Spray heat exchanger and refrigeration system equipped therewith

Abstract

To improve the heat exchange efficiency of spray-type heat exchangers. [Solution] In the spray-type heat exchanger of the present disclosure, a plurality of heat transfer tubes 202 are configured such that a heat transfer medium flows from the heat transfer tube 202 located at the top of the row in the row direction to the heat transfer tube 202 located at the bottom of the row in the row direction, and a plurality of nozzles 204 include a first nozzle 204a, a second nozzle 204b, and a third nozzle 204c, the first nozzle 204a, the second nozzle 204b, and the third nozzle 204c are arranged in this order along the row direction, the first nozzle 204a sprays a liquid-phase refrigerant between the heat transfer tube 202 located at the top of the row and the heat transfer tube 202 located at the row directly below the top of the row, and the number of rows of heat transfer tubes 202 located between the second nozzle 204b and the third nozzle 204c is greater than the number of rows of heat transfer tubes 202 located between the first nozzle 204a and the second nozzle 204b.

Description

Technical Field

[0001] The present disclosure relates to a spray-type heat exchanger and a refrigeration apparatus including the same.

Background Art

[0002] A technique for cooling the inside of heat transfer tubes by spraying cooling water toward the heat transfer tubes is known. liquid The conventional evaporative condenser described in Patent Document 1 includes a plurality of water spray nozzles that spray cooling water toward a condensation coil. Heat exchange between the cooling water and the refrigerant flowing through the condensation coil causes the cooling water to evaporate, and the refrigerant is cooled and condensed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In a spray-type heat exchanger, the temperature difference between the liquid-phase refrigerant and the heat medium is the largest near the inlet of the heat medium to the spray-type heat exchanger, and the smallest near the outlet of the heat medium from the spray-type heat exchanger. Therefore, if the spray amount of the liquid-phase refrigerant is set based on the vicinity of the inlet of the heat medium, the spray amount of the liquid-phase refrigerant becomes excessive near the outlet of the heat medium. In this case, the thickness of the liquid-phase refrigerant film on the surface of the heat transfer tube increases, and the thermal resistance increases, so that the heat transfer tube cannot exhibit its original heat transfer performance. As a result, the heat exchange efficiency of the spray-type heat exchanger decreases.

[0005] The present disclosure provides a technique for improving the heat exchange efficiency of a spray-type heat exchanger.

Means for Solving the Problem

[0006] The present disclosure relates to A spray-type heat exchanger that exchanges heat between a liquid-phase refrigerant and a heat transfer medium, Shell and, Multiple heat transfer tubes arranged inside the shell along the row and column directions, A plurality of nozzles are arranged inside the shell and spray liquid phase refrigerant toward the plurality of heat transfer tubes, Equipped with, The plurality of heat transfer tubes are configured such that the heat transfer medium flows from the heat transfer tube located at the uppermost stage in the stage direction toward the heat transfer tube located at the lowermost stage in the stage direction. The plurality of nozzles include a first nozzle, a second nozzle, and a third nozzle, The first nozzle, the second nozzle, and the third nozzle are arranged in this order along the step direction, The first nozzle sprays the liquid phase refrigerant between the heat transfer tube located at the uppermost stage and the heat transfer tube located in the stage directly below the uppermost stage. The number of stages of the heat transfer tube located between the second nozzle and the third nozzle is greater than the number of stages of the heat transfer tube located between the first nozzle and the second nozzle. We provide a spray-type heat exchanger. [Effects of the Invention]

[0007] The technology disclosed herein can improve the heat exchange efficiency of a spray-type heat exchanger. [Brief explanation of the drawing]

[0008] [Figure 1] Configuration diagram of an absorption refrigeration system according to Embodiment 1 [Figure 2] Figure 1 shows a longitudinal cross-sectional view of the evaporator of an absorption refrigeration system. [Figure 3] Longitudinal cross-section of the evaporator along line III-III shown in Figure 2. [Figure 4] Top view showing the positional relationship between the heat transfer tube and the nozzle. [Figure 5A] A diagram showing the spray pattern of liquid phase refrigerant sprayed from a nozzle. [Figure 5B]A diagram showing the spray pattern of liquid phase refrigerant sprayed from a nozzle. [Figure 6] A graph showing the relationship between the position of the heat transfer tubes in the step direction and the amount of heat received by the heat transfer medium flowing through the heat transfer tubes. [Modes for carrying out the invention]

[0009] (Embodiment 1) Embodiment 1 will be described below with reference to Figures 1 to 6.

[0010] [1-1. Configuration of an absorption refrigeration system] Figure 1 is a diagram of the configuration of an absorption refrigeration system 100 according to Embodiment 1. The absorption refrigeration system 100 comprises an evaporator 101, an absorber 102, a regenerator 103, and a condenser 104. These are interconnected by pathways 110a, 110b, 110c, 110d, and 209. The refrigerant and absorbent in the absorption refrigeration system 100 are, for example, water and a lithium bromide solution. Other examples of refrigerant and absorbent are ammonia and water.

[0011] The evaporator 101 is composed of a spray-type heat exchanger according to Embodiment 1. The evaporator 101 includes heat transfer tubes 202 and a circulation circuit 205. A heat transfer medium such as water flows inside the heat transfer tubes 202. The circulation circuit 205 includes a pump 206. A nozzle 204 is provided at the downstream end of the circulation circuit 205. The upstream end of the circulation circuit 205 is connected to the bottom of the evaporator 101. Liquid-phase refrigerant is stored at the bottom of the evaporator 101. The liquid-phase refrigerant circulates through the circulation circuit 205 by the action of the pump 206. Specifically, the liquid-phase refrigerant is sent to the nozzle 204 by the pump 206 and sprayed from the nozzle 204 toward the heat transfer tubes 202. Heat exchange occurs between the heat transfer medium inside the heat transfer tubes 202 and the sprayed liquid-phase refrigerant, thereby extracting cooling energy from the refrigerant. The refrigerant is heated and evaporates on the surface of the heat transfer tubes 202. The outlet of the evaporator 101 is connected to the absorber 102 via the path 209.

[0012] The absorber 102 is constituted by, for example, a shell-and-tube heat exchanger. The absorber 102 includes heat transfer tubes 121 and a spray tray 107. A heat medium such as water flows inside the heat transfer tubes 121. Absorbent liquid is sprayed from the spray tray 107 toward the heat transfer tubes 121. The absorbent liquid is cooled on the surfaces of the heat transfer tubes 121, and a gaseous refrigerant is absorbed into the absorbent liquid. The outlet of the absorber 102 is connected to the inlet of the regenerator 103 via a path 110a. The path 110a includes a pump 106.

[0013] The regenerator 103 is provided with a heater 123 for heating the absorbent liquid. The heater 123 may be a boiler itself, or may be a circuit in which a heat medium heated by a boiler circulates. The bottom of the regenerator 103 is connected to the spray tray 107 of the absorber 102 via a path 110d. Since the internal pressure of the regenerator 103 is higher than the internal pressure of the absorber 102, the absorbent liquid is sent from the bottom of the regenerator 103 to the spray tray 107 by the pressure difference. The outlet of the regenerator 103 is connected to the inlet of the condenser 104 via a path 110b.

[0014] The condenser 104 is constituted by, for example, a shell-and-tube heat exchanger. The condenser 104 is a heat exchanger for cooling and liquefying the refrigerant that has been heated and vaporized in the regenerator 103. The condenser 104 is provided with, for example, heat transfer tubes 124. A heat medium such as water flows inside the heat transfer tubes 124. The refrigerant is cooled and liquefied on the surfaces of the heat transfer tubes 124. The outlet of the condenser 104 is connected to the inlet of the evaporator 101 via a path 110c.

[0015] The path 110a and the path 110b are vapor paths. The path 110c and the path 110d are liquid paths. Each path is constituted by at least one metal pipe.

[0016] [1-2. Operation of absorption refrigeration apparatus] The operation and effect of the absorption refrigeration apparatus 100 configured as described above will be described below.

[0017] In the evaporator 101, liquid-phase refrigerant is pumped by the pump 206 through the circulation circuit 205 to the nozzle 204 and sprayed from the nozzle 204 as a mist onto the heat transfer tubes 202. The sprayed liquid-phase refrigerant evaporates by exchanging heat with the heat transfer medium flowing inside the heat transfer tubes 202 on the surface of the heat transfer tubes 202. This generates a low-temperature, low-pressure gaseous-phase refrigerant. The gaseous-phase refrigerant is drawn into the absorber 102 via the path 209. In the absorber 102, the gaseous-phase refrigerant is absorbed by the absorbent liquid dripped from the spray tray 107. At this time, the absorbent liquid is cooled by the heat transfer tubes 121 and absorbs the gaseous-phase refrigerant on the surface of the heat transfer tubes 121. After that, the absorbent liquid flows down to the bottom of the absorber 102 and is sent to the regenerator 103 via the path 110a. Just before flowing into the regenerator 103, the absorbent liquid is a mixture of absorbent and refrigerant. After flowing into the regenerator 103, the absorbent liquid is heated by the heater 123. Heating vaporizes the refrigerant components with lower boiling points, separating them as high-temperature gaseous refrigerant. The absorbent liquid is sent to the spray tray 107 via path 110d. The separated high-temperature gaseous refrigerant is sent to the condenser 104 via path 110b. The high-temperature gaseous refrigerant is cooled and condensed by the heat transfer tube 124. This generates liquid refrigerant. The liquid refrigerant is sent to the evaporator 101 via path 110c. The above cycle is repeated.

[0018] The absorption refrigeration system 100 is applied, for example, to commercial or residential air conditioning systems. The heat transfer medium cooled in the evaporator 101 is supplied to the room and used for cooling the room. Alternatively, the heat transfer medium heated in the condenser 104 is supplied to the room and used for heating the room. The heat transfer medium is, for example, water. However, the application of the absorption refrigeration system 100 is not limited to air conditioning systems, and may also be other devices such as chillers or thermal storage devices.

[0019] [1-3. Evaporator Configuration] Figure 2 is a longitudinal cross-sectional view of the evaporator 101 of the absorption chiller 100 shown in Figure 1. Figure 3 is a longitudinal cross-sectional view of the evaporator 101 along line III-III shown in Figure 2. The evaporator 101 is composed of a spray heat exchanger. A spray heat exchanger is a type of shell-and-tube heat exchanger. The evaporator 101 comprises a shell 201, a plurality of heat transfer tubes 202, and a plurality of nozzles 204. In Figures 2 and 3, the Z axis represents an axis parallel to the vertical direction. The X and Y axes represent axes parallel to the horizontal direction.

[0020] The shell 201 is, for example, a container having a rectangular or circular cross-sectional shape. The container may be a pressure vessel. The shell 201 includes an inlet 201a and an outlet 201b. A path 110c is connected to the inlet 201a. An absorber 102 is connected to the outlet 201b via a path 209. Through the inlet 201a, liquid-phase refrigerant flows into the shell 201 from the outside. Through the outlet 201b, gaseous-phase refrigerant generated on the surfaces of the multiple heat transfer tubes 202 is guided to the outside of the shell 201.

[0021] Multiple heat transfer tubes 202 are arranged parallel to each other inside the shell 201 along the tier direction and the column direction. In this embodiment, the tier direction is parallel to the vertical direction, and the column direction is parallel to the horizontal direction. With this configuration, liquid phase refrigerant can be dripped from the heat transfer tubes 202 of the upper tier to the heat transfer tubes 202 of the lower tier by gravity. Multiple heat transfer tubes 202 are arranged in multiple tiers along the vertical direction (Z-axis direction) and in multiple columns along the horizontal direction (Y-axis direction). The longitudinal direction of the heat transfer tubes 202 is parallel to the horizontal direction (X-axis direction). The heat transfer tubes 202 are, for example, heat transfer tubes having a circular cross-sectional shape. The heat transfer tubes 202 are made of metal such as copper or stainless steel, and are typically copper tubes.

[0022] In this embodiment, twelve heat transfer tubes 202 are arranged in the row direction (Y-axis direction). However, the number of heat transfer tubes 202 in the row direction is not particularly limited. For example, the number of heat transfer tubes 202 in the row direction is between 12 and 24. Eighteen heat transfer tubes 202 are arranged in the stage direction (Z-axis direction). However, the number of heat transfer tubes 202 in the stage direction is not particularly limited. For example, the number of heat transfer tubes 202 in the stage direction is between 18 and 36.

[0023] The evaporator 101 further includes a flow path cover 207, a flow path cover 208, and a circulation circuit 205. The configuration of the circulation circuit 205 is as described with reference to Figure 1. A nozzle 204 is provided at the downstream end of the circulation circuit 205. The flow path cover 208 has an inlet 211 and an outlet 212 for the heat transfer medium. The flow path cover 208 is attached to the shell 201 so as to cover the inlets or outlets of a plurality of heat transfer tubes 202. The flow path cover 207 is attached to the shell 201 so as to cover the inlets or outlets of a plurality of heat transfer tubes 202. The heat transfer medium flows into the evaporator 101 through the flow path cover 208 and flows out of the evaporator 101 through the flow path cover 208. The inlet 211 may be provided on the flow path cover 207 and the outlet 212 on the flow path cover 208.

[0024] In this embodiment, the heat transfer medium is configured to flow from the uppermost heat transfer medium 202 in the step direction to the lowermost heat transfer medium 202 in the step direction. The heat transfer medium is distributed and flows through the 3-stage × 12-row heat transfer medium 202.

[0025] Multiple partition plates 210 are arranged inside the flow path cover 207. Multiple partition plates 210 are arranged inside the flow path cover 208. The partition plates 210 are arranged every three stages inside either the flow path cover 207 or the flow path cover 208. The flow direction of the heat transfer medium reverses inside the flow path cover 207 and the flow path cover 208. After flowing into the flow path cover 208, the heat transfer medium flows through the uppermost group of heat transfer tubes, meandering in a serpentine shape, towards the lowermost group of heat transfer tubes. After flowing through the lowermost group of heat transfer tubes, the heat transfer medium flows out to the outside through the flow path cover 208. "Group of heat transfer tubes" refers to multiple heat transfer tubes 202 arranged in sets of three stages.

[0026] The flow path cover 207 connects the inlet and outlet of the heat transfer medium in an adjacent heat transfer tube group. The flow path cover 208 connects the inlet and outlet of the heat transfer medium in an adjacent heat transfer tube group. Through the action of flow path covers 207 and 208, the flow direction of the heat transfer medium can be smoothly changed.

[0027] Each of the multiple nozzles 204 is located inside the shell 201 and sprays a liquid-phase coolant toward the multiple heat transfer tubes 202. The liquid-phase coolant is, for example, liquid water. The spray axis Am of the nozzle 204 passes between a pair of heat transfer tubes 202 located in the row closest to the nozzle 204.

[0028] In this embodiment, the nozzles 204 are arranged at multiple positions in the stepped direction. The nozzles 204 may also be arranged at multiple positions along the longitudinal direction of the heat transfer tubes 202. With this configuration, the surfaces of multiple heat transfer tubes 202 can be uniformly wetted with liquid-phase coolant.

[0029] In this embodiment, the plurality of nozzles 204 include a first nozzle 204a, a second nozzle 204b, and a third nozzle 204c. The first nozzle 204a, the second nozzle 204b, and the third nozzle 204c are arranged in this order along the stepped direction.

[0030] The first nozzle 204a sprays liquid-phase refrigerant between the uppermost heat transfer tube 202 and the heat transfer tube 202 located directly below the uppermost one. The number of stages of the heat transfer tube 202 located between the second nozzle 204b and the third nozzle 204c is greater than the number of stages of the heat transfer tube 202 located between the first nozzle 204a and the second nozzle 204b. According to this embodiment, the number of stages of the heat transfer tube 202 located between the first nozzle 204a and the second nozzle 204b is 2. The number of stages of the heat transfer tube 202 located between the second nozzle 204b and the third nozzle 204c is 5. The number of stages of the heat transfer tube 202 located below the third nozzle 204c is 10.

[0031] As shown in Figure 3, the plurality of heat transfer tubes 202 includes a plurality of first heat transfer tubes 202a, a plurality of second heat transfer tubes 202b, and a plurality of third heat transfer tubes 202c. The plurality of first heat transfer tubes 202a are heat transfer tubes included in a plurality of stages (3 stages in this embodiment) from the top stage to the stage directly above the second nozzle 204b. The plurality of second heat transfer tubes 202b are heat transfer tubes included in a plurality of stages (5 stages in this embodiment) located between the second nozzle 204b and the third nozzle 204c. The third heat transfer tubes 202c are heat transfer tubes included in a plurality of stages (10 stages in this embodiment) from the stage directly below the third nozzle 204c to the bottom stage.

[0032] The number of nozzles 204 in the step direction is not limited to 3. In other words, the number of stages of the heat transfer tube 202 located between the (n+1) nozzle and the (n+2) nozzle may be greater than the number of stages of the heat transfer tube 202 located between the n nozzle and the (n+1) nozzle. Here, n is an integer of 1 or greater.

[0033] In this embodiment, each of the multiple nozzles 204 sprays liquid phase refrigerant in a flattened spray pattern toward the multiple heat transfer tubes 202. The long axis of the flattened spray pattern is perpendicular to the step direction. The plane containing the spray axis Am of the nozzle 204 passes between the heat transfer tubes 202. With this configuration, a sufficient amount of liquid phase refrigerant can be delivered to the surface of the heat transfer tubes 202 that are located at a distance from the nozzles 204.

[0034] The spray axis Am of the first nozzle 204a passes between the heat transfer tube 202 located in the uppermost row and the heat transfer tube 202 located in the row directly below the uppermost row. By spraying liquid-phase refrigerant between the uppermost row and the second row from the top, it is possible to avoid the creation of heat transfer tubes 202 that do not contribute to heat exchange. The spray axis Am of the second nozzle 204b also passes between a pair of heat transfer tubes 202 located in the row closest to the second nozzle 204b. The spray axis Am of the third nozzle 204c also passes between a pair of heat transfer tubes 202 located in the row closest to the third nozzle 204c.

[0035] The structure and characteristics of each nozzle 204 are identical to those of the others. In other words, nozzles from the same product can be used for each nozzle 204. This reduces the cost of the evaporator 101. In this embodiment, the circulation circuit 205 is shared by each nozzle 204. Therefore, excluding the pressure loss in the circulation circuit 205, the spray pressure of each nozzle 204 is equal to those of the others.

[0036] Figure 4 is a top view showing the positional relationship between the heat transfer tube 202 and the nozzle 204. The dashed lines represent the outer edges E1 and E2 in plan view of the sprayed liquid phase refrigerant flow. The spray axis Am is the central axis of the nozzle 204 and passes through the center of the nozzle hole. The spray axis Am passes through the center of the sprayed liquid phase refrigerant flow. The sprayed liquid phase refrigerant flow is a sector with a spread angle α in plan view. The spread angle α is, for example, 120 degrees.

[0037] The spray axis Am is parallel to the plane (XY plane) containing the central axis Bx of the heat transfer tube 202. The central axis Bx is parallel to the longitudinal direction of the heat transfer tube 202 and passes through the center of the cross-section of the heat transfer tube 202. The spray axis Am is inclined with respect to the Y axis, which is perpendicular to the longitudinal direction of the heat transfer tube 202, and is also inclined with respect to the central axis Bx of the heat transfer tube 202. The angle θ between the central axis Bx and the spray axis Am is, for example, 60 degrees.

[0038] In this embodiment, the nozzle 204 is located on only one side in the row direction (Y-axis direction) and not on the other side in the row direction. According to this embodiment, even if the nozzle 204 is located on only one side in the row direction, a sufficient amount of liquid-phase coolant can be delivered to the surface of the heat transfer tube 202, which is located at a distance from the nozzle 204.

[0039] For example, in the absorption refrigeration system 100 shown in Figure 1, when the evaporator 101 and absorber 102 are integrally formed, an eliminator is provided in the path 209 to prevent refrigerant droplets from moving directly from the evaporator 101 to the absorber 102. In this case, it is difficult to secure space to place a nozzle 204 between the path 209 and the heat transfer tubes 202 of the evaporator 101. Such space may lead to an increase in the size of the evaporator 101 and absorber 102. Therefore, it is sometimes required to place the nozzle 204 on only one side in the row direction. If the nozzle 204 is placed on only one side in the row direction, it is difficult for the liquid phase refrigerant to reach the heat transfer tubes 202 located far from the nozzle 204. However, with the evaporator 101 of this embodiment, a sufficient amount of liquid phase refrigerant can be delivered to the heat transfer tubes 202 located far from the nozzle 204. When there are space constraints for the nozzle 204, adopting the evaporator 101 of this embodiment can provide a higher dry-out suppression effect.

[0040] Figures 5A and 5B show the spray patterns of the liquid phase refrigerant sprayed from the nozzle 204. As shown in Figure 5A, the liquid phase refrigerant sprayed from the nozzle 204 forms a fan-shaped spray region M. Furthermore, the shape of the spray region S that appears when this spray pattern is projected onto a plane H perpendicular to the spray axis Am is flattened. The liquid phase refrigerant sprayed in this spray pattern passes between the heat transfer tubes 202.

[0041] The spray region S, which represents the spray pattern, has a major axis L. The major axis L is parallel to the XY plane and perpendicular to the stage direction (Z-axis direction) of the evaporator 101. The plane containing the major axis L and the spray axis Am passes between adjacent heat transfer tubes 202 in the stage direction.

[0042] [1-4. Evaporator Operation] The operation and function of the evaporator 101, configured as described above, will be explained below.

[0043] A heat transfer medium such as water flows from the inlet 211 into the flow path cover 208, and then flows through the flow path cover 208 into the heat transfer tube 202. The heat transfer medium then flows through the heat transfer tube 202, passes through the flow path cover 208, and flows out from the outlet 212.

[0044] The liquid-phase refrigerant is pumped by the pump 206 through the circulation circuit 205 to the nozzle 204, and sprayed from the nozzle 204 in a mist state onto the heat transfer tube 202. The flow of the liquid-phase refrigerant has a spread angle α. The sprayed liquid-phase refrigerant evaporates upon heat exchange with the heat transfer medium on the surface of the heat transfer tube 202.

[0045] The liquid-phase refrigerant sprayed from the nozzle 204 travels in a row direction through the space between the heat transfer tubes 202. A portion of the liquid-phase refrigerant comes into contact with the heat transfer tubes 202, flows along the surface of the heat transfer tubes 202, and drips onto the heat transfer tubes 202 below.

[0046] In this embodiment, the inlet 211 of the heat transfer medium to the evaporator 101 is located on the upper side in the step direction, and the outlet 212 of the heat transfer medium from the evaporator 101 is located on the lower side in the step direction. The heat transfer medium flows through a plurality of heat transfer tubes 202 from top to bottom in the step direction. The temperature of the heat transfer medium is high at the inlet 211 and low at the outlet 212. The larger the temperature difference between the liquid phase refrigerant and the heat transfer medium, the greater the amount of liquid phase refrigerant required for heat exchange, so the amount of liquid phase refrigerant required gradually decreases from top to bottom in the vertical direction.

[0047] According to this embodiment, the first nozzle 204a sprays liquid-phase refrigerant between the uppermost heat transfer tube 202 and the heat transfer tube 202 located in the step directly below the uppermost tube. The number of steps of the heat transfer tube 202 located between the second nozzle 204b and the third nozzle 204c is greater than the number of steps of the heat transfer tube 202 located between the first nozzle 204a and the second nozzle 204b. Therefore, according to this embodiment, an appropriate amount of liquid-phase refrigerant can be supplied to each step of the heat transfer tube 202. As a result, an excess or deficiency of liquid-phase refrigerant is less likely to occur in the step direction, and consequently, the heat exchange efficiency of the evaporator 101 is improved. The fact that an excess or deficiency of liquid-phase refrigerant is less likely means that the thickness of the liquid-phase refrigerant film on the surface of the heat transfer tube 202 is less likely to be excessive, and that dry-out is less likely to occur. "Dry-out" refers to the phenomenon in which a large dry surface is formed on the surface of the heat transfer tube.

[0048] The flow rate (mL / min) of the liquid-phase refrigerant sprayed from the first nozzle 204a is preferably equal to the flow rate of the liquid-phase refrigerant sprayed from the second nozzle 204b and equal to the flow rate of the liquid-phase refrigerant sprayed from the third nozzle 204c. With this configuration, the circulation circuit 205 and the pump 206 can be shared among multiple nozzles 204, and the cost of the nozzles 204 can also be reduced.

[0049] Figure 6 is a graph showing the relationship between the position of the heat transfer tube 202 in the stage direction and the amount of heat received by the heat transfer medium flowing through the heat transfer tube 202. The vertical axis represents the amount of heat released from the heat transfer medium flowing through the heat transfer tube 202. The horizontal axis represents the position of the heat transfer tube 202 in the stage direction. The position of the inlet 211 corresponds to the uppermost stage in the stage direction. The position of the outlet 212 corresponds to the lowermost stage in the stage direction. Region A1 represents the region occupied by the first heat transfer tube 202a shown in Figure 3. Region A2 represents the region occupied by the second heat transfer tube 202b shown in Figure 3. Region A3 represents the region occupied by the third heat transfer tube 202c shown in Figure 3.

[0050] In Figure 6, the area of ​​region A1 is equal to the area of ​​region A2. The area of ​​region A2 is equal to the area of ​​region A3. In other words, the amount of heat released from the multiple first heat transfer tubes 202a to the liquid phase refrigerant is equal to the amount of heat released from the multiple second heat transfer tubes 202b to the liquid phase refrigerant. Similarly, the amount of heat released from the multiple second heat transfer tubes 202b to the liquid phase refrigerant is equal to the amount of heat released from the multiple third heat transfer tubes 202c to the liquid phase refrigerant. According to this embodiment, the heat transfer area of ​​the multiple heat transfer tubes 202 is optimized for the amount of liquid phase refrigerant sprayed in the step direction. As a result, excess or deficiency of liquid phase refrigerant is less likely to occur in the step direction, and consequently the heat exchange efficiency of the evaporator 101 is improved.

[0051] Furthermore, if the inlet for the heat transfer medium to the evaporator is located at the lowest stage and the outlet for the heat transfer medium to the evaporator is located at the highest stage, it is difficult to apply the technology of this disclosure. The reasons for this are as follows. First, in order to avoid wasting the heat transfer tubes located at the highest stage, a nozzle is required between the highest stage and the next stage. The temperature difference between the heat transfer medium and the liquid phase refrigerant flowing through the heat transfer tubes of the highest stage is the smallest, so the amount of liquid phase refrigerant required by the heat transfer tubes of the highest stage is small. On the other hand, the temperature difference between the heat transfer medium and the liquid phase refrigerant flowing through the heat transfer tubes of the lowest stage is the largest, so it is desirable to supply a sufficient amount of liquid phase refrigerant to the heat transfer tubes of the lowest stage. However, if a nozzle is provided between the lowest stage and the stage directly above it, the amount of liquid phase refrigerant that drips to the bottom of the shell without evaporating tends to increase. Considering these circumstances, it is not easy to place the nozzles in the optimal location, and the number of nozzles in the stage direction also increases.

[0052] [2. Addendum] Based on the above description of embodiments, the following technologies are disclosed.

[0053] (Technology 1) A spray-type heat exchanger that exchanges heat between a liquid-phase refrigerant and a heat transfer medium, Shell and, Multiple heat transfer tubes arranged inside the shell along the row and column directions, A plurality of nozzles are arranged inside the shell and spray liquid phase refrigerant toward the plurality of heat transfer tubes, Equipped with, The plurality of heat transfer tubes are configured such that the heat transfer medium flows from the heat transfer tube located at the uppermost stage in the stage direction toward the heat transfer tube located at the lowermost stage in the stage direction. The plurality of nozzles include a first nozzle, a second nozzle, and a third nozzle, The first nozzle, the second nozzle, and the third nozzle are arranged in this order along the step direction, The first nozzle sprays the liquid phase refrigerant between the heat transfer tube located at the uppermost stage and the heat transfer tube located in the stage directly below the uppermost stage. The number of stages of the heat transfer tube located between the second nozzle and the third nozzle is greater than the number of stages of the heat transfer tube located between the first nozzle and the second nozzle. Spray heat exchanger.

[0054] The technology disclosed herein can improve the heat exchange efficiency of a spray-type heat exchanger.

[0055] (Technology 2) A spray-type heat exchanger according to Technology 1, wherein each of the plurality of nozzles sprays the liquid phase refrigerant in a flat spray pattern toward the plurality of heat transfer tubes. A sufficient amount of liquid phase refrigerant can be delivered to the surface of heat transfer tubes located at a distance from the nozzles.

[0056] (Technology 3) A spray-type heat exchanger according to Technology 1 or 2, wherein the spray axis of the first nozzle passes between the heat transfer tube located at the uppermost stage and the heat transfer tube located at the stage directly below the uppermost stage. By spraying a liquid-phase refrigerant between the uppermost stage and the second stage from the top, it is possible to avoid the formation of heat transfer tubes that do not contribute to heat exchange.

[0057] (Technology 4) A spray-type heat exchanger according to any one of the technologies 1 to 3, wherein the stage direction is parallel to the vertical direction and the column direction is parallel to the horizontal direction. With such a configuration, liquid phase refrigerant can be dripped from the heat transfer tubes of the upper stage to the heat transfer tubes of the lower stage by gravity.

[0058] (Technology 5) A spray-type heat exchanger according to any one of the technologies 1 to 4, wherein the flow rate of the liquid phase refrigerant sprayed from the first nozzle is equal to the flow rate of the liquid phase refrigerant sprayed from the second nozzle and the flow rate of the liquid phase refrigerant sprayed from the third nozzle. With such a configuration, the circulation circuit and pump can be shared among multiple nozzles, and the cost of the nozzles can also be reduced.

[0059] (Technology 6) The plurality of heat transfer tubes include a plurality of first heat transfer tubes included in a plurality of stages from the uppermost stage to the stage directly above the second nozzle, and a plurality of second heat transfer tubes included in a plurality of stages located between the second nozzle and the third nozzle, wherein the amount of heat released from the plurality of first heat transfer tubes to the liquid phase refrigerant is equal to the amount of heat released from the plurality of second heat transfer tubes to the liquid phase refrigerant, as described in any one of the technologies 1 to 5. With such a configuration, an excess or deficiency of liquid phase refrigerant is less likely to occur in the stage direction, and consequently the heat exchange efficiency of the evaporator is improved.

[0060] (Technology 7) A refrigeration system comprising, as at least one of the evaporator and condenser, a spray heat exchanger as described in any one of the Technical Sections 1 to 6. [Industrial applicability]

[0061] The spray heat exchanger disclosed herein is useful as an evaporator in an absorption refrigeration system. However, the spray heat exchanger may be used not only as an evaporator but also as a condenser. Furthermore, the spray heat exchanger disclosed herein can be used in refrigeration systems other than absorption refrigeration systems, such as turbo refrigeration systems and vapor compression refrigeration systems. The applications of the refrigeration system are not particularly limited and include household or commercial air conditioning systems, chillers, process cooling systems, and thermal energy storage systems. [Explanation of Symbols]

[0062] 100 Absorption Refrigeration System 101 Evaporator 102 Absorber 103 Regenerator 104 Condenser 106 Pump 107 Spray Tray Routes 110a, 110b, 110c, 110d 121 Heat transfer tube 123 Heater 124 Heat transfer tubes 201 Shell 202 Heat transfer tube 202a First heat transfer tube 202b Second heat transfer tube 202c Third heat transfer tube 204 nozzles 204a Nozzle No. 1 204b Second nozzle 204c Nozzle No. 3 205 Circulation circuit 206 Pump 207,208 Flow channel cover 209 routes 210 Partition Plate 211 Inlet 212 Outlet Am spray shaft Bx center axis

Claims

1. A spray-type heat exchanger that exchanges heat between a liquid-phase refrigerant and a heat transfer medium, Shell and, Multiple heat transfer tubes arranged inside the shell along the row and column directions, A plurality of nozzles are arranged inside the shell and spray liquid phase refrigerant toward the plurality of heat transfer tubes, Equipped with, The plurality of heat transfer tubes are configured such that the heat transfer medium flows from the heat transfer tube located at the uppermost stage in the stage direction toward the heat transfer tube located at the lowermost stage in the stage direction. The plurality of nozzles include a first nozzle, a second nozzle, and a third nozzle. The first nozzle, the second nozzle, and the third nozzle are arranged in this order along the stepped direction. The first nozzle sprays the liquid phase refrigerant between the heat transfer tube located at the uppermost level and the heat transfer tube located in the level directly below the uppermost level. The number of stages of the heat transfer tube located between the second nozzle and the third nozzle is greater than the number of stages of the heat transfer tube located between the first nozzle and the second nozzle. Spray heat exchanger.

2. Each of the plurality of nozzles sprays the liquid phase refrigerant toward the plurality of heat transfer tubes in a flat spray pattern. A spray-type heat exchanger according to claim 1.

3. The spray shaft of the first nozzle passes between the heat transfer tube located at the uppermost stage and the heat transfer tube located at the stage directly below the uppermost stage. A spray-type heat exchanger according to claim 1.

4. The aforementioned step direction is parallel to the vertical direction, The aforementioned column direction is parallel to the horizontal direction. A spray-type heat exchanger according to claim 1.

5. The flow rate of the liquid phase refrigerant sprayed from the first nozzle is equal to the flow rate of the liquid phase refrigerant sprayed from the second nozzle and the flow rate of the liquid phase refrigerant sprayed from the third nozzle. A spray-type heat exchanger according to claim 1.

6. The plurality of heat transfer tubes include a plurality of first heat transfer tubes included in a plurality of stages from the uppermost stage to the stage directly above the second nozzle, and a plurality of second heat transfer tubes included in a plurality of stages located between the second nozzle and the third nozzle. The amount of heat released from the plurality of first heat transfer tubes to the liquid phase refrigerant is equal to the amount of heat released from the plurality of second heat transfer tubes to the liquid phase refrigerant. A spray-type heat exchanger according to claim 1.

7. The spray-type heat exchanger described in claim 1 is provided as at least one of the evaporator and the condenser. Refrigeration equipment.

Images