the flow paths are alternately orthogonal to each other, and the side edges are removed to form the heat exchanger commission core.
In heat exchangers, it is generally known that the heat transfer coefficient in a heat exchanger tube is proportional to the inverse of the cross-partial dimension of the tube channel, and a high heat transfer coefficient can be obtained when the heat exchanger is micro channelized. When the fluid in the narrow channel is a high velocity flow, the boundary layer becomes thinner, but the temperature gradient in the tube is even larger, so the heat exchange rate through the tube wall is expected to increase. Especially in the field of refrigeration equipment, micro channelization is expected to dramatically reduce the size and weight of heat exchangers and improve their heat transfer performance.
Microchannels refer to narrow flow channels that have been descended using microfabrication techniques or other methods, and are generally referred to as those with a diameter of a few millimeters or less, where the effects of surface tension appear.
The advantages of using microchannels are as follows;
The following disadvantages can be assumed;
The general manufacturing method for stacked compact heat exchangers (microchannel heat exchangers) is to etch thin plate materials (stainless steel plates, aluminum plates, copper plates, etc.) from one side to form a concave, non-through (called half-etching) flow channel part, since the through-hole is etched from the opposite side at the same time to create the through-hole and the un-etched area, those two types of plates are required.
In the patent reference as shown in the above, an example is disclosed in which the flow channel portion of the plate is stamped through without using an etching process. However, because the structure as it is does not allow the flow channel portion to be secured after joining, machining is unavoidably performed in a subsequent process. Machining can secure the flow path, but there is a risk of cutting dust and debris-containing cutting oil entering the narrow flow path, and the added cutting process increases costs.
In addition, since the plate is not integrated with the housing, the cost reduction effect is incomplete even if the plate is pressed.
Therefore, the present invention provides a microchannel heat exchanger that does not require cutting, has a structure that can secure the flow path after plate bonding, and consists of components that can be formed by inexpensive press working, etching, or laser machining.
Thus, the microchannel heat exchanger of the present invention is constituted of a cylindrical housing part; rectangular shaped heat exchange part with four corners integrally connected to an inner surface of the cylindrical housing part, four fluid passages defined between the inner surface of the cylindrical housing part and the heat exchange part; a lid plate that closes one end of the cylindrical housing part and has four fluid inlets and outlets that are connected to each of the four fluid passages; and a bottom plate shielding the other end of the cylindrical housing part,
According to the above configuration, according to the present invention, for example, one fluid with which heat is exchanged flows into one of the fluid passages (a first fluid passage) connected from one of the fluid inlet/outlet parts (a first fluid inlet) formed in the lid plate, passes through the first heat exchange passage connected to this first fluid passage, and is discharged through the other fluid passage (a third fluid passage) located opposite to the first fluid passage from the fluid inlet/outlet part (a first fluid outlet) opposite to one of the fluid inlet/outlet part. This constitutes the first fluid circulation cycle.
In contrast, the other fluid to be heat exchanged flows from the fluid inlet/outlet part (a second fluid inlet) adjacent to one of the fluid inlet/outlet parts (the first fluid inlet) into the fluid passage (a second fluid passage) that is connected to the second fluid inlet, through the second heat exchange passage that is connected to the second fluid passage, and through the second fluid passage at a position opposite to the second fluid passage through the other fluid passage (a fourth fluid passage), which is connected to the fourth fluid passage, and discharged from the second fluid outlet that is connected to the second fluid inlet. This constitutes the second fluid circulation cycle. In this way, heat exchange can be performed between the fluid flowing in the first heat exchange passage and the fluid flowing in the second heat exchange passage which is orthogonal to the first heat exchange passage.
With the above configuration, the first plate unit and the second plate unit are alternately stacked, and the second plate unit is sandwiched and fixed by the first plate unit located above and below the second plate unit. As a result, the top and bottom of the heat exchange channel plate part of the second plate unit are closed by the closing plate part of the first plate unit, so that the opening surfaces of the plurality of microchannel openings extending along the longitudinal direction of the heat exchange channel plate part are closed, forming a plurality of microchannels extending along the longitudinal direction of the heat exchange channel plate part. In addition, this creates, for example, a first heat exchange passage that connects the first fluid passage and the third fluid passage. A second heat exchange flow passage orthogonal to the first heat exchange flow passage can be formed by rotating the second plate unit, which is located below the first plate unit that closes below the second plate unit, by 90° relative to the second plate unit above it. By repeating this process, the four fluid passages and microchannels that alternately connect each of the opposing fluid passages are formed to form the first heat exchange passage and the second heat exchange passage.
This allows a microchannel heat exchanger to be configured with a small number of components.
In addition, since only two molds for manufacturing each of the first plate and the second plate needs to be made, manufacturing costs can be reduced.
According to the microchannel heat exchanger of the present invention, the number of parts can be reduced and manufacturing costs can be lowered because the microchannel openings have been changed to a structure that can be manufactured by press punching and only two types of plates such as the first plate and the second plate are used.
In addition, the outer diameter is cylindrical, which improves pressure resistance performance. In addition, the joining of the first and second plate units is strengthened because the microchannels are arranged so that they cross each other.
Since the two fluids (e.g., gas and liquid) that exchange heat are completely separated, only the outer circumference of the cylindrical housing part needs to be sealed, allowing inexpensive adhesives or brazing to be used for joining without the need for expensive processing methods such as diffusion bonding.
Hereinafter, an example of this invention will be described based on the drawings.
As shown in
According to the above configuration, according to the present invention, for example, one of the fluids to be heat exchanged flows from the first fluid inlet 8 formed in the lid plate into the connecting first fluid passage 4, through the first heat exchange passage 14 which is connected to this first fluid passage 4, through the third fluid passage 6 which is located opposite to the first fluid passage 4 through the first fluid outlet 9 opposite the first fluid inlet 8. This constitutes the first fluid circulation cycle.
In contrast, the other fluid to be heat exchanged flows from the second fluid inlet 10 into the second fluid passage 5 connected therewith, passes through the second heat exchange passage 15 connected to this second fluid passage 5, and is discharged from the second fluid outlet 11 through the fourth fluid passage 7 located opposite the second fluid passage 5.
This constitutes the second fluid circulation cycle. In this way, heat exchange can take place between the fluid flowing in the first heat exchange passage 14 and the fluid flowing in the second heat exchange passage 15, which is orthogonal to the first heat exchange passage 14.
With the above configuration, heat exchange of the two fluids is achieved because the two fluids flow through the first heat exchange passage 14 and the second heat exchange passage 15, which are arranged in an alternating and intersecting manner in the heat exchange part 3.
The cylindrical housing part 2 and the heat exchanger part 3 are composed, for example, of a first plate unit 30 as shown in
As shown in
The closing plate part 32 has a length of L-a on one side. The first plate unit 30 is preferably formed by a stamping process.
As shown in
In the second plate unit 40, a plurality of microchannel openings 44 extending along the longitudinal direction are formed in the heat exchange fluid plate part 42. The second plate 40 is preferably formed by press working in the same manner as the first plate unit 30, and at the time of this press working, the microchannel openings 44 are preferably formed at the same time. The second plate unit 40 rotated by 90° is referred to as the third plate unit 40′.
The first plate unit 30 and second plate unit 40 (and third plate unit 40′) in the above configuration form the cylindrical housing part 2 and the heat exchange part 3. Specifically, as shown in
The first fluid passage 4 is formed by a fluid passage forming space 4′ of the first plate unit 30 and a fluid passage forming space 4″ of the second plate unit 40. The second fluid passage 5 is formed by the fluid passage forming space 5′ of the first plate unit 30 and the fluid passage forming space 5″ of the second plate unit 40, and the third fluid passage 6 is formed by the fluid passage forming space 6′ of the first plate unit 30 and the fluid passage forming space 6″ of the second plate unit 40. The fourth fluid passage 7 is formed by the fluid passage forming space 7′ of the first plate unit 30 and the fluid passage forming space 7″ of the second plate unit 40.
As shown in
The four corners 21, 22, 23, 24 of the heat exchange part 3 are formed by stacking the four corners 21′, 22′, 23′, 24′ of the first plate unit 30 and the four corners 21″, 22″, 23″, 24″ of the second plate unit 40, which block the first, second, third and fourth fluid passages 5, 6, 7, 8.
As described above, according to the present invention, the microchannel heat exchanger 1 can be configured with a small number of parts.
In addition, since the first plate unit 30 and the second plate unit 40 can be manufactured by punching with a press, and only the press mold needs to be created, manufacturing costs can be reduced.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2024-004362 | Jan 2024 | JP | national |
