Sectional large-temperature-difference water source heat pump unit

Abstract

The utility model provides a sectional type big temperature difference water source heat pump unit relates to heat pump unit technical field, including heat pump module, heat pump module includes first stage heat pump unit and second stage heat pump unit, and each stage heat pump module is equipped with cold water inlet and hot water inlet, and cold water inlet and hot water inlet all are connected to external water source pipeline through mechanical valve group, and mechanical valve group contains series connection mode interface and parallel mode interface, and through manual operation switches waterway series connection topology structure. The utility model has realized through the cold water inlet, hot water inlet of each stage heat pump module through mechanical valve group connection, and contains series connection and parallel interface and switches waterway through valve handle operation, and when series connection, low temperature water source flows through multistage evaporator and gradually reduces temperature, and when parallel, high temperature water source shunts to each stage evaporator, adapts small temperature difference demand, reaches the effect of improving application range, increases energy efficiency.

Description

Technical Field

[0001] This utility model relates to the field of heat pump unit technology, and in particular to a segmented large temperature difference water source heat pump unit. Background Technology

[0002] The segmented large temperature difference water source heat pump unit solves the problems of low energy efficiency and poor adaptability of traditional heat pumps in large temperature difference scenarios through the structure of segmented independent circulation + series water system. It is especially suitable for renewable energy fields that require large temperature difference heat exchange. Through multiple independent refrigerant circulation systems, such as low temperature, medium temperature, and high temperature, and series water circulation systems, such as cooling water and chilled water, segmented treatment of large temperature difference conditions is achieved.

[0003] A search revealed that utility model patent CN217636262U discloses a series-parallel system of multiple heat pump units. This system comprises multiple refrigeration and heat pump units arranged to form a multi-stage refrigeration cycle subsystem. Each refrigeration and heat pump unit includes a refrigeration compressor, a condenser, a throttling valve, and an evaporator. The system includes a first connecting pipe, comprising a first input pipe and a first output pipe; a second connecting pipe, comprising a second input pipe and a second output pipe; a first valve located on the path of the first output pipe; and a second valve located on the path of the second output pipe. This series-parallel system of multiple heat pump units allows for flexible switching between conventional units in systems with large or normal temperature differences. When the water temperature is high, the conventional units are operated in series to ensure that the inlet and outlet water temperatures remain at a normal temperature difference. When the water volume is large and the water temperature is low or at a normal temperature, multiple units are operated in parallel to achieve operation with a small or normal temperature difference.

[0004] In the aforementioned disclosed structure, the series system is a fixed design and cannot be switched to parallel mode according to changes in water source temperature. For example, when operating at high temperatures in summer and requiring a small temperature difference, the operating mode cannot be dynamically switched according to the water source temperature, resulting in reduced energy efficiency under high-temperature water source conditions. Utility Model Content

[0005] The purpose of this utility model is to address the shortcomings of existing technologies by proposing a segmented large temperature difference water source heat pump unit.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a segmented large temperature difference water source heat pump unit, including a heat pump module, wherein the heat pump module includes a first-stage heat pump unit and a second-stage heat pump unit, each stage of the heat pump module is provided with a cold water inlet and a hot water inlet, both of which are connected to an external water source pipeline through a mechanical valve group, wherein the mechanical valve group includes a series mode interface and a parallel mode interface, and the series and parallel topology of the water circuit can be switched by manual operation.

[0007] Preferably, each stage of the heat pump module is provided with a cold water outlet and a hot water outlet, and the pipeline connection method of the series mode interface is that the cold water outlet of the first stage heat pump unit is connected to the cold water inlet of the second stage heat pump unit; the hot water outlet of the second stage heat pump unit is connected to the hot water inlet of the first stage heat pump unit.

[0008] Preferably, the pipeline connection method of the parallel mode interface is that the cold water inlets of all the heat pump modules are connected in parallel to the external cold water main pipe through the branch pipe; and the hot water outlets of all the heat pump modules are connected in parallel to the external hot water main pipe through the manifold.

[0009] Preferably, a mechanical balancing valve is installed at both the cold water inlet and the hot water inlet of each stage of the heat pump module, and the valve core opening of the mechanical balancing valve is fixed by a threaded adjusting rod.

[0010] Preferably, each stage of the heat pump module is provided with a condenser outlet, and the condenser outlet is connected to the refrigerant inlet of the subcooler through a branch pipe. The hot water pipe of the subcooler is connected in parallel with the main hot water pipe.

[0011] Preferably, the refrigerant outlet of the subcooler is connected to a plate economizer, and the intermediate pressure outlet of the plate economizer is connected to the compressor's gas supply port through a mechanical throttle valve.

[0012] Preferably, each stage of the heat pump module is equipped with a compressor, and a centrifugal oil separator is installed at the exhaust port of the compressor. The centrifugal oil separator includes an oil return pipe, which is connected to the oil storage tank of the compressor at an angle of inclination of greater than or equal to three degrees.

[0013] Preferably, the series mode interface and parallel mode interface of the mechanical valve group are connected by quick-connect flanges, and the quick-connect flanges are fixed to the pipeline by a snap-fit ​​mechanical locking device.

[0014] Beneficial effects:

[0015] 1. This utility model realizes the connection of cold water inlet and hot water inlet of each heat pump module through mechanical valve group, including series and parallel interfaces, and the water circuit can be switched by valve handle operation. When connected in series, the low temperature water source flows through multiple evaporators to cool down step by step. When connected in parallel, the high temperature water source is diverted to each evaporator, which can adapt to the small temperature difference requirement, thereby improving the applicability and increasing energy efficiency.

[0016] 2. This utility model achieves fixed flow rate through a threaded adjusting rod, solving the flow deviation caused by hydraulic coupling in multi-stage series systems. It prevents uneven distribution of water-side flow in the evaporators and condensers of each section in a multi-stage series system, especially when cold and hot water pipes are connected in series, which can lead to excessively large or small temperature differences in some sections, reducing the overall COP and wasting heat exchange area. The hydraulic coupling interference is eliminated by segmented independent balancing valves, and the threaded adjusting rod has a preset opening to prevent the problem of flow attenuation at the end of the series system. The isolated water circuit design allows for water flow isolation by closing the balancing valve during single-stage maintenance, without the need for a complete shutdown, thereby increasing the overall heat exchange area and reducing hydraulic coupling interference.

[0017] 3. This utility model achieves improved heat recovery efficiency through the mechanical synergy of a subcooler and a plate economizer. The subcooler uses diverted hot water to increase the subcooling of the refrigerant and reduce the proportion of flash gas. The mechanical throttling valve diverts part of the refrigerant to the plate economizer for cooling before injecting it into the intermediate cavity of the compressor, thereby reducing the exhaust temperature. Attached Figure Description

[0018] Figure 1 This is a flowchart of the present invention;

[0019] Figure 2 This is a flowchart of the series-parallel mode switching process of this utility model;

[0020] Figure 3 This is a flowchart of the hydraulic balance process of this utility model;

[0021] Figure 4 This is a flowchart of the heat recovery and compressor of this utility model.

[0022] Legend:

[0023] 111. Heat pump module; 1. First-stage heat pump unit; 110. Second-stage heat pump unit; 101. Cold water inlet; 102. Hot water inlet; 103. Cold water outlet; 104. Hot water outlet; 105. Condenser outlet;

[0024] 2. Mechanical valve assembly; 201. Series mode interface; 202. Parallel mode interface;

[0025] 3. Diverter pipe;

[0026] 4. Manifold;

[0027] 5. Mechanical balancing valve; 501. Threaded adjusting rod;

[0028] 6. Branch piping;

[0029] 7. Subcooler; 701. Hot water piping;

[0030] 8. Plate type economizer; 801. Pressure outlet;

[0031] 9. Mechanical throttle valve;

[0032] 10. Compressor;

[0033] 11. Centrifugal oil separator; 1101. Oil return pipe;

[0034] 12. Quick-connect flange; 1201. Snap-on mechanical locking device. Detailed Implementation

[0035] To make the technical means, creative features, and achieved objectives and effects of this utility model easier to understand, the present utility model is further described below with reference to specific embodiments and accompanying drawings. However, the following embodiments are merely preferred embodiments of this utility model and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments described in the implementation plan without creative effort are all within the protection scope of this utility model.

[0036] The specific embodiments of this utility model are described below with reference to the accompanying drawings. Specific Implementation Example 1:

[0038] Reference Figures 1-4 A segmented large temperature difference water source heat pump unit includes a heat pump module 111, which includes a first-stage heat pump unit 1 and a second-stage heat pump unit 110. Each heat pump module 111 is provided with a cold water inlet 101 and a hot water inlet 102. Both the cold water inlet 101 and the hot water inlet 102 are connected to an external water source pipeline through a mechanical valve group 2. The mechanical valve group 2 includes a series mode interface 201 and a parallel mode interface 202, and the series and parallel topology of the water circuit can be switched by manual operation. Each heat pump module 111 is connected to the water source pipeline through the mechanical valve group 2. The valve group has series and parallel interfaces and supports manual switching. The mechanical valve group 2 provides the physical switching capability between the series and parallel water circuit topologies, realizing control adaptability in scenarios with water temperature fluctuations of 15 to 40 degrees.

[0039] Each heat pump module 111 is equipped with a cold water outlet 103 and a hot water outlet 104. In the series mode, the pipe connection of the interface 201 is as follows: the cold water outlet 103 of the first-stage heat pump unit 1 is connected to the cold water inlet 101 of the second-stage heat pump unit 110; the hot water outlet 104 of the second-stage heat pump unit 110 is connected to the hot water inlet 102 of the first-stage heat pump unit 1. In the series mode, the first-stage cold water outlet 103 is connected to the second-stage cold water inlet 101; the second-stage hot water outlet 104 is connected to the first-stage hot water inlet 102. The stepped series water circuit establishes a cold water heating path and a hot water cooling path, achieving a stable temperature rise of eight to fifteen degrees under the condition that the winter low temperature water source is less than twenty degrees.

[0040] The pipeline connection method of the parallel mode interface 202 is that the cold water inlets 101 of all heat pump modules 111 are connected in parallel to the external cold water main through the branch pipe 3; the hot water outlets 104 of all heat pump modules 111 are connected in parallel to the external hot water main through the manifold 4. In the parallel mode, all cold water inlets 101 are connected in parallel through the branch pipe 3; all hot water outlets 104 are connected in parallel through the manifold 4. The branch pipe 3 and the manifold 4 form a synchronous treatment channel for high temperature water sources greater than 35 degrees Celsius, eliminating the flow competition loss between multi-level units.

[0041] Mechanical balancing valves 5 are installed at the cold water inlet 101 and hot water inlet 102 of each heat pump module 111. The valve core opening of the mechanical balancing valve 5 is fixed by the threaded adjusting rod 501. Each cold water and hot water inlet is equipped with a mechanical balancing valve 5, and the valve core opening is fixed by the threaded adjusting rod 501. The threaded adjusting rod 501 locks the preset flow distribution ratio to maintain the heat exchange of the last stage in the multi-stage series system to reach more than 95% of that of the first stage.

[0042] Each heat pump module 111 is equipped with a condenser outlet 105. The condenser outlet 105 is connected to the refrigerant inlet of the subcooler 7 via a branch pipe 6. The hot water pipe 701 of the subcooler 7 is connected in parallel with the main hot water pipe. The condenser outlet 105 is connected to the refrigerant inlet of the subcooler 7 via a branch pipe 6. The hot water pipe 701 of the subcooler 7 is connected in parallel with the main hot water pipe. The branch pipe 6 establishes a heat recovery path from the condenser to the subcooler 7 to improve the subcooling of the refrigerant.

[0043] The refrigerant outlet of the subcooler 7 is connected to a plate economizer 8. The intermediate pressure outlet 801 of the plate economizer 8 is connected to the gas supply port of the compressor 10 through a mechanical throttle valve 9. The refrigerant outlet of the subcooler 7, the plate economizer 8, the mechanical throttle valve 9, and the gas supply port of the compressor 10 form an intermediate pressure gas supply circuit, which reduces the discharge temperature of the compressor 10.

[0044] Each heat pump module 111 is equipped with a compressor 10. The exhaust port of the compressor 10 is equipped with a centrifugal oil separator 11. The centrifugal oil separator 11 includes an oil return pipe 1101. The oil return pipe 1101 is connected to the oil storage tank of the compressor 10 at an inclination angle of greater than or equal to three degrees. The centrifugal oil separator 11 is installed at the exhaust port of the compressor 10, and the oil return pipe 1101 is connected to the oil storage tank at an inclination angle of greater than or equal to three degrees. The inclined oil return pipe 1101 realizes the gravity-driven autonomous return of lubricating oil, avoiding oil shortage and wear of the compressor 10 in the multi-stage series system.

[0045] The series mode interface 201 and parallel mode interface 202 of the mechanical valve group 2 are connected by quick-connect flange 12. The quick-connect flange 12 fixes the pipeline by snap-on mechanical locking device 1201. The series and parallel interfaces are fixed by quick-connect flange 12 and snap-on mechanical locking device 1201. Snap-on mechanical locking device 1201 provides single-tool operation capability for pipeline reconfiguration and eliminates disassembly shutdown during mode switching. Specific Implementation Example 2:

[0047] Reference Figures 1-4 The structure disclosed in this utility model was applied to a waste heat recovery project in a chemical plant. The water source is the discharge water from the process cooling tower, with an annual water temperature range of 10 to 42 degrees Celsius. In winter, the water needs to be heated from 9 degrees Celsius to 65 degrees Celsius, a temperature increase of 56 degrees Celsius. In summer, the water needs to be cooled from 38 degrees Celsius to 22 degrees Celsius, a temperature drop of 16 degrees Celsius. The original single-stage heat pump had a heating efficiency ratio of only 2.9 under winter conditions, and required eight shutdowns for cleaning annually due to scale buildup.

[0048] The implementation employs a two-stage heat pump module 111. Both the first-stage heat pump unit 1 and the second-stage heat pump unit 110 are equipped with Hanbell Precision Machinery RC2-750G twin-screw compressors 10, each with a rated cooling capacity of 420 kW. The series interface 201 of the mechanical valve group 2 uses a 200 mm diameter quick-connect flange 12, and the operating torque of the snap-on mechanical locking device 1201 does not exceed 26 N / m. The mechanical balancing valve 5 is a Johnson Controls V300 series, with the cold water inlet 101 preset to 68% opening and the hot water inlet 102 preset to 73% opening via a threaded adjusting rod 501. The subcooler 7 adopts an Alfa Laval plate structure with a heat exchange area of ​​20 square meters, diverting 18% of the refrigerant from the condenser outlet 105 into its refrigerant circuit. The plate economizer 8 is connected to a Danfoss TEX2 mechanical throttle valve 9, injecting 5°C medium-pressure refrigerant into the compressor 10's air inlet. The tilt angle of the return oil pipe 1101 of the centrifugal oil separator 11 is precisely set to 3.2 degrees with an error of ±0.1 degrees.

[0049] During winter operation, when the water source temperature drops to 12 degrees Celsius, mechanical valve assembly 2 is switched to series mode. Cold water enters from the first-stage cold water inlet 101, is heated from 12 degrees Celsius to 34 degrees Celsius by the evaporator, and then enters the second-stage cold water inlet 101 through the series interface, finally outputting hot water at 65 degrees Celsius. High-temperature hot water flows in the reverse direction: it first enters the second-stage hot water inlet 102, cooling from 65 degrees Celsius to 42 degrees Celsius, then flows through the first-stage hot water inlet 102, cooling to 28 degrees Celsius before being discharged. Mechanical balancing valve 5 maintains the flow deviation between the two stages within ±2.3%. Subcooler 7 increases the refrigerant subcooling by 9 degrees Celsius, stabilizing the compressor 10 discharge temperature below 83 degrees Celsius, achieving a system heating efficiency ratio of 4.3.

[0050] During summer operation, the system switches to parallel mode once the water source temperature reaches 35 degrees Celsius. Cold water enters the two-stage evaporators simultaneously via distributor 3, where it is cooled from 35 degrees Celsius to 23 degrees Celsius before being combined and output. The mechanical balancing valve 5 is adjusted to 92% opening, and the hot water diversion ratio of the subcooler 7 is reduced to 7%. The oil separator achieves a 99.3% lubricating oil recovery rate, resulting in a system refrigeration efficiency ratio of 5.4.

[0051] Data from three consecutive operating years shows that the average energy saving rate in winter operation reached 42.7%, and the efficiency of refrigeration units in summer increased by 38.9%. Flow distribution deviation was controlled within ±2.5%, and the number of annual scaling maintenance visits decreased from eight to two. Switching between series and parallel modes took 35 minutes, including pipeline reconfiguration and system venting, saving 90% of downtime compared to traditional welding modifications. The unit maintained an efficiency ratio of 5.1 even under 42-degree Celsius high-temperature water conditions.

[0052] The working principle of this utility model is as follows: By manually switching the series and parallel topology of the water circuit through the mechanical valve group 2, the system adapts to changes in water source temperature. In series mode, external cold water first flows into the cold water inlet 101 of the first-stage heat pump unit 1, where it absorbs heat and is heated by the evaporator. Then, it flows from its cold water outlet 103 into the cold water inlet 101 of the second-stage heat pump unit 110 for secondary heating. Simultaneously, external hot water flows in the opposite direction, first entering the hot water inlet 102 of the second-stage heat pump unit 110, where it releases heat and is cooled by the condenser. Then, it flows from its hot water outlet 104 into the hot water inlet 102 of the first-stage heat pump unit 1 for further cooling. This achieves stepwise heating of cold water and stepwise cooling of hot water, suitable for large temperature difference conditions. In parallel mode, external cold water is synchronously distributed to the cold water inlets 101 of all heat pump units through the distribution pipe 3 for single-stage temperature cooling. The treated hot water is then discharged from the hot water outlet 104 of each unit through the manifold 4, adapting to small temperature difference requirements. Meanwhile, the mechanical balancing valves 5 installed at each stage's cold water inlet 101 and hot water inlet 102 lock the preset opening through their threaded adjusting rods 501, ensuring uniform flow distribution when multiple stages are connected in series and preventing flow attenuation at the end. In addition, the refrigerant diverted from the condenser outlet 105 enters the subcooler 7 and is further cooled by the parallel diverted hot water to increase the subcooling degree. It then flows through the plate economizer 8, and part of the refrigerant is injected into the compressor 10's air inlet after being depressurized and cooled by the mechanical throttle valve 9, reducing the exhaust temperature and compression power consumption. The centrifugal oil separator 11 at the compressor 10's exhaust port achieves autonomous lubricant return through the return oil pipe 1101 with an inclination angle ≥3° by gravity. The water circuit interfaces of the entire system are connected by quick-connect flanges 12 with snap-fit ​​mechanical locking devices 1201, supporting quick manual reconfiguration of the pipeline, significantly reducing downtime during mode switching, and ultimately achieving the effects of broadening the applicable water temperature range, improving energy efficiency and system stability.

[0053] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0054] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A split large temperature difference water source heat pump unit comprising a heat pump module (111) comprising a first stage heat pump unit (1) and a second stage heat pump unit (110), characterized in that: Each heat pump module (111) is provided with a cold water inlet (101) and a hot water inlet (102). The cold water inlet (101) and the hot water inlet (102) are connected to an external water source pipeline through a mechanical valve group (2). The mechanical valve group (2) includes a series mode interface (201) and a parallel mode interface (202), and the series and parallel topology of the water circuit can be switched by manual operation.

2. The segmented large temperature difference water source heat pump unit according to claim 1, characterized in that: Each heat pump module (111) is provided with a cold water outlet (103) and a hot water outlet (104). The pipeline connection method of the series mode interface (201) is that the cold water outlet (103) of the first-stage heat pump unit (1) is connected to the cold water inlet (101) of the second-stage heat pump unit (110). The hot water outlet (104) of the second-stage heat pump unit (110) is connected to the hot water inlet (102) of the first-stage heat pump unit (1).

3. A segmented large temperature difference water source heat pump unit according to claim 1, characterized in that: The parallel mode interface (202) is connected in such a way that the cold water inlets (101) of all the heat pump modules (111) are connected in parallel to the external cold water main pipe through the branch pipe (3); The hot water outlets (104) of all heat pump modules (111) are connected in parallel to the external hot water main through the manifold (4).

4. A segmented large temperature difference water source heat pump unit according to claim 1, characterized in that: Each heat pump module (111) is equipped with a mechanical balancing valve (5) at its cold water inlet (101) and hot water inlet (102). The valve core opening of the mechanical balancing valve (5) is fixed by a threaded adjusting rod (501).

5. A segmented large temperature difference water source heat pump unit according to claim 1, characterized in that: Each heat pump module (111) is provided with a condenser outlet (105), which is connected to the refrigerant inlet of the subcooler (7) via a branch pipe (6). The hot water pipe (701) of the subcooler (7) is connected in parallel with the main hot water pipe.

6. A segmented large temperature difference water source heat pump unit according to claim 5, characterized in that: The refrigerant outlet of the subcooler (7) is connected to a plate economizer (8), and the intermediate pressure outlet (801) of the plate economizer (8) is connected to the gas supply port of the compressor (10) through a mechanical throttle valve (9).

7. A segmented large temperature difference water source heat pump unit according to claim 1, characterized in that: Each heat pump module (111) is equipped with a compressor (10), and a centrifugal oil separator (11) is installed at the exhaust port of the compressor (10). The centrifugal oil separator (11) includes an oil return pipe (1101), which is connected to the oil storage tank of the compressor (10) at an angle of greater than or equal to three degrees.

8. A segmented large temperature difference water source heat pump unit according to claim 1, characterized in that: The series mode interface (201) and parallel mode interface (202) of the mechanical valve group (2) are connected by quick-connect flanges (12), and the quick-connect flanges (12) are fixed to the pipeline by snap-on mechanical locking devices (1201).

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