Gas suspension cryogenic heat pump evaporator and method of use

Abstract

This invention discloses an air-suspension low-temperature heat pump evaporation device and its usage method, including an evaporator. The lower part of the evaporator forms a heat exchange cycle with a hot-side heat exchanger, and the top of the evaporator is connected to a cold-side heat exchanger, which is connected to a distilled water system. The outlet of the hot-side heat exchanger is connected to the inlet of the cold-side heat exchanger via a flash tank, and the outlet of the cold-side heat exchanger is connected to the inlet of the hot-side heat exchanger via an air-suspension compressor to form a cycle. The outlet of the flash tank is also connected to the motors of the frequency converter and the air-suspension compressor. In actual use, the connection of the hot-side heat exchanger, the cold-side heat exchanger, the flash tank, and the air-suspension compressor allows the steam heat to be recovered and utilized, effectively improving the heat utilization rate and helping to reduce operating energy consumption. Furthermore, the flash tank ensures a stable liquid intake for the cooling needs of the motor and the frequency converter, while also ensuring the overall heat exchange capacity of the system and avoiding the impact of sudden load drops on the compressor, thereby greatly improving and ensuring the operating energy efficiency of the compressor and the whole system.

Description

Technical Field

[0001] This invention relates to the field of low-temperature evaporation equipment technology, and in particular to an air-suspension low-temperature heat pump evaporation device and its usage method. Background Technology

[0002] Conventional low-temperature evaporators mostly use single-effect evaporation mode, resulting in significant waste of waste heat and low heat utilization rate. Furthermore, heat pumps often use oil-lubricated compressors, which can easily lead to difficulties in lubricating oil return, potentially causing compressor wear or even damage and affecting the long-term stable operation of the system.

[0003] In existing technologies, some heat pumps also use air-suspension compressors, which utilize gas dynamic pressure bearing technology. The rotor does not contact the bearing during operation, which can solve the problem of difficult oil return in conventional oil-bearing compressors. It has the advantages of being oil-free, having low wear, and high energy efficiency. However, it still has limitations in actual use: the concentration of the raw liquid changes greatly in the early, middle and late stages, the heat pump load fluctuates drastically, evaporation is difficult in the later stage, and sudden load drops can easily cause the air-suspension compressor to surge and stop. The heat exchanger liquid level fluctuates greatly, the cooling refrigerant liquid extraction is unstable, and the motor / inverter high temperature alarm is caused. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a structurally sound air-suspension low-temperature heat pump evaporator and its usage method, thereby effectively improving heat utilization and helping to reduce operating energy consumption. At the same time, it can effectively ensure the overall heat exchange capacity of the system, avoid the impact of sudden load drops on the compressor, and greatly improve and guarantee the operating energy efficiency of the compressor and the entire system.

[0005] The technical solution adopted in this invention is as follows: An air-suspension low-temperature heat pump evaporation device includes an evaporator, with a heat exchange loop formed between the lower part of the evaporator and a hot-side heat exchanger, and the top of the evaporator connected to a cold-side heat exchanger, which is connected to a distilled water system; the outlet of the hot-side heat exchanger is connected to the inlet of the cold-side heat exchanger via a flash tank, and the outlet of the cold-side heat exchanger is connected to the inlet of the hot-side heat exchanger via an air-suspension compressor to form a loop; the outlet of the flash tank is also connected to a frequency converter and the motor of the air-suspension compressor.

[0006] As a further improvement to the above technical solution: The flash tank is equipped with a coil, which forms a heat exchange cycle with the circulating water system.

[0007] The circulating water system is equipped with control valves on its pipelines; a level sensor is installed inside the flash tank.

[0008] The air supply port of the flash tank is connected to the air supply port of the air suspension compressor.

[0009] The evaporator inlet is connected to a raw liquid inlet system, which is connected to the evaporator and then to a vacuum system.

[0010] The distilled water system discharges distilled water while simultaneously expelling non-condensable gases via a vacuum system.

[0011] A control valve is installed on the pipeline between the hot-side heat exchanger and the flash tank, and a control valve is installed on the pipeline between the flash tank and the cold-side heat exchanger.

[0012] A circulating pump is installed on the heat exchange cycle between the evaporator and the hot-side heat exchanger.

[0013] A method of using the aforementioned air-suspension low-temperature heat pump evaporator includes the following steps: The raw liquid in the evaporator is heated by the hot-side heat exchanger to generate steam, which enters the cold-side heat exchanger for condensation and is discharged through the distillation water system. In the hot-side heat exchanger, the refrigerant passes sequentially through the flash tank, the cold-side heat exchanger, and the air-suspension compressor, and then flows back to the hot-side heat exchanger after forming a heat medium. The liquid level in the flash tank is stabilized. The frequency converter and the air suspension compressor motor draw coolant from the flash tank and return it to the hot-side heat exchanger. The refrigerant gas in the flash tank returns to the air suspension compressor's gas inlet.

[0014] As a further improvement to the above technical solution: When the concentration of the original liquid in the evaporator increases and the evaporation rate decreases, the circulating water system that forms a thermal cycle with the flash tank is turned on to increase the heat exchange and maintain the subcooling of the refrigerant.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention, through the interconnection of a hot-side heat exchanger, a cold-side heat exchanger, a flash tank, and an air-suspension compressor, enables the recovery and utilization of steam heat, effectively improving heat utilization and helping to reduce operating energy consumption. Furthermore, the flash tank ensures a stable supply of liquid for cooling the motor and frequency converter, while also guaranteeing the overall heat exchange capacity of the system and avoiding the impact of sudden load drops on the compressor, thereby greatly improving and ensuring the operating energy efficiency of the compressor and the entire system. The present invention also includes the following advantages: By setting up liquid level control in the flash tank, the liquid level is stabilized, ensuring the stability and reliability of the cooling liquid intake from the flash tank for the motor and frequency converter, which helps to ensure the cooling effect and effectively solves the high temperature alarm situation of the motor and frequency converter. When the concentration of the raw liquid increases and the evaporation rate decreases, the heat exchange cycle between the flash tank and the circulating water system can be started. The circulating water system will then cool the refrigerant inside the flash tank, thereby effectively ensuring the subcooling of the refrigerant, increasing the heat exchange capacity, improving the system's heat exchange capacity, effectively alleviating the problems of large load fluctuations and evaporation difficulties, and ensuring the smooth and uninterrupted operation of the compressor. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the present invention.

[0017] The system includes: 1. Raw material inlet system; 2. Evaporator; 3. Circulating pump; 4. Air suspension compressor; 5. Hot-side heat exchanger; 6. Flash tank; 7. Circulating water system; 8. Cold-side heat exchanger; 9. Frequency converter; 10. Vacuum system; 11. Distilled water system. Detailed Implementation

[0018] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0019] like Figure 1 As shown, an air-suspension low-temperature heat pump evaporation device of this embodiment includes an evaporator 2. The lower part of the evaporator 2 forms a heat exchange cycle with the hot-side heat exchanger 5. The top of the evaporator 2 is connected to the cold-side heat exchanger 8, which is connected to the distilled water system 11. The outlet of the hot-side heat exchanger 5 is connected to the inlet of the cold-side heat exchanger 8 via a flash tank 6. The outlet of the cold-side heat exchanger 8 is connected to the inlet of the hot-side heat exchanger 5 via an air-suspension compressor 4 to form a cycle. The outlet of the flash tank 6 is also connected to the frequency converter 9 and the motor of the air-suspension compressor 4.

[0020] In this embodiment, the air-suspension compressor 4 is used as the power core of the low-temperature heat pump evaporation device. Combined with the hot-side heat exchanger 5 and the cold-side heat exchanger 8, it forms an air-suspension heat pump system, achieving oil-free, highly reliable, and highly energy-efficient operation of the device. The raw liquid in the evaporator 2 is heated, and the generated steam is drawn out from the top steam outlet and enters the cold-side heat exchanger 8 for condensation. After condensation, it is discharged through the distillation water system 11. Through the connection of the hot-side heat exchanger 5, the cold-side heat exchanger 8, the flash tank 6, and the air-suspension compressor 4, the heat of the steam can be recovered and utilized by heat exchange at the cold-side heat exchanger 8, effectively improving the heat utilization rate and helping to reduce operating energy consumption.

[0021] In this embodiment, the flash tank 6 can ensure a stable supply of liquid to meet the cooling needs of the motor and frequency converter, providing stable and reliable cooling for the motor and frequency converter, while ensuring the overall heat exchange capacity of the system and avoiding the impact of sudden load drops on the compressor.

[0022] The heat pump evaporator in this embodiment does not require external steam or cooling water, effectively reducing operation and maintenance costs.

[0023] The flash tank 6 is equipped with a coil, which forms a heat exchange cycle with the circulating water system 7; thus, the flash tank 6 has a heat exchange function and can perform heat exchange when needed.

[0024] In practical use, when the concentration of the raw liquid increases and the evaporation rate decreases, the heat exchange cycle between the flash tank 6 and the circulating water system 7 can be started. The circulating water system 7 will then cool the refrigerant inside the flash tank 6, thereby effectively ensuring the subcooling of the refrigerant, increasing the heat exchange capacity, improving the system's heat exchange capacity, effectively alleviating the problems of large load fluctuations and evaporation difficulties, and ensuring the smooth and uninterrupted operation of the compressor.

[0025] Control valves are installed on the pipelines of the circulating water system 7; a liquid level sensor is installed inside the flash tank 6.

[0026] In this embodiment, by setting a liquid level control in the flash tank 6, the liquid level is stabilized, ensuring the stability and reliability of the motor and frequency converter's cooling liquid intake from the flash tank 6, which helps to ensure the cooling effect and effectively solves the high temperature alarm situation of the motor and frequency converter.

[0027] The air supply port of the flash tank 6 is connected to the air supply port of the air suspension compressor 4.

[0028] In practical use, the refrigerant gas in the flash tank 6 can be returned to the gas injection port of the air suspension compressor 4 to increase the refrigerant flow and improve the energy efficiency of the compressor and the whole machine.

[0029] The inlet of evaporator 2 is connected to raw liquid inlet system 1, and raw liquid inlet system 1 is connected to evaporator 2 to vacuum system.

[0030] In this embodiment, by setting up a vacuum system, the device operates under negative pressure, and the boiling point of the raw liquid drops to a preset low temperature range, thereby suppressing scaling and corrosion phenomena that are prone to occur at high temperatures, and effectively reducing scaling of the liquid and corrosion of the equipment.

[0031] Distilled water is discharged from the distilled water system 11, while non-condensable gas is discharged through the vacuum system 10.

[0032] A control valve is installed on the pipeline between the hot-side heat exchanger 5 and the flash tank 6, and a control valve is installed on the pipeline between the flash tank 6 and the cold-side heat exchanger 8.

[0033] A circulating pump 3 is installed on the heat exchange loop between the evaporator 2 and the hot-side heat exchanger 5.

[0034] In this embodiment, a heat exchange structure such as a coil can be installed inside the evaporator 2. The heat exchange structure forms a heat exchange cycle with the hot-side heat exchanger 5 via the circulation pump 3. The inside of the heat exchange structure is high-temperature and high-pressure refrigerant gas from the hot-side heat exchanger 5, and the outside of the heat exchange structure is the raw liquid heated in the evaporator 2.

[0035] The air-suspension low-temperature heat pump evaporator in this embodiment operates as follows: At startup, the vacuum system is first activated to draw the pressure in the feed liquid system 1 and the evaporator 2 to the set vacuum level to lower the boiling point of the feed liquid. Then, the feed liquid to be treated is injected into the evaporator 2 through the feed liquid system 1 to the working level. During the evaporation process, the air suspension heat pump system is activated, the air suspension compressor 4 starts working, and the circulation pump 3 is started. The air suspension compressor 4 compresses the refrigerant into a high-temperature, high-pressure gas, which is then transported to the evaporator 2 through the hot-side heat exchanger 5. In the evaporator 2, the high-temperature, high-pressure gas releases its latent heat of condensation, heating the feed liquid in the evaporator 2 to boiling point and generating steam. The steam is discharged from the top of the evaporator 2 and enters the cold-side heat exchanger 8 for heat exchange and condensation, and is discharged in conjunction with the distillation water system. The high-temperature, high-pressure gaseous refrigerant, after heat exchange in the evaporator 2, flows back to the hot-side heat exchanger 5 through the circulation pump 3. After passing through the flash tank 6, it undergoes heat exchange and temperature rise in the cold-side heat exchanger 8, and is then compressed by the air suspension compressor 4 and returned to the hot-side heat exchanger 5 to form a cycle.

[0036] During the evaporation process, the flash tank 6 provides a stable supply of cooling refrigerant to the motors of the frequency converter 9 and the air suspension compressor 4.

[0037] As evaporation proceeds, the concentration of the raw liquid in the evaporator 2 gradually increases. When it reaches the preset value, the circulating water system 7 connected to the flash tank 6 is activated to increase and ensure the heat exchange and subcooling of the refrigerant, thereby ensuring the heat exchange capacity of the system.

[0038] This embodiment also provides a method for using an air-suspension low-temperature heat pump evaporator, including the following steps: Step 1: The raw liquid in the evaporator 2 is heated by the hot-side heat exchanger 5 to generate steam, which enters the cold-side heat exchanger 8 for condensation and is discharged through the distilled water system 11. Step 2: The refrigerant in the hot-side heat exchanger 5 passes through the flash tank 6, the cold-side heat exchanger 8, and the air suspension compressor 4 in sequence, and then flows back to the hot-side heat exchanger 5 after forming a heat medium. Step 3: Stabilize the liquid level in flash tank 6. The frequency converter 9 and the motor of air suspension compressor 4 take coolant from flash tank 6 and return it to the hot side heat exchanger 5. The refrigerant gas in flash tank 6 returns to the air supply port of air suspension compressor 4.

[0039] Step 4: When the concentration of the original liquid in the evaporator 2 increases and the evaporation rate decreases, the circulating water system 7, which forms a heat cycle with the flash tank 6, is turned on to increase the heat exchange and maintain the subcooling of the refrigerant.

[0040] This invention effectively improves heat utilization, helps reduce operating energy consumption, effectively ensures the overall heat exchange capacity of the system, and avoids the impact of sudden load drops on the compressor, thus greatly improving and ensuring the operating energy efficiency of the compressor and the whole system.

[0041] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0042] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. An air-suspended cryogenic heat pump evaporator apparatus, characterized by: The system includes an evaporator (2), the lower part of which forms a heat exchange cycle with the hot-side heat exchanger (5), the top of which is connected to the cold-side heat exchanger (8), and the cold-side heat exchanger (8) is connected to the distilled water system (11); the outlet of the hot-side heat exchanger (5) is connected to the inlet of the cold-side heat exchanger (8) via a flash tank (6), and the outlet of the cold-side heat exchanger (8) is connected to the inlet of the hot-side heat exchanger (5) via an air-suspension compressor (4) to form a cycle; the outlet of the flash tank (6) is also connected to the frequency converter (9) and the motor of the air-suspension compressor (4).

2. An airborne cryogenic heat pump evaporator as claimed in claim 1, wherein: The flash tank (6) is equipped with a coil inside, and the coil and the circulating water system (7) form a heat exchange cycle.

3. An airborne cryogenic heat pump evaporator as claimed in claim 2, wherein: The circulating water system (7) is equipped with a control valve on its pipeline; the flash tank (6) is equipped with a liquid level sensor.

4. An airborne cryogenic heat pump evaporator as claimed in claim 1, wherein: The air inlet of the flash tank (6) is connected to the air inlet of the air suspension compressor (4).

5. An airborne cryogenic heat pump evaporator as claimed in claim 1, wherein: the evaporator is a Stirling cycle engine. 5 The inlet of the evaporator (2) is connected to the raw liquid inlet system (1), and the raw liquid inlet system (1) is connected to the vacuum system of the evaporator (2).

6. An airborne cryogenic heat pump evaporator as claimed in claim 1, wherein: The distilled water system (11) discharges distilled water while simultaneously expelling non-condensable gases through the vacuum system (10).

7. An airborne cryogenic heat pump evaporator as claimed in claim 1, wherein: A control valve is installed on the pipeline between the hot-side heat exchanger (5) and the flash tank (6), and a control valve is installed on the pipeline between the flash tank (6) and the cold-side heat exchanger (8).

8. The air-suspension low-temperature heat pump evaporator as described in claim 1, characterized in that: A circulating pump (3) is installed on the heat exchange loop between the evaporator (2) and the hot-side heat exchanger (5).

9. A method of using the air-suspension low-temperature heat pump evaporator as described in claim 1, characterized in that: Includes the following steps: The raw liquid in the evaporator (2) is heated by the hot-side heat exchanger (5) to generate steam which enters the cold-side heat exchanger (8) for condensation and is discharged through the distilled water system (11); In the hot-side heat exchanger (5), the refrigerant passes through the flash tank (6), the cold-side heat exchanger (8), and the air suspension compressor (4) in sequence, and then flows back to the hot-side heat exchanger (5) after forming a heat medium. The liquid level in the flash tank (6) is stabilized. The inverter (9) and the motor of the air suspension compressor (4) take coolant from the flash tank (6) and return it to the heat exchanger (5) on the hot side. The refrigerant gas in the flash tank (6) returns to the air supply port of the air suspension compressor (4).

10. The method of using the air-suspension low-temperature heat pump evaporation device as described in claim 9, characterized in that: When the concentration of the original liquid in the evaporator (2) increases and the evaporation rate decreases, the circulating water system (7) that forms a heat cycle with the flash tank (6) is turned on to increase the heat exchange and maintain the subcooling of the refrigerant.

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