Absorber unit, heat exchange unit, and absorption chiller

Abstract

To provide an absorber unit which is advantageous in terms of the prevention of the lowering of a refrigeration capacity due to the mixing of an absorption liquid into a liquid phase refrigerant.SOLUTION: An absorber unit 1a comprises a first heat transmission pipe group 12a, a first dripper 13a, a second heat transmission pipe group 12b, a second dripper 13b, a partition 14, and a supply path 15. The second dripper 13b drips an absorption liquid which is dripped from the first dripper 13a, and made to flow down in the first heat transmission pipe group 12a toward the second heat transmission pipe group 12b. The supply path 15 is formed at the partition 14, and introduces the absorption liquid flowing down in the first heat transmission pipe group 12a to the second dripper 13b. The supply path 15 has an inlet 15a and an outlet 15b located below the inlet 15a in a gravity direction. The supply path 15 has an upstream-side part 15c to which the absorption liquid is guided following the gravity from the inlet 15a, and a downstream-side part 15d to which the absorption liquid which has passed the upstream-side part 15c is guided toward the outlet 15b while withstanding the gravity.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an absorber unit, a heat exchange unit, and an absorption refrigerator.

Background Art

[0002] Patent Document 1 describes a multi-stage evaporation absorption type absorption chiller. This absorption chiller includes an evaporator and an absorber formed in multiple stages in the vertical direction by a partition wall. A refrigerant redistributor for storing refrigerant and a solution redistributor for storing solution are formed on this partition wall. A number of dropping holes for guiding the refrigerant to the lower evaporator are formed at the bottom of the refrigerant redistributor. In addition, a number of dropping holes for guiding the solution to the lower absorber are formed at the bottom of the solution redistributor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides an absorber unit that is advantageous from the viewpoint of allowing a vapor-phase refrigerant to be absorbed by an absorption liquid in a plurality of stages and preventing the absorption liquid from mixing into the liquid-phase refrigerant and reducing the refrigeration capacity.

Means for Solving the Problems

[0005] The absorber unit in the present disclosure is a first heat transfer tube group, a first dropper that drops the absorption liquid toward the first heat transfer tube group, a second heat transfer tube group disposed below the first heat transfer tube group in the direction of gravity, a second dropper that drops the absorption liquid that has dropped from the first dropper and flowed down the first heat transfer tube group toward the second heat transfer tube group, A partition separates the first space where the first heat transfer tube group is located from the second space where the second heat transfer tube group is located. The partition includes a supply path formed therein, which guides the absorbent liquid that has flowed down the first heat transfer tube group to the second dropper, The supply path has an inlet in contact with the first space, an outlet located below the inlet in the direction of gravity and in contact with the second space, an upstream section through which the absorbent liquid is guided from the inlet according to gravity, and a downstream section through which the absorbent liquid that has passed through the upstream section is guided toward the outlet against gravity. [Effects of the Invention]

[0006] According to the absorber unit in this disclosure, the absorbent liquid is guided by gravity from the inlet to the upstream part of the supply passage, passes through the upstream part, and is then guided against gravity towards the outlet of the supply passage in the downstream part. As a result, the absorbent liquid easily forms a liquid seal in the supply passage. Therefore, the gaseous refrigerant present in the second space is less likely to be guided into the first space, and the mist of the absorbent liquid present in the first space is less likely to scatter outside the absorber unit. As a result, it is easier to prevent the absorbent liquid from mixing with the liquid refrigerant and reducing its refrigeration capacity. [Brief explanation of the drawing]

[0007] [Figure 1] Diagram showing the heat exchange unit in Embodiment 1 [Figure 2] Diagram showing the supply path and second dropper in Embodiment 1 [Figure 3] Diagram showing the supply path in Embodiment 1 [Figure 4] Diagram showing the absorber unit in Embodiment 2 [Figure 5] Diagram showing the absorber unit in Embodiment 3 [Figure 6] Diagram showing the absorber unit in Embodiment 4 [Figure 7] Diagram showing an absorption chiller in Embodiment 5 [Modes for carrying out the invention]

[0008] (Knowledge and other information that formed the basis of this disclosure) At the time the inventors conceived this disclosure, it was known that in a multi-stage evaporation-absorption type absorption refrigerator, in which evaporators and absorbers are each arranged in multiple stages, a large concentration difference between a high-concentration absorbent and a low-concentration absorbent improves the coefficient of performance (COP). A large concentration difference between a high-concentration absorbent and a low-concentration absorbent reduces the circulation rate of the absorbent, improving the temperature efficiency in the absorber. As a result, the COP can be improved.

[0009] In this industry, it was common practice to maintain a pressure difference between the high-pressure and low-pressure stages by forming a liquid seal using the liquid phase refrigerant head in the liquid phase refrigerant supply and the absorbent head in the absorbent supply. Under these circumstances, the inventors conceived the idea of ​​reducing the heat transfer area and miniaturizing the absorber by utilizing the increase in capacity resulting from the widening of the concentration difference between the high-concentration and low-concentration absorbent. To realize this idea, the inventors focused on the fact that the number of absorbent heads required in the absorbent supply is determined by the absorbent head for maintaining the pressure difference between the high-pressure and low-pressure stages and the absorbent head for dripping the absorbent from the supply. On the other hand, the liquid level of the absorbent in the absorbent supply can be disturbed by the flow of the absorbent.

[0010] In the fixed operation, the pressure difference between the high-pressure stage and the low-pressure stage is large, and the flow rate of the absorbent liquid is also large. Therefore, the head of the absorbent liquid in the absorbent liquid supply device is high. As a result, even if the liquid surface of the absorbent liquid in the absorbent liquid supply device is disturbed, the hole for dropping the absorbent liquid in the absorbent liquid supply device is liquid-sealed. As a result, it is difficult for the high-pressure vapor refrigerant to blow through from the high-pressure stage to the low-pressure stage. However, in the low-load operation, the pressure difference between the high-pressure stage and the low-pressure stage is small, and the flow rate of the absorbent liquid is also small. Therefore, the head of the absorbent liquid in the absorbent liquid supply device decreases. As a result, due to the disturbance of the liquid surface of the absorbent liquid in the absorbent liquid supply device, the absorbent liquid is locally insufficient and a liquid seal cannot be formed, and the high-pressure vapor refrigerant blows through from the high-pressure stage to the low-pressure stage, and the mist of the absorbent liquid present in the low-pressure stage may scatter toward the low-pressure evaporator. When the scattered absorbent liquid mixes into the liquid-phase refrigerant, a decrease in the vapor pressure of the refrigerant and an increase in the saturation concentration of the low-concentration absorbent liquid occur, and there may arise a problem that the amount of absorbable vapor refrigerant decreases and the refrigerating capacity decreases. In order to solve that problem, the inventors have arrived at the subject matter of the present disclosure.

[0011] Therefore, the present disclosure provides an absorber unit that is advantageous from the viewpoint of being able to absorb a vapor refrigerant into an absorbent liquid in a plurality of stages and preventing the refrigerating capacity from decreasing due to the absorbent liquid mixing into the liquid-phase refrigerant.

[0012] Hereinafter, embodiments will be described in detail with reference to the drawings. However, a more detailed description than necessary may be omitted. For example, a detailed description of well-known matters or a redundant description of substantially the same configuration may be omitted. This is to avoid making the following description overly redundant and to facilitate the understanding of those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0013] (Embodiment 1) Hereinafter, Embodiment will be described with reference to FIGS. 1, 2, and 3. In the accompanying drawings, the positive direction of the Z axis is the direction of gravity, and the X axis, Y axis, and Z axis are perpendicular to each other.

[0014] [1-1. Configuration] FIG. 1 is a schematic view of the heat exchange unit 5 in Embodiment 1. In FIG. 1, the heat exchange unit 5 includes an absorber unit 1a, an evaporator unit 2, a first vapor flow path 31a, and a second vapor flow path 31b. The evaporator unit 2 generates a vapor refrigerant. The absorber unit 1a absorbs the vapor refrigerant generated by the evaporator unit 2. The first vapor flow path 31a and the second vapor flow path 31b guide the vapor refrigerant generated by the evaporator unit 2 to the absorber unit 1a.

[0015] The absorber unit 1a includes a first heat transfer tube group 12a, a first drip pan 13a, a second heat transfer tube group 12b, a second drip pan 13b, and a partition 14. The first drip pan 13a drips the absorbent liquid toward the first heat transfer tube group 12a. The second heat transfer tube group 12b is disposed below the first heat transfer tube group 12a in the gravitational direction. The first heat transfer tube group 12a has a flow path for a heat medium such as water inside. The second heat transfer tube group 12b has a flow path for a heat medium such as water inside. Each of the first heat transfer tube group 12a and the second heat transfer tube group 12b includes, for example, a plurality of heat transfer tubes arranged in a plurality of stages and a plurality of rows. The second drip pan 13b drips the absorbent liquid that has dripped from the first drip pan 13a and flowed down the first heat transfer tube group 12a toward the second heat transfer tube group 12b. The partition 14 partitions a first space 16a in which the first heat transfer tube group 12a is disposed and a second space 16b in which the second heat transfer tube group 12b is disposed. In this specification, the "space" does not mean a vacuum region where no substance exists, but means a place where a substance exists and a phenomenon occurs. The absorber unit 1a has a first absorber 10a provided with the first heat transfer tube group 12a and the first drip pan 13a above the partition 14 in the gravitational direction, and a second absorber 10b provided with the second heat transfer tube group 12b and the second drip pan 13b below the partition 14.

[0016] For example, in the absorber unit 1a, the absorbent liquid is supplied to the first absorber 10a and flows down the first heat transfer tube group 12a. Thereafter, the absorbent liquid is supplied to the second absorber 10b, flows down the second heat transfer tube group 12b, and is discharged outside the absorber unit 1a.

[0017] The first absorber 10a and the second absorber 10b in the absorber unit 1a are each shell-and-tube heat exchangers. For example, a spray method can be used to supply the absorbent liquid.

[0018] The first dropper 13a drops the absorbent liquid towards the first heat transfer tube group 12a. The first dropper 13a, for example, is equipped with a tray for storing the absorbent liquid, and drops the absorbent liquid stored in the tray towards the first heat transfer tube group 12a.

[0019] Figure 2 is a schematic diagram of the supply path 15 and the second dripper 13b in the absorber unit 1a. As shown in Figure 2, the second dripper 13b includes, for example, a tray 13t for storing absorbent liquid, and drips the absorbent liquid stored in the tray 13t towards the second heat transfer tube group 12b. Holes 13h are formed in the bottom of the tray 13t. The absorbent liquid stored in the tray 13t passes through the holes 13h and is dripped towards the second heat transfer tube group 12b.

[0020] The first dropper 13a and the second dropper 13b are each manufactured, for example, by welding pressed stainless steel plates.

[0021] As shown in Figure 1, a supply passage 15 is formed in the partition 14. The supply passage 15 guides the absorbent liquid that has flowed down the first heat transfer tube group 12a to the second dripper 13b. Figure 3 is a perspective view of the portion of the partition 14 that forms the supply passage 15.

[0022] As shown in Figures 2 and 3, the supply channel 15 has an inlet 15a, an outlet 15b, an upstream section 15c, and a downstream section 15d. The inlet 15a is in contact with the first space 16a. The outlet 15b is located below the inlet 15a in the direction of gravity. The outlet 15b is in contact with the second space 16b. As indicated by arrow c in Figure 2, the absorbent liquid is guided from the inlet 15a in the upstream section 15c according to gravity. On the other hand, as indicated by arrow d in Figure 2, the absorbent liquid that has passed through the upstream section 15c is guided against gravity towards the outlet 15b in the downstream section 15d. The downstream section 15d is formed, for example, below the outlet 15b in the direction of gravity.

[0023] The supply passage 15 is enclosed, for example, by a part of the partition 14. This configuration prevents the absorbent liquid from leaking out of the supply passage 15. The supply passage 15 can be formed by pressing the plate material that makes up the partition 14. The supply passage 15 may also be formed integrally with the partition 14 by welding the portion of the partition 14 that forms the supply passage 15 to the other parts of the partition 14.

[0024] As shown in Figure 2, the inlet 15a of the supply path 15 is, for example, in contact with the lowest part of the first space 16a in the direction of gravity. The outlet 15b of the supply path 15 is, for example, in contact with the second space 16b above the second dropper 13b in the direction of gravity. The outlet 15b is formed so as to overlap with a part of the tray 13t when viewed from the first space 16a to the outlet 15b in plan.

[0025] As shown in Figure 2, the supply channel 15 is in contact with a partition wall 15j formed between the upstream section 15c and the downstream section 15d in a direction perpendicular to the direction of gravity. The supply channel 15 has a connecting section 15k that connects the upstream section 15c and the downstream section 15d. The connecting section 15k is formed, for example, directly below the partition wall 15j. The connecting section 15k is formed, for example, below the inlet 15a and outlet 15b in the direction of gravity. The supply channel 15 may be formed as a U-shaped channel.

[0026] As shown in Figure 1, the evaporator unit 2 comprises a first evaporator 20a and a second evaporator 20b. The second evaporator 20b generates a gaseous refrigerant at a pressure higher than that in the first evaporator 20a. In the direction of gravity, the first evaporator 20a is located in the upper position, and the second evaporator 20b is located in the lower position. The first vapor channel 31a guides the gaseous refrigerant generated in the first evaporator 20a to the first space 16a. The second vapor channel 31b guides the gaseous refrigerant generated in the second evaporator 20b to the second space 16b. The members forming the first vapor channel 31a and the second vapor channel 31b are made of materials including metals such as iron that have thermal insulation and pressure resistance properties.

[0027] The evaporator unit 2 is equipped with a partition 24, which separates the first evaporator 20a from the second evaporator 20b. The first evaporator 20a is equipped with a third heat transfer tube group 22a and a first feeder 23a. The second evaporator 20b is equipped with a fourth heat transfer tube group 22b and a second feeder 23b. Each of the third heat transfer tube group 22a and the fourth heat transfer tube group 22b includes, for example, multiple heat transfer tubes arranged in multiple stages and multiple rows.

[0028] In each of the first heat transfer tube group 12a, the second heat transfer tube group 12b, the third heat transfer tube group 22a, and the fourth heat transfer tube group 22b, the heat transfer tubes are arranged, for example, parallel to each other and in multiple layers in the direction of gravity. In each of the first heat transfer tube group 12a, the second heat transfer tube group 12b, the third heat transfer tube group 22a, and the fourth heat transfer tube group 22b, the heat transfer tubes are arranged, for example, to form a square grid in a plane (ZY plane) perpendicular to the longitudinal direction (X axis direction) of the heat transfer tubes. The heat transfer tubes may also be arranged to form a rectangular grid or a parallelogram grid in that plane. The heat transfer tubes are, for example, made of copper or stainless steel. Grooves may be formed on the inner or outer surface of the heat transfer tubes. Multiple heat transfer tubes may be arranged in an irregular pattern of square, rectangular, or parallelogram grids in a plane (ZY plane) perpendicular to the longitudinal direction (X-axis direction) of the heat transfer tubes.

[0029] In evaporator unit 2, the first evaporator 20a and the second evaporator 20b are, for example, shell-and-tube heat exchangers. For example, when a refrigerant such as water, whose saturated vapor pressure at room temperature (20°C ± 15°C) is negative, is used, the influence of the water level head of the liquid phase refrigerant on the evaporation pressure tends to be large in a full-liquid shell-and-tube heat exchanger. For this reason, when a refrigerant such as water is used, it is advantageous for the first evaporator 20a and the second evaporator 20b to be spray-type or spray-type shell-and-tube heat exchangers.

[0030] The first feeder 23a and the second feeder 23b are each manufactured, for example, by welding pressed stainless steel plates.

[0031] The heat exchange unit 5 is filled with a refrigerant and an absorbent liquid. The refrigerant is, for example, a fluorocarbon refrigerant such as hydrofluorocarbons (HFCs) or a natural refrigerant such as water and ammonia. The absorbent liquid is, for example, an aqueous lithium bromide solution or an ionic fluid.

[0032] As shown in Figure 1, the heat exchange unit 5 includes, for example, a shell 3. The shell 3 is configured as a container with thermal insulation and pressure resistance. A liquid phase refrigerant and an absorbent liquid are stored inside the shell 3. The shell 3 isolates the gaseous phase refrigerant inside the shell 3 from the outside air, such as atmospheric pressure air.

[0033] As shown in Figure 1, the heat exchange unit 5 is equipped with an absorbent liquid supply passage 17a, an absorbent liquid discharge passage 17b, and an absorbent liquid pump 19.

[0034] The absorbent liquid supply channel 17a is a path that guides the absorbent liquid from outside the absorber unit 1a into the inside of the absorber unit 1a. The absorbent liquid supply channel 17a is made of piping that has heat insulation and pressure resistance.

[0035] The absorbent liquid discharge channel 17b is a path that guides the absorbent liquid from inside the absorber unit 1a to outside the absorber unit 1a. The absorbent liquid discharge channel 17b is made of piping that has thermal insulation and pressure resistance.

[0036] The absorbent liquid pump 19 is, for example, a velocity-type canned pump. When the absorbent liquid pump 19 is operated, the absorbent liquid stored in the absorber unit 1a is pumped and discharged from the absorbent liquid unit 1a through the absorbent liquid discharge passage 17b.

[0037] As shown in Figure 1, the heat exchange unit 5 is equipped with a refrigerant supply path 26, a circulation path 27, and a refrigerant pump 28.

[0038] The refrigerant supply passage 26 is a path that guides liquid-phase refrigerant from outside the evaporator unit 2 to inside the evaporator unit 2. The refrigerant supply passage 26 is made up of piping that has thermal insulation and pressure resistance.

[0039] The circulation path 27 is a route for circulating the liquid phase refrigerant stored in the second evaporator 20b. For example, the circulation path 27 leads the liquid phase refrigerant stored in the second evaporator 20b to the first supply unit 23a of the first evaporator 20a. The circulation path 27 is constructed of piping that has thermal insulation and pressure resistance.

[0040] The refrigerant pump 28 is, for example, a velocity-type canned pump. When the refrigerant pump 28 is operated, the liquid phase refrigerant stored in the second evaporator 20b is pumped and circulated through the circulation path 27.

[0041] As shown in Figure 1, the heat exchange unit 5 is equipped with a first eliminator 32a and a second eliminator 32b. The first eliminator 32a and the second eliminator 32b are a gas-liquid separation mechanism that prevents liquid droplets of the liquid phase refrigerant in the evaporator unit 2 from being dragged by the flow of the gas phase refrigerant and carried to the absorber unit 1a. Each of the first eliminator 32a and the second eliminator 32b is manufactured, for example, by welding pressed stainless steel plates. The first eliminator 32a is located, for example, in the first vapor passage 31a. The second eliminator 32b is located, for example, in the second vapor passage 31b.

[0042] [1-2. Operation] The operation and function of the heat exchange unit 5, configured as described above, will be explained below.

[0043] The operation of the heat exchange unit 5 will be explained based on Figures 1 and 2. When the heat exchange unit 5 is left unattended for a predetermined period, such as overnight, the internal temperature of the heat exchange unit 5 is uniform and approximately equal to room temperature. In addition, the internal pressure of the heat exchange unit 5 is also uniform. For example, if the room temperature is 25°C, the internal temperature of the heat exchange unit 5 is also uniform and approximately 25°C.

[0044] When the heat exchange unit 5 is in use, a heat transfer medium such as water, which has absorbed heat from outside the heat exchange unit 5, flows inside the heat transfer tubes of the third heat transfer tube group 22a and the fourth heat transfer tube group 22b. This heat transfer medium flows into the fourth heat transfer tube group 22b at 12°C, for example. The heat transfer medium that has passed through the fourth heat transfer tube group 22b is led to the third heat transfer tube group 22a. A heat transfer medium such as water, which has released heat to the outside of the heat exchange unit 5, flows inside the heat transfer tubes of the first heat transfer tube group 12a and the second heat transfer tube group 12b. This heat transfer medium flows into the second heat transfer tube group 12b at 32°C, for example. The heat transfer medium that has passed through the second heat transfer tube group 12b is led to the first heat transfer tube group 12a.

[0045] When the heat exchange unit 5 starts operation, absorbent liquid is supplied to the absorber unit 1a through the absorbent liquid supply passage 17a. The temperature of the supplied absorbent liquid is approximately 50°C, and the solute concentration of the supplied absorbent liquid is approximately 63% by mass. The absorbent liquid supplied to the absorber unit 1a is stored in the first dripper 13a and dripped toward the first heat transfer tube group 12a. As the dripped absorbent liquid flows down around the outer surface of the heat transfer tubes in the first heat transfer tube group 12a, it absorbs the gaseous refrigerant generated in the first evaporator 20a. As a result, the solute concentration of the absorbent liquid decreases and it is stored at the bottom of the first space 16a in contact with the partition 14. At the same time, the liquid-phase refrigerant stored in the second evaporator 20b is pumped by the refrigerant pump 28 and supplied to the first supplyer 23a through the circulation passage 27. The liquid-phase refrigerant supplied to the first supplyer 23a is supplied toward the third heat transfer tube group 22a. The liquid-phase refrigerant forms a liquid film around the heat transfer tubes of the third heat transfer tube group 22a and flows down. As the liquid-phase refrigerant flows down, it absorbs heat from the heat transfer medium flowing through the heat transfer tubes of the third heat transfer tube group 22a and evaporates. Any liquid-phase refrigerant that does not evaporate is stored in the second supply unit 23b.

[0046] As the absorbent liquid flows down around the outer surface of the heat transfer tubes of the first heat transfer tube group 12a, the gaseous refrigerant in the first evaporator 20a is absorbed by the absorbent liquid. Due to the absorption of the gaseous refrigerant, the temperature of the absorbent liquid rises. However, at the same time, it is cooled by the heat transfer medium flowing inside the heat transfer tubes of the first heat transfer tube group 12a, so continuous supercooling absorption occurs. As a result, the pressure in the low-pressure stage of the heat exchange unit 5, including the first evaporator 20a and the first absorber 10a, decreases. This causes the liquid-phase refrigerant flowing down around the outer surface of the heat transfer tubes of the third heat transfer tube group 22a to evaporate. As the liquid-phase refrigerant evaporates, its temperature decreases. However, at the same time, the liquid-phase refrigerant is heated by the heat transfer medium flowing inside the heat transfer tubes of the third heat transfer tube group 22a, so continuous evaporation of the liquid-phase refrigerant occurs.

[0047] Next, the absorbent liquid that has flowed down the first heat transfer tube group 12a flows into the supply channel 15 from the inlet 15a, and in the upstream section 15c, the absorbent liquid is guided from the inlet 15a by gravity. The absorbent liquid that has passed through the upstream section 15c is guided against gravity towards the outlet 15b in the downstream section 15d. As a result, a liquid seal can be formed in the supply channel 15 by the absorbent liquid, as shown in Figure 2. The absorbent liquid passes through the downstream section 15d and the outlet 15b and is supplied to the second dripper 13b, where it is stored.

[0048] The absorbent liquid stored in the second dripper 13b is at a temperature of approximately 44°C, and its solute concentration is approximately 59% by mass. The absorbent liquid stored in the second dripper 13b is dripped towards the second heat transfer tube group 12b. As the dripped absorbent liquid flows down around the outer surface of the heat transfer tubes in the second heat transfer tube group 12b, it absorbs the gaseous refrigerant generated in the second evaporator 20b. This reduces the solute concentration of the absorbent liquid, and the absorbent liquid is stored in the lower part of the second space 16b. The absorbent liquid stored in the lower part of the second space 16b is pumped by the absorbent liquid pump 19 and discharged from the absorber unit 1a through the absorbent liquid discharge passage 17b. The temperature of the discharged absorbent liquid is approximately 37°C, and its solute concentration is approximately 55% by mass. Simultaneously, the liquid-phase refrigerant stored in the second supplyer 23b is supplied towards the fourth heat transfer tube group 22b. As a result, the liquid-phase refrigerant forms a liquid film around the heat transfer tubes of the fourth heat transfer tube group 22b and flows down. During the period when the liquid-phase refrigerant flows down around the heat transfer tubes of the fourth heat transfer tube group 22b, the liquid-phase refrigerant absorbs heat from the heat transfer medium flowing inside the heat transfer tubes and evaporates. Any liquid-phase refrigerant that does not evaporate is stored inside the shell 3 below the fourth heat transfer tube group 22b.

[0049] When the absorbent liquid flows down around the outer surface of the heat transfer tubes of the second heat transfer tube group 12b, the gas phase in the second evaporator 20b refrigerantThe gaseous refrigerant is absorbed into the absorbent liquid. As the gaseous refrigerant is absorbed, the temperature of the absorbent liquid rises. However, at the same time, the absorbent liquid is cooled by the heat transfer medium flowing inside the heat transfer tubes of the second heat transfer tube group 12b, so continuous supercooling absorption occurs, and the pressure in the high-pressure stage, including the second evaporator 20b and the second absorber 10b, decreases. Consequently, the liquid-phase refrigerant flowing down around the outer surface of the heat transfer tubes of the fourth heat transfer tube group 22b evaporates. As the liquid-phase refrigerant evaporates, its temperature decreases. However, at the same time, the liquid-phase refrigerant is heated by the heat transfer medium flowing inside the heat transfer tubes of the second heat transfer tube group 12b, so continuous evaporation of the liquid-phase refrigerant occurs.

[0050] In this way, the pressures in the high-pressure and low-pressure stages of the heat exchange unit 5 are maintained at predetermined pressures, and the heat exchange unit 5 enters a steady state.

[0051] In the steady state of rated operation of the heat exchange unit 5, the heat transfer medium flowing inside the heat transfer tubes of the fourth heat transfer tube group 22b is cooled from 12°C to approximately 9.75°C. In addition, the heat transfer medium flowing inside the heat transfer tubes of the third heat transfer tube group 22a is cooled from 9.75°C to approximately 7°C. Consequently, the temperature of the liquid-phase refrigerant stored in the second evaporator 20b is approximately 7.6°C, and the pressure of the gaseous refrigerant inside the second evaporator 20b is approximately 1044 Pa, which is the saturated vapor pressure of the liquid-phase refrigerant at approximately 7.6°C. The temperature of the liquid-phase refrigerant stored in the first evaporator 20a is approximately 6.1°C, and the pressure of the gaseous refrigerant inside the first evaporator 20a is approximately 942 Pa, which is the saturated vapor pressure of the liquid-phase refrigerant at approximately 6.1°C. Therefore, the pressure difference between the high-pressure stage, which includes the second evaporator 20b and the second absorber 10b, and the low-pressure stage, which includes the first evaporator 20a and the first absorber 10a, is approximately 100 Pa.

[0052] In the steady state of rated operation, the heat transfer medium flowing inside the heat transfer tubes of the second heat transfer tube group 12b is heated from approximately 32°C to 34.25°C, and the heat transfer medium flowing inside the heat transfer tubes of the first heat transfer tube group 12a is heated from approximately 34.25°C to 36.5°C. The temperature of the absorbent liquid stored in the first dripper 13a and dripped towards the first heat transfer tube group 12a is 50°C, and the density of the absorbent liquid is 1750 kg / m³. 3The temperature of the absorbent liquid supplied through the supply channel 15 toward the second dropper 13b is 44°C, and the density of the absorbent liquid is 1680 kg / m³. 3 The temperature of the absorbent liquid stored in the lower part of the second space 16b is 37°C, and the density of the absorbent liquid is 1610 kg / m³. 3 It is to that extent.

[0053] On the other hand, in steady-state low-load operation such as 25% load operation, the heat transfer medium flowing inside the heat transfer tubes of the fourth heat transfer tube group 22b is cooled from 8.4°C to approximately 7.7°C. In addition, the heat transfer medium flowing inside the heat transfer tubes of the third heat transfer tube group 22a is cooled from approximately 7.7°C to approximately 7°C. Consequently, the temperature of the liquid-phase refrigerant stored inside the second evaporator 20b is approximately 6.4°C, and the pressure of the gaseous refrigerant inside the second evaporator 20b is approximately 963 Pa, which is the saturated vapor pressure of the liquid-phase refrigerant at approximately 6.4°C. The temperature of the liquid-phase refrigerant stored inside the first evaporator 20a is approximately 6.1°C, and the pressure of the gaseous refrigerant inside the first evaporator 20a is approximately 942 Pa, which is the saturated vapor pressure of the liquid-phase refrigerant at approximately 6.1°C. Therefore, the pressure difference between the high-pressure stage, which includes the second evaporator 20b and the second absorber 10b, and the low-pressure stage, which includes the first evaporator 20a and the first absorber 10a, is approximately 21 Pa.

[0054] For example, in a steady state of 25% load operation, the heat transfer medium flowing inside the heat transfer tubes of the second heat transfer tube group 12b is heated to approximately 18°C ​​to 18.6°C. In addition, the heat transfer medium flowing inside the heat transfer tubes of the first heat transfer tube group 12a is heated to approximately 18.6°C to 19.1°C. The temperature of the absorbent liquid stored in the first dripper 13a and dripped towards the first heat transfer tube group 12a is approximately 28°C, and the density of the absorbent liquid is 1500 kg / m³. 3 The temperature of the absorbent liquid supplied to the second dropper 13b via the supply path 15 is 21°C, and the density of the absorbent liquid is 1460 kg / m³. 3 The temperature of the absorbent liquid stored in the lower part of the second space 16b is 18°C, and the density of the absorbent liquid is 1420 kg / m³. 3 It is to that extent.

[0055] In Figure 2, in the steady state of rated operation, the head h1 of the absorbent liquid in the supply path 15 for maintaining the pressure difference between the high-pressure stage and the low-pressure stage is approximately 6 mm, and the head h2 for flowing the absorbent liquid is approximately 11.6 mm. As shown in Figure 2, in the upstream section 15c, for example, the liquid level of the absorbent liquid may be disturbed by a height tb of 2 mm. The velocity of the absorbent liquid passing through the hole 13h of the second dropper 13b is approximately 0.4 m / sec. The head h3 of the absorbent liquid inside the second dropper 13b is approximately 7.6 mm.

[0056] For example, in the supply path 15 under steady-state conditions of 25% load operation, the head h1 of the absorbent liquid for maintaining the pressure difference between the high-pressure stage and the low-pressure stage is about 1.5 mm, and the head h2 for flowing the absorbent liquid is about 2.3 mm. In the upstream section 15c, for example, the liquid level of the absorbent liquid may be disturbed by a height tb of 2 mm. The velocity of the absorbent liquid passing through the hole 13h of the second dropper 13b is about 0.1 m / sec. The head h3 of the absorbent liquid inside the second dropper 13b is about 0.5 mm.

[0057] [1-3. Effects, etc.] As described above, in this embodiment, the absorber unit 1a comprises a first heat transfer tube group 12a, a first dripper 13a, a second heat transfer tube group 12b, a second dripper 13b, a partition 14, and a supply path 15. The first dripper 13a drops the absorbent liquid toward the first heat transfer tube group 12a. The second heat transfer tube group 12b is positioned below the first heat transfer tube group 12a in the direction of gravity. The second dripper 13b drops the absorbent liquid that has been dropped from the first dripper 13a and flowed down the first heat transfer tube group 12a toward the second heat transfer tube group 12b. The partition 14 separates the first space 16a where the first heat transfer tube group 12a is located from the second space 16b where the second heat transfer tube group 12b is located. The supply passage 15 is formed in the partition 14 and guides the absorbent liquid that has flowed down the first heat transfer tube group 12a to the second dripper 13b. The supply passage 15 has an inlet 15a that is in contact with the first space 16a and an outlet 15b that is located below the inlet 15a in the direction of gravity and is in contact with the second space 16b. The supply passage 15 has an upstream section 15c through which the absorbent liquid is guided from the inlet 15a according to gravity, and a downstream section 15d through which the absorbent liquid that has passed through the upstream section 15c is guided toward the outlet 15b against gravity.

[0058] As a result, even if the liquid level of the absorbent liquid in the supply passage 15 is disturbed by the absorbent liquid flowing down the first heat transfer tube group 12a, a liquid seal is formed by the absorbent liquid in the supply passage 15. As a result, the gaseous refrigerant present in the second space 16b is less likely to blow through from the second space 16b to the first space 16a, and the mist of the absorbent liquid present in the first space 16a is less likely to blow through. absorber It is less likely to scatter inside 10a. Therefore, a decrease in refrigeration capacity caused by the mixing of absorbent liquid with the liquid phase refrigerant is easily prevented.

[0059] As in this embodiment, the downstream section 15d may be formed below the outlet 15b in the direction of gravity. This makes it easier to simplify the supply path 15. The downstream section 15d may also be formed above the outlet 15b in the direction of gravity.

[0060] As in this embodiment, the heat exchange unit 5 may include an absorber unit 1a, a first evaporator 20a, and a second evaporator 20b. The second evaporator 20b generates a gaseous refrigerant at a pressure higher than that in the first evaporator 20a. The absorbent liquid dripped toward the first heat transfer tube group 12a absorbs the gaseous refrigerant generated in the first evaporator 20a. The absorbent liquid dripped toward the second heat transfer tube group 12b absorbs the gaseous refrigerant generated in the second evaporator 20b. This makes it easier for a refrigerator equipped with the heat exchange unit 5 to achieve a high COP.

[0061] (Embodiment 2) Embodiment 2 will be described below with reference to Figure 4.

[0062] [2-1. Structure] Figure 4 is a schematic diagram of the absorber unit 1b in Embodiment 2. The absorber unit 1b is configured in the same way as the absorber unit 1a, except for parts that are not specifically described. Components of the absorber unit 1b that are the same as or correspond to components of the absorber unit 1a are denoted by the same reference numerals, and detailed descriptions are omitted. Descriptions of the absorber unit 1a also apply to the absorber unit 1b, unless they are technically inconsistent.

[0063] As shown in Figure 4, the second space 16b has a side portion 16s that is in contact with the flow path of the gaseous refrigerant. For example, the side portion 16s is in contact with the second vapor flow path 31b. In the absorber unit 1b, the outlet 15b of the supply path 15 is formed at a position closer to the side portion 16s than the inlet 15a in a direction perpendicular to the direction of gravity. For example, the outlet 15b is formed at a position closer to the side portion 16s than the inlet 15a in a direction perpendicular to the direction of gravity and perpendicular to the longitudinal direction of the heat transfer tubes of the second heat transfer tube group 12b.

[0064] [2-2. Operation] The operation and function of the absorber unit 1b, configured as described above, will now be explained. Based on Figure 4, the operation of the heat exchange unit equipped with absorber unit 1b will be explained. This heat exchange unit is configured similarly to heat exchange unit 5, except that it is equipped with absorber unit 1b instead of absorber unit 1a.

[0065] During the startup operation of the heat exchange unit equipped with absorber unit 1b, the absorbent liquid supplied to the first heat transfer tube group 12a absorbs the gaseous refrigerant introduced from the first evaporator 20a to the first space 16a while releasing heat to the heat transfer medium flowing inside the heat transfer tubes. This reduces the concentration of the absorbent liquid. Simultaneously, the liquid-phase refrigerant supplied to the third heat transfer tube group 22a evaporates due to heat absorption from the heat transfer medium flowing inside the heat transfer tubes, and the temperature of the liquid-phase refrigerant decreases. As a result, the pressure in the low-pressure stage, including the first evaporator 20a and the first absorber 10a, decreases. On the other hand, the absorbent liquid that has flowed down the first heat transfer tube group 12a is introduced to the supply path 15 from the inlet 15a. In this case, the pressure in the high-pressure stage, including the second evaporator 20b and the second absorber 10b, is high because evaporation of the liquid-phase refrigerant and absorption of the gaseous refrigerant into the absorbent liquid have not yet begun. For example, the pressure in the low-pressure stage may be around 940 Pa, and the pressure in the high-pressure stage may be around 1150 Pa. The pressure difference between the high-pressure stage, which includes the second evaporator 20b and the second absorber 10b, and the low-pressure stage, which includes the first evaporator 20a and the first absorber 10a, can be as large as approximately 210 Pa, which is larger than the pressure difference of approximately 100 Pa during rated operation.

[0066] [2-3. Effects, etc.] As described above, in this embodiment, the second space 16b has a side portion 16s that is in contact with the flow path of the gaseous refrigerant. In addition, the outlet 15b is formed in a position closer to the side portion 16s than the inlet 15a in a direction perpendicular to the direction of gravity.

[0067] As a result, for example, under operating conditions such as startup, where there is not enough absorbent liquid in the supply passage 15 to form a liquid seal and the pressure difference between the high-pressure stage and the low-pressure stage is large, mist of the absorbent liquid is less likely to scatter into the first evaporator 20a. This is because even if some of the gaseous refrigerant present in the high-pressure stage blows through the supply passage 15 into the first space 16a, the gaseous refrigerant in the high-pressure stage is more likely to pass through the outlet 15b and inlet 15a and enter the first space 16a away from the first evaporator 20a. Therefore, a decrease in refrigeration capacity due to the mixing of absorbent liquid with the liquid refrigerant is less likely to occur.

[0068] (Embodiment 3) Embodiment 3 will be described below with reference to Figure 5.

[0069] [3-1. Structure] Figure 5 is a schematic diagram of the absorber unit 1c in Embodiment 3. The absorber unit 1c is configured similarly to the absorber unit 1b, except for parts that are not specifically described. Components of the absorber unit 1c that are the same as or correspond to components of the absorber unit 1b are denoted by the same reference numerals, and detailed descriptions are omitted. The descriptions of absorber units 1a and 1b also apply to absorber unit 1c, unless otherwise technically contradictory.

[0070] As shown in Figure 5, the absorber unit 1c is further equipped with a cover 18. The cover 18 is positioned between the first heat transfer tube group 12a and the inlet 15a in the direction of gravity and covers the inlet 15a.

[0071] [3-2. Operation] The operation and function of the absorber unit 1c, configured as described above, will now be explained. Based on Figure 5, the operation of the heat exchange unit equipped with the absorber unit 1c will be explained. This heat exchange unit is configured similarly to the heat exchange unit 5, except that it is equipped with the absorber unit 1c instead of the absorber unit 1a.

[0072] A heat exchange unit equipped with absorber unit 1c can be started, for example, under conditions where the ambient temperature is high and the pressure difference between the high-pressure stage and the low-pressure stage is large. For example, a heat exchange unit equipped with absorber unit 1c can be started when the ambient temperature is around 30°C, the pressure in the high-pressure stage is around 940 Pa, and the pressure in the low-pressure stage is around 1350 Pa. In this case, the pressure difference between the high-pressure stage, which includes the second evaporator 20b and the second absorber 10b, and the low-pressure stage, which includes the first evaporator 20a and the first absorber 10a, can be around 410 Pa, which is larger than the pressure difference of about 100 Pa during rated operation.

[0073] [3-3. Effects, etc.] As described above, in this embodiment, the absorber unit 1c further comprises a cover 18. The cover 18 is positioned between the first heat transfer tube group 12a and the inlet 15a in the direction of gravity and covers the inlet 15a.

[0074] As a result, even when there is not enough absorbent liquid in the supply passage 15 to form a liquid seal, such as during startup under high ambient temperature conditions, absorbent liquid mist is less likely to scatter into the first evaporator 20a. This is because even if the gaseous refrigerant present in the high-pressure stage blows through the supply passage 15 into the first space 16a, absorbent liquid mist is more likely to adhere to the cover 18, or the absorbent liquid mist is more likely to bounce off the cover 18 and fall. Therefore, a decrease in refrigeration capacity caused by the mixing of absorbent liquid with the liquid refrigerant is more easily prevented.

[0075] (Embodiment 4) Embodiment 4 will be described below with reference to Figure 6.

[0076] [4-1. Structure] Figure 6 is a schematic diagram of absorber unit 1d in Embodiment 4. Absorber unit 1d is configured similarly to absorber unit 1c, except for parts that are not specifically described. Components of absorber unit 1d that are the same as or correspond to components of absorber unit 1c are denoted by the same reference numerals, and detailed descriptions are omitted. Descriptions of absorber units 1a, 1b, and 1c also apply to absorber unit 1d, unless otherwise technically contradictory.

[0077] As shown in Figure 6, in the absorber unit 1d, the cover 18 is positioned between the first heat transfer tube group 12a and the inlet 15a in the direction of gravity, and covers the inlet 15a. In addition, the cover 18 has a side wall 18s. The side wall 18s is positioned closer to the gaseous refrigerant flow path than the inlet 15a in a direction perpendicular to the direction of gravity. For example, the side wall 18s is positioned perpendicular to the direction of gravity and also perpendicular to the longitudinal direction of the heat transfer tubes of the first heat transfer tube group 12a, and is positioned closer to the first vapor flow path 31a than the inlet 15a.

[0078] [4-2. Operation] The operation and function of the absorber unit 1d, configured as described above, will now be explained. Based on Figure 6, the operation of the heat exchange unit equipped with the absorber unit 1d will be explained. This heat exchange unit is configured similarly to the heat exchange unit 5, except that it is equipped with the absorber unit 1d instead of the absorber unit 1a.

[0079] A heat exchange unit equipped with absorber unit 1d can be started, for example, under conditions where the ambient temperature is high and the pressure difference between the high-pressure stage and the low-pressure stage is large. For example, a heat exchange unit equipped with absorber unit 1d can be started when the ambient temperature is around 30°C, the pressure in the high-pressure stage is around 940 Pa, and the pressure in the low-pressure stage is around 1350 Pa. In this case, the pressure difference between the high-pressure stage, which includes the second evaporator 20b and the second absorber 10b, and the low-pressure stage, which includes the first evaporator 20a and the first absorber 10a, can be around 410 Pa, which is larger than the pressure difference of about 100 Pa during rated operation.

[0080] [4-3. Effects, etc.] As described above, in this embodiment, the absorber unit 1d further comprises a cover 18. The cover 18 is positioned between the first heat transfer tube group 12a and the inlet 15a in the direction of gravity and covers the inlet 15a. In addition, the cover 18 has a side wall 18s. The side wall 18s is positioned closer to the gaseous refrigerant flow path than the inlet 15a in a direction perpendicular to the direction of gravity.

[0081] As a result, even when there is not enough absorbent liquid in the supply passage 15 to form a liquid seal, such as during startup under high ambient temperature conditions, absorbent liquid mist is less likely to scatter to the first evaporator 20a. This is because even if the gaseous refrigerant present in the high-pressure stage blows through the supply passage 15 into the first space 16a, the side wall 18s prevents the movement of absorbent liquid mist, making it difficult for absorbent liquid mist to be guided to the first evaporator 20a. Therefore, a decrease in refrigeration capacity caused by the mixing of absorbent liquid with the liquid refrigerant is less likely to occur.

[0082] (Embodiment 5) Embodiment 5 will be described below with reference to Figure 7.

[0083] [5-1. Structure] As shown in Figure 7, the absorption chiller 100 includes, for example, a heat exchange unit 5. The absorption chiller 100 further includes, for example, a regenerator 80 and a condenser 90. The absorption chiller 100 is, for example, a single-effect cycle absorption chiller. The absorption chiller 100 may be a double-effect cycle or a triple-effect cycle absorption chiller. When a gas burner is used as the heat source for the regenerator 80, the absorption chiller 100 may be a gas chiller.

[0084] [5-2. Operation] The operation and function of the absorption chiller 100, configured as described above, will now be explained. The absorbent liquid stored in the absorber unit 1a is led to the regenerator 80 through the absorbent liquid discharge passage 17b. In the regenerator 80, the concentration of the solute in the absorbent liquid is increased by heating. The absorbent liquid with increased solute concentration is led to the absorber unit 1a through the absorbent liquid supply passage 17a. Meanwhile, a gaseous refrigerant is generated by heating the absorbent liquid in the regenerator 80. This gaseous refrigerant is led to the condenser 90, where it is cooled and condensed to produce a liquid refrigerant. The liquid refrigerant is then, for example, depressurized and led to the evaporator unit 2 through the refrigerant supply passage 26. In the absorption chiller 100, the absorber unit may be absorber unit 1b, absorber unit 1c, or absorber unit 1d.

[0085] [5-3. Effects] As described above, in this embodiment, the absorption chiller 100 is equipped with a heat exchange unit 5. This makes it easier to prevent a decrease in the chilling capacity of the absorption chiller 100 due to the mixing of absorbent liquid with the liquid phase refrigerant.

[0086] As described above, embodiments 1, 2, 3, 4, and 5 have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited thereto and can be applied to embodiments that have been modified, replaced, added, or omitted. For example, the inlet 15a may be formed closer to the side portion 16s than the outlet 15b in a direction perpendicular to the direction of gravity. [Industrial applicability]

[0087] This disclosure is applicable to absorption chillers adapted for use in central air conditioning systems in buildings and chillers for process cooling, etc. [Explanation of Symbols]

[0088] 1a, 1b, 1c, 1d Absorber Unit 5 Heat exchange unit 12a First group of heat transfer tubes 12b Second group of heat transfer tubes 13a First dropper 13b Second dropper 14 dividers 15 Supply route 15a Entrance 15b Exit 15c upstream part 15d downstream 16a First space 16b Second space 16s side 18 Cover 20a First evaporator 20b Second evaporator 100 Absorption chillers

Claims

1. The first group of heat transfer tubes, A first dripper for dripping absorbent liquid toward the first heat transfer tube group, A second group of heat transfer tubes is positioned below the first group of heat transfer tubes in the direction of gravity, A second dropper drops the absorbent liquid, which has been dropped from the first dropper and flowed down the first heat transfer tube group, toward the second heat transfer tube group. A partition separates the first space where the first heat transfer tube group is located from the second space where the second heat transfer tube group is located. A supply path is formed in the partition and guides the absorbent liquid that has flowed down the first heat transfer tube group to the second dropper, Equipped with a cover, The supply path has an inlet in contact with the first space, an outlet located below the inlet in the direction of gravity and in contact with the second space, an upstream section through which the absorbent liquid is guided from the inlet according to gravity, and a downstream section through which the absorbent liquid that has passed through the upstream section is guided toward the outlet against gravity. The cover is positioned between the first heat transfer tube group and the inlet in the direction of gravity, and covers the inlet. Absorber unit.

2. The absorber unit according to claim 1, wherein the downstream portion is formed below the outlet in the direction of gravity.

3. The second space has a side portion that is in contact with the flow path of the gaseous refrigerant, The outlet is formed in a position closer to the side than the inlet in a direction perpendicular to the direction of gravity. The absorber unit according to claim 1 or 2.

4. An absorber unit according to any one of claims 1 to 3, First evaporator and The system comprises a second evaporator that generates a gaseous refrigerant at a pressure higher than the pressure in the first evaporator, The absorbent liquid dripped toward the first heat transfer tube group absorbs the gaseous refrigerant generated in the first evaporator. The absorbent liquid dripped toward the second heat transfer tube group absorbs the gaseous refrigerant generated in the second evaporator. Heat exchange unit.

5. An absorption chiller comprising the heat exchange unit described in claim 4.

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