阅读说明：本技术 热泵系统及其控制方法 (Heat pump system and control method thereof ) 是由 周建武 李艳敏 张恩太 于 2020-06-18 设计创作，主要内容包括：本发明公开了一种热泵系统及其控制方法,所述系统包括：压缩机,第一单向阀,其入口与所述压缩机的出口连接；四通阀,四通阀的第一端与第一单向阀的出口连接；冷凝器,其第一端与四通阀的第二端连接；第二单向阀,其入口与所述冷凝器的第二端连接；第一膨胀阀,其第一端与所述第二单向阀的出口连接；蒸发器,其第一端与所述第一膨胀阀的第二端连接,所述蒸发器的第二端与所述四通阀的第四端连接；第二膨胀阀,其第一端与所述第二单向阀的出口连接；捕水器,其第一端与所述第二膨胀阀的第二端连接,所述补水器的第二端与所述四通阀的第三端和压缩机入口连接。本发明可以实现多模式切换,充分利用冷量。本发明可以应用于热泵技术领域。(The invention discloses a heat pump system and a control method thereof, wherein the system comprises: the inlet of the first check valve is connected with the outlet of the compressor; the first end of the four-way valve is connected with the outlet of the first one-way valve; a first end of the condenser is connected with a second end of the four-way valve; a second one-way valve, an inlet of which is connected with the second end of the condenser; a first expansion valve, a first end of which is connected with an outlet of the second one-way valve; a first end of the evaporator is connected with a second end of the first expansion valve, and a second end of the evaporator is connected with a fourth end of the four-way valve; a second expansion valve, a first end of which is connected with an outlet of the second one-way valve; and the first end of the water catcher is connected with the second end of the second expansion valve, and the second end of the water replenishing device is connected with the third end of the four-way valve and the inlet of the compressor. The invention can realize multi-mode switching and fully utilize the cold quantity. The invention can be applied to the technical field of heat pumps.)

1. A heat pump system, comprising:

a compressor for compressing a refrigerant gas;

a first check valve, an inlet of which is connected with an outlet of the compressor;

a four-way valve comprising a first end, a second end, a third end and a fourth end; when the first end of the four-way valve is connected with the second end of the four-way valve, the third end of the four-way valve is connected with the fourth end of the four-way valve; when the first end of the four-way valve is connected with the fourth end of the four-way valve, the third end of the four-way valve is connected with the second end of the four-way valve; the first end of the four-way valve is connected with the outlet of the first one-way valve;

a condenser, the first end of which is connected with the second end of the four-way valve;

a second one-way valve, an inlet of which is connected with the second end of the condenser;

a first expansion valve, a first end of which is connected with an outlet of the second one-way valve;

a first end of the evaporator is connected with a second end of the first expansion valve, and a second end of the evaporator is connected with a fourth end of the four-way valve;

a second expansion valve, a first end of which is connected with an outlet of the second one-way valve;

a first end of the water catcher is connected with a second end of the second expansion valve, and a second end of the water replenishing device is connected with a third end of the four-way valve;

and the first end of the air separation device is connected with the third end of the four-way valve, and the second end of the air separation device is connected with the inlet of the compressor.

2. A heat pump system according to claim 1, wherein said system further comprises:

a third expansion valve, a first end of which is connected with an outlet of the second one-way valve;

a first end of the heat exchanger is connected with a second end of the third expansion valve, and a second end of the heat exchanger is connected with a third end of the four-way valve;

and the water pump is connected in the heat exchange waterway of the heat exchanger.

3. A heat pump system according to claim 1, wherein said system further comprises:

the heat storage tank and the filter are connected in series between the condenser and the second one-way valve.

4. A heat pump system according to claim 2, wherein said first expansion valve, said second expansion valve and said third expansion valve are electronic expansion valves.

5. A heat pump system according to claim 2, wherein said system further comprises:

the first temperature sensor is arranged at the outlet of the first one-way valve;

a second temperature sensor disposed at the compressor inlet;

a third temperature sensor disposed on the evaporator;

a fourth temperature sensor disposed in the system deployment environment;

a fifth temperature sensor disposed on the water trap;

a sixth temperature sensor disposed at a second end of the heat exchanger;

and the controller controls the four-way valve and the first to third expansion valves according to output signals of the first to sixth temperature sensors.

6. A heat pump system according to claim 1, wherein: the condenser, the evaporator and the water catcher are all provided with fans.

7. A control method of a heat pump system according to claim 2, characterized by comprising the steps of:

determining a working mode;

and controlling the states of the first to third expansion valves and the four-way valve according to the working mode.

8. The control method of the heat pump system according to claim 7, wherein the operation mode includes a drying mode, a drying and dehumidifying mode, a drying and air-conditioning mode, an air-conditioning mode, a dehumidifying mode, and a standby mode;

the control of the states of the first to third expansion valves and the four-way valve according to the working mode specifically comprises:

when the working mode is determined to be the drying mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the first expansion valve to be opened, and controlling the second expansion valve and the third expansion valve to be closed;

when the working mode is determined to be a drying and dehumidifying mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the second expansion valve to be opened, and controlling the first expansion valve and the third expansion valve to be closed;

when the working mode is determined to be a drying air-conditioning mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the third expansion valve to be opened and controlling the first expansion valve and the second expansion valve to be closed;

when the working mode is determined to be a dehumidification mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a fourth end of the four-way valve, controlling the first expansion valve and the second expansion valve to be opened and controlling the third expansion valve to be closed;

and when the working mode is determined to be an air-conditioning mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a fourth end of the four-way valve, controlling the first expansion valve and the third expansion valve to be opened and controlling the second expansion valve to be closed.

9. The method of controlling a heat pump system according to claim 8, further comprising the steps of:

acquiring the water temperature of an air conditioner;

acquiring the ambient temperature of a drying room;

acquiring humidity of a drying room;

and determining a working mode according to the air conditioner water temperature, the drying room environment temperature and the drying room humidity.

10. The method for controlling a heat pump system according to claim 9, wherein said determining an operation mode according to the air conditioner water temperature, the drying room ambient temperature and the drying room humidity comprises:

when the temperature of the drying room is lower than a first drying room temperature threshold value, the humidity of the drying room is higher than a first drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a drying and dehumidifying mode;

when the temperature of the drying room is lower than a first drying room temperature threshold value, the water temperature of the air conditioner is higher than a second air conditioner water temperature threshold value, and the humidity of the drying room is lower than a second drying room humidity threshold value, determining that the working mode is a drying air-conditioning mode;

when the temperature of the drying room is higher than a second drying room temperature threshold value, the water temperature of the air conditioner is higher than a first air conditioner water temperature threshold value, and the humidity of the drying room is lower than a second drying room humidity threshold value, determining that the working mode is the air conditioning mode;

when the temperature of the drying room is higher than a second drying room temperature threshold value, the humidity of the drying room is higher than a first drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a dehumidification mode;

when the temperature of the drying room is lower than a first drying room temperature threshold value, the humidity of the drying room is lower than a second drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a drying mode;

and when the temperature of the drying room is higher than a second drying room temperature threshold value, the humidity of the drying room is lower than a second drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, entering a standby mode.

Technical Field

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

Background

In the traditional drying room, along with the gradual development and maturity of the heat pump technology, the air source heat pump is more and more favored by people because of a series of advantages of energy conservation, environmental protection and the like. At present, the air source heat pump is generally applied to various fields of civil building heating, wood drying, tobacco drying, crop drying, paint drying, industrial hot water preparation, industrial product drying and the like.

In many heat pump products at present, the energy utilization mode is single, and the heat pump products are generally only used for generating hot water or only generating hot air.

However, according to the reverse carnot cycle principle of heat pump operation, it is known that a heat pump is often accompanied by the generation of a large part of cold energy while producing heat, and the part of cold energy is not fully utilized, which actually results in the waste of resources.

Disclosure of Invention

To solve at least one of the above-mentioned technical problems, the present invention is directed to: a heat pump system and a control method thereof are provided to realize the multi-functionalization of a heat pump by using cold energy.

In a first aspect, an embodiment of the present invention provides:

a heat pump system, comprising:

a compressor for compressing a refrigerant gas;

a first check valve, an inlet of which is connected with an outlet of the compressor;

a four-way valve comprising a first end, a second end, a third end and a fourth end; when the first end of the four-way valve is connected with the second end of the four-way valve, the third end of the four-way valve is connected with the fourth end of the four-way valve; when the first end of the four-way valve is connected with the fourth end of the four-way valve, the third end of the four-way valve is connected with the second end of the four-way valve; the first end of the four-way valve is connected with the outlet of the first one-way valve;

a condenser, the first end of which is connected with the second end of the four-way valve;

a second one-way valve, an inlet of which is connected with the second end of the condenser;

a first expansion valve, a first end of which is connected with an outlet of the second one-way valve;

a first end of the evaporator is connected with a second end of the first expansion valve, and a second end of the evaporator is connected with a fourth end of the four-way valve;

a second expansion valve, a first end of which is connected with an outlet of the second one-way valve;

a first end of the water catcher is connected with a second end of the second expansion valve, and a second end of the water replenishing device is connected with a third end of the four-way valve;

and the first end of the air separation device is connected with the third end of the four-way valve, and the second end of the air separation device is connected with the inlet of the compressor.

Further, the system further comprises:

a third expansion valve, a first end of which is connected with an outlet of the second one-way valve;

a first end of the heat exchanger is connected with a second end of the third expansion valve, and a second end of the heat exchanger is connected with a third end of the four-way valve;

and the water pump is connected in the heat exchange waterway of the heat exchanger.

Further, the system further comprises:

the heat storage tank and the filter are connected in series between the condenser and the second one-way valve.

Further, the first expansion valve, the second expansion valve and the third expansion valve are all electronic expansion valves.

Further, the system further comprises:

the first temperature sensor is arranged at the outlet of the first one-way valve;

a second temperature sensor disposed at the compressor inlet;

a third temperature sensor disposed on the evaporator;

a fourth temperature sensor disposed in the system deployment environment;

a fifth temperature sensor disposed on the water trap;

a sixth temperature sensor disposed at a second end of the heat exchanger;

and the controller controls the four-way valve and the first to third expansion valves according to output signals of the first to sixth temperature sensors.

Further, the condenser, the evaporator and the water catcher are all provided with fans.

In a second aspect, an embodiment of the present invention provides:

a control method of a heat pump system, comprising the steps of:

determining a working mode;

and controlling the states of the first to third expansion valves and the four-way valve according to the working mode.

Further, the working modes comprise a drying mode, a drying and dehumidifying mode, a drying and air conditioning mode, an air conditioning mode, a dehumidifying mode and a standby mode;

the control of the states of the first to third expansion valves and the four-way valve according to the working mode specifically comprises:

when the working mode is determined to be the drying mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the first expansion valve to be opened, and controlling the second expansion valve and the third expansion valve to be closed;

when the working mode is determined to be a drying and dehumidifying mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the second expansion valve to be opened, and controlling the first expansion valve and the third expansion valve to be closed;

when the working mode is determined to be a drying air-conditioning mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the third expansion valve to be opened and controlling the first expansion valve and the second expansion valve to be closed;

when the working mode is determined to be a dehumidification mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a fourth end of the four-way valve, controlling the first expansion valve and the second expansion valve to be opened and controlling the third expansion valve to be closed;

and when the working mode is determined to be an air-conditioning mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a fourth end of the four-way valve, controlling the first expansion valve and the third expansion valve to be opened and controlling the second expansion valve to be closed.

Further, the method comprises the following steps:

acquiring the water temperature of an air conditioner;

acquiring the ambient temperature of a drying room;

acquiring humidity of a drying room;

and determining a working mode according to the air conditioner water temperature, the drying room environment temperature and the drying room humidity.

Further, determining a working mode according to the air conditioner water temperature, the drying room ambient temperature and the drying room humidity comprises:

when the temperature of the drying room is lower than a first drying room temperature threshold value, the humidity of the drying room is higher than a first drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a drying and dehumidifying mode;

when the temperature of the drying room is lower than a first drying room temperature threshold value, the water temperature of the air conditioner is higher than a second air conditioner water temperature threshold value, and the humidity of the drying room is lower than a second drying room humidity threshold value, determining that the working mode is a drying air-conditioning mode;

when the temperature of the drying room is higher than a second drying room temperature threshold value, the water temperature of the air conditioner is higher than a first air conditioner water temperature threshold value, and the humidity of the drying room is lower than a second drying room humidity threshold value, determining that the working mode is the air conditioning mode;

when the temperature of the drying room is higher than a second drying room temperature threshold value, the humidity of the drying room is higher than a first drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a dehumidification mode;

when the temperature of the drying room is lower than a first drying room temperature threshold value, the humidity of the drying room is lower than a second drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a drying mode;

and when the temperature of the drying room is higher than a second drying room temperature threshold value, the humidity of the drying room is lower than a second drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, entering a standby mode.

The embodiment of the invention has the beneficial effects that: the invention is provided with a first one-way valve, a second one-way valve, a four-way valve, a water catcher, an evaporator, a condenser, a first expansion valve and a second expansion valve, and can realize a drying mode, a dehumidifying mode and a drying dehumidifying mode by matching the water catcher, the condenser and the evaporator by changing the states of the four-way valve, the first expansion valve and the second expansion valve.

Drawings

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

fig. 2 is an equivalent schematic diagram of a heat pump system in a drying mode according to an embodiment of the present invention;

fig. 3 is an equivalent schematic diagram of a heat pump system in a drying and dehumidifying mode according to an embodiment of the present invention;

fig. 4 is an equivalent schematic diagram of a heat pump system in a drying air-conditioning mode according to an embodiment of the present invention;

fig. 5 is an equivalent schematic diagram of a heat pump system in a dehumidification mode according to an embodiment of the present invention;

fig. 6 is an equivalent schematic diagram of a heat pump system in an air conditioning mode according to an embodiment of the present invention;

fig. 7 is a flowchart of a control method of a heat pump system according to an embodiment of the present invention;

fig. 8 is a flowchart of another control method for a heat pump system according to an embodiment of the present invention.

Detailed Description

The invention is further described with reference to the drawings and the specific examples.

Referring to fig. 1, the present embodiment discloses a heat pump system, which is mainly applied in a drying room, and includes:

a compressor for compressing a refrigerant gas; the compressor includes an inlet through which a refrigerant gas is sucked into the compressor, compressed into a high-temperature and high-pressure refrigerant gas, and an outlet through which the refrigerant gas is discharged.

A first check valve, namely a check valve A, the inlet of which is connected with the outlet of the compressor; the first check valve restricts the flow direction of the refrigerant gas.

A four-way valve comprising a first end, a second end, a third end and a fourth end; when the first end of the four-way valve is connected with the second end of the four-way valve, the third end of the four-way valve is connected with the fourth end of the four-way valve; when the first end of the four-way valve is connected with the fourth end of the four-way valve, the third end of the four-way valve is connected with the second end of the four-way valve; the first end of the four-way valve is connected with the outlet of the first one-way valve; wherein the four-way valve is an electric four-way valve.

A condenser, the first end of which is connected with the second end of the four-way valve;

a second check valve, check valve B, the inlet of which is connected to the second end of the condenser; the second one-way valve restricts the flow direction of the liquid.

A first expansion valve, namely an electronic expansion valve A, the first end of which is connected with the outlet of the second one-way valve;

a first end of the evaporator is connected with a second end of the first expansion valve, and a second end of the evaporator is connected with a fourth end of the four-way valve;

a second expansion valve, namely an electronic expansion valve B, the first end of which is connected with the outlet of the second one-way valve;

a first end of the water catcher is connected with a second end of the second expansion valve, and a second end of the water replenishing device is connected with a third end of the four-way valve;

and the first end of the air separation device is connected with the third end of the four-way valve, and the second end of the air separation device is connected with the inlet of the compressor.

A third expansion valve, namely an electronic expansion valve C, the first end of which is connected with the outlet of the second one-way valve;

the first end of the heat exchanger, namely a change plate, is connected with the second end of the third expansion valve, and the second end of the heat exchanger is connected with the third end of the four-way valve;

and the water pump is connected in the heat exchange waterway of the heat exchanger.

The condenser is provided with a high-temperature fan, the evaporator is provided with an outer fan, and the water catcher is provided with a water catching fan.

And a liquid storage tank and a filter are arranged between the condenser and the second one-way valve.

In some embodiments, the system further comprises:

the first temperature sensor is arranged at the outlet of the first one-way valve;

a second temperature sensor disposed at the compressor inlet;

a third temperature sensor disposed on the evaporator;

a fourth temperature sensor disposed in the system deployment environment;

a fifth temperature sensor disposed on the water trap;

a sixth temperature sensor disposed at a second end of the heat exchanger;

and the controller controls the four-way valve and the first to third expansion valves according to output signals of the first to sixth temperature sensors.

The following description is made with respect to the principles of the embodiment shown in fig. 1.

Referring to fig. 2, fig. 2 is an equivalent schematic diagram of the heat pump system of fig. 1 when the drying mode is implemented.

When the four-way valve is powered off, the first end and the second end of the four-way valve are connected, the third end and the fourth end of the four-way valve are connected, at the moment, the electronic expansion valve A is opened, and the electronic expansion valve B and the electronic expansion valve C are closed.

At this time, the high-temperature and high-pressure refrigerant gas output by the compressor flows to the condenser through the one-way valve A and the four-way valve, and is condensed into liquid, and the heat is used as a heat source of the drying room. The liquid flows to the evaporator through the liquid storage tank, the filter and the one-way valve B, the evaporator absorbs heat, the liquid is changed into refrigerant gas, and the refrigerant gas flows back to the compressor through the gas separation device. Thus, the drying mode can be realized.

Referring to fig. 3, fig. 3 is an equivalent schematic diagram of the heat pump system of fig. 1 when the drying and dehumidifying mode is implemented.

When the four-way valve is powered off, the first end and the second end of the four-way valve are connected, the third end and the fourth end of the four-way valve are connected, at the moment, the electronic expansion valve B is opened, and the electronic expansion valve A and the electronic expansion valve C are closed.

At this time, the high-temperature and high-pressure refrigerant gas output by the compressor flows to the condenser through the one-way valve A and the four-way valve, and is condensed into liquid, and the heat is used as a heat source of the drying room. The liquid flows to the water catcher through the liquid storage tank, the filter and the one-way valve B, the water catcher absorbs heat from the outside, the liquid in the water catcher is changed into refrigerant gas, and the refrigerant gas flows back to the compressor through the gas separation device. The water replenishing device absorbs heat outwards to liquefy moisture in the air and realize dehumidification. Thus, a drying and dehumidifying mode can be implemented.

Referring to fig. 4, fig. 4 is an equivalent schematic diagram of the heat pump system of fig. 1 when the drying air-conditioning mode is implemented.

When the four-way valve is powered off, the first end and the second end of the four-way valve are connected, the third end and the fourth end of the four-way valve are connected, at the moment, the electronic expansion valve C is opened, and the electronic expansion valve A and the electronic expansion valve B are closed.

At this time, the high-temperature and high-pressure refrigerant gas output by the compressor flows to the condenser through the one-way valve A and the four-way valve, and is condensed into liquid, and the heat is used as a heat source of the drying room. Liquid flows to the plate through the liquid storage tank, the filter and the one-way valve B, the plate is provided with the freezing water pump and the refrigeration water path, and liquid in the plate absorbs heat from water, so that the temperature of water in the refrigeration water path is reduced, and meanwhile, liquid in the plate is changed into refrigerant gas which flows back to the compressor through the gas separation device. The water flowing through the water pump is cooled due to the absorption of heat, and can be used for air conditioning refrigeration. Thus, a drying and dehumidifying mode can be implemented.

Referring to fig. 5, fig. 5 is an equivalent schematic diagram of the heat pump system of fig. 1 when the dehumidification mode is implemented.

When the four-way valve is electrified, the first end and the fourth end of the four-way valve are connected, the second end and the third end of the four-way valve are connected, at the moment, the electronic expansion valve A and the electronic expansion valve B are opened, and the electronic expansion valve C is closed.

High-temperature and high-pressure refrigerant gas output by the compressor flows to the evaporator through the one-way valve A and the four-way valve, the refrigerant gas is changed into liquid, then enters the water catcher, and then flows back to the compressor through the gas separation device, so that the dehumidification mode is realized.

Referring to fig. 6, fig. 6 is an equivalent schematic diagram of the heat pump system of fig. 1 when the air-conditioning mode is implemented.

When the four-way valve is electrified, the first end and the fourth end of the four-way valve are connected, the second end and the third end of the four-way valve are connected, at the moment, the electronic expansion valve A and the electronic expansion valve C are opened, and the electronic expansion valve B is closed.

High-temperature and high-pressure refrigerant gas output by the compressor flows to the evaporator through the one-way valve A and the four-way valve, the refrigerant gas is changed into liquid, then enters the change plate and exchanges heat with water flowing through the water pump, then flows back to the compressor through the air separation device, and the water flowing through the water pump is cooled and then used for air-conditioning refrigeration, so that an air-conditioning mode is realized.

It can be seen that a combination of functions can be realized by the embodiment shown in fig. 1, and the cold energy generated by the heat pump can be fully utilized.

Referring to fig. 7, a control method of a heat pump system includes the steps of:

and step 710, determining the working mode. In the present embodiment, there are two ways of determining the operation mode, one is manually set, that is, the operation mode is manually set, and the heat pump system operates according to the operation mode. And the other mode is to automatically switch different working modes according to the temperature data collected by the sensor based on manually set operating parameters.

And 720, controlling the states of the first to third expansion valves and the four-way valve according to the working mode. The present step controls the states of the expansion valve and the four-way valve according to a plurality of working modes described below.

In some embodiments, the operation mode includes a drying mode, a drying and dehumidifying mode, a drying and air-conditioning mode, an air-conditioning mode, a dehumidifying mode, and a standby mode;

the control of the states of the first to third expansion valves and the four-way valve according to the working mode specifically comprises:

when the working mode is determined to be the drying mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the first expansion valve to be opened, and controlling the second expansion valve and the third expansion valve to be closed;

when the working mode is determined to be a drying and dehumidifying mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the second expansion valve to be opened, and controlling the first expansion valve and the third expansion valve to be closed;

when the working mode is determined to be a drying air-conditioning mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a second end of the four-way valve, controlling the third expansion valve to be opened and controlling the first expansion valve and the second expansion valve to be closed;

when the working mode is determined to be a dehumidification mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a fourth end of the four-way valve, controlling the first expansion valve and the second expansion valve to be opened and controlling the third expansion valve to be closed;

and when the working mode is determined to be an air-conditioning mode, controlling the four-way valve to enable a first end of the four-way valve to be connected with a fourth end of the four-way valve, controlling the first expansion valve and the third expansion valve to be opened and controlling the second expansion valve to be closed.

In some embodiments, the method further comprises the steps of:

acquiring the water temperature of an air conditioner;

acquiring the ambient temperature of a drying room;

acquiring humidity of a drying room;

and determining a working mode according to the air conditioner water temperature, the drying room environment temperature and the drying room humidity.

In this embodiment, after setting each temperature threshold, switching may be performed according to the relationship between each actual temperature and the threshold. The cold energy is fully utilized, and meanwhile, the automatic control is realized.

In some embodiments, the determining the operation mode according to the air conditioner water temperature, the drying room ambient temperature and the drying room humidity includes:

when the temperature of the drying room is lower than a first drying room temperature threshold value, the humidity of the drying room is higher than a first drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a drying and dehumidifying mode;

when the temperature of the drying room is lower than a first drying room temperature threshold value, the water temperature of the air conditioner is higher than a second air conditioner water temperature threshold value, and the humidity of the drying room is lower than a second drying room humidity threshold value, determining that the working mode is a drying air-conditioning mode;

when the temperature of the drying room is higher than a second drying room temperature threshold value, the water temperature of the air conditioner is higher than a first air conditioner water temperature threshold value, and the humidity of the drying room is lower than a second drying room humidity threshold value, determining that the working mode is the air conditioning mode;

when the temperature of the drying room is higher than a second drying room temperature threshold value, the humidity of the drying room is higher than a first drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a dehumidification mode;

when the temperature of the drying room is lower than a first drying room temperature threshold value, the humidity of the drying room is lower than a second drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, determining that the working mode is a drying mode;

and when the temperature of the drying room is higher than a second drying room temperature threshold value, the humidity of the drying room is lower than a second drying room humidity threshold value, and the water temperature of the air conditioner is lower than a first air conditioner water temperature threshold value, entering a standby mode.

When the temperature of the drying room is lower than a first drying room temperature threshold value, the humidity of the drying room is higher than a first drying room humidity threshold value, and the water temperature of the air conditioner is higher than a second air conditioner water temperature threshold value, the priority of air conditioning and dehumidification is determined according to the current user setting, when the priority of the air conditioner is higher than the dehumidification priority, a drying air conditioning mode is started, and when the priority of the air conditioner is lower than the dehumidification priority, the drying dehumidification mode is started.

Referring to fig. 8, in the present embodiment, the operation mode of the heat pump system is shown in the functions of drying, dehumidifying, and air conditioning, in which T1 represents the detected temperature of the drying room, T2 represents the detected temperature of the air-conditioning water, and M1 represents the detected temperature of the drying room. In the figure, K1, K2 and K3 respectively indicate the functional states of heating, dehumidifying and air-conditioning, 1 indicates the function activation, and 0 indicates the function deactivation. Wherein the range of heating start-up is controlled by setting the thresholds T12 and T11, and the thresholds M11 and M12 are set to control the range of dehumidification start-up. The range of the air conditioner start-up is controlled by setting the thresholds T21 and T22.

The step numbers in the above method embodiments are set for convenience of illustration only, the order between the steps is not limited at all, and the execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.