Falling film evaporator with heat recovery function

Abstract

The utility model discloses a falling film evaporator with heat recovery function, its evaporator main part is equipped with the evaporation heat exchange pipe connected with evaporator inlet and outlet water gap, its characterized in that, one end of evaporator main part is equipped with the heat recovery water inlet of connecting external heat source, and the other end is equipped with the heat recovery water outlet, and the upper side of evaporation heat exchange pipe in evaporator main part is equipped with the heat recovery heat exchange pipe connected with heat recovery water inlet and heat recovery water outlet, is equipped with temperature sensor and flow sensor on heat recovery water inlet, connects electric governing valve, and the evaporator outlet of being connected with compressor and the evaporator liquid inlet of being connected with condenser are equipped on evaporator main part, and the lower extreme of evaporator liquid inlet is connected with the liquid distribution device of being arranged in the upper side of evaporation heat exchange pipe. The utility model directly, fast control superheat degree, make it stable in the best set value, guarantee that compressor inhales is superheated gaseous refrigerant, prevent the liquid knock of compressor operation, and energy efficiency is high, has reduced maintenance cost, and operation is safer and more reliable.

Description

Technical Field

[0001] This utility model relates to a falling film evaporator with heat recovery function, belonging to the field of evaporator technology for air conditioning engineering. Background Technology

[0002] Currently, commonly used falling film evaporators for refrigeration cycles include evaporator heat exchange tubes, evaporator inlet, evaporator outlet, liquid inlet, and gas outlet. They lack heat recovery treatment. To prevent gas from entering the two-phase zone during compressor operation, the unit typically uses an electronic expansion valve to control the refrigerant vapor temperature at the evaporator outlet above its saturation temperature (usually set at a superheat of 5°C), ensuring complete vaporization of the liquid refrigerant within the evaporator. However, adjusting the suction superheat via an electronic expansion valve can lead to insufficient utilization of the heat exchange area, resulting in a decrease in evaporation temperature, an increase in temperature difference, a reduction in the unit's cooling and heating capacity, an increase in the compressor's compression ratio, and increased power consumption. This can negatively impact the compressor's operational safety, reliability, and lifespan.

[0003] If R245fa is used as the refrigerant in a refrigeration cycle under special operating conditions, when the refrigerant enters the compressor from the evaporator for compression, the required cooling capacity of the system is very small due to the low temperature environment. The refrigerant only undergoes normal evaporation and heat exchange at the heat exchange tubes of the evaporator. The heat exchange capacity of the evaporator is excessive, resulting in insufficient heat for the flowing liquid refrigerant to completely vaporize. The compressor does not draw in superheated gaseous refrigerant, but a mixture containing liquid refrigerant. This causes liquid slugging in the compressor, which endangers the operation of the entire system and reduces the service life of the compressor. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a falling film evaporator with heat recovery function.

[0005] The technical solution provided by this utility model is as follows: A falling film evaporator with heat recovery function includes an evaporator body, with an evaporator inlet and an evaporator outlet at both ends of the evaporator body, and an evaporation heat exchange tube connected to the evaporator inlet and the evaporator outlet inside the evaporator body. The evaporator body is characterized by having a heat recovery inlet at one end connected to an external heat source water source and a heat recovery outlet at the other end; a heat recovery heat exchange tube above the evaporation heat exchange tube inside the evaporator body, with both ends connected to the heat recovery inlet and the heat recovery outlet respectively; a temperature sensor and a flow sensor are provided on the heat recovery inlet, which is connected to an electric regulating valve; the evaporator body has an evaporator outlet connected to a compressor and an evaporator liquid inlet connected to a condenser; a liquid distribution device is connected to the lower end of the evaporator liquid inlet, and the liquid distribution device is positioned above the evaporation heat exchange tube.

[0006] Furthermore, the upper part of the evaporation heat exchange tube is connected to the evaporator body by a baffle plate with evenly distributed vent holes.

[0007] The beneficial effects of this utility model are: 1. This utility model is equipped with a regenerative heat exchange tube and a regenerative water inlet connected to an external heat source water. The heat source water enters the evaporator and undergoes secondary heat exchange with the refrigerant gas in the evaporator at the regenerative heat exchange tube. The introduction of actively controlled heat source water can accurately ensure that the refrigerant leaving the evaporator is a vapor with stable and sufficient superheat, providing the highest level of protection for the compressor.

[0008] 2. In traditional evaporators, to achieve a certain degree of superheat, a portion of the heat exchange area must be reserved specifically for steam superheating. The heat transfer efficiency of this portion is far lower than that of the liquid boiling heat exchange section. Using this invention, the superheating task is partially or entirely undertaken by the "heat source water." This means that the main heat exchange section of the evaporator (for refrigerant boiling) can focus more on phase change heat transfer, resulting in a more compact and efficient design.

[0009] 3. Superheat control becomes easier and more precise. Temperature and flow sensors installed at the regenerator inlet monitor in real time and automatically adjust the flow or temperature of the heat source water via an electric regulating valve based on the set superheat value. This allows for direct and rapid control of the superheat, stabilizing it at the optimal set value. This helps the system operate smoothly and avoids frequent compressor adjustments or starts / stops caused by superheat fluctuations.

[0010] This utility model has high safety performance, low maintenance cost, and high energy efficiency. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the internal structure of the present invention; Figure 3 This is a schematic diagram illustrating the usage state of this utility model.

[0012] In the diagram, 1. Evaporator body; 2. Regenerative heat exchange tube; 3. Evaporator outlet; 4. Evaporator inlet; 5. Evaporator heat exchange tube; 6. Baffle plate; 7. Liquid distribution device; 8. Regenerative water inlet; 9. Regenerative water outlet; 10. Evaporator inlet; 11. Evaporator outlet; 12. Condenser; 13. Adjustable flow valve; 14. Orifice plate; 15. Compressor; 16. Condenser inlet; 17. Condenser outlet; 18. Temperature sensor; 19. Flow sensor; 20. Electric regulating valve. Detailed Implementation

[0013] The preferred embodiment of this utility model will be described in detail below with reference to the accompanying drawings: like Figure 1 , Figure 2 As shown, a falling film evaporator with heat recovery function includes an evaporator body 1, which is a horizontal cylindrical body with support feet installed at both ends of the bottom. The left end of the evaporator body 1 has a heat recovery inlet 8 and an evaporator inlet 10, while the right end has a heat recovery outlet 9 and an evaporator outlet 11. A heat recovery heat exchange tube 2 is located in the upper part of the evaporator body 1, with both ends connected to the heat recovery inlet 8 and the heat recovery outlet 9, respectively. A temperature sensor 18 and a flow sensor 19 are installed on the heat recovery inlet 8, which is connected to an electric regulating valve 20. An evaporation heat exchange tube 5 is located in the lower middle part of the evaporator body 1, with both ends connected to the evaporator inlet 10 and the evaporator outlet 11, respectively. An air baffle 6 is welded between the upper part of the evaporation heat exchange tube 5 and the evaporator body 1, and the air baffle 6 has evenly distributed air vents. The top of the evaporator body 1 is provided with an evaporator outlet 3 and an evaporator liquid inlet 4. The lower end of the evaporator liquid inlet 4 is connected to a liquid distribution device 7, which is located above the evaporation heat exchange tube 5.

[0014] like Figure 3 As shown, when this utility model is in use, the evaporator outlet 11 is connected to the user's water inlet, the evaporator inlet 10 is connected to the user's return water, the regenerated water inlet 8 is connected to the external heat source water, the regenerated water outlet 9 is connected to the industrial water storage tank for recycling, the evaporator liquid inlet 4 is connected to the condenser 12 through the orifice plate 14 and the adjustable flow valve 13, and the evaporator air outlet 3 is connected to the suction port of the compressor 15.

[0015] User return water enters the evaporator heat exchange tube 5 of this invention, while external heat source water enters the regenerative heat exchange tube 2 of this invention through the regenerative water inlet 8. During unit operation, the compressor 15 first compresses the low-pressure refrigerant gas from the evaporator outlet 3 of this invention into a high-temperature, high-pressure refrigerant gas. This gas is then transported through the exhaust pipe into the condenser 12 for cooling and liquefaction into a high-pressure liquid refrigerant. It is then transported through the liquid circuit pipe, passing sequentially through the adjustable flow valve 13 and the orifice plate 14. Under the action of the adjustable flow valve 13 and the orifice plate 14, the high-pressure liquid refrigerant is throttled and depressurized, transforming into a low-pressure, low-temperature refrigerant. The low-temperature, low-pressure refrigerant then enters the evaporator inlet 4 of this invention. The liquid refrigerant is evenly distributed to the top of the evaporator heat exchange tube bundle 5 by the liquid distribution device 7. Under gravity, a thin liquid film forms along the inner wall of the tube, while simultaneously absorbing heat from the heat source inside the tube (usually water or process fluid) and partially evaporating. Finally, the gas-liquid mixture is separated at the bottom. To ensure that the refrigerant leaving the evaporator is a stable vapor with sufficient superheat, the separated refrigerant vapor passes through the baffle plate 6 to the regenerative heat exchange tube 2, where it undergoes secondary heat exchange. After the heat source water completes the heat exchange, it leaves the evaporator through the regenerative outlet 9. The unit automatically adjusts the flow rate or temperature of the regenerative heat source water in the regenerative heat exchange tube 2 via the electric regulating valve 20, which can directly and quickly control the superheat, stabilizing it at the optimal set value. This ensures that the compressor 15 draws in superheated gaseous refrigerant, preventing liquid slugging during compressor 15 operation, resulting in high energy efficiency, reduced maintenance costs, and safer and more reliable operation. After secondary heat exchange, the refrigerant gas has sufficient superheat and is transported from the evaporator outlet 3 through the suction pipe to connect with the compressor 15, thus circulating.

[0016] It should be understood that any parts not described in detail in this specification belong to the prior art. The above embodiments are merely descriptions of preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and improvements to the technical solutions of this utility model made by those skilled in the art without departing from the spirit of this utility model should fall within the protection scope defined by the claims of this utility model.

Claims

1. A falling film evaporator with heat recovery function, comprising an evaporator body, an evaporator inlet and an evaporator outlet respectively provided at both ends of the evaporator body, and an evaporation heat exchange tube connected to the evaporator inlet and the evaporator outlet inside the evaporator body, characterized in that, One end of the evaporator body is provided with a regenerative water inlet for connecting to an external heat source water, and the other end is provided with a regenerative water outlet. A regenerative heat exchange tube is provided above the evaporation heat exchange tube inside the evaporator body, and the two ends of the regenerative heat exchange tube are connected to the regenerative water inlet and the regenerative water outlet, respectively. A temperature sensor and a flow sensor are provided on the regenerative water inlet, and the regenerative water inlet is connected to an electric regulating valve. The evaporator body is provided with an evaporator gas outlet connected to the compressor and an evaporator liquid inlet connected to the condenser. The lower end of the evaporator liquid inlet is connected to a liquid distribution device, which is located above the evaporation heat exchange tube.

2. A falling film evaporator with heat recovery function according to claim 1, characterized in that... The upper part of the evaporation heat exchange tube is connected to the evaporator body by a baffle plate with evenly distributed vent holes.

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