Composite flash economizer, water chiller and operation method

Abstract

The application discloses a composite flash economizer, a water chilling unit and an operation method. The composite flash economizer is used for processing of refrigerant of the water chilling unit. The composite flash economizer comprises a flash tank body, a main liquid inlet pipeline, a main liquid outlet pipeline and a gas supplement outlet pipeline which is communicated with a gas inlet end of a compressor to supplement gas. A heat exchange pipeline is arranged in the flash tank body and is used for cooling saturated liquid refrigerant to form supercooled refrigerant. An outlet end of the heat exchange pipeline is communicated with an evaporator of the water chilling unit. Gaseous refrigerant generated by heat exchange directly enters the evaporator. The heat exchange pipeline is arranged in the flash tank body and exchanges heat with the saturated liquid refrigerant to form the supercooled liquid refrigerant. The application can reduce generation of flash gas, reduce the risk of containing liquid refrigerant in the compressor gas supplement and reduce the probability of liquid hammer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration and air conditioning, in particular to a composite flash economizer, a water chiller and an operation method. BACKGROUND

[0002] In the operation process of the water chiller, a plate heat exchanger or a flash tank is generally used as an economizer. When the plate heat exchanger is used as an economizer, a larger plate heat exchanger is often configured to make the high-pressure refrigerant reach the corresponding supercooling degree, and the pipeline connected in the refrigeration system is also more complex, which leads to a decrease in assembly efficiency and an increase in product production cost. When the flash tank is used as an economizer, the pipeline assembly is simple, the cost is lower, the system energy efficiency is improved, and the flash tank has a good application prospect.

[0003] The liquid in the existing flash tank is in a saturated state without supercooling degree. After entering the connecting pipeline between the flash tank and the secondary throttling device, flash gas is easily generated. After the flash gas is generated, it will affect the passage of the liquid refrigerant of the secondary throttling device. In severe cases, a large amount of liquid refrigerant can be accumulated in the flash tank, even the liquid-carrying gas phenomenon can be generated, and finally the compressor can be damaged, causing the unit to be unable to operate normally. SUMMARY

[0004] Technical purpose: in view of the above-mentioned deficiencies of the existing water chiller, the present application discloses a composite flash economizer, a water chiller and an operation method.

[0005] Technical scheme: in order to achieve the above technical purpose, the present application adopts the following technical scheme:

[0006] A composite flash economizer for processing of refrigerant of a water chiller, comprising a flash tank body, a main liquid inlet pipeline, a main liquid outlet pipeline and a gas supplement outlet pipeline connected with an air inlet end of a compressor for gas supplement on the flash tank body, a heat exchange pipe arranged in the flash tank body for cooling the transported saturated liquid refrigerant to form supercooled refrigerant, an outlet end of the heat exchange pipe being connected with an evaporator of the water chiller, and gaseous refrigerant generated by heat exchange directly entering the evaporator.

[0007] Preferably, an auxiliary throttling valve is arranged at an inlet end of the heat exchange pipe of the present application, and the auxiliary throttling valve is connected with the main liquid inlet pipeline to directly introduce the throttled liquid refrigerant into the heat exchange pipe.

[0008] Preferably, a main throttling valve is arranged on the main liquid inlet pipeline of the present application, and the connection point of the auxiliary throttling valve and the main liquid inlet pipeline is located on the front side of the main throttling valve.

[0009] The application discloses a water chilling unit using the composite flash economizer, comprising a refrigerant pipeline which is sequentially connected with an evaporator, a compressor and a condenser to form a circulation loop, the composite flash economizer is arranged between the condenser and the evaporator, a main liquid inlet pipeline is connected with a refrigerant outlet of the evaporator, a main liquid outlet pipeline is connected with a liquid inlet of the evaporator, an auxiliary liquid pipeline is arranged on the main liquid inlet pipeline at the front side of a main throttling valve, and the auxiliary liquid pipeline is connected with the main throttling valve.

[0010] Preferably, a secondary main throttling valve is arranged on the main liquid outlet pipeline of the application.

[0011] The application also provides an operation method based on the water chilling unit, low-temperature and low-pressure gas refrigerant is compressed into high-temperature and high-pressure gas refrigerant in the compressor, the high-temperature and high-pressure gas refrigerant enters the condenser, the high-temperature and high-pressure gas refrigerant is condensed into high-temperature and high-pressure liquid refrigerant in the condenser, the high-temperature and high-pressure liquid refrigerant is throttled by the main throttling valve from the main liquid inlet pipeline to form medium-temperature and medium-pressure gas-liquid mixed refrigerant and enters the composite flash economizer, gas-liquid separation is performed in the composite flash economizer to form saturated liquid refrigerant and saturated gas refrigerant, the saturated gas refrigerant enters the compressor from the gas supplement outlet pipeline, the liquid refrigerant is cooled by the heat exchange pipe in the composite flash economizer to form supercooled liquid refrigerant and is then transported to the evaporator, low-temperature and low-pressure gas refrigerant is formed after heat exchange in the evaporator and is then sucked into the compressor, compression is performed again to form a refrigerant circulation.

[0012] Preferably, the refrigerant in the heat exchange pipe of the composite flash economizer of the application is introduced from the main liquid inlet pipeline through the auxiliary liquid pipeline, the high-temperature and high-pressure liquid refrigerant is throttled by the auxiliary throttling valve on the auxiliary liquid pipeline to form low-temperature and low-pressure gas-liquid mixed refrigerant, the low-temperature and low-pressure gas-liquid mixed refrigerant absorbs the heat of the saturated liquid refrigerant to form gaseous refrigerant which enters the evaporator.

[0013] Advantages: the composite flash economizer, the water chilling unit and the operation method provided by the application have the following advantages:

[0014] 1. The heat exchange pipe is arranged in the flash tank body, heat exchange is performed between the heat exchange pipe and the saturated liquid refrigerant to form supercooled liquid refrigerant, the generation of flash gas can be reduced, the risk of liquid refrigerant in the compressor gas supplement can be reduced, and the probability of liquid hammer can be reduced.

[0015] 2. The heat exchange pipe is connected with the main liquid inlet pipeline through the auxiliary throttling valve, the opening degree of the auxiliary throttling valve can be adjusted to change the refrigerant flow entering the heat exchange pipe, and the supercooling degree of the refrigerant of the water chilling unit can be controlled.

[0016] 3. The gaseous refrigerant generated by the heat exchange pipe can ensure the normal pressure of the evaporator when the refrigerant supply of the evaporator is insufficient, the unit can be normally operated, and the service life of the unit can be prolonged. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 This is a structural diagram of the composite flash evaporator of the present invention;

[0019] Figure 2 This is a structural diagram of the chiller unit of the present invention;

[0020] Among them, 1-flash tank, 2-main liquid inlet pipeline, 3-main liquid outlet pipeline, 4-gas replenishment outlet pipeline, 5-heat exchanger pipe, 6-evaporator, 7-auxiliary throttle valve, 8-main throttle valve, 9-compressor, 10-condenser, 11-auxiliary liquid pipeline, 12-secondary main throttle valve. Detailed Implementation

[0021] Reference will now be made in detail to embodiments of the present disclosure, one or more of which are set forth herein. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. Rather, the following description provides convenient illustrations for implementing exemplary embodiments of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0022] like Figure 1 As shown, this invention discloses a composite flash economizer for treating refrigerant in a chiller unit. It includes a flash tank 1, a main liquid inlet pipe 2, a main liquid outlet pipe 3, and a supplementary gas outlet pipe 4 connected to the compressor inlet for supplementary gas supply. A heat exchange tube 5 is installed inside the flash tank 1 to cool the transported saturated liquid refrigerant to form a subcooled refrigerant. The outlet end of the heat exchange tube 5 is connected to the evaporator 6 of the chiller unit, and the gaseous refrigerant generated during heat exchange directly enters the evaporator 6.

[0023] The heat exchange tube 5 allows for subcooling of the liquid refrigerant, reducing the generation of flash gas and ensuring smooth entry of the refrigerant into the evaporator. It also prevents refrigerant flow obstruction, which could lead to liquid carrying into the compressor, thus protecting the compressor and maintaining the operation of the chiller unit. An auxiliary throttling valve 7 is installed at the inlet of the heat exchange tube 5, connected to the main liquid inlet pipe 2. This valve directly throttles the liquid refrigerant before introducing it into the heat exchange tube 5. Adjusting the opening of the auxiliary throttling valve 7 changes the degree of subcooling. Furthermore, controlling the refrigerant flow rate into the heat exchange tube 5 replenishes the pressure in the evaporator, ensuring the chiller unit continues to operate even when the evaporator pressure is insufficient.

[0024] The main throttle valve 8 is arranged on the main liquid inlet pipeline 2, and the connection point of the auxiliary throttle valve 7 and the main liquid inlet pipeline 2 is located on the front side of the main throttle valve 8, so that the temperature difference between the refrigerant in the heat exchange pipe and the refrigerant entering the flash tank is increased, and the supercooling heat exchange effect is improved.

[0025] As shown in Figure 2 The application discloses a water chiller using the composite flash economizer, which comprises a refrigerant pipeline, an evaporator 6, a compressor 9 and a condenser 10 which are sequentially connected to form a circulation loop, the composite flash economizer is arranged between the condenser 10 and the evaporator 6, a main liquid inlet pipeline 2 is connected to a refrigerant outlet of the evaporator 6, a main liquid outlet pipeline 3 is connected to a liquid inlet of the evaporator 6, an auxiliary liquid pipeline 11 is arranged on the main liquid inlet pipeline 2 on the front side of a main throttle valve 8, and the auxiliary liquid pipeline 11 is connected to an auxiliary throttle valve 7; and a secondary main throttle valve 12 is arranged on the main liquid outlet pipeline 3 to adjust the amount of refrigerant entering the evaporator.

[0026] Meanwhile, the application also provides an operation method based on the water chiller, low-temperature and low-pressure gas refrigerant is compressed into high-temperature and high-pressure gas refrigerant in the compressor, the high-temperature and high-pressure gas refrigerant enters the condenser, the high-temperature and high-pressure gas refrigerant is condensed into high-temperature and high-pressure liquid refrigerant in the condenser, the high-temperature and high-pressure liquid refrigerant is throttled by the main throttle valve after passing through the main liquid inlet pipeline to form medium-temperature and medium-pressure gas-liquid mixed refrigerant and enters the composite flash economizer, the gas-liquid separation is performed in the composite flash economizer to form saturated liquid refrigerant and saturated gas refrigerant, the saturated gas refrigerant enters the compressor from the gas supplement outlet pipe, the liquid refrigerant is cooled by the heat exchange pipe in the composite flash economizer to form supercooled liquid refrigerant and is then transported to the evaporator, the low-temperature and low-pressure gas refrigerant is formed after heat exchange in the evaporator and is then sucked into the compressor to be compressed again, and the refrigerant circulation is formed.

[0027] The refrigerant in the heat exchange pipe of the composite flash economizer is introduced from the main liquid inlet pipeline through the auxiliary liquid pipeline, the high-temperature and high-pressure liquid refrigerant is throttled by the auxiliary throttle valve on the auxiliary liquid pipeline to form low-temperature and low-pressure gas-liquid mixed refrigerant, the low-temperature and low-pressure gas-liquid mixed refrigerant absorbs the heat of the saturated liquid refrigerant to form gaseous refrigerant which enters the evaporator, the cooling circuit of the heat exchange pipe is not needed to be arranged separately, the supercooling heat exchange of the liquid refrigerant is directly realized by using the refrigerant of the water chiller itself, the structure of the water chiller can be simplified, and the gaseous refrigerant generated by heat exchange can be used to supplement the pressure of the evaporator.

Claims

1. A composite flash economizer for treating refrigerant in a chiller unit, characterized in that, The system includes a flash tank (1), which has a main liquid inlet pipe (2), a main liquid outlet pipe (3), and a supplementary gas outlet pipe (4) connected to the compressor inlet for supplementary gas supply. A heat exchange tube (5) is installed inside the flash tank (1) to cool the saturated liquid refrigerant being transported to form a subcooled refrigerant. The outlet end of the heat exchange tube (5) is connected to the evaporator (6) of the chiller unit. The gaseous refrigerant generated by the heat exchange of the refrigerant in the heat exchange tube (5) directly enters the evaporator (6). An auxiliary throttling valve (7) is provided at the inlet end of the heat exchange tube (5). The auxiliary throttling valve (7) is connected to the main liquid inlet pipe (2) to directly introduce liquid refrigerant into the heat exchange tube (5) after throttling. A main throttle valve (8) is installed on the main inlet pipeline (2), and the connection point between the auxiliary throttle valve (7) and the main inlet pipeline (2) is located in front of the main throttle valve (8). High-temperature and high-pressure liquid refrigerant is throttled by the main throttle valve after entering the main liquid inlet pipeline to form a medium-temperature and medium-pressure gas-liquid mixture refrigerant, which then enters the composite flash economizer. The liquid refrigerant is cooled by the heat exchange tubes in the composite flash economizer to form a subcooled liquid refrigerant, which is then transported to the evaporator. After heat exchange in the evaporator, it forms a low-temperature and low-pressure gaseous refrigerant, which is then drawn into the compressor.

2. A chiller unit using the composite flash economizer as described in claim 1, characterized in that, The refrigerant pipeline is connected in sequence to form a circulation loop, including an evaporator (6), a compressor (9), and a condenser (10). A compound flash economizer is set between the condenser (10) and the evaporator (6). The main liquid inlet pipeline (2) is connected to the refrigerant outlet of the condenser (10), and the main liquid outlet pipeline (3) is connected to the liquid inlet of the evaporator (6). An auxiliary liquid pipeline (11) is set in front of the main throttle valve (8) of the main liquid inlet pipeline (2), and the auxiliary liquid pipeline (11) is connected to the auxiliary throttle valve (7).

3. A chiller unit according to claim 2, characterized in that, A secondary main throttle valve (12) is installed on the main liquid outlet pipeline (3).

4. A method for operating a chiller unit according to any one of claims 2-3, characterized in that, Low-temperature, low-pressure gaseous refrigerant is compressed in the compressor to become high-temperature, high-pressure gaseous refrigerant. This high-temperature, high-pressure gaseous refrigerant enters the condenser, where it is condensed into a high-temperature, high-pressure liquid refrigerant. This liquid refrigerant then flows from the main inlet pipe through the main throttle valve to form a medium-temperature, medium-pressure gas-liquid mixture, which enters the composite flash economizer. In the composite flash economizer, gas-liquid separation occurs, forming saturated liquid refrigerant and saturated gaseous refrigerant. The saturated gaseous refrigerant enters the compressor from the make-up gas outlet pipe. The liquid refrigerant is cooled by the heat exchange tubes in the composite flash economizer to form a subcooled liquid refrigerant, which is then transported to the evaporator. After heat exchange in the evaporator, it forms a low-temperature, low-pressure gaseous refrigerant, which is then drawn into the compressor for further compression, thus forming a refrigerant cycle.

5. The method for operating a chiller unit according to claim 4, characterized in that, The refrigerant in the heat exchange tube of the composite flash economizer is introduced from the main liquid inlet pipe through the auxiliary liquid pipe. The high-temperature and high-pressure liquid refrigerant is throttled by the auxiliary throttling valve on the auxiliary liquid pipe to form a low-temperature and low-pressure gas-liquid mixture refrigerant. The low-temperature and low-pressure gas-liquid mixture refrigerant absorbs the heat of the saturated liquid refrigerant and forms a gaseous refrigerant that enters the evaporator.

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