Patent Application
20250044035
The present disclosure relates to a heat exchanger and a refrigeration apparatus.
A refrigeration apparatus that performs a refrigeration cycle has been known in the art. A refrigeration apparatus disclosed in Patent Document 1 has a refrigerant circuit that includes a compressor, a condenser, an expansion valve, and an evaporator. This refrigeration apparatus uses a refrigerant, which is, for example, R-1233zd (1-chloro-3,3,3-trifluoropropene). R-1233zd is a so-called low-pressure refrigerant.
Patent Document 1: Japanese Unexamined Patent Publication No. 2019-45135
A first aspect is directed to a heat exchanger that is provided in a refrigeration apparatus (R) configured to be capable of performing a refrigeration cycle where an evaporation pressure of a refrigerant is lower than an atmospheric pressure, and that functions as an evaporator, the heat exchanger comprising: a shell (20) forming an internal space (21); and a plate stack (40) arranged in the internal space (21) and including a plurality of heat transfer plates (50a, 50b).
Embodiments will be described below with reference to the drawings. The following embodiments are merely exemplary ones in nature, and are not intended to limit the scope, applications, or use of the invention.
A heat exchanger (10) of the present disclosure is a shell-and-plate heat exchanger. The heat exchanger (10) is provided in a refrigeration apparatus (R). The refrigeration apparatus (R) of this example is a chiller unit that produces cold water.
As illustrated in
In the refrigeration cycle, the refrigerant compressed by the compressor (2) dissipates heat in the radiator (3). The refrigerant which has dissipated heat is decompressed by the decompression mechanism (4) and evaporates in the evaporator (5). The evaporated refrigerant is sucked into the compressor (2).
The refrigerant circuit (1) may include a switching mechanism such as a four-way switching valve that switches channels of a refrigerant. In this case, the heat exchanger (10) functions as an evaporator or a condenser.
As illustrated in
The shell (20) is comprised of a closed container having a horizontally long, cylindrical shape. The shell (20) has a barrel (20a), a first sidewall (20b), and a second sidewall (20c). The barrel (20a) is formed in a cylindrical shape. The first sidewall (20b) is formed in a circular shape and blocks a left end of the barrel (20a). The second sidewall (20c) is formed in a circular shape and blocks a right end of the barrel (20a). The shell (20) forms the internal space (21) defined by the barrel (20a), the first sidewall (20b), and the second sidewall (20c). The internal space (21) stores a liquid refrigerant.
The barrel (20a) has a refrigerant inlet (32) and a refrigerant outlet (33). The refrigerant inlet (32) is formed at the bottom of the barrel (20a). A refrigerant is introduced into the internal space (21) through the refrigerant inlet (32). The refrigerant outlet (33) is formed at the top of the barrel (20a). The refrigerant evaporated in the internal space (21) is emitted out of the shell (20) through the refrigerant outlet (33). The refrigerant inlet (32) and the refrigerant outlet (33) are connected to the refrigerant circuit via pipes.
The first sidewall (20b) is provided with a heating medium inlet (23) and a heating medium outlet (24). The heating medium inlet (23) and the heating medium outlet (24) are tubular members. In this example, the heating medium inlet (23) is disposed above the heating medium outlet (24). In other words, a heating medium flows from the upper side toward the lower side of the plate stack (40). The heating medium inlet (23) may be disposed below the heating medium outlet (24). In this case, the heating medium flows from the lower side toward the upper side of the plate stack (40).
The heating medium inlet (23) penetrates substantially the center of the first sidewall (20b). The heating medium inlet (23) is connected to a heating medium introduction path (43) of the plate stack (40) to supply the heating medium to the plate stack (40).
The heating medium outlet (24) penetrates the first sidewall (20b) at a substantially intermediate position between the heating medium inlet (23) and a lower end of the first sidewall (20b). The heating medium outlet (24) is connected to a heating medium emission path (44) of the plate stack (40) to emit the heating medium out of the plate stack.
The plate stack (40) includes a plurality of heat transfer plates (50a, 50b) stacked in the lateral direction and joined together. The plate stack (40) is housed in the internal space (21) of the shell (20) with the stacking direction of the heat transfer plates (50a, 50b) extending in the lateral direction.
As illustrated in
As illustrated in
The first plate (50a) has a lower protrusion (51a) and an upper protrusion (53a). Each of the lower protrusion (51a) and the upper protrusion (53a) is a circular portion bulging toward the front side of the first plate (50a). Each of the lower protrusion (51a) and the upper protrusion (53a) is formed in a widthwise center portion of the first plate (50a). The lower protrusion (51a) is formed in a lower portion of the first plate (50a). The upper protrusion (53a) is formed in an upper portion of the first plate (50a). A first lower hole (52a) is formed in a center portion of the lower protrusion (51a). A first upper hole (54a) is formed in a center portion of the upper protrusion (53a). Each of the first lower hole (52a) and the first upper hole (54a) is a circular hole penetrating the first plate (50a) in a thickness direction.
The second plate (50b) has a lower recess (51b) and an upper recess (53b). Each of the lower recess (51b) and the upper recess (53b) is a circular portion bulging toward the back side of the second plate (50b). Each of the lower recess (51b) and the upper recess (53b) is formed in a widthwise center portion of the second plate (50b). The lower recess (51b) is formed in a lower portion of the second plate (50b). The upper recess (53b) is formed in an upper portion of the second plate (50b). A second lower hole (52b) is formed in a center portion of the lower recess (51b). A second upper hole (54b) is formed in a center portion of the upper recess (53b). Each of the second lower hole (52b) and the second upper hole (54b) is a circular hole penetrating the second plate (50b) in a thickness direction.
The second plate (50b) has the lower recess (51b) formed at a position corresponding to the lower protrusion (51a) of the first plate (50a), and the upper recess (53b) formed at a position corresponding to the upper protrusion (53a) of the first plate (50a). The second plate (50b) has the second lower hole (52b) formed at a position corresponding to the first lower hole (52a) of the first plate (50a), and the second upper hole (54b) formed at a position corresponding to the first upper hole (54a) of the first plate (50a). The first lower hole (52a) and the second lower hole (52b) have a substantially equal diameter. The first upper hole (54a) and the second upper hole (54b) have a substantially equal diameter.
In the plate stack (40), each first plate (50a) and an adjacent one of the second plates (50b) on the back side of the first plate (50a) are welded together at their peripheral portions along the whole perimeter. In the plate stack (40), the first lower hole (52a) of each first plate (50a) overlaps the second lower hole (52b) of an adjacent one of the second plates (50b) on the front side of the first plate (50a), and the rims of the overlapping first lower hole (52a) and second lower hole (52b) are welded together along the entire perimeter. In the plate stack (40), the first upper hole (54a) of each first plate (50a) overlaps the second upper hole (54b) of an adjacent one of the second plates (50b) on the front side of the first plate (50a), and the rims of the overlapping first upper hole (54a) and second upper hole (54b) are welded together along the entire perimeter.
In the plate stack (40), the lower protrusions (51a) and first lower holes (52a) of the first plates (50a) and the lower recesses (51b) and second lower holes (52b) of the second plates (50b) form the heating medium emission path (44). In the plate stack (40), the upper protrusions (53a) and first upper holes (54a) of the first plates (50a) and the upper recesses (53b) and second upper holes (54b) of the second plates (50b) form the heating medium introduction path (43).
The heating medium introduction path (43) and the heating medium emission path (44) are passages extending in the stacking direction of the heat transfer plates (50a, 50b) in the plate stack (40). The heating medium introduction path (43) and the heating medium emission path (44) are passages blocked from the internal space (21) of the shell (20).
The heating medium introduction path (43) communicates with all the heating medium channels (42), and is connected to the heating medium inlet (23). The heating medium emission path (44) communicates with all the heating medium channels (42), and is connected to the heating medium outlet (24).
The plate stack (40) includes refrigerant channels (41) and heating medium channels (42), each of the heating medium channels (42) being adjacent to an associated one of the refrigerant channels (41) with the heat transfer plate (50a, 50b) interposed therebetween. The refrigerant channel (41) and the corresponding heating medium channel (42) are separated from each other by the heat transfer plate (50a, 50b). The first plate (50a) and the second plate (50b) have a first corrugated pattern (62a) a second corrugated pattern (62b), respectively, each of which includes repetition of long, narrow ridges and grooves. As illustrated in
The refrigerant channel (41) is a channel sandwiched between the front surface of the first plate (50a) and the back surface of the second plate (50b). The refrigerant channel (41) is a channel that communicating with the internal space (21) of the shell (20) and allowing the refrigerant to flow therethrough. The heating medium channel (42) is a channel sandwiched between the back surface of the first plate (50a) and the front surface of the second plate (50b). The heating medium channel (42) is blocked from the internal space of the shell (20).
As illustrated in
The first linear flat portion is linearly formed on the back surface of the first plate (50a). The first linear flat portion (65a) bulges toward the back side of the first plate (50a), and has a flat bulging top. The first linear flat portion (65a) extends linearly in the width direction of the heat transfer plate (50a, 50b).
The second linear flat portion (65b) is linearly formed on the front surface of the second plate (50b). The second linear flat portion (65b) bulges toward the front side of the second plate (50b), and has a flat bulging top. The second linear flat portion (65b) extends linearly in the width direction of the heat transfer plate (50a, 50b). The second linear flat portion (65b) is formed at a position corresponding to the first linear flat portion (65a) with the first plate (50a) and the second plate (50b) being stacked. The guide (70) is arranged symmetrically with respect to a center line Y of the heat transfer plate (50a, 50b).
How the heating medium and the refrigerant flow in the heat exchanger (10) will be specifically described with reference to
As illustrated in
As illustrated in
Next, how the refrigerant flows will be described below. The refrigerant that has passed through an expansion valve in the refrigerant circuit flows toward the heat exchanger (10). This liquid refrigerant flows into the internal space (21) of the shell (20) through the refrigerant inlet (32). The liquid refrigerant stored in the internal space (21) reaches close to the upper end of the plate stack (40). The plate stack (40) is immersed in the liquid refrigerant. The refrigerant stored in the internal space (21) has a relatively low pressure. The low-pressure refrigerant exchanges heat with the heating medium flowing through the heating medium channels (42). Precisely, the refrigerant channel (41) and the heating medium channel (42) are adjacent to each other with the heat transfer plate (50a, 50b) interposed therebetween. Thus, the liquid refrigerant absorbs heat from the heating medium flowing through the heating medium channel (42) and evaporates. The evaporated refrigerant moves from the refrigerant channel (41) to the upper space (21a) which is an upper portion of the internal space (21). The refrigerant in the upper space (21a) flows into the refrigerant circuit through the refrigerant outlet (33).
The refrigeration apparatus (R) of the present disclosure uses a refrigerant, in particular, a so-called low-pressure refrigerant. Specifically, the refrigeration apparatus (R) uses a refrigerant of which the evaporation pressure at 0° C. or more is lower than the atmospheric pressure. In this example, this refrigerant is, for example, R-1233zd (1-chloro-3,3,3-trifluoropropene). The refrigerant R-1233zd has a low global warming potential (GWP), and thus enables the refrigeration apparatus (R) to be environmentally friendly.
Other than the above refrigerant, the refrigeration apparatus (R) may use refrigerants, such as R1233zd(E) (trans-1-chloro-3,3,3-trifluoropropene), R1224yd(z) (1-chloro-2,3,3,3-tetrafluoropropene), and R-1336mzz(Z) (1,1,1,4,4,4-hexafluoro-2-butene).
The refrigeration apparatus (R) is capable of performing a refrigeration cycle where the evaporation pressure of the refrigerant is lower than the atmospheric pressure in the heat exchanger (10) functioning as an evaporator. The refrigeration apparatus (R) performs the refrigeration cycle where the evaporation pressure of the refrigerant is lower than the atmospheric pressure during rated operation. More precisely, the refrigeration apparatus (R) performs the refrigeration cycle where the evaporation pressure of a refrigerant at 0° C. or more is lower than the atmospheric pressure during rated operation.
As illustrated in
The plurality of heat transfer plates (50a, 50b) are arranged in the front-to-rear direction. The first plate (50a) and the second plate (50b) are alternately and repeatedly arranged. As illustrated in
The pitch P between the heat transfer plates (50a, 50b) adjacent to each other is the pitch between the center line m1 and the center line m2. The pitch P is the interval between the center line m1 of the channel height (P1) of the first channel (41a) on the back side of the second plate (50b) and the center line m2 of the channel height (P2) of the second channel (41b) on the front side of the first plate (50a). Here, the center line m1 is a line segment that passes through the intermediate position of the first channel (41a) in the front-to-rear direction and that is orthogonal to the front-to-rear direction. The center line m2 is a line segment that passes through the intermediate position of the second channel (41b) in the front-to-rear direction and that is orthogonal to the front-to-rear direction. In the plate stack (40) of this example, the pitch P is equal to P1 and P2.
For the heat exchanger (10) of this example, the pitch P is set so as to improve the heat exchange performance of the plate stack (40). The pitch P is preferably more than 1.2 mm, and more preferably 1.5 mm or more. The pitch P is preferably 2.1 mm or less, and more preferably 1.8 mm or less.
In other words, P1 and P2 are preferably more than 1.2 mm, and more preferably 1.5 mm or more. P1 and the P2 are preferably 2.1 mm or less, and more preferably 1.8 mm or less.
As can be clarified from
In the refrigerant channel (41), the refrigerant is gasified, thereby producing bubbles. Here, if a refrigerant, in particular, a so-called low-pressure refrigerant such as R-1233zd is used, the volume of the bubbles is likely to increase. If the pitch P is too small, the bubbles become spreadable along the heat transfer plates (50a, 50b). Thus, the contact area between the liquid refrigerant and the heat transfer plates (50a, 50b) are reduced, and the heat transfer coefficient is also likely to be reduced. In contrast, if the pitch is greater than 1.2 mm, the bubbles become less spreadable along the heat transfer plates (50a, 50b). Thus, the reduction in the heat transfer coefficient due to production of the bubbles can be reduced.
In particular, as can be seen from
The above evaluation results show that the pitch P is preferably more than 1.2 mm, more preferably 1.5 mm or more, and still more preferably 1.5 mm or more and 2.1 mm or less.
(7-1)
The heat exchanger (10) is provided in the refrigeration apparatus (R) configured to be capable of performing a refrigeration cycle where the evaporation pressure of a refrigerant is lower than the atmospheric pressure, and the heat exchanger (10) functions as an evaporator. The heat exchanger (10) includes the shell (20) forming the internal space (21) and includes the plate stack (40) arranged in the internal space (21) and including the plurality of heat transfer plates (50a, 50b).
If the refrigeration apparatus (R) performs a refrigeration cycle where the evaporation pressure of a refrigerant is lower than the atmospheric pressure, the heat exchanger (10) serving as an evaporator is likely to exhibit poorer performance of heat exchange because the volume of a gasified refrigerant increases. However, the heat exchanger (10) consists of the plate stack (40) including the plurality of heat transfer plates (50a, 50b) stacked together, and thus the heat exchanger (10) can exhibit secure performance while avoiding being oversized.
(7-2)
The heat exchanger (10) is provided in the refrigeration apparatus (R) configured to be capable of performing a refrigeration cycle where the evaporation pressure of a refrigerant at 0° C. or more is lower than the atmospheric pressure. Specifically, the heat exchanger (10) is provided in the refrigeration apparatus (R) using 1-chloro-3,3,3-trifluoropropene as a refrigerant.
This refrigeration apparatus (R) using a so-called low-pressure refrigerant can still allow the heat exchanger (10) to exhibit secure performance while avoiding being oversized.
(7-3)
If the pitch P between the plurality of heat transfer plates (50a, 50b) is 1.2 mm or more, poorer performance of the heat exchanger (10) due to production of the bubbles can be reduced. If the pitch P is particularly 1.5 mm or more, the performance of the heat exchanger (10) can be improved as can be clarified from
The above embodiment may be modified as follows.
As illustrated in
The roughness of the rough portion (80) of the heat transfer plate (50a, 50b) improves the wettability of a liquid refrigerant on the surface of the heat transfer plate (50a, 50b). Accordingly, the performance of the heat exchanger (10) can be improved.
The heat exchanger (10) of the embodiment may be a falling-film-type, shell-and-plate heat exchanger. Precisely, the heat exchanger (10) may include a sprayer arranged above the plate stack (40) in the shell (20) to spray the liquid refrigerant onto the plate stack (40). Alternatively, the heat exchanger (10) may include a plate stack having a structure that enables spraying of a liquid refrigerant.
While the embodiment and variations thereof have been described above, it will be understood that various changes in form and details may be made without departing from the spirit and scope of the claims. The elements according to the embodiment, the variations thereof, and the other embodiments may be combined and replaced with each other. The ordinal numbers such as “first,” “second,” “third,” . . . , described above are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.
As described above, the present disclosure is useful for a heat exchanger and a refrigeration apparatus.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-072413 | Apr 2022 | JP | national |
The present application is a continuation of PCT Application No. PCT/JP2023/013850, filed on Apr. 3, 2023, which claims priority from Japanese Patent Application No. 2022-072413 filed on Apr. 26, 2022, with the Japan Patent Office, and the entire disclosures of these applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/013850 | Apr 2023 | WO |
| Child | 18922465 | US |
