CN117570594A

CN117570594A - Heat pump system

Info

Publication number: CN117570594A
Application number: CN202311648428.2A
Authority: CN
Inventors: 陶宏; 朱杰; 吴生礼
Original assignee: Shanghai Highly New Energy Technology Co Ltd
Current assignee: Shanghai Highly New Energy Technology Co Ltd
Priority date: 2023-12-04
Filing date: 2023-12-04
Publication date: 2024-02-20

Abstract

The invention provides a heat pump system, which comprises a refrigerant loop and a cold-carrying liquid loop, wherein the refrigerant loop comprises a compressor, an opening control part, a first heat exchanger and a second heat exchanger which are sequentially connected, the opening control part is used for controlling the exhaust pressure of the compressor, the exhaust end of the compressor is connected with the first heat exchanger, and the air inlet end of the compressor is connected with the second heat exchanger; the cold-carrying liquid loop comprises a water pump, and two ends of the water pump are respectively connected with the first heat exchanger and the second heat exchanger; in the first working mode, the refrigerant loop and the cold-carrying liquid loop share the first heat exchanger and the second heat exchanger for heat exchange. In the heat pump system provided by the invention, in the first working mode, the opening control part increases the exhaust pressure of the compressor, the refrigerant loop and the cold-carrying liquid loop share the first heat exchanger and the second heat exchanger so as to increase the pressure of the refrigerant at the air inlet end of the compressor, thereby increasing the power of the compressor in the starting stage under the lower temperature working condition, increasing the temperature rising speed of the system and reducing the time of the starting stage of the system.

Description

Heat pump system

Technical Field

The invention relates to the technical field of heat pumps, in particular to a heat pump system.

Background

The heat pump system can transfer heat from a place with low temperature to a place with high temperature through the control of a plurality of valves and pumps, and has two working conditions of refrigeration and heating. In the prior art, under the condition of lower temperature in winter, the rotating speed of a compressor in a starting stage is lower, the temperature of the system is slowly increased, and a PTC (Positive Temperature Coefficient) heater with higher power is used in the starting stage to rapidly increase the temperature of the system to solve the problem. Usually, the PTC heater is arranged at the low-pressure side of the secondary refrigerant loop to solve the problem of heating the space in the vehicle at low temperature, but the PTC technology has larger power consumption, high cost and large occupied space, and is not beneficial to energy conservation, cost reduction and the like. Therefore, a fast start heat pump system needs to be explored.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a heat pump system, which can improve the power of a compressor in the heat pump system in a low-temperature working condition at a low temperature, improve the temperature rising speed of the system and reduce the time of the system in the starting stage.

An embodiment of the present invention provides a heat pump system including:

the refrigerant loop comprises a compressor, an opening control part, a first heat exchanger and a second heat exchanger which are sequentially connected, wherein the opening control part is used for controlling the exhaust pressure of the compressor, the exhaust end of the compressor is connected with the first heat exchanger, and the air inlet end of the compressor is connected with the second heat exchanger;

the cold-carrying liquid loop comprises a water pump, and two ends of the water pump are respectively connected with the first heat exchanger and the second heat exchanger; and in the first working mode, the refrigerant loop and the cold-carrying liquid loop share the first heat exchanger and the second heat exchanger to exchange heat.

In some embodiments, the refrigerant circuit includes a first conduit, a second conduit, and a third conduit, the discharge end of the compressor is connected to the first end of the first heat exchanger by the first conduit, the second end of the first heat exchanger is connected to the second end of the second heat exchanger by the second conduit, and the first end of the second heat exchanger is connected to the inlet end of the compressor by the third conduit.

In some embodiments, the cold carrier liquid loop includes a fourth pipe, a fifth pipe, and a sixth pipe, the first end of the water pump is connected to the third end of the first heat exchanger through the fourth pipe, the fourth end of the first heat exchanger is connected to the fourth end of the second heat exchanger through the fifth pipe, and the third end of the second heat exchanger is connected to the second end of the water pump through the sixth pipe.

In some embodiments, the proportional solenoid valve is located on the first conduit.

In some embodiments, the proportional solenoid valve is disposed inside the compressor.

In some embodiments, the cold carrier liquid circuit includes a heating device disposed between the third end of the second heat exchanger and the second end of the water pump.

In some embodiments, the heating device is a PTC heater.

In some embodiments, the refrigerant circuit further comprises an expansion valve disposed between the second end of the first heat exchanger and the second end of the second heat exchanger.

In some embodiments, a pressure sensor is disposed on the third conduit to monitor the pressure at the intake end of the compressor.

In some embodiments, a control unit is further included in electrical communication with the pressure sensor; when the system includes a proportional solenoid valve, to control an opening of the proportional solenoid valve; when the system comprises a heating device, to control the power of the heating device.

The heat pump system provided by the invention has the following advantages:

the heat pump system comprises a refrigerant loop and a cold-carrying liquid loop, wherein the refrigerant loop comprises a compressor, an opening control part, a first heat exchanger and a second heat exchanger which are sequentially connected, the opening control part is used for controlling the exhaust pressure of the compressor, the exhaust end of the compressor is connected with the first heat exchanger, and the air inlet end of the compressor is connected with the second heat exchanger; the cold-carrying liquid loop comprises a water pump, and two ends of the water pump are respectively connected with the first heat exchanger and the second heat exchanger; in the first working mode, the refrigerant loop and the cold-carrying liquid loop share the first heat exchanger and the second heat exchanger for heat exchange. In the heat pump system provided by the invention, in the first working mode, the opening control part increases the pressure of the exhaust end of the compressor, the refrigerant loop and the cold-carrying liquid loop share the first heat exchanger and the second heat exchanger so as to increase the pressure of the refrigerant at the air inlet end of the compressor, thereby increasing the power of the compressor in the starting stage under the lower temperature working condition, increasing the heating speed of the system and reducing the time of the starting stage of the system.

Drawings

Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings.

FIG. 1 is a schematic diagram of a heat pump system according to an embodiment of the present invention;

fig. 2 is a pressure-enthalpy diagram of a refrigerant circuit of a heat pump system according to another embodiment of the invention in a first operating mode;

fig. 3 is a schematic diagram of a heat pump system according to another embodiment of the invention.

Reference numerals:

1. compressor with a compressor body having a rotor with a rotor shaft

2. First heat exchanger

3. Expansion valve

4. Second heat exchanger

5. Water pump

61. Proportional solenoid valve

62. Heating device

11. First pipeline

12. Second pipeline

13. Third pipeline

14. Fourth pipeline

15. Fifth pipeline

16. Sixth pipeline

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. "or", "or" in the specification may each mean "and" or ".

In the description of the present application, reference to the terms "one embodiment," "some embodiments," "examples," "particular examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the various embodiments or examples, and features of the various embodiments or examples, presented herein may be combined and combined by those skilled in the art without conflict.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the context of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" specify the presence of stated features, steps, operations, elements, components, items, categories, and/or groups, but do not preclude the presence, presence or addition of one or more other features, steps, operations, elements, components, items, categories, and/or groups. The terms "or" and/or "as used herein are to be construed as inclusive, or meaning any one or any combination. Thus, "A, B or C" or "A, B and/or C" means "any of the following: a, A is as follows; b, a step of preparing a composite material; c, performing operation; a and B; a and C; b and C; A. b and C). An exception to this definition will occur only when a combination of elements, functions, steps or operations are in some way inherently mutually exclusive.

In order to solve the problems that in the prior art, in a low-temperature environment, the compressor of a heat pump system is affected by temperature, and the gas pressure of the air inlet end of the heat pump system is low, the rotating speed of the compressor in the starting stage is low, so that the heat pump system heats slowly, the embodiment of the invention provides the heat pump system. The heat pump system of the present application will be explained with reference to specific embodiments.

Example 1

Fig. 1 shows a schematic diagram of a heat pump system according to an embodiment of the invention. As shown in fig. 1, the heat pump system includes a compressor 1, a first heat exchanger 2, an expansion valve 3, a second heat exchanger 4, a water pump 5, and a proportional solenoid valve 61, wherein the compressor 1, the proportional solenoid valve 61, the first heat exchanger 2, the expansion valve 3, and the second heat exchanger 4 are sequentially connected through pipes to form a refrigerant circuit. In the present embodiment, the proportional solenoid valve 61 is an opening degree control means, and the proportional solenoid valve 61 can be used to control the discharge pressure of the compressor 1, and when the opening degree of the proportional solenoid valve 61 is controlled to be reduced (smaller than the opening degree when the solenoid valve is fully opened), the pressure of the refrigerant discharged from the compressor 1 can be increased, and the temperature of the refrigerant can be increased.

The water pump 5, the first heat exchanger 2 and the second heat exchanger 4 are sequentially connected through pipelines to form a cold-carrying liquid loop; in the first operating mode, the refrigerant circuit and the cold carrier liquid circuit share the first heat exchanger 2 and the second heat exchanger 4; the first mode of operation is herein a low temperature mode of operation. The refrigerant loop realizes the circulation heat exchange by transporting the refrigerant, and the cold-carrying liquid loop realizes the circulation heat exchange by transporting the cooling liquid. It should be noted that, the first heat exchanger 2 and the second heat exchanger 4 each include a first flow channel and a second flow channel, where the first flow channel is communicated with the refrigerant circuit, the second flow channel is communicated with the cold-carrying liquid circuit, and the refrigerant in the first flow channel and the cooling liquid in the second flow channel can realize heat exchange in the first heat exchanger 2 or the second heat exchanger 4.

By controlling the opening degree of the proportional solenoid valve 61, the gas pressure at the discharge end of the compressor 1 is increased, so that the temperature of the refrigerant discharged by the compressor 1 is increased, the cooling liquid absorbs the heat of the refrigerant in the first heat exchanger 2, the cooling liquid supplies heat to the refrigerant in the second heat exchanger 4, the pressure at the air inlet end of the compressor is increased, the pressure ratio of the compressor is increased, the rotation speed of the compressor is increased, the temperature rising speed of the system is further increased, the system starting period time is reduced, and the rapid heating of the system is realized.

With continued reference to fig. 1, the refrigerant circuit further includes a first pipe 11, a second pipe 12, and a third pipe 13, where the exhaust end of the compressor 1 is connected to the first end of the first heat exchanger 2 through the first pipe 11, the second end of the first heat exchanger 2 is connected to the second end of the second heat exchanger 4 through the second pipe 12, and the first end of the second heat exchanger 4 is connected to the air inlet end of the compressor 1 through the third pipe 13; the expansion valve 3 is arranged between the second end of the first heat exchanger 2 and the second end of the second heat exchanger 4, and the expansion valve 3 is arranged on the second pipeline 12; the proportional solenoid valve 61 is disposed between the discharge end of the compressor 1 and the first end of the first heat exchanger 2, in this embodiment, the proportional solenoid valve 61 is disposed on the first pipe 11, the first end of the proportional solenoid valve 61 is connected to the discharge end of the compressor 1, the second end of the proportional solenoid valve 61 is connected to the first end of the first heat exchanger 2, and when the proportional solenoid valve 61 is in an open state, the refrigerant can reenter the first heat exchanger 2 through the proportional solenoid valve 61.

The working valve element in the proportional solenoid valve 61 is capable of generating a plurality of displacements, and by controlling the displacement of the valve element, the flow rate of the refrigerant flowing through the proportional solenoid valve 61 per unit time can be controlled, thereby realizing the change of the refrigerant pressure at the discharge end of the compressor 1. When the compressor 1 is in the start-up phase, the valve opening of the proportional solenoid valve 61 is controlled to be reduced (smaller than the opening at full-open), so that the discharge pressure at the discharge end of the compressor 1 is increased by passing through the proportional solenoid valve 61, and the temperature is increased. When the proportional solenoid valve 61 is in the fully open state, the pressure of the refrigerant flowing through the proportional solenoid valve 61 is the same as the discharge pressure of the compressor 1, and the proportional solenoid valve 61 only functions as a conduction, and has no influence on the discharge pressure of the compressor 1.

The cold-carrying liquid loop further comprises a fourth pipeline 14, a fifth pipeline 15 and a sixth pipeline 16, wherein the first end of the water pump 5 is connected with the third end of the first heat exchanger 2 through the fourth pipeline 14, the fourth end of the first heat exchanger 2 is connected with the fourth end of the second heat exchanger 4 through the fifth pipeline 15, and the third end of the second heat exchanger 4 is connected with the second end of the water pump 5 through the sixth pipeline 16.

The heat pump system provided by the embodiment of the invention further comprises a pressure sensor and a control unit (not shown in the figure), wherein the pressure sensor is arranged on the third pipeline 13 and is used for monitoring the gas pressure of the air inlet end of the compressor 1; the control unit is electrically connected with the pressure sensor, and is used for controlling the opening degree of the proportional solenoid valve 61 according to the pressure measured by the pressure sensor. For example, when the pressure sensor detects that the gas pressure at the gas inlet end of the compressor 1 is in a normal state, the control unit controls the valve of the proportional solenoid valve 61 to be fully opened, so that the gas pressure at the gas outlet end of the compressor 1 is not increased, and the normal operation of the compressor 1 can be realized. If the pressure sensor measures that the gas pressure at the gas inlet end of the compressor 1 is smaller, the control unit controls the valve displacement of the proportional solenoid valve 61 to be reduced, that is, the opening of the solenoid valve to be reduced, so that the gas discharged from the gas outlet end of the compressor 1 passes through the proportional solenoid valve 61 to be subjected to pressure and temperature elevation, and the gas pressure of the refrigerant entering the gas inlet end of the compressor 1 is increased.

Fig. 2 shows a pressure-enthalpy diagram of the refrigerant circuit of the heat pump system in the present embodiment in the first operation mode, wherein the abscissa represents the enthalpy value h and the ordinate represents the absolute pressure P. As can be taken in connection with fig. 2, the refrigerant circuit operating principle in the first operating mode is:

in the refrigerant circuit: the compressor 1 starts to operate, the refrigerant is discharged from the discharge end of the compressor 1 after being compressed, and when the refrigerant passes through the proportional solenoid valve 61, the refrigerant is accumulated to generate higher pressure because of the non-fully-opened state of the proportional solenoid valve 61, and the temperature of the refrigerant is increased while the pressure is increased; further, after the refrigerant exchanges heat through the first heat exchanger 2, the refrigerant is throttled, cooled and depressurized through the expansion valve 3, enters the second heat exchanger 4 to exchange heat, and reenters the air inlet end of the compressor 1 after passing through the second heat exchanger 4, so that the circulation is repeated, and the system heating is realized.

In the cold-carrying liquid loop: the water pump 5 starts to operate, and the cooling liquid enters the second heat exchanger 4 for heat exchange, then enters the first heat exchanger 2 for heat exchange, and finally enters the water pump 5 again, so that the circulation is repeated.

The refrigerant loop and the cold-carrying liquid loop share a first heat exchanger 2 and a second heat exchanger 4, wherein the temperature of the refrigerant in the first heat exchanger 2 is higher than that of the cooling liquid, the cooling liquid exchanges heat with the refrigerant, and the cooling liquid absorbs heat of the refrigerant; in the second heat exchanger 4, the temperature of the cooling liquid is higher than the temperature of the refrigerant, the cooling liquid exchanges heat with the refrigerant, and the cooling liquid provides heat for the refrigerant to raise the temperature of the refrigerant, and the temperature and pressure of the refrigerant discharged through the second heat exchanger 4 are raised, so that the gas pressure of the air inlet end of the compressor is raised, and the compressor can normally operate.

When the cooling liquid enters the first heat exchanger 2, the temperature of the refrigerant in the first heat exchanger 2 is higher, the cooling liquid exchanges heat with the refrigerant in the first heat exchanger 2, the temperature of the cooling liquid rises and enters the second heat exchanger 4 from the first heat exchanger 2, in the second heat exchanger 4, the cooling liquid with the temperature rising exchanges heat with the refrigerant again, the refrigerant absorbs heat in the cooling liquid, so that the temperature of the refrigerant entering the air inlet end of the compressor 1 rises, the air pressure is increased, the air inlet pressure of the air inlet end of the compressor can be increased, the power of the compressor is increased, and the system heating speed is increased under the condition of low temperature. When the pressure at the intake end of the compressor 1 reaches the safe range of operation of the compressor 1, the opening of the proportional solenoid valve 61 may be gradually opened up to full opening. In some embodiments, the operation power of the water pump 5 may be associated with a pressure sensor, and when the pressure at the air inlet end of the compressor 1 is smaller, the operation power of the water pump 5 may be increased, so as to increase the circulation rate of the cold carrier liquid, so as to accelerate the heat transfer from the first heat exchanger 2 to the second heat exchanger 4, thereby increasing the gas pressure at the air inlet end of the compressor 1; when the pressure of the air inlet end of the compressor 1 is recovered to be normal, the running power of the water pump 5 can be reduced, and the cold-carrying liquid circulation rate can be reduced.

In the present embodiment, in the stage of starting the compressor 1, the opening degree of the proportional solenoid valve 61 is controlled gradually to maintain the gas pressure at the air inlet end of the compressor within the safe range, the system arrangement is simple, the heating device is completely canceled, rapid temperature rise can be realized, and the starting process is completed.

Example 2

Fig. 3 shows a schematic diagram of a heat pump system of another embodiment. As shown in fig. 3, the heat pump system includes a refrigerant circuit and a cold-carrying liquid circuit, and the refrigerant circuit in this embodiment is different from that in fig. 1 in that the opening and closing control part in this embodiment is a back pressure valve and a heating device 62 is added to the cold-carrying liquid circuit, and the back pressure valve is integrally disposed in the compressor 1 (not shown in the figure). The arrangement of the internal back pressure valve of the compressor 1 can save the arrangement space of the system under the condition of realizing the adjustable exhaust pressure of the compressor; the heating device 62 is disposed between the second heat exchanger 4 and the second end of the water pump 5, and the heating device 62 is used for heating the temperature of the cooling liquid passing through the fifth pipeline 15, so that the temperature of the cooling liquid entering the second heat exchanger 4 can be further increased when the cooling liquid enters the second heat exchanger 4, and further, the temperature of the refrigerant can be increased in the second heat exchanger 4, so that the pressure of the refrigerant at the air inlet end of the compressor 1 is increased, so that the pressure at the air inlet side of the compressor 1 is increased, so that the power of the compressor 1 is high in a low-temperature starting stage, the time of the system starting stage is reduced, and the temperature rising speed of the system is increased. Also, the heat pump system in this embodiment further includes a pressure sensor disposed on the third pipe 13 for monitoring the gas pressure at the inlet end of the compressor 1, and a control unit electrically connected to the pressure sensor for controlling the power of the heating device. When the pressure at the air inlet end of the compressor 1 is lower and the rotating speed of the compressor 1 is lower in the starting stage, the power of the heating device 62 can be increased to provide more heat for the cooling liquid, so that the pressure at the air inlet end of the compressor 1 is increased; when the pressure of the air inlet end of the compressor 1 is in the normal range, the power of the heating device 62 can be gradually reduced, and the energy consumption of the system can be reduced.

The heating device in this embodiment may be a PTC heater.

In this embodiment, the working principle of the refrigerant circuit is the same as that in embodiment 1, and will not be described here again. The working principle of the cold-carrying liquid loop is as follows:

the water pump 5 and the PTC heater are turned on, the PTC heater increases the temperature of the refrigerant liquid in the refrigerant liquid carrying circuit, and then increases the temperature of the refrigerant liquid in the refrigerant liquid carrying circuit 4, and when the refrigerant liquid enters the second heat exchanger 4, the refrigerant liquid exchanges heat with the refrigerant liquid in the refrigerant liquid carrying circuit 4, that is, the refrigerant liquid absorbs heat of the refrigerant liquid, and then increases the gas pressure of the refrigerant liquid at the gas inlet end of the compressor 1, so that the compressor 1 is rapidly increased to high-rotation-speed operation. When the compressor 1 is operated at a high speed, the PTC heater may be operated at a reduced power or stopped. By arranging the heating device in the cold-carrying liquid loop, the power of the compressor in the starting stage and the heating speed of the system can be further improved.

The heat pump system provided by the invention has the following advantages:

the heat pump system comprises a refrigerant loop and a cold-carrying liquid loop, wherein the refrigerant loop comprises a compressor, an opening control part, a first heat exchanger and a second heat exchanger which are sequentially connected, the opening control part is used for controlling the exhaust pressure of the compressor, the exhaust end of the compressor is connected with the first heat exchanger, and the air inlet end of the compressor is connected with the second heat exchanger; the cold-carrying liquid loop comprises a water pump, and two ends of the water pump are respectively connected with the first heat exchanger and the second heat exchanger; in the first working mode, the refrigerant loop and the cold-carrying liquid loop share the first heat exchanger and the second heat exchanger for heat exchange. In the heat pump system provided by the invention, in the first working mode, the refrigerant loop and the cold-carrying liquid loop share the first heat exchanger and the second heat exchanger so as to improve the pressure of the refrigerant at the air inlet end of the compressor, improve the power of the compressor in the starting stage under the low-temperature working condition, reduce the time of the starting stage of the system, improve the temperature rising speed of the system and enable the system to realize rapid heating.

The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.

Claims

1. A heat pump system, comprising:

2. The heat pump system of claim 1, wherein the refrigerant circuit comprises a first conduit, a second conduit, and a third conduit, wherein the discharge end of the compressor is connected to the first end of the first heat exchanger by the first conduit, wherein the second end of the first heat exchanger is connected to the second end of the second heat exchanger by the second conduit, and wherein the first end of the second heat exchanger is connected to the inlet end of the compressor by the third conduit.

3. The heat pump system of claim 2, wherein the cold carrier liquid circuit comprises a fourth conduit, a fifth conduit, and a sixth conduit, the first end of the water pump is connected to the third end of the first heat exchanger through the fourth conduit, the fourth end of the first heat exchanger is connected to the fourth end of the second heat exchanger through the fifth conduit, and the third end of the second heat exchanger is connected to the second end of the water pump through the sixth conduit.

4. A heat pump system according to claim 3, wherein the opening control means is a proportional solenoid valve located on the first conduit.

5. A heat pump system according to claim 3, wherein the opening control member is a back pressure valve disposed inside the compressor.

6. The heat pump system of claim 4 or 5, wherein the cold carrier liquid circuit comprises a heating device disposed between a third end of the second heat exchanger and a second end of the water pump.

7. The heat pump system of claim 6, wherein the heating device is a PTC heater.

8. The heat pump system of claim 1, wherein the refrigerant circuit further comprises an expansion valve disposed between the second end of the first heat exchanger and the second end of the second heat exchanger.

9. The heat pump system of claim 7, further comprising a pressure sensor disposed on the third conduit for monitoring a pressure at an intake end of the compressor.

10. The heat pump system of claim 9, further comprising a control unit electrically connected to the pressure sensor; when the system includes a proportional solenoid valve, to control an opening of the proportional solenoid valve; when the system comprises a heating device, to control the power of the heating device.