US20190041100A1

US20190041100A1 - Condenser, and centrifugal chiller equipped with the same

Info

Publication number: US20190041100A1
Application number: US16/076,477
Authority: US
Inventors: Naoya Miyoshi; Kazuki Wajima
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2016-04-15
Filing date: 2017-04-12
Publication date: 2019-02-07
Also published as: WO2017179631A1; JP2017190927A; JP6821321B2; CN108700354A; CN108700354B

Abstract

The present invention makes it possible in a centrifugal chiller utilizing a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG to effectively extract, in high concentration, non-condensible gas that has mixed into the low pressure refrigerant, and thus suppresses reductions in condensing efficiency. This condenser (3) is equipped with: a shell vessel (21) into which a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG is introduced; a refrigerant inlet (22) which is provided to the top portion of the shell vessel (21); a refrigerant outlet (23) which is provided to the bottom portion of the shell vessel (21); a heat transfer tube bundle (25) in which a plurality of heat transfer tubes (25a) circulating a chilled liquid in the interior thereof are bundled, and which extends along the interior of the shell vessel (21); a gas extraction tube (31) in the heat transfer tube bundle interior, the gas extraction tube being disposed in the center region in the radial direction of the heat transfer tube bundle (25), forming a tubular shape arranged parallel to the axial direction of the heat transfer tube bundle (25), and having formed in the bottom surface thereof non-condensible gas extraction holes (31a) for extracting non-condensible gas that has mixed into the low pressure refrigerant; and a gas extraction device (33) which is connected to the gas extraction tube (31) in the heat transfer tube bundle interior and extracts the non-condensible gas.

Description

TECHNICAL FIELD

The present invention relates to a condenser gasifying a low pressure refrigerant, and a centrifugal chiller provided with the same.

BACKGROUND ART

For example, as a centrifugal chiller used as a heat source for district cooling and heating, a centrifugal chiller configured to include a turbo compressor that compresses a refrigerant, a condenser that condenses the compressed refrigerant, an expansion valve that expands the condensed refrigerant, and an evaporator that evaporates the expanded refrigerant is known.
Generally, a condenser includes a shell container having a cylindrical shell shape extending in a horizontal direction, and a heat transfer pipe bundle is installed so as to penetrate the shell container in a longitudinal direction. The heat transfer pipe bundle is constituted of a number of heat transfer pipes which are bundled at narrow intervals and cause a cooling liquid such as water to circulate therein. The heat transfer pipe bundle is laid out so as to pass through the inside of the shell container in the horizontal direction, in other words, the longitudinal direction.
A high temperature high pressure refrigerant gas compressed by a turbo compressor flows into the shell container through a refrigerant inlet provided in an upper portion thereof, comes into contact with the heat transfer pipe bundle having a large surface area, and is subjected to heat exchange, thereby being cooled and condensed. The refrigerant gas becomes a refrigerant liquid and is fed to an evaporator side through a refrigerant outlet provided in a lower portion of the shell container.
Low pressure refrigerants such as R1233zd used at a maximum pressure of less than 0.2 MPaG are expected as next generation refrigerants because they can improve efficiency of a centrifugal chiller and have a low global warming potential. However, due to the characteristics of the low pressure refrigerants, when a suction force of the turbo compressor acts, there are cases where a part of the inside of a refrigerant passage may be under a negative pressure. In this case, a non-condensable gas (air or the like) may sometimes be incorporated into the refrigerant passage from the outside through a gap or the like of a shaft sealing. In this manner, the non-condensable gas which has been incorporated into the refrigerant passage stays in the condenser, causes deterioration in condensation efficiency, and impairs performance as a cold instrument.
PTL 1 discloses a condenser in which a non-condensable gas staying inside the condenser is separated from a refrigerant gas and is removed by an air bleeding device. As a separation method thereof, the non-condensable gas is subjected to air bleeding together with the refrigerant gas by the air bleeding device, and they are cooled inside the air bleeding device. Then, the refrigerant gas is condensed, and only the non-condensable gas is separated. Since a non-condensable gas such as air has specific gravity lower than that of a refrigerant and tends to be distributed above inside a condenser, the non-condensable gas distributed above inside a shell container is subjected to air bleeding through an air bleeding port provided in the uppermost portion of the shell container in an air bleeding device in the related art.

CITATION LIST

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2-254271

SUMMARY OF INVENTION

Technical Problem

As described above, since a non-condensable gas has specific gravity lower than that of a refrigerant, the non-condensable gas tends to be distributed in an upper space of a condenser when a centrifugal chiller stops being operated. Therefore, when the centrifugal chiller stops being operated, the non-condensable gas can be efficiently subjected to air bleeding through an air bleeding port provided in an upper portion of a shell container as in the related art.
However, when the centrifugal chiller is operated, a compressed refrigerant compressed by a turbo compressor is blown down into the shell container through a refrigerant inlet provided in the upper portion of the shell container. Therefore, due to the influence of a descending air flow of the compressed refrigerant, more non-condensable gas is distributed inside a heat transfer pipe bundle, in which the compressed refrigerant is condensed and liquefied, than in the upper space of the shell container.
Therefore, the concentration of a non-condensable gas in the upper space of the shell container when the centrifugal chiller is operated becomes lower than the concentration inside the heat transfer pipe bundle. Therefore, if air bleeding of a non-condensable gas is performed from the upper space of the shell container during an operation, a high purity refrigerant gas is also subjected to air bleeding together with the non-condensable gas. Accordingly, there is concern that the non-condensable gas cannot be efficiently subjected to air bleeding, thereby leading to deterioration in condensation efficiency due to the depleted refrigerant gas.
The present invention has been made in consideration of such circumstances, and an object thereof is to provide a condenser and a centrifugal chiller provided with the same. In the centrifugal chiller using a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG, it is possible to effectively perform air bleeding in high concentration with respect to a non-condensable gas which has been incorporated into the low pressure refrigerant, and it is possible to suppress deterioration in condensation efficiency.

Solution to Problem

In order to solve the problems, the present invention employs the following means.
According to a first aspect of the present invention, there is provided a condenser including a shell container into which a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG is introduced; a refrigerant inlet which is provided in an upper portion of the shell container; a refrigerant outlet which is provided in a lower portion of the shell container; a heat transfer pipe bundle in which a number of heat transfer pipes causing a cooling liquid to circulate therein are bundled and which extends inside the shell container; an intra-heat transfer pipe bundle air bleeding pipe which is disposed in a central region of the heat transfer pipe bundle in a bundle diameter direction, which has a pipe shape parallel to an axial direction of the heat transfer pipe bundle, and in which a non-condensable gas air bleeding hole for performing air bleeding of a non-condensable gas mixed in the low pressure refrigerant is formed on a lower surface thereof; and an air bleeding device which is connected to the intra-heat transfer pipe bundle air bleeding pipe and performs air bleeding of the non-condensable gas.
According to the condenser having this configuration, since the intra-heat transfer pipe bundle air bleeding pipe is disposed inside the heat transfer pipe bundle in which a non-condensable gas is maximally distributed in high concentration when a centrifugal chiller is operated, it is possible to effectively perform air bleeding in high concentration with respect to the non-condensable gas which has been incorporated into a low pressure refrigerant, by operating the air bleeding device. Accordingly, it is possible to suppress deterioration in condensation efficiency caused by the incorporated non-condensable gas.
A refrigerant gas containing a non-condensable gas is subjected to air bleeding into the intra-heat transfer pipe bundle air bleeding pipe through the non-condensable gas air bleeding hole, but the non-condensable gas air bleeding hole is formed on the lower surface of the intra-heat transfer pipe bundle air bleeding pipe. Accordingly, a condensed liquid refrigerant is unlikely to flow into the non-condensable gas air bleeding hole. Therefore, it is possible to suppress deterioration in condensation efficiency caused by a condensed liquid refrigerant being extracted.
The condenser having the above-described configuration may further include an extra-heat transfer pipe bundle air bleeding pipe which is disposed in an upper space inside the shell container, in which a non-condensable gas air bleeding hole is formed on a lower surface thereof, and which is connected to the air bleeding device. The air bleeding device may be capable of independently performing air bleeding of the non-condensable gas through each of the intra-heat transfer pipe bundle air bleeding pipe and the extra-heat transfer pipe bundle air bleeding pipe.
According to the condenser having this configuration, in addition to the intra-heat transfer pipe bundle air bleeding pipe being disposed inside the heat transfer pipe bundle in which a non-condensable gas is maximally distributed when the centrifugal chiller is operated, the extra-heat transfer pipe bundle air bleeding pipe is disposed in the upper space inside the shell container in which the non-condensable gas is maximally distributed when the centrifugal chiller is at a stop. Then, the air bleeding device is capable of independently performing air bleeding of the non-condensable gas through each of the intra-heat transfer pipe bundle air bleeding pipe and the extra-heat transfer pipe bundle air bleeding pipe.
Therefore, air bleeding is performed through the extra-heat transfer pipe bundle air bleeding pipe positioned in the upper space inside the shell container when the centrifugal chiller stops being operated, and air bleeding is performed through the intra-heat transfer pipe bundle air bleeding pipe positioned inside the heat transfer pipe bundle when the centrifugal chiller is operated. Accordingly, regardless of an operational state of the centrifugal chiller, it is possible to effectively perform air bleeding in high concentration with respect to a non-condensable gas at all times, and it is possible to suppress deterioration in condensation efficiency caused by the incorporated non-condensable gas. Naturally, air bleeding may be performed through both the intra-heat transfer pipe bundle air bleeding pipe and the extra-heat transfer pipe bundle air bleeding pipe at the same time.
In the condenser having the above-described configuration, the shell container may be configured to have a cylindrical shape extending in a horizontal direction. The heat transfer pipe bundle may be configured to include an outbound pipe bundle which extends from one end to the other end in a longitudinal direction inside the shell container, and an inbound pipe bundle which communicates with the outbound pipe bundle at the other end in the longitudinal direction inside the shell container and returns from the other end to the one end in the longitudinal direction inside the shell container. The outbound pipe bundle may be configured to be disposed below and the inbound pipe bundle may be configured to be disposed above inside the shell container. The intra-heat transfer pipe bundle air bleeding pipe may be configured to be disposed in a central region of the inbound pipe bundle in the bundle diameter direction.
In this configuration, the intra-heat transfer pipe bundle air bleeding pipe is disposed inside the inbound pipe bundle in which a condensation amount of a gas refrigerant is small because the inbound pipe bundle is positioned above the outbound pipe bundle and is on a downstream side of the outbound pipe bundle. Therefore, there is a low probability that the intra-heat transfer pipe bundle air bleeding pipe will be immersed in a liquid refrigerant, so that it is possible to prevent the liquid refrigerant from entering the inside of the intra-heat transfer pipe bundle air bleeding pipe through the non-condensable gas air bleeding hole and being extracted, and it is possible to suppress deterioration in condensation efficiency caused by the extracted liquid refrigerant.
According to a second aspect of the present invention, there is provided a centrifugal chiller including a turbo compressor which compresses a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG, the condenser according to any one of claims 1 to 3, which condenses the compressed low pressure refrigerant, an expansion valve which expands the condensed low pressure refrigerant, and an evaporator which evaporates the expanded low pressure refrigerant. Accordingly, it is possible to exhibit each of the operations and the effects described above.

Advantageous Effects of Invention

As described above, according to the condenser of the present invention and the centrifugal chiller provided with the same, in the centrifugal chiller using a low pressure refrigerant used at the maximum pressure of less than 0.2 MPaG, it is possible to effectively perform air bleeding in high concentration with respect to a non-condensable gas which has been incorporated into the low pressure refrigerant, and it is possible to suppress deterioration in condensation efficiency.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a general view of a centrifugal chiller according to an embodiment of the present invention.

FIG. 2 is a perspective view of a condenser illustrated in FIG. 1, and the diagram illustrates the embodiment of the present invention.

DESCRIPTION OF EMBODIMENT

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a general view of a centrifugal chiller according to an embodiment of the present invention. A centrifugal chiller 1 is configured in a unit state including a turbo compressor 2 that compresses a refrigerant, a condenser 3, a high-pressure expansion valve 4, an economizer 5, a low-pressure expansion valve 6, an evaporator 7, a lubricant tank 8, a circuit box 9, an inverter unit 10, an operation panel 11, and the like. The lubricant tank 8 is a tank storing lubricant supplied to bearings, a speed increaser, and the like of the turbo compressor 2.
The condenser 3 and the evaporator 7 are formed in cylindrical shell shapes having high pressure resistance and are disposed so as to be parallel and adjacent to each other in a state where their axis lines extend in a substantially horizontal direction. The condenser 3 is disposed at a position relatively higher than the evaporator 7, and the circuit box 9 is installed below thereof. The economizer 5 and the lubricant tank 8 are installed while being interposed between the condenser 3 and the evaporator 7. The inverter unit 10 is installed in an upper portion of the condenser 3, and the operation panel 11 is disposed above the evaporator 7.
The turbo compressor 2 is a known centrifugal turbine-type compressor which is rotatively driven by an electric motor 13. The turbo compressor 2 is disposed above the evaporator 7 in a posture having its axis line extending in the substantially horizontal direction. The electric motor 13 is driven by the inverter unit 10. As described below, the turbo compressor 2 compresses a gas-phase refrigerant supplied from the evaporator 7 via a suction pipe 14. A low pressure refrigerant such as R1233zd used at a maximum pressure of less than 0.2 MPaG is used as the refrigerant, for example.
A discharge port of the turbo compressor 2 and a refrigerant inlet 22 provided in the upper portion of the condenser 3 are connected to each other through a discharge pipe 15, and a refrigerant outlet 23 provided in a bottom portion of the condenser 3 and a bottom portion of the economizer 5 are connected to each other through a refrigerant pipe 16. In addition, the bottom portion of the economizer 5 and the evaporator 7 are connected to each other through a refrigerant pipe 17, and an upper portion of the economizer 5 and a middle stage of the turbo compressor 2 are connected to each other through a refrigerant pipe 18. The high-pressure expansion valve 4 is provided in the refrigerant pipe 16, and the low-pressure expansion valve 6 is provided in the refrigerant pipe 17.
In the centrifugal chiller 1 configured as described above, the turbo compressor 2 is rotatively driven by the electric motor 13, compresses a gas-phase low pressure refrigerant supplied from the evaporator 7 via the suction pipe 14, and feeds this compressed low pressure refrigerant to the condenser 3 through the discharge pipe 15.
Inside the condenser 3, when a high temperature low pressure refrigerant compressed in the turbo compressor 2 is subjected to heat exchange with a cooling liquid such as water, condensed heat is cooled, so that the low pressure refrigerant is condensed and liquefied. The cooling liquid heated herein is utilized as a heat medium for heating, and the like. The low pressure refrigerant caused to be in a liquid phase by the condenser 3 expands after passing through the high-pressure expansion valve 4 provided in the refrigerant pipe 16 extending from the condenser 3. The low pressure refrigerant is transported to the economizer 5 in a gas-liquid mixed state and is temporarily stored therein.
Inside the economizer 5, the low pressure refrigerant which has expanded through the high-pressure expansion valve 4 in a gas-liquid mixed state is subjected to gas-liquid separation into a gas-phase part and a liquid-phase part. The liquid-phase part of the low pressure refrigerant separated herein is caused to further expand through the low-pressure expansion valve 6 provided in the refrigerant pipe 17 extending from the bottom portion of the economizer 5 and becomes a gas-liquid two-phase flow, thereby being transported to the evaporator 7. In addition, the gas-phase part of the low pressure refrigerant separated in the economizer 5 is transported to a middle stage portion of the turbo compressor 2 via the refrigerant pipe 18 extending from the upper portion of the economizer 5 and is compressed again.
Inside the evaporator 7, a low temperature liquid refrigerant which has adiabatically expanded through the low-pressure expansion valve 6 is subjected to heat exchange with a cooling target liquid such as water, the cooling target liquid which has been cooled herein is used as a cold heat medium for air conditioning or an industrial cooling liquid. The refrigerant gasified through heat exchange with the cooling target liquid is suctioned again by the turbo compressor 2 via the suction pipe 14 and is compressed. Thereafter, this cycle is repeated.
FIG. 2 is a perspective view of the condenser 3 illustrating the embodiment of the present invention.
The condenser 3 has a cylindrical shape extending in the horizontal direction as described above and is configured to include a shell container 21 into which a low pressure refrigerant used at the maximum pressure of less than 0.2 MPaG is introduced, the refrigerant inlet 22 which is provided in an the upper portion of the shell container 21, the refrigerant outlet 23 which is provided in a lower portion of the shell container 21, a heat transfer pipe bundle 25 which horizontally extends along a longitudinal direction inside the shell container 21, and an air bleeding system 30 which serves as a main portion of the present invention.
Each of the refrigerant inlet 22 and the refrigerant outlet 23 is disposed in an intermediate portion of the shell container 21 in the longitudinal direction. As illustrated in FIG. 1, the refrigerant inlet 22 is connected to the discharge port of the turbo compressor 2 via the discharge pipe 15, and the refrigerant outlet 23 is connected to the economizer 5 via the refrigerant pipe 16.
The heat transfer pipe bundle 25 includes an outbound pipe bundle 25A which horizontally extends from one end (left end in FIG. 2) to the other end (right end in FIG. 2) in the longitudinal direction inside the shell container 21, and an inbound pipe bundle 25B which communicates with the outbound pipe bundle 25A at the other end in the longitudinal direction inside the shell container 21 and horizontally returns from the other end to one end in the longitudinal direction inside the shell container 21. Both the outbound pipe bundle 25A and the inbound pipe bundle 25B have a known pipe bundle structure in which a number of heat transfer pipes 25 a causing a cooling liquid such as water to circulate therein are inserted through a plurality of porous heat transfer pipe support plates (not illustrated) and are bundled.
Inside the shell container 21, the outbound pipe bundle 25A is disposed below and the inbound pipe bundle 25B is disposed above. A U-turn chamber (not illustrated) is provided at the other end (right end in FIG. 2) of the shell container 21, and end portions of the outbound pipe bundle 25A and the inbound pipe bundle 25B are connected to the U-turn chamber such that they communicate with each other. In addition, at one end (left end in FIG. 2) of the shell container 21, a nozzle-shaped cooling water inlet (not illustrated) which is connected to one end of the outbound pipe bundle 25A, and a nozzle-shaped cooling water outlet (not illustrated) which is positioned above the cooling water inlet and is connected to one end of the inbound pipe bundle 25B are provided.
The cooling liquid flowing in the heat transfer pipe bundle 25 flows from one end of the outbound pipe bundle 25A (left end in FIG. 2) through the cooling water inlet and flows to the other end (right end in FIG. 2). After a U-turn in the U-turn chamber, the cooling liquid flows from the other end (right end in FIG. 2) to one end (left end in FIG. 2) of the inbound pipe bundle 25B and is discharged via the cooling water outlet. On the other hand, a high temperature high pressure gas refrigerant compressed by the turbo compressor 2 enters the inside of the shell container 21 through the refrigerant inlet 22 and is dispersed in the longitudinal direction of the shell container 21 by a distribution plate 27. Then, the gas refrigerant comes into contact with the inbound pipe bundle 25B and the outbound pipe bundle 25A in this order, is subjected to heat exchange, and is condensed, thereby becoming a liquid refrigerant and being discharged through the refrigerant outlet 23.
The air bleeding system 30 serving as the main portion of the present invention is a system performing air bleeding of a non-condensable gas such as air which is likely to be incorporated into a low pressure refrigerant. The air bleeding system 30 is configured to include an intra-heat transfer pipe bundle air bleeding pipe 31, an extra-heat transfer pipe bundle air bleeding pipe 32, an air bleeding device 33, and partition valves 34 and 35.
The intra-heat transfer pipe bundle air bleeding pipe 31 is disposed in a central region of the inbound pipe bundle 25B in a bundle diameter direction in the heat transfer pipe bundle 25, has a horizontal pipe shape parallel to an axial direction of the inbound pipe bundle 25B, and has a plurality of round hole-shaped non-condensable gas air bleeding holes 31 a formed on a lower surface thereof. For example, the length of the intra-heat transfer pipe bundle air bleeding pipe 31 is set to be a length corresponding to approximately the entire length of the inbound pipe bundle 25B but may be shorter. A non-condensable gas discharge pipe 37 extending upward is connected to one end or the intermediate portion of the intra-heat transfer pipe bundle air bleeding pipe 31. In the present embodiment, one end of the intra-heat transfer pipe bundle air bleeding pipe 31 is curved or bent upward and serves as the non-condensable gas discharge pipe 37 as it stands. The other end of the intra-heat transfer pipe bundle air bleeding pipe 31 is blocked. The non-condensable gas discharge pipe 37 penetrates a peripheral surface of the shell container 21 upward and is connected to a non-condensable gas collecting pipe 40 extending from the air bleeding device 33, via the partition valve 34.
For example, the pipe diameter of the intra-heat transfer pipe bundle air bleeding pipe 31 ranges approximately from 15 mm to 20 mm. For example, the non-condensable gas air bleeding holes 31 a are bored at intervals of approximately 20 cm along the axial direction, and their hole diameters range approximately from 5 to 10 mm, for example. If the hole diameters of the non-condensable gas air bleeding holes 31 a are excessively small, there are cases where the non-condensable gas air bleeding holes 31 a may be liquid-sealed due to surface tension of a liquid refrigerant when being submerged in the liquid refrigerant. In contrast, if the holes are excessively large, a liquid refrigerant is likely to flow into the intra-heat transfer pipe bundle air bleeding pipe 31 through the non-condensable gas air bleeding holes 31 a. The hole shapes of the non-condensable gas air bleeding holes 31 a are not necessarily round hole shapes. For example, it is possible to consider to have square hole shapes, long hole shapes inclined with respect to the axial direction of the intra-heat transfer pipe bundle air bleeding pipe 31, slit shapes along the axial direction of the intra-heat transfer pipe bundle air bleeding pipe 31, or the like.
In addition, the hole diameters of the non-condensable gas air bleeding holes 31 a may sequentially increase from the outlet side (non-condensable gas discharge pipe 37 side) to the inlet side (tip end side) of the intra-heat transfer pipe bundle air bleeding pipe 31. In this manner, it is possible to uniformly perform air bleeding of a non-condensable gas over the entire length of the intra-heat transfer pipe bundle air bleeding pipe 31 by reducing the hole diameters on the outlet side where a suction force is strong (a pressure loss is small) and increasing the hole diameters on the inlet side where a suction force is weak (a pressure loss is significant).
On the other hand, the extra-heat transfer pipe bundle air bleeding pipe 32 is a pipe-shaped member which is disposed in an upper space inside the shell container 21, that is, above the outbound pipe bundle 25A and horizontally extends along the longitudinal direction of the shell container 21. For example, the pipe diameter of the extra-heat transfer pipe bundle air bleeding pipe 32 is the same diameter as that of the intra-heat transfer pipe bundle air bleeding pipe 31, and non-condensable gas air bleeding holes 32 a similar to the non-condensable gas air bleeding holes 31 a of the intra-heat transfer pipe bundle air bleeding pipe 31 are bored on the lower surface thereof. A non-condensable gas discharge pipe 38 extending upward is connected to the extra-heat transfer pipe bundle air bleeding pipe 32 as well. The non-condensable gas discharge pipe 38 penetrates the peripheral surface of the shell container 21 upward and is connected to the non-condensable gas collecting pipe 40 extending from the air bleeding device 33, via the partition valve 35.
The air bleeding device 33 is a known device configured to perform air bleeding of a non-condensable gas such as air which has been incorporated into a refrigerant in the shell container 21, together with a refrigerant gas. Then, they are cooled, and only the refrigerant gas is condensed and liquefied so as to be separated from the non-condensable gas. If the air bleeding device 33 is operated, a predetermined negative pressure is applied to the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32 via the non-condensable gas collecting pipe 40 and the non-condensable gas discharge pipes 37 and 38. Then, the non-condensable gas, which has been incorporated into the refrigerant in the shell container 21 together with a part of the refrigerant gas through the non-condensable gas air bleeding holes 31 a and 32 a formed in the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32, is subjected to air bleeding.
As described above, the non-condensable gas discharge pipe 37 extending from the intra-heat transfer pipe bundle air bleeding pipe 31 and the non-condensable gas discharge pipe 38 extending from the extra-heat transfer pipe bundle air bleeding pipe 32 are connected to the non-condensable gas collecting pipe 40 extending from the air bleeding device 33 via the partition valves 34 and 35 respectively. The air bleeding device 33 is capable of independently performing air bleeding of a non-condensable gas through each of the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32 by opening the partition valve or the partition valve 35. In addition, it is also possible to perform air bleeding of a non-condensable gas from both the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32 by opening both the partition valves 34 and 35. Moreover, the ratio of air bleeding in the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32 can be varied by varying valve-opening degrees of the partition valves 34 and 35.
The condenser 3 is configured as follows.
In the condenser 3, the intra-heat transfer pipe bundle air bleeding pipe 31, which is connected to the air bleeding device 33 and through which a non-condensable gas such as air that has been incorporated into a refrigerant inside the shell container 21 is subjected to air bleeding, is disposed in the central region of the heat transfer pipe bundle 25 (inbound pipe bundle 25B) in the bundle diameter direction and is provided to be parallel to the axial direction of the heat transfer pipe bundle 25. According to this configuration, since the intra-heat transfer pipe bundle air bleeding pipe 31 is disposed inside the heat transfer pipe bundle 25 in which a non-condensable gas is maximally distributed in high concentration when the centrifugal chiller 1 is operated, it is possible to effectively perform air bleeding in high concentration with respect to the non-condensable gas which has been incorporated into a low pressure refrigerant, by operating the air bleeding device 33. Accordingly, it is possible to suppress deterioration in condensation efficiency caused by the incorporated non-condensable gas.
A refrigerant gas containing a non-condensable gas is subjected to air bleeding into the intra-heat transfer pipe bundle air bleeding pipe 31 through the plurality of non-condensable gas air bleeding holes 31 a, but the non-condensable gas air bleeding holes 31 a are formed on the lower surface of the intra-heat transfer pipe bundle air bleeding pipe 31, a condensed liquid refrigerant is unlikely to flow into the non-condensable gas air bleeding holes 31 a. Therefore, it is possible to suppress deterioration in condensation efficiency caused by a condensed liquid refrigerant being extracted.
In addition, in the outbound pipe bundle 25A and the inbound pipe bundle 25B configuring the heat transfer pipe bundle 25, the intra-heat transfer pipe bundle air bleeding pipe 31 is disposed in the central region of the inbound pipe bundle 25B in the bundle diameter direction in which a condensation amount of a gas refrigerant is small because the inbound pipe bundle 25B is positioned above the outbound pipe bundle 25A and is on a downstream side of the outbound pipe bundle 25A. Therefore, there is a low probability that the intra-heat transfer pipe bundle air bleeding pipe 31 will be immersed in a liquid refrigerant, so that it is possible to prevent the liquid refrigerant from entering the inside of the intra-heat transfer pipe bundle air bleeding pipe 31 through the non-condensable gas air bleeding holes 31 a and being extracted, and it is possible to suppress deterioration in condensation efficiency caused by the extracted liquid refrigerant.
In addition, the condenser 3 further includes the extra-heat transfer pipe bundle air bleeding pipe 32 which is disposed outside the heat transfer pipe bundle 25 (25B) and in the upper space inside the shell container 21. The extra-heat transfer pipe bundle air bleeding pipe 32 is connected to the air bleeding device 33, and the non-condensable gas air bleeding holes 32 a are formed on the lower surface thereof. Then, the air bleeding device 33 is capable of independently performing air bleeding of a non-condensable gas through each of the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32.
According to this configuration, in addition to that the intra-heat transfer pipe bundle air bleeding pipe 31 is disposed inside the heat transfer pipe bundle 25 (25B) in which a non-condensable gas is maximally distributed when the centrifugal chiller 1 is operated, the extra-heat transfer pipe bundle air bleeding pipe 32 is disposed in the upper space inside the shell container 21 in which the non-condensable gas is maximally distributed when the centrifugal chiller 1 is at a stop. Then, the air bleeding device 33 is capable of independently performing air bleeding of the non-condensable gas through each of the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32.
Therefore, air bleeding can be performed through the extra-heat transfer pipe bundle air bleeding pipe 32 positioned in the upper space inside the shell container 21 when the centrifugal chiller 1 stops being operated, and air bleeding can be performed through the intra-heat transfer pipe bundle air bleeding pipe 31 positioned inside the heat transfer pipe bundle 25 (25B) when the centrifugal chiller 1 is operated. Accordingly, regardless of an operational state of the centrifugal chiller 1, it is possible to effectively perform air bleeding in high concentration with respect to a non-condensable gas at all times, and it is possible to suppress deterioration in condensation efficiency caused by the incorporated non-condensable gas. Naturally, air bleeding may be performed through both the intra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundle air bleeding pipe 32 at the same time.
As described above, according to the condenser 3 of the present embodiment and the centrifugal chiller 1 provided with the condenser 3, in the centrifugal chiller using a low pressure refrigerant used at the maximum pressure of less than 0.2 MPaG, it is possible to effectively perform air bleeding in high concentration with respect to a non-condensable gas which has been incorporated into the low pressure refrigerant, and it is possible to suppress deterioration in condensation efficiency.
The present invention is not limited to only the configurations of the embodiment described above, and changes or modifications can be suitably added. An embodiment having such changes or modifications added thereto is also included in the scope of rights of the present invention.
For example, in the embodiment, one intra-heat transfer pipe bundle air bleeding pipe 31 and one extra-heat transfer pipe bundle air bleeding pipe 32 are provided, but there may be provided two or more each. In addition, in the embodiment, the intra-heat transfer pipe bundle air bleeding pipe 31 is installed inside the inbound pipe bundle 25B configuring an upper portion of the heat transfer pipe bundle 25, but it may be installed inside the outbound pipe bundle 25A configuring a lower portion of the heat transfer pipe bundle 25.

REFERENCE SIGNS LIST

1 CENTRIFUGAL CHILLER
2 TURBO COMPRESSOR
3 CONDENSER
4, 6 EXPANSION VALVE
7 EVAPORATOR
21 SHELL CONTAINER
22 REFRIGERANT INLET
23 REFRIGERANT OUTLET
25 HEAT TRANSFER PIPE BUNDLE
25A OUTBOUND PIPE BUNDLE
25B INBOUND PIPE BUNDLE
25 a HEAT TRANSFER PIPE
31 INTRA-HEAT TRANSFER PIPE BUNDLE AIR BLEEDING PIPE
31 a, 32 a NON-condensable GAS AIR BLEEDING HOLE
32 EXTRA-HEAT TRANSFER PIPE BUNDLE AIR BLEEDING PIPE
33 AIR BLEEDING DEVICE

Claims

1. A condenser comprising:

a shell container into which a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG is introduced;

a refrigerant inlet which is provided in an upper portion of the shell container;

a refrigerant outlet which is provided in a lower portion of the shell container;

a heat transfer pipe bundle in which a number of heat transfer pipes causing a cooling liquid to circulate therein are bundled and which extends inside the shell container;

an intra-heat transfer pipe bundle air bleeding pipe which is disposed in a central region of the heat transfer pipe bundle in a bundle diameter direction, which has a pipe shape parallel to an axial direction of the heat transfer pipe bundle, and in which a non-condensable gas air bleeding hole for performing air bleeding of a non-condensable gas mixed in the low pressure refrigerant is formed on a lower surface thereof; and

an air bleeding device which is connected to the intra-heat transfer pipe bundle air bleeding pipe and performs air bleeding of the non-condensable gas.

2. The condenser according to claim 1, further comprising:

an extra-heat transfer pipe bundle air bleeding pipe which is disposed in an upper space inside the shell container, in which a non-condensable gas air bleeding hole is formed on a lower surface thereof, and which is connected to the air bleeding device,

wherein the air bleeding device is capable of independently performing air bleeding of the non-condensable gas through each of the intra-heat transfer pipe bundle air bleeding pipe and the extra-heat transfer pipe bundle air bleeding pipe.

3. The condenser according to claim 1,

wherein the shell container has a cylindrical shape extending in a horizontal direction,

wherein the heat transfer pipe bundle includes an outbound pipe bundle which extends from one end to the other end in a longitudinal direction inside the shell container, and an inbound pipe bundle which communicates with the outbound pipe bundle at the other end in the longitudinal direction inside the shell container and returns from the other end to the one end in the longitudinal direction inside the shell container,

wherein the outbound pipe bundle is disposed below and the inbound pipe bundle is disposed above inside the shell container, and

wherein the intra-heat transfer pipe bundle air bleeding pipe is disposed in a central region of the inbound pipe bundle in the bundle diameter direction.

4. A centrifugal chiller comprising:

a turbo compressor which compresses a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG;

the condenser according to claim 1, which condenses the compressed low pressure refrigerant;

an expansion valve which expands the condensed low pressure refrigerant; and

an evaporator which evaporates the expanded low pressure refrigerant.

5. The condenser according to claim 2,

6. A centrifugal chiller comprising:

the condenser according to claim 2, which condenses the compressed low pressure refrigerant;

an expansion valve which expands the condensed low pressure refrigerant; and

an evaporator which evaporates the expanded low pressure refrigerant.

7. A centrifugal chiller comprising:

the condenser according to claim 3, which condenses the compressed low pressure refrigerant;

an expansion valve which expands the condensed low pressure refrigerant; and

an evaporator which evaporates the expanded low pressure refrigerant.