CN114992907B

CN114992907B - Control method of heat pump system, heat pump system and readable storage medium

Info

Publication number: CN114992907B
Application number: CN202110229411.8A
Authority: CN
Inventors: 刘加劲; 陈柯壁; 丁云霄
Original assignee: GD Midea Heating and Ventilating Equipment Co Ltd; Hefei Midea Heating and Ventilating Equipment Co Ltd
Current assignee: GD Midea Heating and Ventilating Equipment Co Ltd; Hefei Midea Heating and Ventilating Equipment Co Ltd
Priority date: 2021-03-02
Filing date: 2021-03-02
Publication date: 2024-03-19
Anticipated expiration: 2041-03-02
Also published as: CN114992907A

Abstract

The invention provides a control method of a heat pump system, the heat pump system and a readable storage medium. The control method of the heat pump system comprises the following steps: acquiring the supercooling degree of the first heat exchanger, the temperature difference between the refrigerant at the inlet and the refrigerant at the outlet of the first heat exchange channel and the exhaust superheat degree of the compressor; and adjusting the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree, and adjusting the flow of the refrigerant in the first heat exchange channel according to the temperature difference of the refrigerant and the superheat degree of exhaust so as to enable the refrigerant flowing into the jet orifice of the compressor to be in a gas-liquid two-phase state. The invention controls the refrigerant at the injection port into the gas-liquid two-phase state, so that the heat recovery amount of the heat pump system is increased, the capacity energy efficiency of the heat pump system at low temperature is obviously improved, the controllability of the exhaust temperature of the compressor is also improved under the working condition of higher pressure ratio, the exhaust temperature can be ensured to be within the reasonable range requirement, and the energy efficiency of the system is highest.

Description

Control method of heat pump system, heat pump system and readable storage medium

Technical Field

The invention belongs to the technical field of heat pump systems, and particularly relates to a control method of a heat pump system, the heat pump system and a readable storage medium.

Background

In the prior art, in order to improve the heating capacity of a heat pump at a low temperature, an air injection enthalpy-increasing mode is often adopted to supplement air from a medium-pressure cavity of a compressor, so that the total refrigerant circulation quantity of the system is increased, and the total heating capacity of the system is improved. In the related art, under the working condition of high pressure ratio of a heat pump system, the exhaust temperature is too high, the controllability is poor, and the energy efficiency of the whole power is generally reduced.

Disclosure of Invention

The present invention aims to solve one of the technical problems existing in the prior art or related technologies.

To this end, a first aspect of the present invention proposes a control method of a heat pump system.

A second aspect of the present invention proposes a heat pump system.

A third aspect of the present invention proposes a readable storage medium.

In view of this, according to a first aspect of the present invention, there is provided a control method of a heat pump system including a compressor, a first heat exchanger, a second heat exchanger, and an economizer including a first heat exchange passage and a second heat exchange passage, an inlet of the first heat exchange passage being connected to an outlet of the second heat exchange passage, an outlet of the first heat exchange passage being connected to an injection port of the compressor, an outlet of the second heat exchange passage being connected to the second heat exchanger, the control method comprising: acquiring the supercooling degree of the first heat exchanger, the temperature difference between the refrigerant at the inlet and the refrigerant at the outlet of the first heat exchange channel and the exhaust superheat degree of the compressor; and adjusting the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree, and adjusting the flow of the refrigerant in the first heat exchange channel according to the temperature difference of the refrigerant and the superheat degree of exhaust so as to enable the refrigerant flowing into the jet orifice of the compressor to be in a gas-liquid two-phase state.

The invention provides a control method of a heat pump system, which is used for controlling the operation of the heat pump system. The heat pump system comprises a compressor, a first heat exchanger, a second heat exchanger and an economizer. The compressor, the first heat exchanger and the second heat exchanger form a refrigerant loop, and the refrigerant absorbs heat, releases heat and compresses in the refrigerant loop, so that the heat pump system can exchange heat with the outside. The economizer comprises a first heat exchange channel and a second heat exchange channel, wherein an inlet and an outlet of the first heat exchange channel are respectively connected with an outlet of the second heat exchange channel and an injection port of the compressor, the first heat exchange channel is configured as an auxiliary way of the economizer, a refrigerant flows into the first heat exchange channel and exchanges heat with the refrigerant in the second heat exchange channel, and the refrigerant after heat exchange flows out of the first heat exchange channel and enters the injection port of the compressor, so that the injection enthalpy-increasing is performed on the compressor. The inlet and the outlet of the second heat exchange channel are respectively connected with the first heat exchanger and the second heat exchanger, the second heat exchange channel is configured as a main path of the economizer, the first heat exchanger is configured as a condenser in the heat pump system, the second heat exchanger is configured as an evaporator in the heat pump system, the refrigerant flowing out of the first heat exchanger exchanges heat with the second heat exchange channel in the process of passing through the first heat exchange channel of the economizer, and the refrigerant after heat exchange passes through the heat exchanger and enters the air return port of the compressor for compression again. The refrigerant in the first heat exchange channel exchanges heat through the second heat exchange channel, so that the enthalpy value of the refrigerant in the first heat exchange channel can be increased, and the effect of injecting enthalpy increase to the compressor is improved.

According to the control method of the heat pump system, provided by the invention, the refrigerant flow between the outlet of the second heat exchange channel and the second heat exchanger and the refrigerant flow in the first heat exchange channel are controlled, so that the refrigerant entering the injection port of the compressor is in a gas-liquid two-phase state. By controlling the refrigerant at the injection port into a gas-liquid two-phase state, compared with the scheme of performing vapor injection and enthalpy increase through a gaseous refrigerant in the related art, the controllability of the exhaust temperature of the compressor under the working condition of higher pressure ratio is improved, the exhaust temperature can be ensured to be within the reasonable range requirement, and the energy efficiency of the system is highest. The exhaust temperature of the heat pump system at the high pressure ratio can be controlled, so that the heating capacity of the heat pump system is improved, and the operation range of the system is widened. The refrigerant is supercooled through the second heat exchange channel of the economizer and then enters the first heat exchange channel again for evaporation and heat absorption, and the refrigerants in the first heat exchange channel and the second heat exchange channel in the economizer are liquid refrigerants, so that the heat exchange capacity of the economizer is increased, the heat recovery capacity of the system is increased, and the energy efficiency of the heat pump system at low temperature is obviously improved.

It is understood that in the related art heat pump system for injecting enthalpy by a gaseous refrigerant, in the case that the pressure ratio of the compressor is higher than 9, the exhaust temperature may be excessively high, resulting in poor controllability. According to the invention, the gas-liquid two-phase refrigerant is input to the injection port, so that the controllability of the exhaust temperature is improved.

And controlling the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree of the first heat exchanger. In the running process of the heat pump system, the supercooling degree of the first heat exchanger is continuously obtained, the flow of the refrigerant between the second heat exchangers is controlled according to the obtained supercooling degree, the refrigerants in the first heat exchange channel and the second heat exchange channel in the economizer are both guaranteed to be liquid refrigerants, the refrigerants in the injection path are guaranteed to reach the optimal state, and the heat recovery quantity of the heat pump system is improved. And controlling the flow of the refrigerant in the first heat exchange channel according to the temperature difference between the refrigerant at the inlet and the refrigerant at the outlet of the first heat exchange channel and the exhaust superheat degree of the compressor, so that the state of the refrigerant in the injection channel is further controlled, and the heat pump system operates with higher energy efficiency.

In addition, according to the control method of the heat pump system in the technical scheme provided by the invention, the control method also has the following additional technical characteristics:

in one possible design, the step of obtaining the supercooling degree of the first heat exchanger specifically includes: obtaining an exhaust pressure value of a compressor, and obtaining a first temperature value at a refrigerant outlet of a first heat exchanger; and searching a corresponding saturated temperature value according to the exhaust pressure value, and determining the supercooling degree according to the saturated temperature value and the first temperature value.

In the design, the supercooling degree of the first heat exchanger is obtained in a calculation mode, and the specific formula is as follows:

T _sc ＝T _C－ T ₁ 。

wherein T is _sc Is of supercooling degree, T _C Is the saturation temperature value, T ₁ Is the first temperature value.

And obtaining an exhaust pressure value of the compressor and a first temperature value at a refrigerant outlet of the first heat exchanger, finding a saturation temperature value corresponding to the exhaust pressure of the compressor in a table look-up mode, and calculating according to the saturation temperature value and the first temperature value to obtain the supercooling degree of the first heat exchanger. The supercooling degree of the first heat exchanger calculated by the mode is accurate, and the supercooling degree calculated by the formula controls the flow of the refrigerant from the second heat exchange channel to the second heat exchanger, so that the heat recovery amount of the economizer and the injected refrigerant can be ensured to be in a gas-liquid two-phase state.

In one possible design, the heat pump system further includes a throttling component disposed on a pipeline between the outlet of the second heat exchange channel and the second heat exchanger, and the step of adjusting the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree specifically includes: controlling the throttle member to increase the opening degree based on the supercooling degree being equal to or greater than the first set supercooling degree; and controlling the throttling component to reduce the opening degree based on the supercooling degree being smaller than or equal to a second set supercooling degree, wherein the first set supercooling degree is larger than the second set supercooling degree.

In this design, the heat pump system further includes a throttling element disposed on the refrigerant line between the second heat exchange channel and the second heat exchanger. The opening of the throttling component is controlled to directly regulate the flow of the refrigerant from the outlet of the second heat exchange channel to the second heat exchanger. The adjusting mode of the throttling component according to the supercooling degree of the first heat exchanger is specifically as follows:

and continuously acquiring the supercooling degree of the first heat exchanger, and when the detected supercooling degree is greater than or equal to the first set supercooling degree, judging that the supercooling degree is too high at the moment, and controlling the throttling component to increase the opening degree. When the detected supercooling degree is smaller than or equal to the second set supercooling degree, the supercooling degree is judged to be too low at the moment, the expansion valve is controlled to reduce the opening degree, and the first set supercooling degree is larger than the second set supercooling degree. The second set supercooling degree and the first set supercooling degree form a target supercooling degree interval, and when the obtained supercooling degree is within the numerical interval, the throttle part is judged to be unnecessary to adjust the opening degree. The opening degree of the throttling component is adjusted through the outlet supercooling degree of the first heat exchanger, so that the heat recovery amount of the economizer can be ensured, and the refrigerant at the injection port of the compressor is a gas-liquid two-phase refrigerant.

In one possible design, the heat pump system further comprises: the expansion valve is arranged on a pipeline between an inlet of the first heat exchange channel and an outlet of the second heat exchange channel, and the step of adjusting the refrigerant flow in the first heat exchange channel according to the refrigerant temperature difference and the exhaust superheat degree specifically comprises the following steps: acquiring a target exhaust superheat interval and a set temperature difference; and adjusting the opening of the expansion valve to ensure that the temperature difference of the refrigerant is smaller than the set temperature difference and the exhaust superheat degree is in the target exhaust superheat degree interval.

In this design, the heat pump system further includes an expansion valve disposed on the refrigerant line between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel. Whether the refrigerant in the second heat exchange channel is guided into the first heat exchange channel can be controlled by controlling the on-off state of the expansion valve, and the opening of the expansion valve can be adjusted to adjust the flow of the refrigerant entering the first heat exchange channel.

The step of adjusting the refrigerant flow in the first heat exchange channel according to the refrigerant temperature difference at the inlet and the outlet of the first heat exchange channel and the exhaust superheat degree comprises the following steps: and acquiring a target superheat interval and a set temperature difference, and adjusting the opening of the expansion valve according to the numerical relation between the temperature difference of the refrigerant and the set temperature difference and the numerical relation between the exhaust superheat and the target superheat interval. The opening degree of the expansion valve is adjusted to enable the temperature difference of the refrigerant to be smaller than the set temperature difference, and the exhaust superheat degree is in the target exhaust superheat degree interval.

It can be understood that if the temperature difference is smaller than the set temperature difference, it can be determined that the state of the refrigerant is a gas-liquid two-phase refrigerant. In order to reduce the temperature difference, the opening degree of the expansion valve needs to be increased as much as possible, and in order to avoid excessively increasing the opening degree of the expansion valve and excessively reducing the discharge superheat degree of the compressor, the opening degree of the expansion valve is again adjusted according to the discharge superheat degree. The refrigerant at the injection port is in a gas-liquid two-phase state on the premise of ensuring the stable operation of the compressor. The overall capacity energy efficiency of the heat pump system is improved, and the running stability of the heat pump system is ensured.

In one possible design, the step of adjusting the opening of the expansion valve specifically includes: controlling the expansion valve to increase the opening based on the temperature difference of the refrigerant being greater than or equal to the set temperature difference; and determining that the exhaust superheat degree is smaller than the minimum value of the target exhaust superheat degree interval, and controlling the expansion valve to reduce the opening.

In the design, in the process of adjusting the opening of the expansion valve, the opening of the expansion valve needs to be adjusted according to the numerical relation between the temperature difference of the refrigerant and the set temperature difference, and when the temperature difference of the refrigerant is lower than the set temperature difference, the opening of the expansion valve is adjusted according to the exhaust superheat degree of the compressor. In order to make the temperature difference of the refrigerant lower than the set temperature difference, the opening degree of the expansion valve needs to be opened as much as possible, and if the opening degree of the expansion valve is too large, the exhaust superheat degree of the compressor is too low, so in the initial stage of the operation of the heat pump system, the expansion valve is adjusted to be lower than the set temperature difference by adjusting the expansion valve, and then the expansion valve is adjusted according to the exhaust superheat degree.

Specifically, after the heat pump system starts to operate and is in an operating state of injecting enthalpy to the compressor, continuously collecting the refrigerant temperature difference of the first heat exchange channel, and when the detected refrigerant temperature difference is larger than a set temperature difference, opening the expansion opening degree until the refrigerant temperature difference is smaller than the set temperature difference. Based on the working condition that the temperature difference of the refrigerant is smaller than the set temperature difference, the exhaust superheat degree of the compressor is obtained at the moment, the exhaust superheat degree is compared with the target exhaust superheat degree interval in a numerical value mode, when the exhaust superheat degree is smaller than the minimum value of the target exhaust superheat degree interval, the expansion valve is controlled to reduce the opening degree until the exhaust superheat degree is in the target exhaust superheat degree interval, the opening degree of the expansion valve is kept, and the temperature difference of the refrigerant and the exhaust superheat degree are continuously detected. In the subsequent operation, if the temperature difference of the refrigerant rises back to exceed the set temperature difference, the expansion valve is continuously opened, so that the state of the refrigerant flowing to the injection port of the compressor is in a gas-liquid two-phase state. If the exhaust superheat degree of the compressor is not in the target exhaust superheat degree interval, the opening of the expansion valve is adjusted so that the exhaust superheat degree enters the target exhaust superheat degree interval, and the running stability of the compressor is ensured, so that the running stability of the heat pump system is also ensured.

In some embodiments, the set temperature difference is set to 2 ℃.

In one possible design, the step of obtaining the target exhaust superheat interval specifically includes: acquiring a return air pressure value of the compressor and an exhaust air pressure value of the compressor; calculating according to the return air pressure value and the exhaust air pressure value to obtain a target exhaust superheat degree; and determining a target exhaust superheat interval according to the target exhaust superheat.

In the design, a target exhaust superheat degree interval is obtained through calculation by a line, and then the exhaust superheat degree interval is determined according to the target exhaust superheat degree. The calculation of the target exhaust superheat degree is required to be calculated according to a pressure ratio, wherein the pressure ratio is the ratio of the highest pressure to the lowest pressure in the heat pump system, the highest pressure in the heat pump system is the exhaust pressure of the compressor, the lowest pressure in the heat pump system is the return air pressure of the compressor, and a specific calculation formula is as follows:

DSH＝α×(P1/P2)；

wherein D is _SH To target the superheat degree of exhaust, P ₁ Is the discharge pressure value, P of the compressor ₂ Is the return air pressure value of the compressor.

After the target exhaust superheat degree is calculated, the minimum value and the maximum value in the target exhaust superheat degree interval are obtained by adding and subtracting the set value from the target exhaust superheat degree, so that the target exhaust superheat degree interval is determined. The value range of the set value is 3 to 5.

According to a second aspect of the present invention, there is provided a heat pump system comprising a compressor, a first heat exchanger and a second heat exchanger to form a refrigerant circuit, the heat pump system further comprising: the economizer comprises a first heat exchange channel and a second heat exchange channel, wherein an inlet of the first heat exchange channel is connected with an outlet of the second heat exchange channel, an outlet of the first heat exchange channel is connected with an injection port of the compressor, and an outlet of the second heat exchange channel is connected with the second heat exchanger; a memory on which a program or instructions are stored; a processor executing a program or instructions to implement the steps of the control method of the heat pump system in any of the possible designs described above.

The heat pump system provided by the invention comprises a compressor, a first heat exchanger, a second heat exchanger and an economizer. The compressor, the first heat exchanger and the second heat exchanger form a refrigerant loop, and the refrigerant absorbs heat, releases heat and compresses in the refrigerant loop, so that the heat pump system can exchange heat with the outside. The economizer comprises a first heat exchange channel and a second heat exchange channel, wherein an inlet and an outlet of the first heat exchange channel are respectively connected with an outlet of the second heat exchange channel and an injection port of the compressor, the first heat exchange channel is configured as an auxiliary way of the economizer, a refrigerant flows into the first heat exchange channel and exchanges heat with the refrigerant in the second heat exchange channel, and the refrigerant after heat exchange flows out of the first heat exchange channel and enters the injection port of the compressor, so that the injection enthalpy-increasing is performed on the compressor. The inlet and the outlet of the second heat exchange channel are respectively connected with the first heat exchanger and the second heat exchanger, the second heat exchange channel is configured as a main path of the economizer, the first heat exchanger is configured as a condenser in the heat pump system, the second heat exchanger is configured as an evaporator in the heat pump system, the refrigerant flowing out of the first heat exchanger exchanges heat with the second heat exchange channel in the process of passing through the first heat exchange channel of the economizer, and the refrigerant after heat exchange passes through the heat exchanger and enters the air return port of the compressor for compression again. The refrigerant in the first heat exchange channel exchanges heat through the second heat exchange channel, so that the enthalpy value of the refrigerant in the first heat exchange channel can be increased, and the effect of injecting and increasing the enthalpy of the compressor is improved.

The heat pump system provided by the invention further comprises a memory and a processor, wherein the processor executes a program or instruction stored in the memory to control the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger and the flow of the refrigerant in the first heat exchange channel, so that the refrigerant flowing into the injection port of the compressor is in a gas-liquid two-phase state.

Specifically, the control method of the heat pump system controls the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger and the flow of the refrigerant in the first heat exchange channel, so that the refrigerant entering the injection port of the compressor is in a gas-liquid two-phase state. By controlling the refrigerant at the injection port into a gas-liquid two-phase state, compared with the scheme of performing vapor injection and enthalpy increase through a gaseous refrigerant in the related art, the controllability of the exhaust temperature of the compressor under the working condition of higher pressure ratio is improved, the exhaust temperature can be ensured to be within the reasonable range requirement, and the energy efficiency of the system is highest. The exhaust temperature of the heat pump system at the high pressure ratio can be controlled, so that the heating capacity of the heat pump system is improved, and the operation range of the system is widened. The refrigerant is supercooled through the second heat exchange channel of the economizer and then enters the first heat exchange channel again for evaporation and heat absorption, and the refrigerants in the first heat exchange channel and the second heat exchange channel in the economizer are liquid refrigerants, so that the heat exchange capacity of the economizer is increased, the heat recovery capacity of the system is increased, and the energy efficiency of the heat pump system at low temperature is obviously improved.

And controlling the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree of the first heat exchanger. In the running process of the heat pump system, the supercooling degree of the first heat exchanger is continuously obtained, the flow of the refrigerant between the second heat exchangers is controlled according to the obtained supercooling degree, and the refrigerant of the injection path can be ensured to reach the optimal state. And controlling the flow of the refrigerant in the first heat exchange channel according to the temperature difference between the refrigerant at the inlet and the refrigerant at the outlet of the first heat exchange channel and the exhaust superheat degree of the compressor, so that the state of the refrigerant in the injection channel is further controlled, and the heat pump system operates with higher energy efficiency.

In addition, the heat pump system in the technical scheme provided by the invention can also have the following additional technical characteristics:

in one possible design, the heat pump system further comprises: the throttling component is arranged on a pipeline between the outlet of the second heat exchange channel and the second heat exchanger; the expansion valve is arranged on a pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel.

and continuously acquiring the supercooling degree of the first heat exchanger, and when the detected supercooling degree is greater than or equal to the first set supercooling degree, judging that the supercooling degree is too high at the moment, and controlling the throttling component to increase the opening degree. When the detected supercooling degree is smaller than or equal to the second set supercooling degree, the supercooling degree is judged to be too low at the moment, the expansion valve is controlled to reduce the opening degree, and the first set supercooling degree is larger than the second set supercooling degree. The second set supercooling degree and the first set supercooling degree form a numerical interval of supercooling degree, and when the obtained supercooling degree is in the numerical interval, the throttle part is judged to be unnecessary to be adjusted in opening degree. The opening degree of the throttling component is adjusted through the outlet supercooling degree of the first heat exchanger, so that the heat recovery amount of the economizer can be ensured, and the refrigerant at the injection port of the compressor is a gas-liquid two-phase refrigerant.

The heat pump system further comprises an expansion valve, and the expansion valve is arranged on a refrigerant pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel. Whether the refrigerant in the second heat exchange channel is guided into the first heat exchange channel can be controlled by controlling the on-off state of the expansion valve, and the opening of the expansion valve can be adjusted to adjust the flow of the refrigerant entering the first heat exchange channel.

In one possible design, the heat pump system further comprises: the first temperature acquisition device is arranged on a pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel; the second temperature acquisition device is arranged at the outlet of the first heat exchange channel.

In this design, the heat pump system further comprises a first temperature acquisition device and a second temperature acquisition device. The first temperature acquisition device is arranged on a refrigerant pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel, and the second temperature acquisition device is arranged on the refrigerant pipeline between the outlet of the first heat exchange channel and the jet orifice of the compressor. The first temperature acquisition device can acquire the temperature of the refrigerant before entering the first heat exchange channel, the second temperature acquisition device can acquire the temperature value of the refrigerant flowing out of the first heat exchange channel, and the temperature difference of the refrigerant flowing through the first heat exchange channel can be calculated according to the temperature value.

It can be understood that the smaller the temperature difference of the refrigerant is, the closer the refrigerant is to the liquid state, and when the temperature difference of the refrigerant is smaller than the set temperature difference, the refrigerant can be considered to be in a gas-liquid two-phase state. The opening degree of the expansion valve is adjusted and controlled according to the temperature difference of the refrigerant, the refrigerant passing through the first heat exchange channel can be guaranteed to be in a gas-liquid two-phase state, heat exchange of the refrigerant in the first heat exchange channel passing through the second heat exchange channel is improved, the temperature of the refrigerant in the first heat exchange channel can be increased, the temperature of the refrigerant entering the injection port of the compressor is improved, and the effect of injecting enthalpy-increasing of the compressor is improved.

In one possible design, the heat pump system further comprises: the first pressure acquisition device is arranged on a refrigerant pipeline between the exhaust port of the compressor and the first heat exchanger.

In this design, the heat pump system further includes a first pressure acquisition device disposed on the refrigerant line between the exhaust port of the compressor and the first heat exchanger, capable of collecting the exhaust pressure value of the compressor.

Obtaining an exhaust pressure value of a compressor, and obtaining a first temperature value at a refrigerant outlet of a first heat exchanger; and searching a corresponding saturated temperature value according to the exhaust pressure value, and determining the supercooling degree according to the saturated temperature value and the first temperature value. And obtaining an exhaust pressure value of the compressor and a first temperature value at a refrigerant outlet of the first heat exchanger, finding a saturation temperature value corresponding to the exhaust pressure of the compressor in a table look-up mode, and calculating according to the saturation temperature value and the first temperature value to obtain the supercooling degree of the first heat exchanger. The supercooling degree of the first heat exchanger calculated by the mode is accurate, and the supercooling degree calculated by the formula controls the flow of the refrigerant from the second heat exchange channel to the second heat exchanger, so that the heat recovery amount of the economizer and the injected refrigerant can be ensured to be in a gas-liquid two-phase state.

In one possible design, the inlet of the second heat exchange channel is connected to the refrigerant outlet of the first heat exchanger, and the heat pump system further comprises: the third temperature acquisition device is arranged at the outlet of the refrigerant of the first heat exchanger; and the fourth temperature acquisition device is arranged at the inlet of the refrigerant of the first heat exchanger.

In the design, the refrigerant flowing out of the first heat exchanger directly flows into the inlet of the second heat exchange channel, and the refrigerant entering the second heat exchange channel can exchange heat with the refrigerant in the first heat exchange channel. Because the refrigerants in the first heat exchange channel and the second heat exchange channel of the economizer are liquid refrigerants, the refrigerants in the injection channel are guaranteed to reach the optimal state, the heat recovery amount of the heat pump system is increased, and the capacity energy efficiency at low temperature is obviously improved.

The heat pump system further comprises a third temperature acquisition device and a fourth temperature acquisition device. The third temperature acquisition device is arranged at a refrigerant outlet of the first heat exchanger, the refrigerant directly enters an inlet of a second heat exchange channel of the economizer after flowing out of the first heat exchanger, and the third temperature acquisition device can acquire the temperature of the refrigerant flowing out of the first heat exchanger. The fourth temperature acquisition device is arranged at the refrigerant inlet of the first heat exchanger and can acquire the temperature of the refrigerant flowing into the first heat exchanger.

In some embodiments, the refrigerant flow between the outlet of the second heat exchange channel and the second heat exchanger is adjusted according to the degree of supercooling. And controlling the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree of the first heat exchanger. In the running process of the heat pump system, the supercooling degree of the first heat exchanger is continuously obtained, the flow of the refrigerant between the second heat exchangers is controlled according to the obtained supercooling degree, and the refrigerant of the injection path can be ensured to reach the optimal state.

According to a third aspect of the present invention there is provided a readable storage medium having stored thereon a program or instructions which when executed by a processor, implement the steps of a method of controlling a heat pump system as in any of the possible designs described above. Therefore, the control method of the heat pump system in any of the above possible designs has all the advantages and will not be described in detail herein.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

Fig. 1 is a schematic flow chart showing a control method of a heat pump system in a first embodiment of the present invention;

fig. 2 shows one of schematic flowcharts of a control method of the heat pump system in the second embodiment of the present invention;

fig. 3 shows a second schematic flowchart of a control method of the heat pump system in the second embodiment of the present invention;

fig. 4 shows one of schematic flowcharts of a control method of the heat pump system in the third embodiment of the present invention;

fig. 5 shows a second schematic flowchart of a control method of the heat pump system in the third embodiment of the present invention;

fig. 6 shows a schematic flowchart III of a control method of the heat pump system in the third embodiment of the invention;

fig. 7 is a schematic diagram showing the structure of a heat pump system in a fourth embodiment of the present invention;

fig. 8 shows a schematic block diagram of a heat pump system in a fourth embodiment of the invention;

fig. 9 shows one of schematic flowcharts of a control method of the heat pump system in the fifth embodiment of the present invention;

fig. 10 shows a second schematic flowchart of a control method of the heat pump system in the fifth embodiment of the present invention.

The correspondence between the reference numerals and the component names in fig. 7 is:

700 heat pump system, 702 compressor, 704 first heat exchanger, 706 second heat exchanger, 708 economizer, 7082 first heat exchange path, 7084 second heat exchange path, 710 throttle component, 712 expansion valve, 714 first temperature acquisition device, 716 second temperature acquisition device, 718 first pressure acquisition device, 724 third temperature acquisition device, 726 fourth temperature acquisition device.

Detailed Description

In order that the above-recited objects, features and advantages of the present invention will be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description. It should be noted that, without conflict, the embodiments of the present invention and features in the embodiments may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those described herein, and therefore the scope of the present invention is not limited to the specific embodiments disclosed below.

A heat pump system, a control method of the heat pump system, and a readable storage medium according to some embodiments of the present invention are described below with reference to fig. 1 to 10.

Embodiment one:

as shown in fig. 1, in one embodiment of the present invention, there is provided a control method of a heat pump system including a compressor, a first heat exchanger, a second heat exchanger, and an economizer including a first heat exchange passage and a second heat exchange passage, an inlet of the first heat exchange passage being connected to an outlet of the second heat exchange passage, an outlet of the first heat exchange passage being connected to an injection port of the compressor, and an outlet of the second heat exchange passage being connected to the second heat exchanger.

The control method of the heat pump system comprises the following steps:

102, acquiring a temperature difference between a refrigerant at an inlet and an outlet of a first heat exchange channel, a supercooling degree of a first heat exchanger and an exhaust superheat degree of a compressor;

104, adjusting the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree;

and step 106, adjusting the flow of the refrigerant in the first heat exchange channel according to the temperature difference of the refrigerant and the superheat degree of the exhaust.

In this embodiment, the present invention provides a control method of a heat pump system for controlling the operation of the heat pump system. The heat pump system comprises a compressor, a first heat exchanger, a second heat exchanger and an economizer. The compressor, the first heat exchanger and the second heat exchanger form a refrigerant loop, and the refrigerant absorbs heat, releases heat and compresses in the refrigerant loop, so that the heat pump system can exchange heat with the outside. The economizer comprises a first heat exchange channel and a second heat exchange channel, wherein an inlet and an outlet of the first heat exchange channel are respectively connected with an outlet of the second heat exchange channel and an injection port of the compressor, the first heat exchange channel is configured as an auxiliary way of the economizer, a refrigerant flows into the first heat exchange channel and exchanges heat with the refrigerant in the second heat exchange channel, and the refrigerant after heat exchange flows out of the first heat exchange channel and enters the injection port of the compressor, so that the injection enthalpy-increasing is performed on the compressor. The inlet and the outlet of the second heat exchange channel are respectively connected with the first heat exchanger and the second heat exchanger, the second heat exchange channel is configured as a main path of the economizer, the first heat exchanger is configured as a condenser in the heat pump system, the second heat exchanger is configured as an evaporator in the heat pump system, the refrigerant flowing out of the first heat exchanger exchanges heat with the second heat exchange channel in the process of passing through the first heat exchange channel of the economizer, and the refrigerant after heat exchange passes through the heat exchanger and enters the air return port of the compressor for compression again. The refrigerant in the first heat exchange channel exchanges heat through the second heat exchange channel, so that the enthalpy value in the first heat exchange channel can be increased, and the effect of injecting enthalpy increase to the compressor is improved.

The control method for the heat pump system controls the flow of the refrigerant between the outlet of the second heat exchange channel and the second heat exchanger and the flow of the refrigerant in the first heat exchange channel, so that the refrigerant entering the injection port of the compressor is in a gas-liquid two-phase state. By controlling the refrigerant at the injection port into a gas-liquid two-phase state, compared with the scheme of performing vapor injection and enthalpy increase through a gaseous refrigerant in the related art, the controllability of the exhaust temperature of the compressor under the working condition of higher pressure ratio is improved, the exhaust temperature can be ensured to be within the reasonable range requirement, and the energy efficiency of the system is highest. The exhaust temperature of the heat pump system at the high pressure ratio can be controlled, so that the heating capacity of the heat pump system is improved, and the operation range of the system is widened. The refrigerant is supercooled through the second heat exchange channel of the economizer and then enters the first heat exchange channel again for evaporation and heat absorption, and the refrigerants in the first heat exchange channel and the second heat exchange channel in the economizer are liquid refrigerants, so that the heat exchange capacity of the economizer is increased, the heat recovery capacity of the system is increased, and the energy efficiency of the heat pump system at low temperature is obviously improved.

Embodiment two:

as shown in fig. 2, on the basis of the control method of the heat pump system in the first embodiment, the step of obtaining the supercooling degree of the first heat exchanger specifically includes:

step 202, obtaining an exhaust pressure value of a compressor and a first temperature value at a refrigerant outlet of a first heat exchanger;

step 204, searching a corresponding saturated temperature value according to the exhaust pressure value;

In step 206, the supercooling degree is determined according to the saturation temperature value and the first temperature value.

In this embodiment, the supercooling degree of the first heat exchanger is obtained by a calculation method, and a specific formula is as follows:

T _sc ＝T _C－ T ₁ 。

In any of the above embodiments, the heat pump system further includes a throttling part disposed on a line between the outlet of the second heat exchange channel and the second heat exchanger;

as shown in fig. 3, the step of adjusting the refrigerant flow between the outlet of the second heat exchange channel and the second heat exchanger according to the supercooling degree specifically includes:

step 302, determining that the supercooling degree is larger than or equal to a first set supercooling degree, and controlling the opening degree of the throttling component to be increased;

And 304, determining that the supercooling degree is smaller than or equal to a second set supercooling degree, and controlling the opening degree of the throttling component to be reduced.

Wherein the first set supercooling degree is greater than the second set supercooling degree.

In this embodiment, the heat pump system further includes a throttling member disposed on the refrigerant line between the second heat exchange passage and the second heat exchanger. The opening of the throttling component is controlled to directly regulate the flow of the refrigerant from the outlet of the second heat exchange channel to the second heat exchanger. The adjusting mode of the throttling component according to the supercooling degree of the first heat exchanger is specifically as follows:

Embodiment III:

on the basis of the control method of the heat pump system in the first embodiment, the heat pump system further includes: the expansion valve is arranged on a pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel.

As shown in fig. 4, the step of adjusting the flow rate of the refrigerant in the first heat exchange channel according to the temperature difference of the refrigerant and the superheat degree of the exhaust specifically includes:

step 402, obtaining a target exhaust superheat interval and a set temperature difference;

and step 404, adjusting the opening of the expansion valve so that the temperature difference of the refrigerant is smaller than the set temperature difference and the exhaust superheat degree is in the target exhaust superheat degree interval.

In this embodiment, the heat pump system further comprises an expansion valve disposed on the refrigerant line between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel. Whether the refrigerant in the second heat exchange channel is guided into the first heat exchange channel can be controlled by controlling the on-off state of the expansion valve, and the opening of the expansion valve can be adjusted to adjust the flow of the refrigerant entering the first heat exchange channel.

As shown in fig. 5, in any of the above embodiments, the step of adjusting the opening degree of the expansion valve specifically includes:

step 502, determining that the temperature difference of the refrigerant is larger than or equal to a set temperature difference, and controlling the expansion valve to increase the opening;

and 504, determining that the exhaust superheat degree is smaller than the minimum value of the target exhaust superheat degree interval, and controlling the expansion valve to reduce the opening degree.

In this embodiment, in the process of adjusting the opening of the expansion valve, it is necessary to adjust the opening of the expansion valve according to the numerical relationship between the temperature difference of the refrigerant and the set temperature difference, and then adjust the opening of the expansion valve according to the exhaust superheat of the compressor when the temperature difference of the refrigerant is lower than the set temperature difference. In order to make the temperature difference of the refrigerant lower than the set temperature difference, the opening degree of the expansion valve needs to be opened as much as possible, and if the opening degree of the expansion valve is too large, the exhaust superheat degree of the compressor is too low, so in the initial stage of the operation of the heat pump system, the expansion valve is adjusted to be lower than the set temperature difference by adjusting the expansion valve, and then the expansion valve is adjusted according to the exhaust superheat degree.

In some embodiments, the set temperature difference is set to 2 ℃.

As shown in fig. 6, in any of the above embodiments, the step of obtaining the target exhaust superheat interval specifically includes:

step 602, obtaining a return air pressure value of a compressor and an exhaust air pressure value of the compressor;

step 604, calculating to obtain a target exhaust superheat degree according to the return air pressure value and the exhaust pressure value;

step 606, determining a target exhaust superheat interval according to the target exhaust superheat.

In this embodiment, the target exhaust superheat degree is calculated by acquiring a target exhaust superheat degree section line, and the exhaust superheat degree section is determined according to the target exhaust superheat degree. The calculation of the target exhaust superheat degree is required to be calculated according to a pressure ratio, wherein the pressure ratio is the ratio of the highest pressure to the lowest pressure in the heat pump system, the highest pressure in the heat pump system is the exhaust pressure of the compressor, the lowest pressure in the heat pump system is the return air pressure of the compressor, and a specific calculation formula is as follows:

D _SH ＝α×(P ₁ /P ₂ )；

It will be appreciated that the return air pressure value of the compressor is calculated from the ambient temperature, the outlet temperature of the second heat exchanger and the operating parameters of the compressor. The corresponding pressure sensor can be arranged at the air return port of the compressor, and the pressure value of the air return port of the compressor can be directly acquired through the pressure sensor.

Embodiment four:

as shown in fig. 7 and 8, in another embodiment of the present invention, there is provided a heat pump system 700, the heat pump system 700 including a compressor 702, a first heat exchanger 704 and a second heat exchanger 706 to form a refrigerant circuit, the heat pump system 700 further including: an economizer 708 comprising a first heat exchange passage 7082 and a second heat exchange passage 7084, an inlet of the first heat exchange passage 7082 being connected to an outlet of the second heat exchange passage 7084, an outlet of the first heat exchange passage 7082 being connected to an injection port of the compressor 702, an outlet of the second heat exchange passage 7084 being connected to the second heat exchanger 706; a memory 720, the memory 720 having stored thereon a program or instructions; the processor 722 executes a program or instructions by the processor 722 to implement the steps of the control method of the heat pump system in any of the embodiments described above.

As shown in fig. 7, the heat pump system 700 provided by the present invention includes a compressor 702, a first heat exchanger 704, a second heat exchanger 706, and an economizer 708. The compressor 702, the first heat exchanger 704 and the second heat exchanger 706 form a refrigerant circuit, and the refrigerant absorbs heat, releases heat and compresses in the refrigerant circuit, so that the heat pump system 700 can exchange heat with the outside. The economizer 708 comprises a first heat exchange channel 7082 and a second heat exchange channel 7084, wherein an inlet and an outlet of the first heat exchange channel 7082 are respectively connected with an outlet of the second heat exchange channel 7084 and an injection port of the compressor 702, the first heat exchange channel 7082 is configured as an auxiliary way of the economizer 708, the refrigerant flows into the first heat exchange channel 7082 and exchanges heat with the refrigerant in the second heat exchange channel 7084, and the heat-exchanged refrigerant flows out of the first heat exchange channel 7082 and enters the injection port of the compressor 702, so that the compressor 702 is injected and enthalpy-increased. The inlet and outlet of the second heat exchange channel 7084 are respectively connected with the first heat exchanger 704 and the second heat exchanger 706, the second heat exchange channel 7084 is configured as a main path of the economizer 708, the first heat exchanger 704 is configured as a condenser in the heat pump system 700, the second heat exchanger 706 is configured as an evaporator in the heat pump system 700, and in the process that the refrigerant flowing out of the first heat exchanger 704 passes through the first heat exchange channel 7082 of the economizer 708, heat exchange is performed with the second heat exchange channel 7084, and the refrigerant after heat exchange passes through the heat exchangers and enters the air return port of the compressor 702 for compression again. The heat exchange of the refrigerant in the first heat exchange channel 7082 through the second heat exchange channel 7084 can raise the enthalpy value of the refrigerant in the first heat exchange channel 7082, thereby improving the effect of injecting the enthalpy increase to the compressor 702.

As shown in fig. 8, the heat pump system 700 provided by the present invention further includes a memory 720 and a processor 722, where the processor 722 can control the flow rate of the refrigerant between the outlet of the second heat exchange channel 7084 and the second heat exchanger 706 and the flow rate of the refrigerant in the first heat exchange channel 7082 by executing the program or the instruction stored in the memory, so that the refrigerant flowing into the injection port of the compressor 702 is in a gas-liquid two-phase state.

Specifically, in the control method for a heat pump system provided by the invention, the refrigerant flow between the outlet of the second heat exchange channel 7084 and the second heat exchanger 706, and the refrigerant flow in the first heat exchange channel 7082 are controlled, so that the refrigerant entering the injection port of the compressor 702 is in a gas-liquid two-phase state. By controlling the refrigerant at the injection port to be in a gas-liquid two-phase state, compared with the scheme of performing the vapor injection enthalpy increase through the gaseous refrigerant in the related art, the controllability of the exhaust temperature of the compressor 702 under the working condition of higher pressure ratio is improved, the exhaust temperature can be ensured to be in a reasonable range requirement, and the energy efficiency of the system is highest. The exhaust temperature of the heat pump system 700 at a high pressure ratio can be controlled, so that the heating capacity of the heat pump system 700 is improved, and the operation range of the system is widened. Because the refrigerant is partially re-evaporated and absorbed in the first heat exchange channel 7082 after being supercooled through the second heat exchange channel 7084 of the economizer 708, and the refrigerant in the first heat exchange channel 7082 and the refrigerant in the second heat exchange channel 7084 of the economizer 708 are both liquid refrigerants, the heat exchange capacity of the economizer 708 is increased, the heat recovery capacity of the system is increased, and the capacity and energy efficiency of the heat pump system 700 at low temperature are obviously improved.

It is understood that in the related art heat pump system 700 for injecting enthalpy by gaseous refrigerant, in case that the pressure ratio of the compressor 702 is higher than 9, the exhaust temperature is too high, resulting in poor controllability. According to the invention, the gas-liquid two-phase refrigerant is input to the injection port, so that the controllability of the exhaust temperature is improved.

And controlling the flow of the refrigerant between the outlet of the second heat exchange channel 7084 and the second heat exchanger 706 according to the supercooling degree of the first heat exchanger 704. In the process of the operation of the heat pump system 700, the supercooling degree of the first heat exchanger 704 is continuously obtained, and the flow of the refrigerant between the second heat exchangers 706 is controlled according to the obtained supercooling degree, so that the refrigerants in the first heat exchange channel 7082 and the second heat exchange channel 7084 in the economizer can be ensured to be liquid refrigerants, the refrigerant in the injection path can be ensured to reach the optimal state, and the heat recovery amount of the heat pump system 700 can be improved. The flow rate of the refrigerant in the first heat exchange channel 7082 is controlled according to the temperature difference between the refrigerant at the inlet and the refrigerant at the outlet of the first heat exchange channel 7082 and the exhaust superheat degree of the compressor 702, so that the state of the refrigerant in the injection path is further controlled, and the heat pump system 700 operates with higher energy efficiency.

In any of the above embodiments, the heat pump system 700 further comprises: a throttle member 710 disposed on a line between the outlet of the second heat exchange passage 7084 and the second heat exchanger 706; an expansion valve 712 is disposed in the line between the inlet of the first heat exchange passage 7082 and the outlet of the second heat exchange passage 7084.

In this embodiment, the heat pump system 700 further includes a throttling component 710, the throttling component 710 being disposed on the refrigerant line between the second heat exchange passage 7084 and the second heat exchanger 706. The opening degree of the throttle 710 is controlled to directly regulate the flow of the refrigerant from the outlet of the second heat exchange passage 7084 to the second heat exchanger 706. The throttle member 710 is adjusted according to the degree of supercooling of the first heat exchanger 704 in the following manner:

the supercooling degree of the first heat exchanger 704 is continuously obtained, and when the detected supercooling degree is equal to or higher than the first set supercooling degree, it is determined that the supercooling degree is excessively high at this time, and the throttle 710 is controlled to increase the opening degree. When the detected supercooling degree is equal to or less than the second set supercooling degree, it is determined that the supercooling degree is too low at this time, the expansion valve 712 is controlled to reduce the opening degree, and the first set supercooling degree is greater than the second set supercooling degree. Wherein, the second set supercooling degree to the first set supercooling degree form a numerical interval of supercooling degree, and when the obtained supercooling degree is within the numerical interval, it is determined that the throttle 710 does not need to be adjusted in opening degree. The opening degree of the throttle 710 is adjusted by the outlet supercooling degree of the first heat exchanger 704, so that the heat recovery amount of the economizer 708 can be ensured, and the refrigerant at the injection port of the compressor 702 is a gas-liquid two-phase refrigerant.

The heat pump system 700 further includes an expansion valve 712, the expansion valve 712 being disposed on the refrigerant line between the inlet of the first heat exchange passage 7082 and the outlet of the second heat exchange passage 7084. Whether the refrigerant in the second heat exchange channel 7084 is guided into the first heat exchange channel 7082 can be controlled by controlling the on-off state of the expansion valve 712, and the opening of the expansion valve 712 can be adjusted to adjust the flow of the refrigerant entering the first heat exchange channel 7082.

The step of adjusting the flow rate of the refrigerant in the first heat exchange channel 7082 according to the temperature difference of the refrigerant at the inlet and the outlet of the first heat exchange channel 7082 and the superheat degree of the exhaust gas includes: the target superheat interval and the set temperature difference are acquired, and the opening of the expansion valve 712 is adjusted according to the numerical relationship between the refrigerant temperature difference and the set temperature difference and the numerical relationship between the exhaust superheat and the target superheat interval. The opening degree of the expansion valve 712 is adjusted so that the refrigerant temperature difference is smaller than the set temperature difference and the exhaust superheat degree is within the target exhaust superheat degree range.

It can be understood that if the temperature difference is smaller than the set temperature difference, it can be determined that the state of the refrigerant is a gas-liquid two-phase refrigerant. In order to reduce the temperature difference, the opening degree of the expansion valve 712 needs to be as large as possible, and in order to avoid excessively large opening degree of the expansion valve 712 and excessively low discharge superheat degree of the compressor 702, the opening degree of the expansion valve 712 is again adjusted according to the discharge superheat degree. The refrigerant at the injection port is in a gas-liquid two-phase state under the premise of ensuring the stable operation of the compressor 702. Not only improves the overall capacity energy efficiency of the heat pump system 700, but also ensures the running stability of the heat pump system 700.

In any of the above embodiments, the heat pump system 700 further comprises: the first temperature acquiring device 714 is arranged on a pipeline between the inlet of the first heat exchange channel 7082 and the outlet of the second heat exchange channel 7084; the second temperature acquiring device 716 is disposed at the outlet of the first heat exchanging channel 7082.

In this embodiment, the heat pump system 700 further includes a first temperature acquisition device 714 and a second temperature acquisition device 716. The first temperature acquiring device 714 is disposed on the refrigerant line between the inlet of the first heat exchanging channel 7082 and the outlet of the second heat exchanging channel 7084, and the second temperature acquiring device 716 is disposed on the refrigerant line between the outlet of the first heat exchanging channel 7082 and the injection port of the compressor 702. The first temperature acquiring device 714 can acquire the temperature of the refrigerant before entering the first heat exchange channel 7082, and the second temperature acquiring device 716 can acquire the temperature value of the refrigerant flowing out of the first heat exchange channel 7082, and can calculate the temperature difference of the refrigerant flowing through the first heat exchange channel 7082 according to the temperature value.

It can be understood that the smaller the temperature difference of the refrigerant is, the closer the refrigerant is to the liquid state, and when the temperature difference of the refrigerant is smaller than the set temperature difference, the refrigerant can be considered to be in a gas-liquid two-phase state. The opening degree of the expansion valve 712 is adjusted and controlled according to the temperature difference of the refrigerant, so that the refrigerant passing through the first heat exchange channel 7082 is in a gas-liquid two-phase state, heat exchange of the refrigerant in the first heat exchange channel 7082 through the second heat exchange channel 7084 is improved, the enthalpy value in the first heat exchange channel 7082 can be increased, and the effect of injecting enthalpy to the compressor 702 is improved.

In any of the above embodiments, the heat pump system 700 further comprises: the first pressure acquiring device 718 is disposed on the refrigerant line between the discharge port of the compressor 702 and the first heat exchanger 704.

In this embodiment, the heat pump system 700 further includes a first pressure acquisition device 718, where the first pressure acquisition device 718 is disposed on a refrigerant line between the exhaust port of the compressor 702 and the first heat exchanger 704, and is capable of acquiring an exhaust pressure value of the compressor 702.

Acquiring an exhaust pressure value of the compressor 702, and acquiring a first temperature value at a refrigerant outlet of the first heat exchanger 704; and searching a corresponding saturated temperature value according to the exhaust pressure value, and determining the supercooling degree according to the saturated temperature value and the first temperature value. The method comprises the steps of obtaining an exhaust pressure value of the compressor 702 and a first temperature value at a refrigerant outlet of the first heat exchanger 704, finding a saturation temperature value corresponding to the exhaust pressure of the compressor 702 in a table look-up mode, and calculating according to the saturation temperature value and the first temperature value to obtain the supercooling degree of the first heat exchanger 704. The supercooling degree of the first heat exchanger 704 calculated in the above manner is accurate, and the control of the refrigerant flow from the second heat exchange channel 7084 to the second heat exchanger 706 according to the supercooling degree calculated in the above formula can ensure that the heat recovery amount of the economizer 708 and the injected refrigerant are in a gas-liquid two-phase state.

In any of the above embodiments, the inlet of the second heat exchange channel 7084 is connected to the refrigerant outlet of the first heat exchanger 704, and the heat pump system 700 further includes: a third temperature acquiring device 724 disposed at the outlet of the refrigerant of the first heat exchanger 704; the fourth temperature acquiring device 726 is disposed at the inlet of the refrigerant of the first heat exchanger 704.

In this embodiment, the refrigerant flowing out of the first heat exchanger 704 directly flows into the inlet of the second heat exchange channel 7084, and the refrigerant entering the second heat exchange channel 7084 can exchange heat with the refrigerant in the first heat exchange channel 7082. Because the refrigerant in the first heat exchange channel 7082 and the refrigerant in the second heat exchange channel 7084 are liquid refrigerant, the heat exchange amount of the economizer 708 is increased, the refrigerant in the injection path is ensured to reach the optimal state, the heat recovery amount of the heat pump system 700 is improved, and the capacity energy efficiency at low temperature is obviously improved.

The heat pump system 700 further comprises a third temperature acquisition device 724, a fourth temperature acquisition device 726. The third temperature acquiring device 724 is disposed at the refrigerant outlet of the first heat exchanger 704, and the refrigerant flows out of the first heat exchanger 704 and directly enters the inlet of the second heat exchanging channel 7084 of the economizer 708, and the third temperature acquiring device 724 can acquire the temperature of the refrigerant flowing out of the first heat exchanger 704. The fourth temperature acquisition device 726 is disposed at the refrigerant inlet of the first heat exchanger 704, and the fourth temperature acquisition device 726 can acquire the temperature of the refrigerant flowing into the first heat exchanger 704.

In some embodiments, the refrigerant flow between the outlet of the second heat exchange passage 7084 and the second heat exchanger 706 is adjusted according to the degree of subcooling. And controlling the flow of the refrigerant between the outlet of the second heat exchange channel 7084 and the second heat exchanger 706 according to the supercooling degree of the first heat exchanger 704. In the process of the operation of the heat pump system 700, the supercooling degree of the first heat exchanger 704 is continuously obtained, and the flow of the refrigerant between the second heat exchangers 706 is controlled according to the obtained supercooling degree, so that the refrigerants in the first heat exchange channel and the second heat exchange channel in the economizer are both guaranteed to be liquid refrigerants, the refrigerant in the injection path is guaranteed to reach the optimal state, and the heat recovery amount of the heat pump system 700 is improved.

Fifth embodiment:

in a complete embodiment of the present invention, a control method of a heat pump system is provided for controlling the heat pump system in the fourth embodiment.

As shown in fig. 9, the control method for controlling the throttle member of the heat pump system includes:

step 902, controlling the heat pump system to start up in a heating mode;

step 904, acquiring the supercooling degree of the first heat exchanger, and determining the relation between the supercooling degree and a set supercooling degree interval;

step 906, controlling the throttling component to keep the current opening degree based on the supercooling degree being in the target supercooling degree interval;

Step 908, controlling the throttle component to increase the opening degree based on the supercooling degree being greater than or equal to the maximum value of the supercooling degree interval;

step 910, controlling the throttle component to reduce the opening degree based on the supercooling degree being less than or equal to the minimum value of the supercooling degree interval;

step 912, maintaining the current state until the end of the run.

In this embodiment, the throttling means is controlled in dependence of the first heat exchanger outlet subcooling. And (3) obtaining the actual supercooling degree through calculation, comparing the actual supercooling degree with a target supercooling degree interval set by a system, and adjusting the throttling component according to the size relation of the actual supercooling degree and the target supercooling degree interval.

The step of obtaining the supercooling degree of the first heat exchanger specifically comprises the following steps: obtaining an exhaust pressure value of a compressor, and obtaining a first temperature value at a refrigerant outlet of a first heat exchanger; and searching a corresponding saturated temperature value according to the exhaust pressure value, and determining the supercooling degree according to the saturated temperature value and the first temperature value.

The supercooling degree of the first heat exchanger is obtained in a calculation mode, and the specific formula is as follows:

T _sc ＝T _C－ T ₁ 。

As shown in fig. 10, the control method for controlling the expansion valve of the heat pump system includes:

step 1002, controlling a compressor to be in an injection enthalpy-increasing operation state;

Step 1004, adjusting the opening degree of an expansion valve;

step 1006, judging whether the temperature difference of the refrigerant is smaller than the set temperature difference, if yes, executing step 1008, and if not, returning to execute step 1004;

step 1008, judging whether the exhaust superheat degree is in the target exhaust superheat degree interval, if yes, executing step 1010, and if not, returning to executing step 1004;

and step 1010, maintaining the current state until the operation is finished.

In this embodiment, after the expansion valve is opened, the initial opening degree is small, the flow rate of the refrigerant in the injection path is small, the refrigerant in the first heat exchange channel in the economizer absorbs heat to become gaseous, and the refrigerant injected into the compressor is gaseous refrigerant. And when the opening degree of the expansion valve is increased, the flow rate of the refrigerant in the injection path is gradually increased, the state of the refrigerant injected into the compressor is excessively changed into a gas-liquid two-phase state, and the temperature difference of the refrigerant is gradually reduced in the valve opening process. When the temperature difference of the refrigerant is smaller than the set temperature difference, the state of the refrigerant can be judged to be a gas-liquid two-phase state, and the set temperature difference is 2 ℃. At this time, the state of the refrigerant at the injection port is substantially in an optimal state, and the expansion valve opening is an optimal opening.

If the opening of the expansion valve is increased again, the flow of the injection path is increased, the power of the compressor is obviously increased, and the performance of the whole machine is reduced.

In the process of adjusting the opening of the expansion valve, the opening of the expansion valve needs to be adjusted according to the numerical relation between the temperature difference of the refrigerant and the set temperature difference, and when the temperature difference of the refrigerant is lower than the set temperature difference, the opening of the expansion valve is adjusted according to the exhaust superheat degree of the compressor. In order to make the temperature difference of the refrigerant lower than the set temperature difference, the opening degree of the expansion valve needs to be opened as much as possible, and if the opening degree of the expansion valve is too large, the exhaust superheat degree of the compressor is too low, so in the initial stage of the operation of the heat pump system, the expansion valve is adjusted to be lower than the set temperature difference by adjusting the expansion valve, and then the expansion valve is adjusted according to the exhaust superheat degree.

Example six:

in still another embodiment of the present invention, there is provided a readable storage medium having a program stored thereon, which when executed by a processor, implements the control method of the heat pump system in any of the above embodiments, thereby having all the advantageous technical effects of the control method of the heat pump system in any of the above embodiments.

Among them, readable storage media such as Read-Only Memory (ROM), random access Memory (Random Access Memory, RAM), magnetic disk or optical disk, and the like.

It should be understood that in the claims, the description, and the drawings of the present invention, the term "plurality" means two or more, and unless otherwise explicitly defined, the orientation or positional relationship indicated by the terms "upper", "lower", etc. are based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present invention and making the description process easier, and not for the purpose of indicating or implying that the apparatus or element in question must have the particular orientation described, be constructed and operated in the particular orientation, and therefore such description should not be construed as limiting the present invention; the terms "connected," "mounted," "secured," and the like are to be construed broadly, and may be, for example, a fixed connection between a plurality of objects, a removable connection between a plurality of objects, or an integral connection; the objects may be directly connected to each other or indirectly connected to each other through an intermediate medium. The specific meaning of the terms in the present invention can be understood in detail from the above data by those of ordinary skill in the art.

The description of the terms "one embodiment," "some embodiments," "particular embodiments," and the like in the claims, specification, and drawings of the present invention mean 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 invention. In the claims, specification and drawings of the invention, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method of a heat pump system, characterized in that the heat pump system includes a compressor, a first heat exchanger, a second heat exchanger, and an economizer including a first heat exchange passage and a second heat exchange passage, an inlet of the first heat exchange passage being connected to an outlet of the second heat exchange passage, an outlet of the first heat exchange passage being connected to an injection port of the compressor, an outlet of the second heat exchange passage being connected to the second heat exchanger, the control method comprising:

Acquiring the supercooling degree of the first heat exchanger, the temperature difference between the refrigerant at the inlet and the refrigerant at the outlet of the first heat exchange channel and the exhaust superheat degree of the compressor;

the refrigerant flow between the outlet of the second heat exchange channel and the second heat exchanger is adjusted according to the supercooling degree, and the refrigerant flow in the first heat exchange channel is adjusted according to the refrigerant temperature difference and the exhaust superheat degree, so that the refrigerant flowing into the jet orifice of the compressor is in a gas-liquid two-phase state;

the heat pump system further includes: the expansion valve is arranged on a pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel, and the step of adjusting the refrigerant flow in the first heat exchange channel according to the refrigerant temperature difference and the exhaust superheat degree specifically comprises the following steps:

acquiring a target exhaust superheat interval and a set temperature difference;

and adjusting the opening of the expansion valve so that the temperature difference of the refrigerant is smaller than a set temperature difference, and the exhaust superheat degree is in the target exhaust superheat degree interval.

2. The method according to claim 1, wherein the step of obtaining the supercooling degree of the first heat exchanger specifically includes:

Acquiring an exhaust pressure value of the compressor, and acquiring a first temperature value at a refrigerant outlet of the first heat exchanger;

and searching a corresponding saturated temperature value according to the exhaust pressure value, and determining the supercooling degree according to the saturated temperature value and the first temperature value.

3. The method according to claim 2, further comprising a throttle member provided in a line between an outlet of the second heat exchanging channel and the second heat exchanger, wherein the step of adjusting a refrigerant flow rate between the outlet of the second heat exchanging channel and the second heat exchanger according to the supercooling degree specifically comprises:

controlling the throttle member to increase the opening degree based on the supercooling degree being equal to or greater than a first set supercooling degree;

and controlling the throttling component to reduce the opening degree based on the supercooling degree being smaller than or equal to a second set supercooling degree, wherein the first set supercooling degree is larger than the second set supercooling degree.

4. A control method of a heat pump system according to any one of claims 1 to 3, characterized in that the step of adjusting the opening degree of the expansion valve specifically comprises:

controlling the expansion valve to increase the opening based on the temperature difference of the refrigerant being greater than or equal to a set temperature difference;

And determining that the exhaust superheat degree is smaller than the minimum value of the target exhaust superheat degree interval, and controlling the expansion valve to reduce the opening.

5. A control method of a heat pump system according to any one of claims 1 to 3, characterized in that the step of obtaining a target exhaust superheat interval specifically includes:

acquiring a return air pressure value of the compressor and an exhaust air pressure value of the compressor;

calculating according to the air return pressure value and the exhaust pressure value to obtain a target exhaust superheat degree;

and determining the target exhaust superheat degree interval according to the target exhaust superheat degree.

6. A heat pump system comprising a compressor, a first heat exchanger, and a second heat exchanger to form a refrigerant circuit, the heat pump system further comprising:

the economizer comprises a first heat exchange channel and a second heat exchange channel, wherein an inlet of the first heat exchange channel is connected with an outlet of the second heat exchange channel, an outlet of the first heat exchange channel is connected with an injection port of the compressor, and an outlet of the second heat exchange channel is connected with a second heat exchanger;

the expansion valve is arranged on a pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel;

A memory having a program or instructions stored thereon;

a processor executing the program or instructions to implement the steps of the control method of the heat pump system according to any one of claims 1 to 5.

7. The heat pump system of claim 6, further comprising:

and the throttling component is arranged on a pipeline between the outlet of the second heat exchange channel and the second heat exchanger.

8. The heat pump system of claim 7, further comprising:

the first temperature acquisition device is arranged on a pipeline between the inlet of the first heat exchange channel and the outlet of the second heat exchange channel;

the second temperature acquisition device is arranged at the outlet of the first heat exchange channel.

9. The heat pump system according to any one of claims 6 to 8, further comprising:

the first pressure acquisition device is arranged on a refrigerant pipeline between an exhaust port of the compressor and the first heat exchanger.

10. The heat pump system of claim 6, wherein the inlet of the second heat exchange channel is connected to the refrigerant outlet of the first heat exchanger, the heat pump system further comprising:

The third temperature acquisition device is arranged at the outlet of the refrigerant of the first heat exchanger;

and the fourth temperature acquisition device is arranged at the inlet of the refrigerant of the first heat exchanger.

11. A readable storage medium, characterized in that the readable storage medium has stored thereon a program or instructions which, when executed by a processor, implement the steps of the control method of the heat pump system according to any one of claims 1 to 5.