Dry evaporator with a regenerator and refrigeration system

Abstract

The application provides a dry evaporator with a regenerator and a refrigeration system, which comprises a cylinder body, end plates arranged at both ends of the cylinder body, heat exchange pipe bundles fixed between the end plates, baffle plates arranged on the heat exchange pipe bundles, a water inlet and a water outlet arranged on the cylinder body, a liquid distribution pipe box arranged at the bottom of the cylinder body, a gas collecting pipe box arranged at the top of the cylinder body, a regenerator arranged in the gas collecting pipe box, and a gas outlet arranged on the upper portion of the gas collecting pipe box; the liquid outlet end of the regenerator is communicated with the liquid distribution pipe box, liquid refrigerant is introduced into the liquid distribution pipe box, the pressure drop of the gas side is reduced, the evaporation temperature of the dry evaporator without the regenerator can be increased by 1-2 DEG C, the energy efficiency is increased by about 5%, and the gasification load of the regenerator is reduced due to the use of the injection system, so that the unevaporated liquid refrigerant can return to the evaporator.

Description

Technical Field

[0001] The present invention relates to the field of heat exchangers, in particular to a dry evaporator with a heat regenerator and a refrigeration system. Background Art

[0002] A refrigeration system includes a condenser and an evaporator. The evaporator is particularly challenging to design, requiring consideration of not only the heat exchange tube configuration but also the heat exchanger flow and appropriate refrigerant distribution. Common heat exchangers include dry evaporators, plate heat exchangers, flooded evaporators, and falling film evaporators.

[0003] A dry evaporator utilizes a circular cylinder with heat exchange tubes installed within it. Refrigerant evaporates within these tubes. To prevent liquid from entering the compressor's intake air, the dry evaporator's outlet must be superheated. This results in localized heat transfer errors within the dry evaporator, leading to low evaporation temperatures and low unit energy efficiency. This typically requires an external regenerator, also known as a gas-to-liquid heat exchanger. In Freon refrigeration systems, this heat exchange device uses refrigerant vapor from the evaporator to cool the high-pressure liquid before it enters the evaporator, resulting in subcooling of the refrigerant liquid and superheating of the vapor. However, external regenerators can suffer from poor heat transfer in the superheated area. Summary of the Invention

[0004] To address the technical issues of uneven distribution and poor heat exchange in the overheating area of ​​a dry evaporator, the present invention proposes a dry evaporator with a regenerator, comprising a cylinder, end plates disposed at both ends of the cylinder, a heat exchange tube bundle fixed between the end plates, baffles arranged on the heat exchange tube bundle, a water inlet and a water outlet provided on the cylinder, a liquid distribution pipe box disposed at the bottom of the cylinder, and a gas collecting pipe box disposed at the top, a regenerator disposed in the gas collecting pipe box, and an air outlet disposed at the top of the gas collecting pipe box.

[0005] A liquid outlet pipe is provided on the side wall of the gas collecting pipe box between the regenerator and the end plate, and the liquid outlet pipe is connected to the liquid distribution pipe box to introduce the unevaporated liquid refrigerant into the liquid distribution pipe box;

[0006] The liquid outlet end of the regenerator is communicated with the liquid distribution pipe box, and the liquid refrigerant is passed into the liquid distribution pipe box.

[0007] Preferably, an ejector is provided at the inlet of the liquid distribution pipe box, and the drainage port of the ejector is connected to the liquid outlet pipe.

[0008] Preferably, the liquid outlet end of the regenerator is communicated with the inlet of the ejector and is connected to an expansion valve.

[0009] Preferably, the regenerator includes a first header and a second header, the first header is provided with a liquid inlet, a plurality of thin tube bundles are connected between the first header and the second header, and the liquid outlet is connected to the second header.

[0010] Preferably, the thin tube bundle is provided with a plurality of fins.

[0011] Preferably, the cylinder is square and the regenerator is square.

[0012] Preferably, the water inlet is located on the cylinder near one side of the gas collecting pipe box, and the water outlet is located on the cylinder near one side of the liquid collecting pipe box.

[0013] Preferably, the expansion valve is controlled by superheat, and the superheat is the superheat of the air outlet of the dry evaporator, and the superheat is 5-10°C.

[0014] Preferably, the superheat of the expansion valve is controlled by PI, with a P value of 20 to 60 and an I value of 1000 to 2000.

[0015] A refrigeration system for a dry evaporator comprises a compressor, a condenser, and a dry evaporator as described above, wherein the condenser outlet is connected to the liquid inlet end of the regenerator of the dry evaporator, and the air outlet on the gas collecting box is connected to the air intake of the compressor.

[0016] The dry evaporator and refrigeration system with a regenerator proposed in this invention have the following beneficial effects: Its gas-side pressure drop is lower than that of existing systems with external regenerators, increasing the evaporation temperature by 1-2°C and energy efficiency by approximately 5% compared to dry evaporators without regenerators. Compared to systems with external regenerators, the suction pressure drop is reduced by approximately 25 kPa, improving energy efficiency by 2%. The use of an ejector system allows unevaporated liquid refrigerant to return to the evaporator, reducing the vaporization load on the regenerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0018] Figure 1 This is a front internal schematic diagram of the present invention;

[0019] Figure 2 It is a side schematic diagram of the present invention;

[0020] Figure 3 is a schematic diagram of a regenerator of the present invention;

[0021] Among them, 1. Cylinder; 2. End plate; 3. Air outlet; 4. Heat exchange tube bundle; 5. Baffle; 6. Water inlet; 7. Water outlet; 8. Liquid distribution pipe box; 9. Gas collecting pipe box; 10. Regenerator; 11. Liquid outlet pipe; 12. Ejector; 13. Liquid outlet end; 14. Expansion valve; 15. Liquid inlet end; 16. First header; 17. Second header; 18. Thin tube bundle; 19. Fin. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0023] like Figure 1 As shown, the present invention proposes a dry evaporator with a regenerator, including a cylinder 1, end plates 2 are provided at both ends of the cylinder 1. In this embodiment, the cylinder 1 is set to be square, including four side plates in the front, back, left and right directions. The square structure reduces the manufacturing difficulty and reduces the cost. A heat exchange tube bundle 4 is fixed between the end plates 2, and the heat exchange tube bundle 4 is connected to the gas collecting pipe box 9 and the liquid distribution pipe box 8 on both sides of the end plate 2. Baffles 5 are arranged on the heat exchange tube bundle 4, and a water inlet 6 and a water outlet 7 are provided on the cylinder 1. A liquid distribution pipe box 8 is provided at the bottom of the cylinder 1, and a gas collecting pipe box 9 is provided at the top. A regenerator 10 is provided in the gas collecting pipe box 9, and an air outlet 3 is provided on the upper part of the gas collecting pipe box 9.

[0024] The regenerator 10 is square to accommodate the structure of the cylinder 1. A liquid outlet pipe 11 is provided on the sidewall of the manifold box 9 between the regenerator 10 and the end plate 2. This outlet pipe 11 communicates with the liquid distribution box 8. In this embodiment, an ejector 12 is provided at the inlet of the liquid distribution box 8 to increase the force for liquid refrigerant to enter the liquid distribution box 8. The liquid outlet 13 of the regenerator 10 communicates with the inlet of the ejector 12. For better control, an expansion valve 114 is provided between the liquid outlet 13 of the regenerator 10 and the inlet of the ejector. This expansion valve 14 utilizes superheat control, which is the superheat of the dry evaporator's gas outlet 3, ranging from 5°C to 10°C, preferably 6°C. The superheat of the expansion valve 14 can be controlled using a PI control, with a P value of 20 to 60 and an I value of 1000 to 2000. The drainage port of the ejector 12 is communicated with the liquid outlet pipe 11. The ejector 12 can allow the unevaporated liquid refrigerant to return to the evaporator, thereby reducing the vaporization load of the regenerator.

[0025] During use, the water inlet 6 on the cylinder 1 is located at the lower part, and the water outlet 7 is located at the upper part. Water is taken in by the water inlet 6 and water is discharged by the water outlet 7. At the same time, the refrigerant is taken in by the liquid inlet end 15 of the regenerator 10, the liquid refrigerant circulates in the thin tube bundle 18, and the gas refrigerant generated by heat exchange circulates outside the thin tube bundle 18 for heat exchange between gas and liquid. The refrigerant passes through the liquid distribution and evenly enters the heat exchange tube from bottom to top. After evaporation, it flows into the gas collecting box 9. The regenerator 10 is set in the gas collecting box 9. The evaporated air flow passes through the regenerator 10 and flows out from the air port. A liquid outlet is set at the lower end of the gas collecting box 9. The unevaporated refrigerant flows down along the liquid outlet and the pipeline to the evaporator inlet, and is injected into the liquid distribution box 8 of the evaporator by the high-speed airflow. By setting up a regenerator 10 inside the evaporator, the refrigerant gas is directly reheated, and the pressure drop on the gas side is lower than the pressure drop of the external regenerator, which can improve the utilization rate of the refrigerant. At the same time, the unevaporated refrigerant can be directly injected into the liquid distribution pipe box 8 to increase efficiency. The system evaporation temperature can be increased by 1 to 2°C, and the cooling capacity is increased by 5%. At the same time, the manufacturing cost of the regenerator is greatly reduced.

[0026] The regenerator 10 includes a first header 16 and a second header 17. The first header 16 is provided with a liquid inlet 15. A plurality of thin tube bundles 18 are connected between the first header 16 and the second header 17. The liquid outlet 13 is connected to the second header 17. The thin tube bundles 18 are provided with a plurality of fins 19. The thin tube bundles 18 are made of stainless steel and have a diameter of about 2 mm. Multiple rows of thin tube bundles 18 are arranged between the first header 16 and the second header 17, which can reduce the amount of refrigerant injected. The Reynolds coefficient outside the heat exchange tube is high, which can facilitate heat exchange.

[0027] A refrigeration system for a dry evaporator includes a compressor, a condenser, and a dry evaporator as described above, wherein the condenser outlet is connected to the liquid inlet end 15 of the regenerator 10 of the dry evaporator, and the air outlet 3 on the gas collecting box 9 is connected to the air intake of the compressor.

Claims

1. A dry evaporator with a regenerator, comprising a cylinder, end plates provided at both ends of the cylinder, a heat exchange tube bundle fixed between the end plates, baffles arranged on the heat exchange tube bundle, a water inlet and a water outlet provided on the cylinder, characterized in that: The bottom of the cylinder is provided with a liquid distribution pipe box, the top is provided with a gas collecting pipe box, the gas collecting pipe box is provided with a regenerator, and the upper part of the gas collecting pipe box is provided with an air outlet; The regenerator includes a first header and a second header, the first header is provided with a liquid inlet, a plurality of thin tube bundles are connected between the first header and the second header, and the liquid outlet is connected to the second header; A liquid outlet pipe is provided on the side wall of the gas collecting pipe box between the regenerator and the end plate, and an ejector is provided at the inlet of the liquid distribution pipe box. The drainage port of the ejector is connected to the liquid outlet pipe to introduce the unevaporated liquid refrigerant into the liquid distribution pipe box. The liquid outlet end of the regenerator is connected to the inlet of the ejector and is connected to an expansion valve. The expansion valve adopts superheat control. The superheat is the superheat of the air outlet of the dry evaporator, and the superheat is 5~10℃.

2. The dry evaporator with a regenerator according to claim 1, characterized in that: The thin tube bundle is provided with a plurality of fins.

3. The dry evaporator with a regenerator according to claim 1, characterized in that: The cylinder is square, and the regenerator is square.

4. The dry evaporator with a regenerator according to claim 1, characterized in that: The water inlet is located on the cylinder near one side of the gas collecting pipe box, and the water outlet is located on the cylinder near one side of the liquid distribution pipe box.

5. The dry evaporator with a regenerator according to claim 1, characterized in that: The expansion valve superheat is controlled by PI, with P value ranging from 20 to 60 and I value ranging from 1000 to 2000.

6. A refrigeration system of a dry evaporator, characterized in that: It comprises a compressor, a condenser, and a dry evaporator according to any one of claims 1 to 5, wherein the condenser outlet is connected to the liquid inlet end of the regenerator of the dry evaporator, and the air outlet on the gas collecting box is connected to the air intake of the compressor.

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