EP4617587A1

EP4617587A1 - Water source heat pump system

Info

Publication number: EP4617587A1
Application number: EP25162446.6A
Authority: EP
Inventors: Jun Cao; Kai DENG; Vishnu Sishtla; Haiping Ding; Danni YUAN; Scott Mcdonough
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2024-03-12
Filing date: 2025-03-07
Publication date: 2025-09-17
Also published as: CN120627440A; US20250290675A1

Abstract

The invention provides a water source heat pump system (100) including a first unit (1) and a second unit (2). The first unit (1) includes a first compressor (10), a first condenser (12) and a first evaporator (14). The second unit (2) includes a second compressor (20), a second condenser (22) and a second evaporator (24). The first compressor (10), the first condenser (12) and the first evaporator (14) are in communication with each other to form a first refrigerant circuit, and the second compressor (20), the second condenser (22) and the second evaporator (24) are in communication with each other to form a second refrigerant circuit. A fluid pipeline in the first condenser (12) and a fluid pipeline in the second condenser (22) are connected in series to allow a heating fluid to pass through the second condenser (22) and the first condenser (12) in sequence. A fluid pipeline in the first evaporator (14) and a fluid pipeline in the second evaporator (24) are connected in series to allow a heat source fluid to pass through the first evaporator (14) and the second evaporator (24) in sequence. The first compressor (10) and the second compressor (20) are both centrifugal direct-drive compressors (5), and each of the centrifugal direct-drive compressors (5) includes a first compression chamber (51), a second compression chamber (52), a driving motor (53) and at least three impellers (54).

Description

Technical Field

This invention relates to a technical field of heat pumps, specifically a water source heat pump system.

Background Art

In the context of the current global energy crisis, it is hoped that a water source heat pump suitable for district heating can be provided to reduce dependence on energy sources such as oil and natural gas to a certain extent.
However, most water source heat pumps in the related art have a problem of low coefficient of performance (COP).

Summary of the Invention

This disclosure aims to provide a water source heat pump system to at least solve or alleviate some of the problems existing in the related art.
According to a first aspect of the invention there is provided a water source heat pump system including a first unit and a second unit. The first unit includes a first compressor, a first condenser and a first evaporator. The second unit includes a second compressor, a second condenser and a second evaporator. The first compressor, the first condenser and the first evaporator are in communication with each other to form a first refrigerant circuit, and the second compressor, the second condenser and the second evaporator are in communication with each other to form a second refrigerant circuit. A fluid pipeline in the first condenser and a fluid pipeline in the second condenser are connected in series to allow a heating fluid to pass through the second condenser and the first condenser in sequence. A fluid pipeline in the first evaporator and a fluid pipeline in the second evaporator are connected in series to allow a heat source fluid to pass through the first evaporator and the second evaporator in sequence. The first compressor and the second compressor are both centrifugal direct-drive compressors, and each of the centrifugal direct-drive compressors includes a first compression chamber, a second compression chamber, a driving motor and at least three impellers. An inlet of the first compression chamber is in communication with an evaporator, and an outlet of the second compression chamber is in communication with a condenser, and an inlet of the second compression chamber is in communication with an outlet of the first compression chamber. The driving motor includes a motor body and a motor shaft, and the motor body is disposed between the first compression chamber and the second compression chamber, and the motor shaft penetrates the motor body and both ends thereof extend into the first compression chamber and the second compression chamber, respectively. The impellers are all fixed on the motor shaft and are separately arranged in the first compression chamber and the second compression chamber.
Optionally, the heat source fluid with a temperature of 0°C to 10°C is guided into the fluid pipeline of the first evaporator, and the heat source fluid is river water, lake water or sea water, and the heating fluid with a temperature of 60°C to 100°C is guided out from the fluid pipeline of the first condenser.
Optionally, the centrifugal direct-drive compressor further includes a frequency converter electrically connected to the driving motor. The centrifugal direct-drive compressor uses the frequency converter to adjust a rotation speed of the impellers.
Optionally, the centrifugal direct-drive compressor further includes a first variable guide vane and a second variable guide vane. The first variable guide vane is disposed corresponding to the inlet of the first compression chamber. The second variable guide vane is disposed corresponding to the inlet of the second compression chamber.
Optionally, the inlet of the first compression chamber is disposed corresponding to one of the impellers which is farthest from the motor body in the first compression chamber. Optionally, the outlet of the first compression chamber is disposed corresponding to one of the impellers which is closest to the motor body in the first compression chamber. Optionally, the inlet of the second compression chamber is disposed corresponding to one of the impellers which is farthest from the motor body in the second compression chamber. Optionally, the outlet of the second compression chamber is disposed corresponding to one of the impellers which is farthest from the motor body in the second compression chamber and is arranged separately from the inlet of the second compression chamber.
Optionally, the first condenser and the first evaporator each have a length extending in an X-axis direction, and the first condenser and the first evaporator are stacked in a Z-axis direction. Optionally, the second condenser and the second evaporator each have a length extending in the X-axis direction, and the second condenser and the second evaporator are stacked in the Z-axis direction. Optionally, the first condenser and the second condenser are arranged side by side in a Y-axis direction, and the first evaporator and the second evaporator are arranged side by side in the Y-axis direction.
Optionally, one end of the second condenser in the X-axis direction is provided with a heating fluid inlet, and the other end is provided with a first connection port. Optionally, one end of the first condenser close to the heating fluid inlet in the X-axis direction is provided with a heating fluid outlet, and the other end is provided with a second connection port connected to the first connection port. Optionally, one end of the first evaporator close to the heating fluid inlet in the X-axis direction is provided with a heat source fluid inlet, and the other end is provided with a third connection port. Optionally, one end of the second evaporator close to the heat source fluid inlet in the X-axis direction is provided with a heat source fluid outlet, and the other end is provided with a fourth connection port connected to the third connection port.
Optionally, the first unit further includes a first economizer connected between the first condenser and the first evaporator. The first economizer is provided with two first outlets. Optionally, the first compressor is provided with two first air supply ports, and the two first outlets are respectively in communication with the two first air supply ports. Optionally, the second unit further includes a second economizer connected between the second condenser and the second evaporator. The second economizer is provided with two second outlets. Optionally, the second compressor is provided with two second air supply ports, and the two second outlets are respectively in communication with the two second air supply ports.
Optionally, the first economizer has a length extending in the X-axis direction and is positioned on a side of the first unit away from the second unit. Optionally, the second economizer has a length extending in the X-axis direction and is positioned on a side of the second unit away from the first unit.
Optionally, the two first air supply ports are arranged on both sides of a central axis of the first compressor extending in the X-axis direction, respectively. Optionally, the two second air supply ports are arranged on both sides of a central axis of the second compressor extending in the X-axis direction, respectively.

Descriptions of the Drawings

Certain exemplary embodiments will now be described in greater detail by way of example only and with reference to the accompanying drawings in which:

FIG. 1 is schematic diagram of a water source heat pump system;
FIGS. 2 to 4 are schematic diagrams of centrifugal direct-drive compressors;
FIG. 5 is a schematic structural diagram of a water source heat pump system;
FIG. 6 is a side view of FIG. 5; and
FIG. 7 is a schematic structural diagram of a water source heat pump system.

List of Reference Numerals:

Water source heat pump system 100, first unit 1, first compressor 10, first air supply port (not shown), first condenser 12, heating fluid outlet 1201, second connection port 1202, first evaporator 14, heat source fluid inlet 1401, third connection port 1402, first economizer 16, first outlet (not shown), second unit 2, second compressor 20, second air supply port 201, second condenser 22, heating fluid inlet 2201, first connection port 2202, second evaporator 24, heat source fluid outlet 2401, fourth connection port 2402, second economizer 26, second outlet 2601, centrifugal direct-drive compressor 5, first compression chamber 51, inlet 511 of first compression chamber, outlet 512 of first compression chamber, second compression chamber 52, inlet 521 of second compression chamber, outlet 522 of second compression chamber, driving motor 53, motor body 531, motor shaft 532, impeller 54, connecting pipe 55, first variable guide vane 56, and second variable guide vane 57.

Detailed Description

It should be noted that working principles, features, advantages, and the like of a water source heat pump system according to the invention will be explained below by way of embodiments. However, it should be understood that all descriptions are only given for exemplification and therefore these embodiments should not be understood as forming any limitation on the invention.
In addition, for any single technical feature described or implicit in the embodiments mentioned herein, or any single technical feature shown or implicit in the drawings, the invention still allows any combination or deletion between these technical features (or their equivalents) without any technical obstacles, thereby obtaining more other embodiments of the invention that may not be directly mentioned herein.
A water source heat pump system 100 in an embodiment of the invention, as shown in FIG. 1, includes a first unit 1 and a second unit 2. The first unit 1 includes a first compressor 10, a first condenser 12 and a first evaporator 14, and the first compressor 10, the first condenser 12 and the first evaporator 14 are in communication with each other to form a first refrigerant circuit. The second unit 2 includes a second compressor 20, a second condenser 22 and a second evaporator 24, and the second compressor 20, the second condenser 22 and the second evaporator 24 are in communication with each other to form a second refrigerant circuit. Here, the first refrigerant circuit and the second refrigerant circuit are independent of each other, that is, if the first compressor 10 does not work, the second refrigerant circuit will not be affected, and vice versa.
In the embodiment of the invention, both the first condenser 12 and the second condenser 22 are shell-and-tube heat exchangers, with a refrigerant passing through the shell side and a heating fluid passing through the tube side. A fluid pipeline in the first condenser 12 and a fluid pipeline in the second condenser 22 are connected in series, and the heating fluid can pass through the two condensers in sequence. The first evaporator 14 and the second evaporator 24 are also shell-and-tube heat exchangers, with the refrigerant passing through the shell side and a heat source fluid passing through the tube side. A fluid pipeline in the first evaporator 14 and a fluid pipeline in the second evaporator 24 are connected in series, and the heat source fluid can pass through the two evaporators in sequence. By connecting the first condenser 12 and the second condenser 22, the first evaporator 14 and the second evaporator 24 in series, a heat exchange area of the working fluid (heating fluid, heat source fluid) in the heat exchangers (condenser, evaporator) is enlarged, which is conducive to improving a heat transfer coefficient and allowing the working fluid to flow more evenly in the pipelines.
In the embodiment of the invention, the heating fluid and the heat source fluid have opposite flow directions. Specifically, the heating fluid first passes through the second condenser 22 of the second unit 2, and then passes through the first condenser 12 of the first unit 1, while the heat source fluid first passes through the first evaporator 14 of the first unit 1, and then passes through the second evaporator 24 of the second unit 2. Since the heating fluid and the heat source fluid flow in opposite directions, the first unit 1 that provides the heating fluid with a higher temperature will also receive the heat source fluid with a higher temperature. In this way, division of labor between the first unit 1 and the second unit 2 is more reasonable, and a lift required for the compressor of each unit is reduced, and efficiency of the heat pump system is significantly improved.
In a specific example, referring to FIG. 1, a heat source fluid with a temperature of 10°C is guided into the fluid pipeline of the first evaporator 14, and after the heat source fluid passes through the first evaporator 14, the temperature thereof drops to 6°C, and after the heat source fluid passes through the second evaporator 24, the temperature thereof further drops to 2°C. A heating fluid with a temperature of 60°C is guided into the fluid pipeline of the second condenser 22, and after the heating fluid passes through the second condenser 22, the temperature thereof rises to 75°C, and after the heating fluid passes through the first condenser 12, the temperature thereof further rises to 90°C. Accordingly, a lift of the first compressor 10 is 84°C (90°C - 6°C), and a lift of the second compressor 20 is 73°C (75°C - 2°C). However, if a single compressor is used, or if the heating fluid and the heat source fluid have the same flow direction, the compressor lift needs to reach 88°C (90°C - 2°C) to achieve the above working conditions.
In the embodiment of the invention, both the first compressor 10 and the second compressor 20 may be centrifugal direct-drive compressors 5. FIG. 2 is a schematic structural diagram of the centrifugal direct-drive compressor 5 in some embodiments. As shown in FIG. 2, the centrifugal direct-drive compressor 5 includes a first compression chamber 51, a second compression chamber 52, a driving motor 53, impellers 54 and a connecting pipe 55. An inlet 511 of the first compression chamber is in communication with an evaporator, and an outlet 522 of the second compression chamber is in communication with a condenser, and an inlet 521 of the second compression chamber is in communication with an outlet 512 of the first compression chamber via the connecting pipe 55. The driving motor 53 includes a motor body 531 (that is, a portion including a stator and a rotor) and a motor shaft 532. The motor body 531 is disposed between the first compression chamber 51 and the second compression chamber 52. The motor shaft 532 penetrates the motor body 531 and both ends thereof extend into the first compression chamber 51 and the second compression chamber 52, respectively. The three impellers 54 are all fixed on the motor shaft 532 and are directly driven by the motor shaft 532. In the embodiment shown in FIG. 2, the first stage impeller 54 and the second stage impeller 54 are positioned in the first compression chamber 51, and the third stage impeller 54 is positioned in the second compression chamber 52. The connecting pipe 55 establishes communication between the outlet 512 of the first compression chamber and the inlet 521 of the second compression chamber, and the outlet 512 of the first compression chamber corresponds to the position of the second stage impeller 54, and the inlet 521 of the second compression chamber corresponds to the position of the third stage impeller 54. A refrigerant gas is sucked in from the inlet 511 of the first compression chamber, and then passes through the first stage impeller 54, the second stage impeller 54, the connecting pipe 55, and the third stage impeller 54 in sequence, and is finally discharged from the outlet 522 of the second compression chamber.
FIG. 3 is a schematic structural diagram of the centrifugal direct-drive compressor 5 in some embodiments, and a difference thereof from the centrifugal direct-drive compressor 5 in the embodiments shown in FIG. 2 is that the first stage impeller 54 is positioned in the first compression chamber 51, and the second stage impeller 54 and the third stage impeller 54 are positioned in the second compression chamber 52. The connecting pipe 55 establishes communication between the outlet 512 of the first compression chamber and the inlet 521 of the second compression chamber, and the outlet 512 of the first compression chamber corresponds to the position of the first stage impeller 54, and the inlet 521 of the second compression chamber corresponds to the position of the second stage impeller 54. A refrigerant gas is sucked in from the inlet 511 of the first compression chamber, and then passes through the first stage impeller 54, the connecting pipe 55, the second stage impeller 54, and the third stage impeller 54 in sequence, and is finally discharged from the outlet 522 of the second compression chamber.
FIG. 4 is a schematic structural diagram of the centrifugal direct-drive compressor 5 in some embodiments, and a difference thereof from the centrifugal direct-drive compressor 5 in the embodiments shown in FIG. 2 is that four impellers 54 are provided. The first stage impeller 54 and the second stage impeller 54 are positioned in the first compression chamber 51, and the third stage impeller 54 and the fourth stage impeller 54 are positioned in the second compression chamber 52. The connecting pipe 55 establishes communication between the outlet 512 of the first compression chamber and the inlet 521 of the second compression chamber, and the outlet 512 of the first compression chamber corresponds to the position of the second stage impeller 54, and the inlet 521 of the second compression chamber corresponds to the position of the third stage impeller 54. A refrigerant gas is sucked in from the inlet 511 of the first compression chamber, and then passes through the first stage impeller 54, the second stage impeller 54, the connecting pipe 55, the third stage impeller 54, and the fourth stage impeller 54 in sequence, and is finally discharged from the outlet 522 of the second compression chamber.
The structures of the centrifugal direct-drive compressors 5 shown in FIGS. 2 to 4 have been described above, but the invention is not limited thereto, and any compressor with three or more impellers 54 directly driven by the motor shaft 532 is within the scope of the centrifugal direct-drive compressor 5 of the invention.
It should be noted that the first compressor 10 and the second compressor 20 in the disclosure may use the same centrifugal direct-drive compressor 5. For example, the first compressor 10 and the second compressor 20 both use the same centrifugal direct-drive compressor 5 as shown in FIG. 2. Alternatively, the first compressor 10 and the second compressor 20 may also use different centrifugal direct-drive compressors 5. For example, the first compressor 10 may use the centrifugal direct-drive compressor 5 as shown in FIG. 2, and the second compressor 20 may use the centrifugal direct-drive compressor 5 as shown in FIG. 4.
According to the water source heat pump provided in the embodiment of the invention, when the temperature of the heat source fluid is low (for example, 0°C to 10°C), the heating fluid can also be heated to a higher temperature (for example, 60°C to 100°C). Specifically, if a heating fluid having a high temperature is to be obtained from a heat source fluid having a low temperature, the lift of the compressor needs to be increased, and the centrifugal direct-drive compressor 5 needs to be a high-lift compressor that can satisfy the requirement. Moreover, through the reasonable division of labor between the first unit 1 and the second unit 2, the lift of the compressor required to obtain the same heating capacity is reduced, thereby alleviating the problem of poor coefficient of performance (COP) caused by the centrifugal direct-drive compressor 5 maintaining high-lift operation.
When one of the units or the compressors fails, the water source heat pump system 100 can still operate normally and has good redundancy. Specifically, since both the first compressor 10 and the second compressor 20 are centrifugal direct-drive compressors 5 and the first refrigerant circuit and the second refrigerant circuit are independent of each other, even if the first compressor 10 or other parts of the first refrigerant circuit fails, by increasing the lift of the second compressor 20, a temperature requirement of the heating fluid can also be satisfied, that is, the heating fluid can still be heated to a high temperature when the temperature of the heat source fluid is low.
When an operating load of the water source heat pump system 100 is reduced, the first compressor 10 and the second compressor 20 can adjust working states thereof to adapt to new operating conditions while reducing occurrence of surges and vibrations to ensure system reliability under a low load. Specifically, since both the first compressor 10 and the second compressor 20 are centrifugal direct-drive compressors 5, the plurality of impellers 54 can provide more compression levels, allowing the gas to flow more smoothly during the compression, thereby reducing the occurrence of surges and vibrations. Moreover, since the impellers 54 are separately arranged in the first compression chamber 51 and the second compression chamber 52 on both sides of the motor body 531 in an axial direction, when a gas flow rate in the first compression chamber 51 decreases, the gas in the second compression chamber 52 tends to maintain continuity of flowing and does not easily flow back to the inlet 511 of the first compression chamber. Therefore, impact between the gas flowing back from the outlet 522 of the second compression chamber and the gas at the inlet of the first compression chamber 51 can be avoided to a large extent, thereby reducing the occurrence of surges and vibrations. When the operating load of the water source heat pump system 100 is further reduced, one of the units can be shut down to improve the coefficient of performance of the heat pump system under a low load.
In some embodiments, a heat source fluid with a low temperature is guided into the fluid pipeline of the first evaporator 14, and a heating fluid with a high temperature is guided out from the fluid pipeline of the first condenser 12.
In some embodiments, a heat source fluid with a temperature of 0°C to 30°C is guided into the fluid pipeline of the first evaporator 14, and a heating fluid with a temperature of 40°C to 100°C is guided out from the fluid pipeline of the first condenser 12.
In some embodiments, a heat source fluid with a temperature of 0°C to 10°C is guided into the fluid pipeline of the first evaporator 14, and the heat source fluid is river water, lake water or sea water, and a heating fluid with a temperature of 60°C to 100°C is guided out from the fluid pipeline of the first condenser 12. By guiding in a heat source fluid with a low temperature but a large volume to exchange heat with the first evaporator 14 and the second evaporator 24, the first condenser 12 and the second condenser 22 can provide sufficient heat to heat the heating fluid, thereby better satisfying the requirement for the heating fluid at the heated end.
It should be noted here that although the water source heat pump provided in the embodiment of the invention is particularly suitable for use in situations where a heating fluid with a high temperature is to be generated from a heat source fluid with a low temperature, the invention is not limited thereto, and the water source heat pump provided by the invention can operate with a better coefficient of performance under more situations, such as a larger heat source fluid temperature range and a larger load range.
In some embodiments, the centrifugal direct-drive compressor 5 further includes a frequency converter (not shown) electrically connected to the driving motor 53. The centrifugal direct-drive compressor 5 uses the frequency converter to change a rotation speed of the motor shaft 532 to adjust a rotation speed of the impellers 54 fixed to the motor shaft 532. Since the frequency converter allows the rotation speed of the impellers 54 to have a larger adjustment range, the centrifugal direct-drive compressor 5 can better cope with operating load fluctuations of the water source heat pump system 100.
In some embodiments, one or both of the first compressor 10 and the second compressor 10 may be fixed frequency compressors.
In some embodiments, referring to FIGS. 2 to 4, the centrifugal direct-drive compressor 5 further includes a first variable guide vane 56 and a second variable guide vane 57. The first variable guide vane 56 is disposed corresponding to the inlet 511 of the first compression chamber to adjust a flow rate of the gas entering the first compression chamber 51. The second variable guide vane 57 is disposed corresponding to the inlet 521 of the second compression chamber to adjust a flow rate of the gas entering the second compression chamber 52. When the operating load of the water source heat pump system 100 fluctuates, the flow rates of the gas in the first compression chamber 51 and the second compression chamber 52 can be controlled by controlling the first variable guide vane 56 and the second variable guide vane 57, thereby reducing the occurrence of surges and vibrations. In some embodiments, the first variable guide vane 56 and the second variable guide vane 57 can also be controlled according to a surge detection result.
In some embodiments, the centrifugal direct-drive compressor 5 further includes a first fixed guide vane and a second fixed guide vane. The first fixed guide vane is disposed corresponding to the inlet 511 of the first compression chamber to guide the gas entering the first compression chamber 51. The second fixed guide vane is disposed corresponding to the inlet 521 of the second compression chamber to guide the gas entering the second compression chamber 52.
In some embodiments, the first variable guide vane 56 or the first fixed guide vane may be provided only at the inlet 511 of the first compression chamber.
In some embodiments, the second variable guide vane 57 or the second fixed guide vane may be provided only at the inlet 521 of the second compression chamber.
In some embodiments, referring to FIGS. 2 to 4, the inlet 511 of the first compression chamber is disposed corresponding to one of the impellers 54 which is farthest from the motor body 531 in the first compression chamber 51. The outlet 512 of the first compression chamber is disposed corresponding to one of the impellers 54 which is closest to the motor body 531 in the first compression chamber 51. The inlet 521 of the second compression chamber is disposed corresponding to one of the impellers 54 which is farthest from the motor body 531 in the second compression chamber 52. The outlet 522 of the second compression chamber is disposed corresponding to one of the impellers 54 which is farthest from the motor body 531 in the second compression chamber 52.
In some embodiments, referring to FIGS. 5 and 6, the first condenser 12 and the first evaporator 14 each have a length extending in an X-axis direction, and the first condenser 12 and the first evaporator 14 are stacked in a Z-axis direction. The second condenser 22 and the second evaporator 24 each have a length extending in the X-axis direction, and the second condenser 22 and the second evaporator 24 are stacked in the Z-axis direction. The first condenser 12 and the second condenser 22 are arranged side by side in a Y-axis direction, and the first evaporator 14 and the second evaporator 24 are arranged side by side in the Y-axis direction. Since the condensers and the evaporators in each unit are stacked in the Z-axis direction, and the two units are arranged side by side in the Y-axis direction, the arrangement of the two units is more compact, thereby reducing a floor space required for the two units and also helping to optimize pipe layout and electrical wiring.
Although in the embodiment shown in FIGS. 5 and 6, the first condenser 12 and the first evaporator 14 are stacked with the first condenser 12 at the bottom and the first evaporator 14 at the top, and a line connecting a center of the first condenser 12 and a center of the first evaporator 14 is parallel to the Z-axis direction, the invention is not limited thereto, and as long as the first condenser 12 and the first evaporator 14 have a stacked positional relation in the Z-axis direction with one at the bottom and the other at the top, such an arrangement is within the scope of the invention, which is as defined by the appended claims. For example, in an embodiment shown in FIG. 7, the first condenser 12 and the first evaporator 14 are stacked with the first evaporator 14 at the bottom and the first condenser 12 at the top, and a line connecting the center of the first condenser 12 and the center of the first evaporator 14 has an included angle with the Z-axis direction.
Similarly, with reference to the above explanation for "the first condenser 12 and the first evaporator 14 are stacked in the Z-axis direction", it also applies to explanations for "the second condenser 22 and the second evaporator 24 are stacked in the Z-axis direction", "the first condenser 12 and the second condenser 22 are arranged side by side in the Y-axis direction", and "the first evaporator 14 and the second evaporator 24 are arranged side by side in the Y-axis direction", and therefore no further details will be given here.
In some embodiments, referring to FIGS. 5 and 6, one end of the second condenser 22 in the X-axis direction is provided with a heating fluid inlet 2201, and the other end is provided with a first connection port 2202. One end of the first condenser 12 close to the heating fluid inlet 2201 in the X-axis direction is provided with a heating fluid outlet 1201, and the other end is provided with a second connection port 1202 connected to the first connection port 2202. The heating fluid enters the fluid pipeline in the second condenser 22 from the heating fluid inlet 2201, and then leaves the second condenser 22 through the first connection port 2202. The first connection port 2202 and the second connection port 1202 are connected through a U-shaped pipeline, and the heating fluid flowing out from the first connection port 2202 passes through the U-shaped pipeline, and then enters the fluid pipeline in the first condenser 12 from the second connection port 1202, and finally, the heating fluid leaves the first condenser 12 through the heating fluid outlet 1201. One end of the first evaporator 14 close to the heating fluid inlet 2201 in the X-axis direction is provided with a heat source fluid inlet 1401, and the other end is provided with a third connection port 1402. One end of the second evaporator 24 close to the heat source fluid inlet 1401 in the X-axis direction is provided with a heat source fluid outlet 2401, and the other end is provided with a fourth connection port 2402 connected to the third connection port 1402. The heat source fluid enters the fluid pipeline in the first evaporator 14 from the heat source fluid inlet 1401, and then leaves the first evaporator 14 through the third connection port 1402. The third connection port 1402 and the fourth connection port 2402 are connected through a U-shaped pipeline, and the heat source fluid flowing out from the third connection port 1402 passes through the U-shaped pipeline, and then enters the fluid pipeline in the second evaporator 24 from the fourth connection port 2402, and finally, the heat source fluid leaves the second evaporator 24 through the heat source fluid outlet 2401. In this way, the heating fluid inlet 2201, the heating fluid outlet 1201, the heat source fluid inlet 1401, and the heat source fluid outlet 2401 are all positioned on the same side of the water source heat pump system 100, that is, the right side in FIG. 5, thereby simplifying the pipe layout in the unit room where the water source heat pump system 100 is installed. For example, both pipes used to transport the heating fluid and pipes used to transport the heat source fluid can be leaded into a unit room from the same side of the unit room and connected to the water source heat pump system 100. Since the pipe layout is simplified, it is also helpful to alleviate pressure drop of the fluid in the pipe to a certain extent, thereby further improving the coefficient of performance of the water source heat pump system 100.
It should be noted that the embodiment shown in FIGS. 5 and 6 is merely an example of the invention, and the arrangement of the first unit 1 and the second unit 2 in the invention is not limited thereto. Specifically, in some embodiments, the first condenser 12 and the first evaporator 14 each have a length extending in the X-axis direction, and the first condenser 12 and the first evaporator 14 are stacked in the Z-axis direction. The second condenser 22 and the second evaporator 24 each have a length extending in the X-axis direction, and the second condenser 22 and the second evaporator 24 are stacked in the Z-axis direction. The first condenser 12 and the second condenser 22 are arranged end-to-end in the X-axis direction, and the first evaporator 14 and the second evaporator 24 are arranged end-to-end in the X-axis direction. In some embodiments, the first condenser 12 and the first evaporator 14 each have a length extending in the X-axis direction, and the first condenser 12 and the first evaporator 14 are arranged side by side in the Y-axis direction. The second condenser 22 and the second evaporator 24 each have a length extending in the X-axis direction, and the second condenser 22 and the second evaporator 24 are arranged side by side in the Y-axis direction. The first condenser 12 and the second condenser 22 are arranged end-to-end in the X-axis direction, and the first evaporator 14 and the second evaporator 24 are arranged end-to-end in the X-axis direction. In some embodiments, the first condenser 12 and the first evaporator 14 each have a length extending in the X-axis direction, and the first condenser 12 and the first evaporator 14 are arranged side by side in the Y-axis direction. The second condenser 22 and the second evaporator 24 each have a length extending in the X-axis direction, and the second condenser 22 and the second evaporator 24 are arranged side by side in the Y-axis direction. The first condenser 12 and the second condenser 22 are stacked in the Z-axis direction, and the first evaporator 14 and the second evaporator 24 are stacked in the Z-axis direction.
The U-shaped pipeline shown in the embodiment shown in FIGS. 5 and 6 is merely an example of the invention, and as long as the fluid pipeline in the first condenser 12 and the fluid pipeline in the second condenser 22, the fluid pipeline in the first evaporator 14 and the fluid pipeline in the second evaporator 24 can be connected, the shape of the connecting pipe is not particularly limited. For example, in other embodiments, the connecting pipe may also be a substantially linear pipeline, or other curved pipelines.
In some embodiments, referring to FIGS. 5 and 6, the second unit 2 includes a second economizer 26 connected between the second condenser 22 and the second evaporator 24. The second economizer 26 is provided with two second outlets 2601, and the second compressor 20 is provided with two second air supply ports 201, and the two second outlets 2601 are respectively in communication with the two second air supply ports 201. The refrigerant gases output from the two second outlets 2601 of the second economizer 26 have different temperatures and pressures. The temperature and pressure of the refrigerant gas flowing out of one of the second outlets 2601 correspond to the temperature and pressure in the second air supply port 201 in communication therewith (for example, the temperature and pressure between the first stage impeller 54 and the second stage impeller 54), and the temperature and pressure of the refrigerant gas output by the other second outlet 2601 correspond to the temperature and pressure in the other second air supply port 201 in communication therewith (for example, the temperature and pressure between the second stage impeller 54 and the third stage impeller 54). Similarly, the first unit 1 includes a first economizer 16 connected between the first condenser 12 and the first evaporator 14. The first economizer 16 is provided with two first outlets (not shown), and the first compressor 10 is provided with two first air supply ports (not shown), and the two first outlets are respectively in communication with the two first air supply ports. Although the first outlets and the first air supply ports are not fully shown in FIG. 5, the first outlets can be provided with reference to the second outlets 2601 of the second economizer 26, and the first air supply ports can be provided with reference to the second air supply ports 201 of the second compressor 20. The refrigerant gases output from the two first outlets of the first economizer 16 have different temperatures and pressures. The temperature and pressure of the refrigerant gas output by one of the first outlets correspond to the temperature and pressure in the first air supply port in communication therewith (for example, the temperature and pressure between the first stage impeller 54 and the second stage impeller 54), and the temperature and pressure of the refrigerant gas output by the other first outlet correspond to the temperature and pressure in the other first air supply port in communication therewith (for example, the temperature and pressure between the second stage impeller 54 and the third stage impeller 54). By increasing interstage air supply, the flow rates of the compressors can be appropriately reduced and work done by the compressors can be reduced, thereby improving the coefficient of performance of the water source heat pump. By cooling the refrigerant through the economizers, it is also helpful to improve compression efficiency.
It should be noted that the embodiment shown in FIGS. 5 and 6 is merely an example of the invention, and whether to adopt an economizer, as well as the number of economizers that can be selected and the number of outlets on each economizer, and the number of air supply ports on the compressors and the like in the invention are all matters that can be adjusted by those skilled in the art according to actual situations. For example, in some embodiments, in the first unit 1 and the second unit 2, only one unit includes an economizer, while the other unit does not include an economizer. In some embodiments, the first economizer 16 is provided with a first outlet, and the first compressor 10 is provided with a first air supply port in communication with the first outlet, and the second economizer 26 is provided with a second outlet 2601, and the second compressor 10 is provided with a second air supply port 201 in communication with the second outlet 2601. In some embodiments, the first economizer 16 is provided with two first outlets, and the first compressor 10 is provided with two first air supply ports, and the two first outlets are respectively in communication with the two first air supply ports, while the second economizer 26 is provided with only one second outlet 2601, and the second compressor 10 is provided with a second air supply port 201 in communication with the second outlet 2601. In some embodiments, referring to FIGS. 5 and 6, the first economizer 16 has a length extending in the X-axis direction and is positioned on a side of the first unit 1 away from the second unit 2. The second economizer 26 has a length extending in the X-axis direction and is positioned on a side of the second unit 2 away from the first unit 1. Since the economizer has a length extending in the X-axis direction, a part of the pipeline from the condenser to the evaporator can be hidden or integrated inside the economizer to simplify the pipeline design and thereby improving the reliability of the system. Since the first economizer 16 is positioned on the side of the first unit 1 away from the second unit 2 and the second economizer 26 is positioned on the side of the second unit 2 away from the first unit 1, it is helpful to reduce a distance between the first unit 1 and the second unit 2 in the Y-axis, so that the layout of the water source heat pump system 100 is more compact. It should be noted here that although in the embodiment shown in FIGS. 5 and 6, the first economizer 16 and the second economizer 26 are continuous integral components, in some alternative embodiments, the first economizer 16 and the second economizer 26 may also include two spaced apart economizer components.
In some embodiments, the two first air supply ports are positioned on both sides of a central axis of the first compressor 10 extending in the X-axis direction (that is, an axis of the motor shaft 532), respectively. The two second air supply ports 201 are positioned on both sides of a central axis of the second compressor 20 extending in the X-axis direction (that is, an axis of the motor shaft 532), respectively. In this way, the distance between the two first air supply ports and the distance between the two second air supply ports 201 can be made larger, which is beneficial to reducing the occurrence of surges and vibrations.
It should be noted that the embodiment shown in FIGS. 5 and 6 is merely an example of the invention, and types of the economizer that can be selected for use in the invention are not limited thereto. For example, one or both of the first economizer 16 and the second economizer 26 may also choose to use economizers such as flash evaporators or plate heat exchangers. Positions of the two second air supply ports 201 can also be adjusted according to actual situations of the heat pump.
The above embodiments are merely preferred embodiments of the invention and are not intended to limit the invention. Any modifications, equivalent substitutions and improvements made within the principles of the invention shall be included in the protection scope of the invention, which is as defined by the appended claims.

Claims

A water source heat pump system (100), comprising:
a first unit (1); and

a second unit (2), wherein

the first unit (1) includes a first compressor (10), a first condenser (12) and a first evaporator (14),

the second unit (2) includes a second compressor (20), a second condenser (22) and a second evaporator (24),

the first compressor (10), the first condenser (12) and the first evaporator (14) are in communication with each other to form a first refrigerant circuit, and the second compressor (20), the second condenser (22) and the second evaporator (24) are in communication with each other to form a second refrigerant circuit,

a fluid pipeline in the first condenser (12) and a fluid pipeline in the second condenser (22) are connected in series to allow a heating fluid to pass through the second condenser (22) and the first condenser (12) in sequence,

a fluid pipeline in the first evaporator (14) and a fluid pipeline in the second evaporator (24) are connected in series to allow a heat source fluid to pass through the first evaporator (14) and the second evaporator (24) in sequence, and

the first compressor (10) and the second compressor (20) are both centrifugal direct-drive compressors (5), and each of the centrifugal direct-drive compressors (5) includes

a first compression chamber (51) having an inlet (511) in communication with an evaporator,

a second compression chamber (52) having an outlet (522) in communication with a condenser, and an inlet (521) in communication with an outlet (512) of the first compression chamber (51),

a driving motor (53) including a motor body (531) and a motor shaft (532), in which the motor body (531) is disposed between the first compression chamber (51) and the second compression chamber (52), and the motor shaft (532) penetrates the motor body (531) and both ends thereof extend into the first compression chamber (51) and the second compression chamber (52), respectively, and

at least three impellers (54) that are all fixed on the motor shaft (532) and are separately arranged in the first compression chamber (51) and the second compression chamber (52).
The water source heat pump system (100) according to claim 1, wherein
the heat source fluid with a temperature of 0°C to 10°C is guided into the fluid pipeline of the first evaporator (14), and the heat source fluid is river water, lake water or sea water, and the heating fluid with a temperature of 60°C to 100°C is guided out from the fluid pipeline of the first condenser (12).
The water source heat pump system (100) according to claim 1 or 2, wherein
the centrifugal direct-drive compressor (5) further includes a frequency converter electrically connected to the driving motor (53), and

the centrifugal direct-drive compressor (5) uses the frequency converter to adjust a rotation speed of the impellers (54).
The water source heat pump system (100) according to any preceding claim, wherein
the centrifugal direct-drive compressor (5) further includes

a first variable guide vane (56) disposed corresponding to the inlet (511) of the first compression chamber (51), and

a second variable guide vane (57) disposed corresponding to the inlet (521) of the second compression chamber (52).
The water source heat pump system (100) according to any preceding claim, wherein
the inlet (511) of the first compression chamber (51) is disposed corresponding to one of the impellers (54) which is farthest from the motor body (531) in the first compression chamber (51),

the outlet (512) of the first compression chamber (51) is disposed corresponding to one of the impellers (54) which is closest to the motor body (531) in the first compression chamber (51),

the inlet (521) of the second compression chamber (52) is disposed corresponding to one of the impellers (54) which is farthest from the motor body (531) in the second compression chamber (52), and

the outlet (522) of the second compression chamber (52) is disposed corresponding to one of the impellers (54) which is farthest from the motor body (531) in the second compression chamber (52) and is arranged separately from the inlet (521) of the second compression chamber (52).
The water source heat pump system (100) according to any preceding claim, wherein
the first condenser (12) and the first evaporator (14) each have a length extending in an X-axis direction, and the first condenser (12) and the first evaporator (14) are stacked in a Z-axis direction,

the second condenser (22) and the second evaporator (24) each have a length extending in the X-axis direction, and the second condenser (22) and the second evaporator (24) are stacked in the Z-axis direction, and

the first condenser (12) and the second condenser (22) are arranged side by side in a Y-axis direction, and the first evaporator (14) and the second evaporator (24) are arranged side by side in the Y-axis direction.
The water source heat pump system (100) according to claim 6, wherein
one end of the second condenser (22) in the X-axis direction is provided with a heating fluid inlet (2201), and the other end is provided with a first connection port (2202),

one end of the first condenser (12) close to the heating fluid inlet (2201) in the X-axis direction is provided with a heating fluid outlet (1201), and the other end is provided with a second connection port (1202) connected to the first connection port (2202),

one end of the first evaporator (14) close to the heating fluid inlet (2201) in the X-axis direction is provided with a heat source fluid inlet (1401), and the other end is provided with a third connection port (1402), and

one end of the second evaporator (24) close to the heat source fluid inlet (1401) in the X-axis direction is provided with a heat source fluid outlet (2401), and the other end is provided with a fourth connection port (2402) connected to the third connection port (1402).
The water source heat pump system (100) according to any preceding claim, wherein
the first unit (1) further includes a first economizer (16) connected between the first condenser (12) and the first evaporator (14) and provided with two first outlets,

the second unit (2) further includes a second economizer (26) connected between the second condenser (22) and the second evaporator (24) and provided with two second outlets (2601),

the first compressor (10) is provided with two first air supply ports, and the two first outlets are respectively in communication with the two first air supply ports, and

the second compressor (20) is provided with two second air supply ports (201), and the two second outlets (2601) are respectively in communication with the two second air supply ports (201).
The water source heat pump system (100) according to claim 8, wherein
the first economizer (16) has a length extending in the X-axis direction and is positioned on a side of the first unit (1) away from the second unit (2), and

the second economizer (26) has a length extending in the X-axis direction and is positioned on a side of the second unit (2) away from the first unit (1).
The water source heat pump system (100) according to claim 8 or 9, wherein
the two first air supply ports are arranged on both sides of a central axis of the first compressor (10) extending in the X-axis direction, respectively, and

the two second air supply ports (201) are arranged on both sides of a central axis of the second compressor (20) extending in the X-axis direction, respectively.