A pipe-box integrated heat pump seawater desalination system and a working method thereof

Abstract

The application discloses a pipe-box integrated heat pump seawater desalination system and a working method thereof, and belongs to the field of seawater desalination and energy power. The system mainly comprises a pipe box, a water pump, an inlet valve, a gas distributor, an inlet valve, a fan, a drainage valve and a heat pump subsystem; the pipe box further comprises a water storage tank, a water collecting tank, a bend pipe, a ventilation pipe, a water collecting pipe and an air outlet; the heat pump subsystem comprises a condenser, an expansion valve, a compressor and an evaporator; the condenser is arranged in the water storage tank; the evaporator is arranged in the water collecting pipe and located above the water collecting tank. The condenser of the heat pump system is arranged in the water storage tank of the pipe box, the evaporator of the heat pump system is arranged in the water collecting pipe of the pipe box, and the original water storage tank of the humidification and dehumidification seawater desalination system is integrated into the pipe box, so that the pipe-box integrated design of the heat pump humidification and dehumidification seawater desalination system is realized, the system has high energy, and the heat loss of fluid flow is small. The system has the advantages of compact structure, small heat loss and high thermal efficiency.

Description

Technical Field

[0001] This invention designs a tubular integrated heat pump seawater desalination system and its working method, belonging to the field of seawater desalination and thermal cycle. Background Technology

[0002] With rapid socio-economic development, the global freshwater crisis is becoming increasingly severe, and energy resources are dwindling. Therefore, the rational utilization of freshwater and energy has become one of the global challenges in the new century. Seawater desalination remains one of the most promising solutions to the freshwater crisis, while heat pump systems are recognized as highly efficient waste heat recovery technologies. Combining these two technologies represents a potential solution to the aforementioned crisis. By recovering waste heat from humid air or concentrated seawater, patents CN202110101839.4 "Cooling and Dehumidifying Seawater Desalination System with Heat Pump Circulation and its Working Method" and CN201811416715.X "Air-Heated Heat Pump Humidification and Dehumidification Seawater Desalination System and its Working Method" disclose two possible solutions for the coupled development of heat pump and humidification / dehumidification seawater desalination systems. In these solutions, the heat pump system is coupled to the humidification / dehumidification seawater desalination system through a double-row condenser or evaporator. This greatly increases the space occupied by the original humidification / dehumidification seawater desalination system, and the long pipeline layout also increases the system's heat loss. Considering the high efficiency and miniaturization requirements of the humidification / dehumidification seawater desalination system, how to integrate the advantages of heat pump waste heat recovery and utilization in a smaller space is a problem that urgently needs to be solved. Summary of the Invention

[0003] This invention addresses the problems of large footprint and low heat transfer efficiency in existing heat pump humidification and dehumidification seawater desalination systems by proposing a compact, high-efficiency integrated tube-and-box heat pump seawater desalination system and its operating method.

[0004] An integrated heat pump seawater desalination system with a tube box, characterized in that: the system mainly includes a tube box, a water pump, an inlet valve, a gas distributor, an air inlet valve, a fan, a drain valve, and a heat pump subsystem;

[0005] The aforementioned pipe box includes a water storage tank, a water collection tank, a bend, a ventilation pipe, a water collection pipe, and an air outlet; the aforementioned pipe box adopts an integrated structure and is distributed in a right-angle shape; the aforementioned water collection tank is composed of a groove on the lower wall of the water collection pipe and is located at the lower edge of the water collection pipe;

[0006] The aforementioned gas distributor is fixed to the bottom of the water storage tank;

[0007] The aforementioned heat pump subsystem includes a condenser, an expansion valve, a compressor, and an evaporator; the condenser is placed inside a water storage tank; the evaporator is placed inside a water collection pipe, located above the water collection tank.

[0008] The outlet of the aforementioned water pump is connected to the inlet of the inlet valve, and the outlet of the inlet valve is connected to the water-side inlet of the water storage tank.

[0009] The outlet of the above-mentioned fan is connected to the inlet of the intake valve, the outlet of the intake valve is connected to the inlet of the gas side of the water storage tank, the outlet of the gas side of the water storage tank is connected to the gas distributor, the upper outlet of the water storage tank is connected to the elbow pipe, the elbow pipe is connected to the ventilation pipe, the ventilation pipe is connected to the water collecting pipe, the water collecting pipe is connected to the air outlet, and the air outlet is communicated with the atmosphere;

[0010] The outlet of the above-mentioned water collecting tank is connected to the inlet of the drain valve, and the outlet of the drain valve is communicated with the atmosphere;

[0011] The above-mentioned heat pump subsystem is connected by an internal cycle. The outlet of the condenser is connected to the inlet of the expansion valve, the outlet of the expansion valve is connected to the inlet of the evaporator, the outlet of the evaporator is connected to the inlet of the compressor, and the outlet of the compressor is connected to the inlet of the condenser.

[0012] The described integrated heat pump seawater desalination system with tube boxes is characterized in that: to improve the heat exchange efficiency and reduce heat loss, the condenser and the evaporator are respectively placed in seawater and an air stream, so the above-mentioned condenser and evaporator are preferably composed of single-row serpentine heat exchange tubes.

[0013] The described integrated heat pump seawater desalination system with tube boxes is characterized in that: to ensure the orderly progress of the humidification and dehumidification seawater desalination process and prevent seawater and fresh water from mixing, the following relationships are satisfied for the height H1 of the above-mentioned water storage tank, the liquid level height H2 of the water storage tank, and the tube layout height H3 of the condenser: 0.7H1 < H2 < 0.85H1 and 0.6H2 ≤ H3 ≤ 0.8H2.

[0014] The working method of the described integrated heat pump seawater desalination system with tube boxes is characterized by including the following working processes: First, seawater is driven by a water pump and enters the bottom water storage tank of the tube box through the inlet valve. The liquid level H2 in the water storage tank is controlled by the inlet valve and cannot be higher than 0.85 times the height H1 of the water storage tank, nor can it be lower than 0.7 times the height H1 of the water storage tank;

[0015] Then, the wet air is sent to the intake valve by the fan, and then enters the gas distributor in the water storage tank from the bottom, is evenly distributed in the seawater, passes through the condenser for heating and seawater humidification from bottom to top, and is discharged from the upper outlet of the water storage tank. The high-temperature and high-humidity wet air flows through the elbow pipe and the ventilation pipe in sequence and enters the water collecting pipe, where it is cooled and dehumidified by the evaporator. The water vapor in the wet air condenses to obtain fresh water, which is collected in the water collecting tank, and then the wet air is discharged from the air outlet of the system;

[0016] The refrigerant in the heat pump subsystem circulates. The liquid refrigerant first exchanges heat with the wet air in the evaporator, evaporates into gaseous refrigerant by absorbing the sensible heat of the wet air cooling and the latent heat of the water vapor condensation, is discharged from the outlet of the evaporator and then enters the compressor for compression, is heated and pressurized and then enters the condenser, is cooled and condensed by the seawater in the water storage tank, and then is depressurized by the expansion valve and enters the evaporator for cyclic evaporation;

[0017] Finally, the fresh water collected in the collection tank can be discharged through the drain valve.

[0018] The beneficial effects of this invention are as follows: Addressing the problems of large footprint and low heat transfer efficiency in existing heat pump humidification and dehumidification seawater desalination systems, this invention utilizes enhanced heat transfer theory. The condenser of the heat pump system is placed in the water storage tank of the pipe box (equivalent to the humidifier in the humidification and dehumidification seawater desalination system), and the evaporator is placed in the water collection pipe of the pipe box (equivalent to the dehumidifier in the humidification and dehumidification seawater desalination system). Furthermore, the original water storage tank of the humidification and dehumidification seawater desalination system is integrated into the pipe box, achieving an integrated pipe-box design for the heat pump humidification and dehumidification seawater desalination system. This fully utilizes the system's energy and reduces heat loss during fluid flow. The system has a compact structure, low heat loss, and high thermal efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a tubular integrated heat pump seawater desalination system.

[0020] The labels in the diagram are as follows: 1. Pipe box, 2. Water storage tank, 3. Condenser, 4. Water pump, 5. Inlet valve, 6. Gas distributor, 7. Inlet valve, 8. Fan, 9. Expansion valve, 10. Compressor, 11. Drain valve, 12. Water collection tank, 13. Evaporator, 14. Bend, 15. Ventilation duct, 16. Water collection pipe, 17. Air outlet, A. Heat pump subsystem. Detailed Implementation

[0021] Figure 1 This invention relates to an integrated heat pump seawater desalination system with a tubular casing. This invention effectively reduces heat loss from fluid flow and the space required for equipment. See below for reference. Figure 1 Describe the specific implementation process of the system.

[0022] First, seawater is driven by water pump 4 and enters the bottom water storage tank 2 of pipe box 1 through water inlet valve 5. The liquid level H2 in water storage tank 2 is controlled by water inlet valve 5 and cannot be higher than 0.85 times the height H1 of water storage tank 2, nor lower than 0.7 times the height H1 of water storage tank 2.

[0023] Then, the humid air is sent to the intake valve 7 by the fan 8, and then enters the gas distributor 6 in the water storage tank 2 from the bottom. It is evenly distributed in the seawater. After being heated by the condenser 3 and humidified by the seawater from bottom to top, it is discharged from the outlet at the top of the water storage tank 2. The high temperature and high humidity humid air flows through the bend pipe 14 and the ventilation pipe 15 in sequence and enters the water collection pipe 16. In the water collection pipe 16, it is cooled and dehumidified by the evaporator 13. The water vapor in the humid air is condensed to obtain fresh water, which is collected in the water collection tank 12. Then the humid air is discharged from the system through the air outlet 17.

[0024] In the heat pump subsystem A, the refrigerant circulates. The liquid refrigerant first exchanges heat with the humid air in the evaporator 13. It evaporates into gaseous refrigerant by absorbing the sensible heat of the humid air and the latent heat of condensation of water vapor. After being discharged from the outlet of the evaporator 13, it enters the compressor 10 for compression. After being heated and pressurized, it enters the condenser 3. After being cooled and condensed by seawater in the water storage tank 2, it is depressurized through the expansion valve 9 and then enters the evaporator 13 for circulation and evaporation.

[0025] Finally, the fresh water collected in the water collection tank 12 can be discharged through the drain valve 11.

Claims

1. A pipe-and-box integrated heat pump seawater desalination system, characterized in that: The system mainly includes a pipe box (1), a water pump (4), an inlet valve (5), a gas distributor (6), an air inlet valve (7), a fan (8), a drain valve (11), and a heat pump subsystem (A); The aforementioned pipe box (1) includes a water storage tank (2), a water collection tank (12), a bend (14), a ventilation pipe (15), a water collection pipe (16), and an air outlet (17); the aforementioned pipe box (1) adopts an integrated structure and is distributed in a right-angle shape; the aforementioned water collection tank (12) is composed of a groove on the lower wall of the water collection pipe (16) and is located at the lower edge of the water collection pipe (16); The gas distributor (6) is fixed to the bottom of the water storage tank (2); The heat pump subsystem (A) includes a condenser (3), an expansion valve (9), a compressor (10), and an evaporator (13); the condenser (3) is placed in a water storage tank (2); the evaporator (13) is placed in a water collection pipe (16) and located above the water collection tank (12); The outlet of the above-mentioned water pump (4) is connected to the inlet of the water inlet valve (5), and the outlet of the water inlet valve (5) is connected to the water-side inlet of the water storage tank (2); The outlet of the above-mentioned fan (8) is connected to the inlet of the air inlet valve (7), the outlet of the air inlet valve (7) is connected to the air-side inlet of the water storage tank (2), the air-side outlet of the water storage tank (2) is connected to the gas distributor (6), the outlet above the water storage tank (2) is connected to the bend pipe (14), the bend pipe (14) is connected to the ventilation pipe (15), the ventilation pipe (15) is connected to the water collection pipe (16), the water collection pipe (16) is connected to the air outlet (17), and the air outlet (17) is connected to the atmosphere. The outlet of the above-mentioned water collection tank (12) is connected to the inlet of the drain valve (11), and the outlet of the drain valve (11) is open to the atmosphere; The above heat pump subsystem (A) is connected by an internal circulation. The outlet of the condenser (3) is connected to the inlet of the expansion valve (9), the outlet of the expansion valve (9) is connected to the inlet of the evaporator (13), the outlet of the evaporator (13) is connected to the inlet of the compressor (10), and the outlet of the compressor (10) is connected to the inlet of the condenser (3). The height H1 of the above-mentioned water storage tank (2), the liquid level height H2 of the water storage tank (2) and the pipe laying height H3 of the condenser (3) satisfy the following relationship: 0.7H1 < H2 < 0.85H1 and 0.6H2≤H3≤0.8H2; Seawater is driven by a water pump (4) and enters the bottom water storage tank (2) of the pipe box (1) through the water inlet valve (5). The liquid level H2 in the water storage tank (2) is controlled by the water inlet valve (5) and cannot be higher than 0.85 times the height H1 of the water storage tank (2) or lower than 0.7 times the height H1 of the water storage tank (2). Humid air is sent to the intake valve (7) by the fan (8), and then enters the gas distributor (6) in the water storage tank (2) from the bottom. It is evenly distributed in the seawater. After being heated by the condenser (3) from bottom to top and humidified by the seawater, it is discharged from the outlet above the water storage tank (2). The hot and humid air flows through the bend pipe (14) and the ventilation pipe (15) in sequence and enters the water collection pipe (16). In the water collection pipe (16), it is cooled and dehumidified by the evaporator (13). The water vapor in the humid air is condensed to obtain fresh water, which is collected in the water collection tank (12). Then the humid air is discharged from the system through the air outlet (17). The refrigerant in the heat pump subsystem (A) circulates. The liquid refrigerant first exchanges heat with the humid air in the evaporator (13). It evaporates into gaseous refrigerant by absorbing the sensible heat of the humid air and the latent heat of condensation of water vapor. After being discharged from the outlet of the evaporator (13), it enters the compressor (10) for compression. After being heated and pressurized, it enters the condenser (3). After being cooled and condensed by seawater in the water storage tank (2), it is depressurized through the expansion valve (9) and then enters the evaporator (13) for circulation and evaporation. Fresh water collected in the water collection tank (12) can be discharged through the drain valve (11).

2. The integrated heat pump seawater desalination system of pipe and box type according to claim 1, characterized in that: The condenser (3) and evaporator (13) mentioned above are preferably composed of a single row of serpentine heat exchange tubes.

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