Heat pump system

A heat pump system includes a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger connected in sequence to form a refrigerant main circuit. The outdoor heat exchanger includes at least one double-rowed heat exchanger. The heat pump system has a cooling mode and a heating mode, and further includes a switching unit. The switching unit is connected in the refrigerant main circuit, and switches a flow direction of a refrigerant, such that the refrigerant flows into the outdoor heat exchanger through one of the first heat exchanger and the second heat exchanger, and flows out of the outdoor heat exchanger through the other one of the first heat exchanger and the second heat exchanger both in the cooling mode and in the heating mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. National Phase application under 35 USC § 371 of the International Patent Application No. PCT/CN2016/105365, filed on Nov. 10, 2016, which claims the benefit of prior Chinese Application No. 201510796839.5, filed with the State Intellectual Property Office of P. R. China on Nov. 18, 2015. The entire contents of the before-mentioned patent applications are incorporated by reference as part of the disclosure of this U.S. application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a technical field of heat exchange, and more particularly to a heat pump system.

2. Description of the Related Art

A commercial air-cooled conditioning unit in the related art is generally composed of a plurality of modules. Each module generally includes at least two sheets of heat exchangers in parallel, and in order to improve a heat exchange area, each heat exchanger is arranged to be double-rowed.

When the heat pump system is switched between a cooling mode and a heating mode, a flow direction of a refrigerant in the double-rowed heat exchanger is changed as well. Since a flow direction of air is not changed, heat exchange effects of the heat exchanger in the cooling mode and in the heating mode are different, such that optimization cannot be achieved in both modes, thereby influencing properties of the heat pump system.

SUMMARY OF THE INVENTION

The present disclosure is made on basis of discoveries of inventors of the present disclosure about following facts and problems.

In the related art, a heat exchanger of each module in a heat pump system is usually configured to include double rows (i.e., a first heat exchanger and a second heat exchanger) in series with each other. For example, supposing when the heat pump system operates in a cooling mode, a refrigerant enters the first heat exchanger firstly, and then flows out of the second heat exchanger; when the heat pump system operates in the heating mode, the refrigerant enters the second heat exchanger firstly, and then flows out of the first heat exchanger.

No matter whether in the cooling mode or in the heating mode, the air exchanges heat with the refrigerant in the second heat exchanger firstly, and then exchanges heat with the refrigerant in the first heat exchanger. Since a flow direction of the air is always constant, a heat exchange sequence of the air with the refrigerant in the first heat exchanger and the second heat exchanger in the cooling mode is different from a heat exchange sequence of the air with the refrigerant in the first heat exchanger and the second heat exchanger in the heating mode. In other words, in the cooling mode, the flow direction of the air is opposite to the flow direction of the refrigerant (i.e., the air and the refrigerant has a countercurrent flow exchange heat therebetween), and in the heating mode, the flow direction of the air is the same with the flow direction of the refrigerant (i.e., the air and the refrigerant flow has a parallel flow exchange heat therebetween).

It is found by the inventors of the present disclosure through a lot of research that, the heat exchange effect in the case that the flow direction of the air is opposite to the flow direction of the refrigerant is better than the heat exchange effect in the case that the flow direction of the air is the same with the flow direction of the refrigerant. Therefore, the heat pump system in the related art cannot achieve the best heat exchange effects both in the cooling mode and in the heating mode at the same time, so that there is a need for improvements.

The present disclosure seeks to solve one of the above technical problems in the related art to some extent. For that reason, the present disclosure provides a heat pump system. The heat pump system enhances the heat exchange capacity of the heat exchanger, improves the heat exchange efficiency, and can achieve the optimal heat exchange effects both in the cooling mode and in the heating mode, thereby improving the properties of the heat pump system.

The heat pump system according to embodiments of the present disclosure includes a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger connected in sequence to form a refrigerant main circuit, in which the outdoor heat exchanger includes at least one double-rowed heat exchanger, the double-rowed heat exchanger includes a first heat exchanger and a second heat exchanger connected in series with each other, an included angle α between the first heat exchanger and the second heat exchanger is larger than or equal to 0 degree and smaller than 180 degrees; the heat pump system has a cooling mode and a heating mode, and also includes a switching unit, the switching unit is connected in the refrigerant main circuit, and switches a flow direction of a refrigerant, such that the refrigerant flows into the outdoor heat exchanger through one of the first heat exchanger and the second heat exchanger, and flows out of the outdoor heat exchanger through the other one of the first heat exchanger and the second heat exchanger both in the cooling mode and in the heating mode.

The heat pump system according to embodiments of the present disclosure uses the switching unit to control the flow direction of the refrigerant in the outdoor heat exchanger, such that there exists the countercurrent flow heat exchange between the refrigerant in the outdoor heat exchanger and the air both in the cooling mode and in the heating mode, thus improving the heat exchange efficiency of the outdoor heat exchanger, ensuring heat exchange effects of the heat pump system to be optimal both in the cooling mode and in the heating mode, thereby improving the heat exchange capacity and the heat exchange efficiency of the heat pump system.

REFERENCE NUMERALS

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present disclosure will be described in details in the following, and examples of the embodiments are illustrated in accompanying drawings. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions. The embodiments described herein with reference to drawings are explanatory, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure.

The present disclosure is made on basis of discoveries of inventors of the present disclosure about the following facts and problems.

As illustrated inFIGS. 1-2, in the related art, a heat exchanger31′ of each module in a heat pump system is usually configured to include double rows (i.e., a first heat exchanger311′ and a second heat exchanger312′) in series with each other. For example, as illustrated inFIG. 1, supposing when the heat pump system operates in a cooling mode, the refrigerant enters the first heat exchanger311′ through a first port31a′ firstly, and then flows out of the second heat exchanger312′ through a second port31b′; as illustrated inFIG. 2, when the heat pump system operates in a heating mode, a flow direction of the refrigerant changes, the refrigerant enters the second heat exchanger312′ through the second port31b′ firstly, and then flows out of the first heat exchanger311′ through the first port31a′. In the drawings, an arrow a denotes a flow direction of air, an arrow b denotes a flow direction of the refrigerant in the first heat exchanger311′, and an arrow c denotes a flow direction of the refrigerant in the second heat exchanger312′.

No matter whether in the cooling mode or in the heating mode, the air exchanges heat with the refrigerant in the second heat exchanger312′ firstly, and then exchanges heat with the refrigerant in the first heat exchanger311′. The flow direction of the air is always constant, therefore, in the cooling mode, the flow direction of the air is opposite to the flow direction of the refrigerant (i.e.,FIG. 1illustrates a countercurrent flow heat exchange between the air and the refrigerant), and in the heating mode, the flow direction of the air is the same with the flow direction of the refrigerant (i.e.,FIG. 2illustrates a concurrent flow heat exchange between the air and the refrigerant).

It is found by the inventors of the present disclosure through a lot of research that, the heat exchange effect in the case that the flow direction of the air is opposite to the flow direction of the refrigerant is better than the heat exchange effect in the case that the flow direction of the air is the same with the flow direction of the refrigerant. Therefore, the heat pump system in the related art cannot achieve the best heat exchange effects both in the cooling mode and in the heating mode at the same time, and thus there is a need for improvements.

For that reason, the present disclosure provides a heat pump system100with high heat exchange efficiency and good heat exchange properties.

The heat pump system100according to embodiments of the present disclosure will be described herein with reference toFIGS. 3-5. The heat pump system100can achieve the optimal heat exchange effects both in the cooling mode and in the heating mode at the same time.

As illustrated inFIGS. 3-5, the heat pump system100according to embodiments of the present disclosure includes a compressor1, a four-way valve2, an outdoor heat exchanger3, a throttling device4and an indoor heat exchanger5connected in sequence to form a refrigerant main circuit.

It could be understood by those skilled in the art that the compressor1may have an air inlet and an air outlet, the refrigerant enters the compressor1through the air inlet and is discharged out of the compressor1through the air outlet. The four-way valve2may have a first port21, a second port22, a third port23and a fourth port24, the first port21is communicated with the air outlet, the second port22is communicated with the outdoor heat exchanger3, the third port23is communicated with the air inlet, and the fourth port24is communicated with the indoor heat exchanger5.

Specifically, the outdoor heat exchanger3includes at least one double-rowed heat exchanger31. The double-rowed heat exchanger31includes a first heat exchanger311and a second heat exchanger312connected in series with each other. An included angle α between the first heat exchanger311and the second heat exchanger312is larger than or equal to 0 degree and smaller than 180 degrees. For example, as illustrated inFIGS. 3-4, the outdoor heat exchanger3includes two double-rowed heat exchangers31, and each double-rowed heat exchanger31includes the first heat exchanger311and the second heat exchanger312connected in series with each other. The first heat exchanger311is arranged to be parallel to the second heat exchanger312, i.e., the angle α equals to 0 degree. The double-rowed heat exchanger31at a left side and the double-rowed heat exchanger31at a right side are connected in parallel, and the refrigerant flows into the outdoor heat exchanger3through the two first heat exchangers311at the same time, and flows out of the outdoor heat exchanger3through the two second heat exchangers312.

It could be understood that, as illustrated inFIG. 5, the first heat exchanger311may also be arranged to be not parallel to the second heat exchanger312, i.e., the angle α may be larger than 0 degree and smaller than 180 degrees. It can also be understood that, the refrigerant may also flow into the outdoor heat exchanger3through the two second heat exchangers312at the same time, and flow out of the outdoor heat exchanger3through the two first heat exchangers311.

The heat pump system100has the cooling mode and the heating mode, and the cooling mode and the heating mode are switched through the four-way valve2. The heat pump system100further includes a switching unit. The switching unit is connected in the refrigerant main circuit, so as to switch the flow direction of the refrigerant, such that the refrigerant can flow into the outdoor heat exchanger3through one of the first heat exchanger311and the second heat exchanger312, and flow out of the outdoor heat exchanger3through the other one of the first heat exchanger311and the second heat exchanger312both in the cooling mode and in the heating mode. For example, the refrigerant flows into the outdoor heat exchanger3through the first heat exchanger311and flows out of the outdoor heat exchanger3through the second heat exchanger312both in the cooling mode and in the heating mode. Thus, the heat pump system100can achieve the countercurrent flow heat exchange between the air and the refrigerant both in the cooling mode and in the heating mode.

Specifically, as illustrated inFIG. 3, when the heat pump system operates in the cooling mode, the first port21of the four-way valve2is communicated with the second port22of the four-way valve2, and the third port23of the four-way valve2is communicated with the fourth port24of the four-way valve2, that is, the four-way valve2controls the refrigerant to flow from the compressor1to the outdoor heat exchanger3, and the switching unit controls the refrigerant to flow through the two first heat exchangers311into the outdoor heat exchanger3respectively, and to flow out of the outdoor heat exchanger3through the two second heat exchangers312respectively. Then, the refrigerant flows through the throttling device4and the indoor heat exchanger5successively. Finally, the four-way valve2controls the refrigerant flowing out of the indoor heat exchanger5to flow into the compressor1again. That is, a flow circuit of the refrigerant is shown as follows: compressor1→four-way valve2→first heat exchanger311→second heat exchanger312→throttling device4→indoor heat exchanger5→four-way valve2→compressor1, which is repeated in this way. In the drawings, an arrow d denotes a flow path of the refrigerant, an arrow e is used for denoting a flow direction of the air, and the flow direction of the refrigerant in the outdoor heat exchanger3is opposite to the flow direction of the air.

As illustrated inFIG. 4, when the heat pump system100operates in the heating mode, the first port21of the four-way valve2is communicated with the fourth port24of the four-way valve2, and the second port22of the four-way valve2is communicated with the third port23of the four-way valve2, that is, the four-way valve2controls the refrigerant to flow from the compressor1into the indoor heat exchanger5and the throttling device4successively. Then, the switching unit controls the refrigerant to flow into the outdoor heat exchanger3through the two first heat exchangers311respectively, and to flow out of the outdoor heat exchanger3through the two second heat exchangers312respectively. Finally, the four-way valve2controls the refrigerant to flow into the compressor1. That is, the flow loop of the refrigerant is shown as follows: compressor1→four-way valve2→indoor heat exchanger5→throttling device4→first heat exchanger311→second heat exchanger312→four-way valve2→compressor1, which is repeated in this way. In the drawings, the arrow d denotes the flow path of the refrigerant, the arrow e is used for denoting the flow direction of the air, and the flow direction of the refrigerant in the outdoor heat exchanger3is opposite to the flow direction of the air.

From the above, no matter whether in the cooling mode or in the heating mode, the refrigerant flows into the outdoor heat exchanger3through the first heat exchanger311firstly, and then flows out of the outdoor heat exchanger3through the second heat exchanger312. Moreover, the flow direction of the air is always constant (always being opposite to the flow direction of the refrigerant); therefore, both in the cooling mode and in heating mode, the countercurrent flow heat exchange between the air and the refrigerant is provided.

The heat pump system100according to embodiments of the present disclosure uses the switching unit to control the flow direction of the refrigerant, such that the refrigerant can flow into the outdoor heat exchanger3through the first heat exchanger311and flow out of the outdoor heat exchanger3through the second heat exchanger312both in the cooling mode and in the heating mode. Thus, both in the cooling mode and in the heating mode, there exists the countercurrent flow heat exchange between the refrigerant in the outdoor heat exchanger3and the air, thus improving the heat exchange efficiency of the outdoor heat exchanger3, ensuring the heat exchange effects of the heat pump system100to be optimal both in the cooling mode and in the heating mode, and thereby improving the properties of the heat pump system100.

In addition, when operating in a frosting condition, the first heat exchanger311in the double-rowed heat exchanger31is seriously frosted. The heat pump system100according to embodiments of the present disclosure can ensure that heat enters the first heat exchanger311preferentially in a defrosting mode, thus accelerating the melting of frost, and reducing the defrosting time. For example, in the heating mode, the gas-liquid two-phase refrigerant enters the outdoor heat exchanger3through the first heat exchanger311, and after entering in the defrosting mode, the high temperature refrigerant enters the outdoor heat exchanger3through the first heat exchanger311firstly, such that the frost of the first heat exchanger311may be heated to melt firstly, thereby shortening the frosting time.

Preferably, the indoor heat exchanger5and the outdoor heat exchanger3both can be a parallel flow micro-channel heat exchanger, such that the heat pump system100can have a more compact structure and better heat exchange properties.

As illustrated inFIGS. 3-5, according to some embodiments of the present disclosure, the double-rowed heat exchanger31may be formed by connecting two heat exchangers in series, or the double-rowed heat exchanger31may also be formed by bending a single heat exchanger, thus facilitating the production of the double-rowed heat exchanger31and providing the double-rowed heat exchanger31with a high structure strength.

According to some embodiments of the present disclosure, two or more than two double-rowed heat exchangers31may be provided and the two or more than two double-rowed heat exchangers31are connected in parallel to one another, such that the heat exchange effects of the outdoor heat exchanger3can be further enhanced and hence the heat exchange efficiency of the outdoor heat exchanger3can be further improved. For example, as illustrated inFIGS. 3-4, two double-rowed heat exchangers31are provided, the first heat exchanger311and the second heat exchanger312of each double-rowed heat exchanger31are connected in series, and the double-rowed heat exchangers31are connected in parallel to each other. Each double-rowed heat exchanger31has a first port31aand a second port31b, the first port31ais provided to the first heat exchanger311and the second port31bis provided to the second heat exchanger312. The first ports31aof the two double-rowed heat exchangers31are connected correspondingly, and the second ports31bof the two double-rowed heat exchangers31are also connected correspondingly, such that the two double-rowed heat exchangers31are connected in parallel, the refrigerant flows into the two first heat exchangers311through the two first ports31arespectively at the same time, and then flows out of the two second heat exchangers312through the two second ports31brespectively.

In embodiments illustrated inFIGS. 3-4, the first heat exchanger311and the second heat exchanger312may be parallel to each other and spaced apart from each other, which is beneficial to improving a heat dissipation area of the outdoor heat exchanger3.

As illustrated inFIGS. 3-4, according to some embodiments of the present disclosure, the switching unit may include a first on-off valve61, a second on-off valve62, a third on-off valve63and a fourth on-off valve64.

Furthermore, as illustrated inFIGS. 3-4, the first on-off valve61is connected between the first port31aof the first heat exchanger311and the second port22of the four-way valve2, and the second on-off valve62is connected between the second port31bof the second heat exchanger312and the throttling device4. The third on-off valve63is disposed in a first refrigerant branch circuit71, a first end711of the first refrigerant branch circuit71is connected between the first on-off valve61and the first port31aof the first heat exchanger311, and a second end712of the first refrigerant branch circuit71is connected between the second on-off valve62and the throttling device4. The fourth on-off valve64is disposed in a second refrigerant branch circuit72, a first end721of the second refrigerant branch circuit72is connected between the first on-off valve61and the second port22of the four-way valve2, and a second end722of the second refrigerant branch circuit72is connected between the second on-off valve62and the second port31bof the second heat exchanger312.

For example, the first on-off valve61is connected between the first port31aand the second port22, the second on-off valve62is connected between the second port31band the throttling device4, the third on-off valve63is disposed in the first refrigerant branch circuit71, and the fourth on-off valve64is disposed in the second refrigerant branch circuit72. The first end711of the first refrigerant branch circuit71is connected between the first on-off valve61and the first port31a, and the second end712of the first refrigerant branch circuit71is connected between the second on-off valve62and the throttling device4. The first end721of the second refrigerant branch circuit72is connected between the first on-off valve61and the second port22, and the second end722of the second refrigerant branch circuit72is connected between the second on-off valve62and the second port31b.

Specifically, as illustrated inFIG. 3, in the cooling mode, the first on-off valve61and the second on-off valve62are switched on, and the third on-off valve63and the fourth on-off valve64are switched off. That is, a circuit between the four-way valve2and the first heat exchanger311and a circuit between the second heat exchanger312and the throttling device4are turned on, and the first refrigerant branch circuit71and the second refrigerant branch circuit72are turned off, such that the refrigerant coming from the compressor1flows through the four-way valve2and the first on-off valve61successively, then flows into the outdoor heat exchanger3through the first heat exchanger311and flows out of the outdoor heat exchanger3through the second heat exchanger312.

As illustrated inFIG. 4, in the heating mode, the first on-off valve61and the second on-off valve62are switched off, and the third on-off valve63and the fourth on-off valve64are switched on. That is, the first refrigerant branch circuit71and the second refrigerant branch circuit72are turned on, and a circuit between the first end711of the first refrigerant branch circuit71and the first end721of the second refrigerant branch circuit72as well as a circuit between the second end712of the first refrigerant branch circuit71and the second end722of the second refrigerant branch circuit72are turned off, such that the refrigerant coming from the compressor1flows through the four-way valve2, the indoor heat exchanger5and the throttling device4successively, further flows to the first heat exchanger311through the first refrigerant branch circuit71, then flows into the outdoor heat exchanger3through the first heat exchanger311and flows out of the outdoor heat exchanger3through the second heat exchanger312.

Preferably, the first on-off valve61, the second on-off valve62, the third on-off valve63and the fourth on-off valve64all can be an electromagnetic valve, thus facilitating switching of the switching unit between the cooling mode and the heating mode, and enabling exact, rapid electronic control and high security.

The heat pump system100according to a specific embodiment of the present disclosure will be described in details with reference to the drawings. It could be understood that, the following descriptions are just explanatory, but should not be construed to limit the present disclosure.

As illustrated inFIGS. 3-5, the heat pump system100according to embodiments of the present disclosure includes the compressor1, the four-way valve2, the outdoor heat exchanger3, the throttling device4and the indoor heat exchanger5connected in sequence to form the refrigerant main circuit.

The compressor1has the air inlet and the air outlet, the refrigerant enters the compressor1through the air inlet and is discharged out of the compressor1through the air outlet. The four-way valve2has the first port21, the second port22, the third port23and the fourth port24, the first port21is communicated with the air outlet, the second port22is communicated with the outdoor heat exchanger3, the third port23is communicated with the air inlet, and the fourth port24is communicated with the indoor heat exchanger5. The indoor heat exchanger5and the outdoor heat exchanger3both are the parallel flow micro-channel heat exchanger. The outdoor heat exchanger3is provided with an air flow orientation component8(for example, a fan), so as to ensure the flow direction of the air to be presented as the arrow e.

Specifically, the outdoor heat exchanger3includes two double-rowed heat exchangers31connected in parallel, each double-rowed heat exchanger31is formed by bending a single heat exchanger and includes the first heat exchanger311and the second heat exchanger312connected in series with each other. The included angle α between the first heat exchanger311and the second heat exchanger312equals to 0 degree, that is, the first heat exchanger311and the second heat exchanger312are parallel to each other and spaced apart from each other. Each double-rowed heat exchanger31has the first port31aand the second port31b, the first port31ais provided to the first heat exchanger311and the second port31bis provided to the second heat exchanger312. The first port31aof the double-rowed heat exchanger31at the left side is communicated with the first port31aof the double-rowed heat exchanger31at the right side, and the second port31bof the double-rowed heat exchanger31at the left side is communicated with the second port31bof the double-rowed heat exchanger31at the right side, such that the two double-rowed heat exchangers31are connected in parallel.

The heat pump system100has the cooling mode and the heating mode, and the heat pump system100further includes the switching unit. The switching unit is connected in the refrigerant main circuit, so as to switch the flow direction of the refrigerant, such that the refrigerant flows into the outdoor heat exchanger3through the first heat exchanger311, and flows out of the outdoor heat exchanger3through the second heat exchanger312both in the cooling mode and in the heating mode. Specifically, the switching unit includes the first on-off valve61, the second on-off valve62, the third on-off valve63and the fourth on-off valve64. The first on-off valve61, the second on-off valve62, the third on-off valve63and the fourth on-off valve64all are an electromagnetic valve. The first on-off valve61is connected between the first port31aand the second port22, the second on-off valve62is connected between the second port31band the throttling device4, the third on-off valve63is disposed in the first refrigerant branch circuit71and the fourth on-off valve64is disposed in the second refrigerant branch circuit72. The first end711of the first refrigerant branch circuit71is connected between the first on-off valve61and the first port31a, and the second end712of the first refrigerant branch circuit71is connected between the second on-off valve62and the throttling device4. The first end721of the second refrigerant branch circuit72is connected between the first on-off valve61and the second port22, and the second end722of the second refrigerant branch circuit72is connected between the second on-off valve62and the second port31b.

As illustrated inFIG. 3, in the cooling mode, the first port21is communicated with the second port22, the third port23is communicated with the fourth port24, the first on-off valve61and the second on-off valve62are switched on, and the third on-off valve63and the fourth on-off valve64are switched off. Thus, the refrigerant is discharged from the air outlet of the compressor1, flows through the first port21, the second port22and the first on-off valve61successively, then flows into the outdoor heat exchanger3through the first ports31aof the two double-rowed heat exchangers31, and flows out of the outdoor heat exchanger3through the second ports31bof the two double-rowed heat exchangers31. Then, the refrigerant flows through the second on-off valve62, the throttling device4, the indoor heat exchanger5, the fourth port24and the third port23successively, and finally flows into the compressor1through the air inlet. That is, the flow circuit of the refrigerant is shown as follows: compressor1→four-way valve2→first on-off valve61→first heat exchanger311→second heat exchanger312→throttling device4→indoor heat exchanger5→four-way valve2→compressor1, which is repeated in this way. In the drawings, the arrow d denotes the flow path of the refrigerant, the arrow e is used for denoting the flow direction of the air, and the flow direction of the refrigerant in the outdoor heat exchanger3is opposite to the flow direction of the air.

As illustrated inFIG. 4, in the heating mode, the first port21is communicated with the fourth port24, the second port22is communicated with the third port23, the first on-off valve61and the second on-off valve62are switched off, and the third on-off valve63and the fourth on-off valve64are switched on. Thus, the refrigerant is discharged from the air outlet of the compressor1, flows through the first port21, the fourth port24, the indoor heat exchanger5and the throttling device4successively, further flows into the first refrigerant branch circuit71and flows through the third on-off valve63. Then, the refrigerant flows into the outdoor heat exchanger3through the first ports31aof the two double-rowed heat exchangers31, flows out of the outdoor heat exchanger3through the second ports31bof the two double-rowed heat exchangers31, then flows into the second refrigerant branch circuit72and flows through the fourth on-off valve64. Finally, the refrigerant flows through the second port22and the third port23successively, and further flows into the compressor1through the air inlet. That is, the flow circuit of the refrigerant is shown as follows: compressor1→four-way valve2→indoor heat exchanger5→throttling device4→third on-off valve63→first heat exchanger311→second heat exchanger312→fourth on-off valve64→four-way valve2→compressor1, which is repeated in this way. In the drawings, the arrow d denotes the flow path of the refrigerant, the arrow e is used for denoting the flow direction of the air, and the flow direction of the refrigerant in the outdoor heat exchanger3is opposite to the flow direction of the air.

The heat pump system100according to embodiments of the present disclosure uses the switching unit to control the flow direction of the refrigerant in the outdoor heat exchanger3, and thus enables the flow direction of the refrigerant in the outdoor heat exchanger3to be opposite to the flow direction of the air both in the cooling mode and in the heating mode, i.e., there exists the countercurrent flow heat exchange between the refrigerant in the outdoor heat exchanger3and the air both in the cooling mode and in the heating mode, thereby ensuring the heat exchange effects of the outdoor heat exchanger3to be optimal both in the cooling mode and in the heating mode, and improving the properties of the heat pump system100.

In the specification, it is to be understood that terms such as “central,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” should be construed to refer to the orientation as then described or as illustrated in the drawings under discussion. These relative terms are for convenience of description and do not require that the present disclosure be constructed or operated in a particular orientation. In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features. Thus, the feature defined with “first” and “second” may comprise one or more of this feature. In the description of the present disclosure, “a plurality of” means two or more than two, unless specified otherwise.

Although explanatory embodiments have been illustrated and described, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present disclosure, and changes, alternatives, and modifications can be made in the embodiments without departing from spirit, principles and scope of the present disclosure.