Composite flash evaporation economizer, water chilling unit and operation method

Abstract

The invention discloses a composite flash evaporation economizer, a water chilling unit and an operation method.The composite flash evaporation economizer is used for treating a refrigerant of the water chilling unit and comprises a flash evaporation tank, and a main liquid inlet pipeline, a main liquid outlet pipeline and an air supply outlet pipe which are arranged on the flash evaporation tank and communicate with the air inlet end of a compressor for air supply; a heat exchange pipe used for cooling a conveyed saturated liquid refrigerant to form a supercooled refrigerant is arranged in a flash tank body, the outlet end of the heat exchange pipe is communicated with an evaporator of a water chilling unit, and a gaseous refrigerant generated by heat exchange directly enters the evaporator; the heat exchange pipe is arranged in the flash tank body and exchanges heat with the saturated liquid refrigerant to form the supercooled liquid refrigerant, so that the generation of flash gas can be reduced, the risk that the liquid refrigerant is contained in the supplemented gas of the compressor is reduced, and the probability of liquid impact is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration and air conditioning, and in particular to a compound flash economizer, a chiller and an operating method. Background Art

[0002] During the operation of the chiller, plate heat exchangers or flash tanks are generally used as economizers. Using plate heat exchangers as economizers: To achieve the corresponding degree of supercooling of high-pressure refrigerant, the plate heat exchangers are often configured to be larger, and the pipes connected in the refrigeration system are also more complicated, resulting in reduced assembly efficiency and increased product production costs. Using flash tanks as economizers: Pipeline assembly is simple, cost is low, and system energy efficiency is improved. It has good application prospects.

[0003] The liquid in the existing flash drum is in a saturated state without supercooling. It is easy to generate flash gas after entering the connecting pipeline between the flash drum and the secondary throttling device. After the flash gas is generated, it will affect the passage of the liquid refrigerant in the secondary throttling device. In severe cases, it will cause a large amount of liquid refrigerant to accumulate in the flash drum, and even produce gas-liquid phenomenon, which may eventually damage the compressor and cause the unit to fail to operate normally. Summary of the invention

[0004] Technical purpose: In view of the above-mentioned deficiencies of the existing chillers, the present invention discloses a composite flash economizer, a chiller and an operating method.

[0005] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution: A composite flash economizer is used for treating refrigerant of a chiller, comprising a flash tank body, a main liquid inlet pipeline, a main liquid outlet pipeline and an air replenishment outlet pipe connected to the air inlet end of a compressor for replenishing air on the flash tank body, a heat exchange tube for cooling the transported saturated liquid refrigerant to form a supercooled refrigerant is arranged in the flash tank body, the outlet end of the heat exchange tube is connected to the evaporator of the chiller, and the gaseous refrigerant generated by heat exchange directly enters the evaporator.

[0006] Preferably, an auxiliary throttle valve is provided at the inlet end of the heat exchange tube of the present invention, and the auxiliary throttle valve is connected with the main liquid inlet pipeline through the auxiliary throttle valve, so that the liquid refrigerant is directly introduced into the heat exchange tube after throttling.

[0007] Preferably, a main throttle valve is arranged on the main liquid inlet pipeline of the present invention, and the connection point between the auxiliary throttle valve and the main liquid inlet pipeline is located in front of the main throttle valve.

[0008] The present invention discloses a chiller, which uses the above-mentioned compound flash economizer, including an evaporator, a compressor and a condenser, which are connected in sequence by refrigerant pipelines to form a circulation loop. The compound flash economizer is arranged between the condenser and the evaporator, the main liquid inlet pipeline is connected to the refrigerant outlet of the evaporator, the main liquid outlet pipeline is connected to the liquid inlet of the evaporator, and the main liquid inlet pipeline is provided with an auxiliary liquid pipeline on the front side of the main throttle valve, and the auxiliary liquid pipeline is connected to the auxiliary throttle valve.

[0009] Preferably, a secondary main throttle valve is provided on the main liquid outlet pipeline of the present invention.

[0010] The present invention also provides an operation method based on the above-mentioned chiller, wherein the low-temperature and low-pressure gas refrigerant is compressed in the compressor to become a high-temperature and high-pressure gas refrigerant, and the high-temperature and high-pressure gas refrigerant enters the condenser, and the high-temperature and high-pressure gas refrigerant is condensed into a high-temperature and high-pressure liquid refrigerant in the condenser, and the high-temperature and high-pressure liquid refrigerant is throttled from the main liquid inlet pipeline through the main throttle valve to form a medium-temperature and medium-pressure gas-liquid mixed refrigerant and enters the compound flash economizer, and gas-liquid separation is performed in the compound flash economizer to form a saturated liquid refrigerant and a saturated gas refrigerant, and the saturated gas refrigerant enters the compressor from the gas replenishment outlet pipe, and the liquid refrigerant is cooled by the heat exchange tube in the compound flash economizer to form a supercooled liquid refrigerant, which is then transported to the evaporator, and the low-temperature and low-pressure gas refrigerant is formed after heat exchange in the evaporator and is sucked into the compressor, and compressed again to form a refrigerant cycle.

[0011] Preferably, the refrigerant in the heat exchange tube of the composite flash economizer of the present invention is introduced from the main liquid inlet pipeline through the auxiliary liquid pipeline, and the high-temperature and high-pressure liquid refrigerant is throttled by the auxiliary throttling valve on the auxiliary liquid pipeline to form a 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 a gaseous refrigerant and enter the evaporator.

[0012] Beneficial effects: The composite flash economizer, chiller and operation method provided by the present invention have the following beneficial effects: 1. The present invention arranges a heat exchange tube in the flash tank body to exchange heat with the saturated liquid refrigerant to form a supercooled liquid refrigerant, which can reduce the generation of flash gas, reduce the risk of liquid refrigerant contained in the compressor replenishment air, and reduce the probability of liquid hammer.

[0013] 2. The heat exchange tube of the present invention is connected to the main liquid inlet pipeline through an auxiliary throttle valve. The opening of the auxiliary throttle valve can be adjusted to change the refrigerant flow entering the heat exchange tube, thereby controlling the subcooling of the refrigerant in the chiller.

[0014] 3. The gas refrigerant generated by the heat exchange tube of the present invention can ensure the normal evaporator pressure when the evaporator refrigerant supply is insufficient, so that the unit can operate normally and extend the service life of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0016] Figure 1 This is a structural diagram of the composite flash economizer of the present invention; Figure 2 This is a structural diagram of the chiller of the present invention; Among them, 1-flash tank body, 2-main liquid inlet pipeline, 3-main liquid outlet pipeline, 4-air supply outlet pipe, 5-heat exchange tube, 6-evaporator, 7-auxiliary throttle valve, 8-main throttle valve, 9-compressor, 10-condenser, 11-auxiliary liquid pipeline, 12-secondary main throttle valve. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are set forth herein below. Each embodiment and example is provided by way of explanation of the apparatus, composition and materials of the present disclosure, rather than limitation. On the contrary, the following description provides a convenient illustration of an exemplary embodiment for implementing the present disclosure. In fact, it will be clear to those skilled in the art that various modifications and variations may be made in the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0018] like Figure 1 As shown, the present invention discloses a composite flash economizer for treating refrigerant of a chiller, comprising a flash tank body 1, a main liquid inlet pipeline 2, a main liquid outlet pipeline 3 and an air replenishment outlet pipe 4 connected to an air inlet end of a compressor for replenishing air on the flash tank body 1, a heat exchange tube 5 for cooling the transported saturated liquid refrigerant to form a supercooled refrigerant is arranged in the flash tank body 1, the outlet end of the heat exchange tube 5 is connected to an evaporator 6 of the chiller, and the gaseous refrigerant generated by heat exchange directly enters the evaporator 6.

[0019] The heat exchange tube 5 is provided to supercool the liquid refrigerant, thereby reducing the generation of flash gas and allowing the refrigerant to smoothly enter the evaporator. It also avoids the phenomenon of compressor air replenishment with liquid due to obstruction of refrigerant flow, thereby protecting the compressor and maintaining the operation of the chiller. An auxiliary throttle valve 7 is provided at the inlet end of the heat exchange tube 5, which is connected to the main liquid inlet pipeline 2 through the auxiliary throttle valve 7. The liquid refrigerant is directly introduced into the heat exchange tube 5 after throttling. The opening of the auxiliary throttle valve 7 can be adjusted to change the degree of supercooling. At the same time, the evaporator pressure can be supplemented by controlling the refrigerant flow entering the heat exchange tube 5. When the evaporator pressure is insufficient, the chiller can still be kept running.

[0020] A main throttle valve 8 is provided on the main liquid inlet pipeline 2 of the present invention, and the connection point between the auxiliary throttle valve 7 and the main liquid inlet pipeline 2 is located in front of the main throttle valve 8, thereby increasing the temperature difference between the refrigerant in the heat exchange tube and the refrigerant entering the flash tank body, thereby improving the supercooling heat exchange effect.

[0021] like Figure 2 As shown, the present invention discloses a chiller using the above-mentioned compound flash economizer, including an evaporator 6, a compressor 9 and a condenser 10, which are connected in sequence by refrigerant pipelines to form a circulation loop. The compound flash economizer is arranged between the condenser 10 and the evaporator 6, the main liquid inlet pipeline 2 is connected to the refrigerant outlet of the evaporator 6, the main liquid outlet pipeline 3 is connected to the liquid inlet of the evaporator 6, the main liquid inlet pipeline 2 is provided with an auxiliary liquid pipeline 11 on the front side of the main throttle valve 8, and the auxiliary liquid pipeline 11 is connected to the auxiliary throttle valve 7; the main liquid outlet pipeline 3 is provided with a secondary main throttle valve 12 to adjust the amount of refrigerant entering the evaporator.

[0022] At the same time, the present invention also provides an operation method based on the above-mentioned chiller, wherein the low-temperature and low-pressure gas refrigerant is compressed in the compressor to become a high-temperature and high-pressure gas refrigerant, and the high-temperature and high-pressure gas refrigerant enters the condenser, and the high-temperature and high-pressure gas refrigerant is condensed into a high-temperature and high-pressure liquid refrigerant in the condenser, and the high-temperature and high-pressure liquid refrigerant is throttled from the main liquid inlet pipeline through the main throttle valve to form a medium-temperature and medium-pressure gas-liquid mixed refrigerant and enters the compound flash economizer, and gas-liquid separation is performed in the compound flash economizer to form saturated liquid refrigerant and saturated gas refrigerant, and the saturated gas refrigerant enters the compressor from the air supply outlet pipe, and the liquid refrigerant is cooled by the heat exchange tube in the compound flash economizer to form a supercooled liquid refrigerant, which is then transported to the evaporator, and the low-temperature and low-pressure gas refrigerant is formed after heat exchange in the evaporator and is sucked into the compressor, and compressed again to form a refrigerant cycle.

[0023] The refrigerant in the heat exchange tube of the composite flash economizer of the present invention 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 a 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 a gaseous refrigerant and enter the evaporator. There is no need to set up a cooling circuit for the heat exchange tube separately. The refrigerant of the chiller itself is directly used to realize the supercooling heat exchange of the liquid refrigerant, which can simplify the structure of the chiller. At the same time, the gas refrigerant generated by heat exchange can also be used to supplement the pressure of the evaporator.

Claims

1. A composite flash economizer for treating refrigerant in a chiller, characterized in that: The flash tank (1) comprises a main liquid inlet pipeline (2), a main liquid outlet pipeline (3) and a gas replenishment outlet pipe (4) connected to the air inlet end of the compressor for replenishing gas. A heat exchange pipe (5) for cooling the transported saturated liquid refrigerant to form a supercooled refrigerant is arranged in the flash tank (1). The outlet end of the heat exchange pipe (5) is connected to the evaporator (6) of the chiller, and the gaseous refrigerant generated by heat exchange directly enters the evaporator (6).

2. A composite flash economizer according to claim 1, characterized in that: An auxiliary circuit throttle valve (7) is provided at the inlet end of the heat exchange tube (5), which is connected to the main liquid inlet pipeline (2) through the auxiliary circuit throttle valve (7) so that the liquid refrigerant is directly introduced into the heat exchange tube (5) after throttling.

3. A composite flash economizer according to claim 2, characterized in that: A main throttle valve (8) is provided on the main liquid inlet pipeline (2), and a connection point between the auxiliary throttle valve (7) and the main liquid inlet pipeline (2) is located in front of the main throttle valve (8).

4. A chiller using the compound flash economizer according to any one of claims 1 to 3, characterized in that: The invention comprises an evaporator (6), a compressor (9) and a condenser (10) which are connected in sequence by refrigerant pipelines to form a circulation loop; a composite flash economizer is arranged between the condenser (10) and the evaporator (6); a main liquid inlet pipeline (2) is connected to the refrigerant outlet of the evaporator (6); a main liquid outlet pipeline (3) is connected to the liquid inlet of the evaporator (6); an auxiliary liquid pipeline (11) is arranged on the front side 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).

5. A water chiller according to claim 4, characterized in that: A secondary main throttle valve (12) is provided on the main liquid outlet pipeline (3).

6. A method for operating a chiller according to any one of claims 4 to 5, characterized in that: After being compressed in the compressor, the low-temperature and low-pressure gas refrigerant becomes a high-temperature and high-pressure gas refrigerant, which enters the condenser. In the condenser, the high-temperature and high-pressure gas refrigerant is condensed into a high-temperature and high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant is throttled from the main liquid inlet pipeline through the main throttle valve to form a medium-temperature and medium-pressure gas-liquid mixed refrigerant and enters the compound flash economizer. In the compound flash economizer, gas-liquid separation is performed to form saturated liquid refrigerant and saturated gas refrigerant. The saturated gas refrigerant enters the compressor from the air supply outlet pipe, and the liquid refrigerant is cooled by the heat exchange tube in the compound flash economizer to form a supercooled liquid refrigerant, which is then transported to the evaporator. After heat exchange in the evaporator, the low-temperature and low-pressure gas refrigerant is sucked into the compressor and compressed again to form a refrigerant cycle.

7. A chiller operation method according to claim 6, characterized in that: The refrigerant in the heat exchange tube of the compound 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 a 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 a gaseous refrigerant and enter the evaporator.

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