JP2002098437A - Heat pump apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump apparatus, having high operation efficiency by adopting a turbo-type compressor. SOLUTION: A heat pump apparatus is adapted to comprise a turbo compressor 10 for compressing a refrigerant, a first heat exchanger 11 for heat exchanging heat between the compressed refrigerant and warm water to condense the refrigerant or exchanging heat between the compressed refrigerant and well water to condense the refrigerant, expansion valves 14a, 14b for reducing pressure of the compressed refrigerant, a second heat exchanger 12 for exchanging heat between well water and the pressure reduced refrigerant to vaporize the refrigerant, a third heat exchanger 13 for exchanging heat between an antifreezing solution of another system different from the refrigerant and the pressure reduced refrigerant to vaporize the refrigerant, and hereby cool the antifreezing solution, and valves 16a, 16b, 16c, and 16d as changeover means for optionally changing over an inflow passage of the compressed refrigerant to any of the second heat exchanger 12 or the third heat exchanger 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump device capable of operating in two modes, for example, heating / cooling.

[0002]

2. Description of the Related Art A heating operation for heating a heating medium (for example, hot water) using well water or groundwater, which is easily available, as a heat source and using it for heating, and an external refrigerant (for example, antifreeze) using well water as a cooling source. 2. Description of the Related Art There is a heat pump device capable of performing cooling operation for cooling and utilizing for cooling. An example is shown in FIG.

FIG. 6 is a piping diagram of the heat pump device. In the drawing, reference numeral 1 denotes a screw compressor, 2 denotes a heat exchanger that heats a refrigerant by taking well water as a heat source or cools a refrigerant by taking well water as a cold heat source, and 3 denotes a refrigerant and hot water (heat medium). 4) a heat exchanger for heating the hot water by exchanging heat with the refrigerant, 4 a heat exchanger for cooling the antifreeze by exchanging heat between the refrigerant and the antifreeze, and 5 a refrigerant discharged from the screw compressor 1. The switching valves for selectively switching the flow destination to either the heat exchanger 2 or the heat exchanger 3, and 6 and 7 are expansion valves. In addition, a dry structure is adopted for each heat exchanger.

[0004] In this heat pump device, the heat exchanger 2 is used as an evaporator and the heat exchanger 3 is used as a condenser during a heating operation. First, the refrigerant is heated by the heat of the well water in the heat exchanger 2. After the heated refrigerant is pressurized in the screw compressor 1, the heated refrigerant is heated in the heat exchanger 3 and condensed. Thereafter, the refrigerant is decompressed in the expansion valve 6 and reenters the heat exchanger 2. The heated hot water is used as a heating medium for heating.

[0005] During the cooling operation, the heat exchanger 2 is used as a condenser and the heat exchanger 4 is used as an evaporator. First, in the heat exchanger 2, the refrigerant is condensed by the cool heat of the well water. After the condensed refrigerant is decompressed in the expansion valve 7, the heat exchanger 4
At which the antifreeze cools and evaporates itself. Thereafter, the refrigerant is pressurized in the screw compressor 1 and reenters the heat exchanger 2. The cooled antifreeze is used for ice heat storage for cooling or the like.

[0006]

In the above heat pump device, it is preferable to employ a turbo compressor in order to improve the operating efficiency. However, due to the characteristics of the turbo compressor, the compressor is simply replaced. It has been found that the heat pump device does not function just by doing.

[0007] In the above heat pump device, a dry structure is adopted for all the heat exchangers. The heat exchanger having a dry structure is one in which a refrigerant flows through a pipe inserted into a container and exchanges heat with a heat medium (or heat source) filled in the container (see FIG. 2B for details of the structure). . This is adopted because it is necessary to switch the flow direction of the refrigerant in the heat exchanger 2 between the forward and reverse directions in accordance with the heating / cooling operation. Mist (mist refrigerant) is likely to be mixed in the phase refrigerant. On the other hand, the turbo compressor has a characteristic that it is weak against mist mixing into the compressed fluid. Therefore, the heat pump device cannot function simply by replacing the compressor.

The present invention has been made in view of the above circumstances, and has as its object to provide a heat pump device having a high operating efficiency by employing a turbo compressor.

[0009]

As means for solving the above problems, a heat pump device having the following structure is employed. That is, in the heat pump device according to claim 1 of the present invention, the heat exchange between the compressed refrigerant and the heat medium is performed by condensing the refrigerant with the turbo-type compressor that compresses the refrigerant. A first heat exchanger that condenses the refrigerant by heating or exchanging heat between the compressed refrigerant and a heat source; an expansion valve that decompresses the condensed refrigerant; A second heat exchanger for evaporating the refrigerant by exchanging heat with the refrigerant, and exchanging heat between an external refrigerant of a different system from the refrigerant and the depressurized refrigerant. And a third heat exchanger that evaporates the external refrigerant and thereby cools the external refrigerant, and connects the inflow path of the condensed refrigerant to the second heat exchanger or the third heat exchanger.
Switching means for selectively switching to any one of the heat exchangers.

In the heat pump device according to the first aspect, the first heat exchanger serves as a condenser during the heating operation.
A second heat exchanger is used as an evaporator. First, the second
In the heat exchanger, the heat source exchanges heat with the refrigerant to heat the refrigerant. After the heated refrigerant is pressurized in the turbo compressor, it exchanges heat with the heat medium in the first heat exchanger to heat the heat medium and is condensed. Thereafter, the refrigerant is decompressed in the expansion valve and reenters the second heat exchanger.

In the cooling operation, the first heat exchanger is used as a condenser and the third heat exchanger is used as an evaporator. First, in the first heat exchanger, the heat source and the refrigerant exchange heat to condense the refrigerant. After the condensed refrigerant is decompressed by the expansion valve, it exchanges heat with the external refrigerant in the third heat exchanger to cool the external refrigerant and evaporate. Thereafter, the refrigerant is pressurized in the turbo compressor and reenters the first heat exchanger.

As described above, in the heat pump apparatus according to the first aspect of the present invention, it is not necessary to switch the flow direction of the refrigerant between the forward and reverse directions inside the heat exchanger unlike the conventional heat pump apparatus. There is no need to use a vessel.
This makes it possible to use a turbo-type compressor by using a heat exchanger other than the dry-type structure that is less likely to generate mist.

According to a second aspect of the present invention, in the heat pump device according to the first aspect, at least the second and third heat exchangers of the first, second, and third heat exchangers are provided. It is characterized by employing a liquid-filled structure.

In the heat exchanger of the liquid-filled type, it is impossible to switch the flow direction of the refrigerant unlike the dry type, but the liquid phase and the gaseous phase of the refrigerant are separated inside and accumulated in the upper layer. It is known that since only gas phase components can be extracted, generation of mist is extremely small.

Therefore, in the heat pump apparatus according to the second aspect, at least the second and third heat exchangers of the first, second and third heat exchangers have a liquid-filled structure. The generation of mist mixed in the refrigerant can be suppressed, and a turbo compressor can be used.

According to a third aspect of the present invention, there is provided a heat pump apparatus according to the first or second aspect, further comprising a connecting pipe for communicating a refrigerant space of the first heat exchanger with a refrigerant space of the second heat exchanger. Opening and closing means for opening and closing the connecting pipe.

[0017] The heat pump device including the present invention includes:
Generally, each heat exchanger may be connected by a piping system different from the above in order to drive accessories. These are normally opened and closed by valves so that unnecessary refrigerant is not exchanged between the heat exchangers. However, it is hard to say that it is perfect, and during the cooling operation, the cooled refrigerant in the third heat exchanger flows into the lower-pressure second heat exchanger (not used during the cooling operation). There is a possibility that the operation may be hindered due to a decrease in the temperature inside the heat exchanger 2 or the like.

Therefore, in the heat pump device according to the third aspect, the first heat exchanger and the second heat exchanger having a higher temperature and a higher pressure are connected to each other by a connecting pipe, and the inside of the second heat exchanger is connected. It is possible to keep the inside of the second heat exchanger in a normal state by opening the opening / closing means while watching the state and introducing the warmed refrigerant in the first heat exchanger to the second heat exchanger. become.

According to a fourth aspect of the present invention, in the heat pump device according to the third aspect, a detecting means for detecting a state inside the second heat exchanger, and the opening / closing means based on a detection result of the detecting means. And a control unit for controlling the driving of the device.

In the heat pump apparatus according to the fourth aspect, the state inside the second heat exchanger is detected, and the drive of the opening / closing means is controlled based on the state, so that the inside of the second heat exchanger is always normal. I can keep it in a state. In addition, a pressure sensor that detects the internal pressure of the second heat exchanger,
It is desirable to use a temperature sensor that detects the internal temperature.

According to a fifth aspect of the present invention, there is provided a heat pump device according to the first, second, third or fourth aspect, further comprising a liquid level detecting means for detecting a liquid level of the refrigerant inside the second heat exchanger. It is characterized by the following.

When the cooling operation is started, if the refrigerant remains inside the second heat exchanger, there is a concern that the accumulation may affect the heat source. Therefore, in the heat pump device according to the fifth aspect, the liquid level of the refrigerant inside the second heat exchanger is detected by the liquid level detecting means, and if the refrigerant remains, the start of the cooling operation is postponed, and the refrigerant is accumulated. Is prevented and the heat medium is not affected.

According to a sixth aspect of the present invention, in the heat pump apparatus of the first, second, third, fourth, or fifth aspect, the flow path of the heat medium and the flow path of the heat source are the first heat exchanger. And a switching means for switching the respective distribution routes so as to secure one of them as necessary.

In the heat pump device according to the sixth aspect, the flow path of the heat medium is also switchably used as the flow path of the heat source, and the supply of the heat medium is facilitated by using a part of the heat source as the heat medium. become. Furthermore, integration and simplification of the piping system can be achieved.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a heat pump device according to the present invention will be described with reference to FIGS. FIG. 1 is a piping diagram of an air conditioning system employing a heat pump device according to the present invention. In the figure, reference numeral 10 denotes a turbo compressor for compressing a refrigerant, and 11 denotes heat exchange between the compressed refrigerant and hot water for air conditioning (heat medium) to condense the refrigerant and thereby heat the hot water or A first heat exchanger for exchanging heat with the pumped well water (heat source) to condense the refrigerant; a second heat exchanger for exchanging heat between the depressurized refrigerant and the well water to evaporate the refrigerant; A heat exchanger 13 for exchanging heat between an antifreeze liquid for ice storage (external refrigerant) prepared in a separate system from the refrigerant and a depressurized refrigerant to evaporate the refrigerant and thereby cool the antifreeze liquid. Heat exchanger, 1
4a and 14b are expansion valves for reducing the pressure of the condensed refrigerant.

The first, second and third heat exchangers 1
1, 12, 13 are turbo-type compressors 1 arranged in series
0, the second and third heat exchangers 1 before and after the first heat exchanger
2 and 13 are arranged in parallel and connected by a refrigerant pipe 15 to form a closed refrigerant circulation system. In addition, in each part of the refrigerant pipe system, switching is performed to selectively switch the inflow path of the refrigerant condensed in the first heat exchanger 11 to either the second heat exchanger 12 or the third heat exchanger 13. Valves 16a, 16b, 16c, 16 as means
d is provided.

The first, second, and third heat exchangers 11, 1
Liquid-filled structures are adopted in all of the tubes 2 and 13. The heat exchanger having a liquid-filled structure is a device in which a heat source (or a heat medium) flows through a pipe inserted into a container and exchanges heat with a refrigerant filled in the container (see FIG. 2A for details of the structure). reference).

The first heat exchanger 11 is provided with a hot water pipe 17 for conducting hot water, and the third heat exchanger 13 is provided with an antifreeze pipe 18 for conducting antifreeze. Also,
The first and second heat exchangers 11 and 12 are provided with well water pipes 19 for conducting well water. The well water pipe 19 can share supply and discharge pipes and can be branched on the way to supply well water to any of the first and second heat exchangers 11 and 12, but is provided at a branch point. The valves 20a and 20b selectively supply well water to only one of the heat exchangers.

Next, the operation of the air-conditioning system configured as described above in the heating / cooling operation will be described. When the heating operation is selected, the valves 16a, 16
When the valve c is opened and the valves 16b and 16d are closed, the refrigerant circulation system surrounding the turbo compressor 10 → the first heat exchanger 11 → the expansion valve 14a → the second heat exchanger 12 → the turbo compressor 10 is opened. Is established. In this refrigerant circulation system, the first heat exchanger 11
Is used as a condenser, and the second heat exchanger 12 is used as an evaporator. Further, the valve 20a is opened and the valve 20b is closed, and the well water is switched to be supplied to the second heat exchanger 12.

When the heating operation is started, the well water and the refrigerant exchange heat in the second heat exchanger 12 to heat the refrigerant. After the heated refrigerant is pressurized in the turbo compressor 10, the first refrigerant exchanges heat with the hot water in the first heat exchanger 11 to heat the hot water and condense itself. Thereafter, the refrigerant is decompressed in the expansion valve 14a and reenters the second heat exchanger 12.

When the cooling operation is selected, the valve 16
b, 16d are opened, and the valves 16a, 16c are closed, and the turbo compressor 10 → first heat exchanger 11 → expansion valve 14b
→ The third heat exchanger 13 → A refrigerant circulation system surrounding the turbo compressor 10 is established. In this refrigerant circulation system, the first heat exchanger 11 is used as a condenser, and the third heat exchanger 13 is used as an evaporator. Further, the valve 20a is closed and the valve 20b is opened, and the well water is supplied to the first heat exchanger 1.
1 to be supplied.

When the cooling operation is started, the well water and the refrigerant exchange heat in the first heat exchanger 11 to condense the refrigerant. After the condensed refrigerant is depressurized by the expansion valve 14b, the refrigerant exchanges heat with the antifreeze in the third heat exchanger 13 to cool the antifreeze and evaporate. Thereafter, the pressure of the refrigerant is increased in the turbo compressor 10 and the first heat exchanger 11
Re-enter.

As described above, in the heat pump device employed in the air conditioning system, it is not necessary to switch the flow direction of the refrigerant between the forward and reverse directions inside the heat exchanger unlike the conventional heat pump device. It is not necessary to use a heat exchanger, and it becomes possible to use a heat exchanger having a liquid-filled structure in which mist hardly occurs. Thereby, the turbo compressor 1
Thus, it is possible to improve the operation efficiency and further increase the size of the heat pump device, thereby improving the heating / cooling capacity.

In the present embodiment, well water is used as a heat source. However, an easily available heat source may be used, and groundwater or river water may be used.
If the air conditioning system is built in a factory or power generation facility, drainage or the like from the facility may be used. In addition, although the antifreeze liquid for ice heat storage is used as the external refrigerant, the refrigerant for cooling may be cooled.

Next, a second embodiment of the heat pump device according to the present invention will be described with reference to FIG. The components already described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. FIG. 3 is a piping diagram of an air conditioning system that employs a heat pump device according to the present invention as in the first embodiment. The air-conditioning system according to the present embodiment includes oil (lubricating oil) of the turbo compressor 10.
Is provided with an oil cooler 21 for cooling the oil. An oil cooler 21 has an oil pipe 22 for circulating oil of the turbo compressor 10, and second and third heat exchangers 12 and 1.
An oil cooler refrigerant pipe 23 that guides a part of the refrigerant from 3 and feeds the refrigerant to the first heat exchanger 11 is connected to the oil pipe 22 and the oil that flows through the oil cooler refrigerant pipe 23. Heat exchange.

Each of the oil cooler refrigerant pipes 23 extending from the second and third heat exchangers 12 and 13 has a valve 2.
4a and 24b are provided, and they are assembled into one piece on the way and connected to an oil cooler. This is because only one of the second and third heat exchangers 12 and 13 is used according to the heating / cooling operation mode, and the valve on the used side is opened and the valve on the unused side is opened. It is closed, and the refrigerant is always supplied from the heat exchanger on the used side.

Further, in the air-conditioning system according to the present embodiment, the connecting pipe 25 for connecting the refrigerant space inside the first heat exchanger 11 and the refrigerant space of the second heat exchanger 12 and the connecting pipe 25 are opened and closed. A valve (opening / closing means) 26 is provided, and the second heat exchanger 1
2 Pressure sensor (detection means) 27 for detecting internal pressure
An automatic monitoring system including a control unit 28 that controls the operation of the valve 26 based on the detection result of the pressure sensor 27 is constructed.

In the air conditioning system configured as described above, the valve 24a is opened and the valve 24b is closed during the heating operation, and the valve 24b is opened and the valve 2 during the cooling operation.
4a is closed so that unnecessary refrigerant is not exchanged between the second and third heat exchangers 12, 13. However, it is hard to say that it is complete. For example, during the cooling operation, the cooled refrigerant in the third heat exchanger 13 flows into the lower-pressure second heat exchanger 12 (unused state), There is a possibility that the operation of the heat exchanger 12 may be hindered by lowering the temperature inside the heat exchanger 12 and freezing the well water.

Therefore, in the heat pump device employed in the air conditioning system, the pressure inside the second heat exchanger 12 is always detected by the pressure sensor 27,
When it is considered that the pressure inside the heat exchanger 12 has decreased and the temperature has decreased accordingly, the valve 26 is opened and the first
Of the warmed refrigerant inside the heat exchanger 11 of the second heat exchanger 1
2, the pressure inside the second heat exchanger 12 and the temperature that changes linearly with it can be kept normal. According to this, even if the operation is switched to the heating operation, the second heat exchanger 12 operates normally and does not hinder the operation.

In this embodiment, the pressure sensor 27 is employed as a means for detecting the state inside the second heat exchanger 12, but a temperature sensor may be used instead. In the present embodiment, the second heat exchanger 1
Although an automatic monitoring system for constantly monitoring the internal state of the second heat exchanger 12 is provided, an operator may monitor the internal state of the second heat exchanger 12 and open / close the valve 26 based on the internal state. .

In this embodiment, a problem which may occur with the installation of the oil cooler 21 has been described as an example. However, this problem may occur when other general auxiliary equipment is provided in the heat pump device. Things. It goes without saying that the mechanism described in the present embodiment is applied to such a case.

Next, a third embodiment of the heat pump device according to the present invention will be described with reference to FIG. Note that the same reference numerals are given to the components already described in the above embodiments, and description thereof will be omitted. FIG. 4 is a piping diagram of an air conditioning system employing the heat pump device according to the present invention, as in the above embodiments. The air conditioning system in the present embodiment is provided with a level switch (liquid level detecting means) 29 for detecting the liquid level of the refrigerant inside the second heat exchanger 12.

In the air-conditioning system configured as described above, when the cooling operation is started, if the refrigerant remains inside the second heat exchanger 12, there is a concern that the accumulation may affect the well water. . Therefore, a level switch 29 is provided to detect the liquid level of the refrigerant inside the second heat exchanger 12, and if the refrigerant remains, the start of the cooling operation is forgotten. Thereby, it is possible to prevent accumulation of the refrigerant and prevent trouble such as freezing of well water.

In this embodiment, the level switch 29 is used as a means for detecting the liquid level of the refrigerant inside the second heat exchanger 12, but the same function is provided inside the second heat exchanger 12. Any structure may be adopted as long as the sensor can be used.

Next, a fourth embodiment of the heat pump device according to the present invention will be described with reference to FIG. Note that the same reference numerals are given to the components already described in the above embodiments, and description thereof will be omitted. FIG. 5 is a piping diagram of an air conditioning system employing the heat pump device according to the present invention, similarly to the above embodiments. In the air conditioning system according to the present embodiment, the hot water pipe 17 and the well water pipe 19 are shared inside the first heat exchanger 11, and the hot water pipe 17 serves as a switching unit for switching a hot water or well water flow path. The valve 30a is connected to the well water pipe 19 with the valve 30a.
b are provided respectively.

In the air-conditioning system configured as described above, when the heating operation is selected, the valve 30a is opened and the valve 30b is closed, so that the hot water flow path is secured inside the first heat exchanger 11. You. When the cooling operation is selected, the valve 30b is opened, the valve 30a is closed, and the first
The flow path of the well water is secured inside the heat exchanger 11.

As described above, in the heat pump device employed in the above air conditioning system, the hot water flow path is also switchably used as the well water flow path, and a part of the well water is used for the hot water. . Thereby, the supply of hot water becomes easy and the operation efficiency can be improved. In addition, the piping system can be integrated and simplified to reduce the equipment cost. However, in order to protect the hot water piping system 17 and the air conditioning equipment connected thereto, it is desirable to provide the well water piping system 19 with a purifying means.

[0048]

As described above, in the heat pump device according to the first aspect of the present invention, since it is not necessary to switch the flow direction of the refrigerant between the forward and reverse directions inside the heat exchanger as in the prior art, the dry pump is used. There is no need to use a structured heat exchanger. This makes it possible to use a turbo-type compressor by using a heat exchanger other than a dry-type structure that is less likely to generate mist, so that it is possible to improve operating efficiency and further increase the size of the heat pump device.

According to the heat pump device of the second aspect, of the first, second, and third heat exchangers, at least the second and third heat exchangers employ a liquid-filled structure. Since the generation of mist mixed in the refrigerant can be suppressed and a turbo-type compressor can be employed, the above effects can be obtained.

According to the heat pump device of the third aspect, the first heat exchanger and the second heat exchanger having a higher temperature and a higher pressure are connected to each other by the connecting pipe, and the inside of the second heat exchanger is connected. By opening the opening / closing means while watching the state and introducing the warmed refrigerant in the first heat exchanger to the second heat exchanger,
It is possible to keep the inside of the heat exchanger in a normal state, so that operation is not hindered.

According to the heat pump device of the fourth aspect, the state inside the second heat exchanger is detected, and the drive of the opening / closing means is controlled according to the state, so that the inside of the second heat exchanger is always kept. Since the normal state can be maintained, it is possible to prevent trouble in driving in any case.

According to the heat pump device of the fifth aspect, the liquid level of the refrigerant inside the second heat exchanger is detected by the liquid level detecting means, and if the refrigerant remains, the start of the cooling operation is postponed. Since the accumulation of water is prevented and the heat medium is not affected, it is possible to prevent the operation from being hindered.

According to the heat pump device of the sixth aspect, the flow path of the heat medium is also switchably used as the flow path of the heat source, and the supply of the heat medium is performed by using a part of the heat source as the heat medium. Since it becomes easy, the efficiency of operation can be improved. Further, the integration and simplification of the piping system can be achieved, so that equipment costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a heat pump device according to the present invention, and is a piping diagram of an air conditioning system employing the heat pump device.

FIG. 2 is a cross-sectional view showing the structure of a liquid-filled heat exchanger and a dry heat exchanger.

FIG. 3 is a diagram showing a second embodiment of the heat pump device according to the present invention, and is a piping system diagram of an air conditioning system employing the heat pump device.

FIG. 4 is a diagram showing a third embodiment of the heat pump device according to the present invention, and is a piping diagram of an air conditioning system employing the heat pump device.

FIG. 5 is a diagram showing a fourth embodiment of the heat pump device according to the present invention, and is a piping diagram of an air conditioning system employing the heat pump device.

FIG. 6 is a piping diagram of an air conditioning system employing a conventional heat pump device.

[Explanation of symbols]

 10 Turbo compressor 11 First heat exchanger 12 Second heat exchanger 13 Third heat exchanger 14a, 14b Expansion valves 16a, 16b, 16c, 16d Valves (switching means)

Claims (6)

[Claims] 1. A turbo compressor for compressing a refrigerant, wherein heat is exchanged between the compressed refrigerant and a heat medium to condense the refrigerant, thereby heating the heat medium or compressing the heat medium. A first heat exchanger that causes heat exchange between the refrigerant and the heat source to condense the refrigerant, an expansion valve that decompresses the condensed refrigerant, and heat exchange between the heat source and the depressurized refrigerant. A second heat exchanger for causing the refrigerant to evaporate, and exchanging heat between an external refrigerant of a different system from the refrigerant and the depressurized refrigerant to evaporate the refrigerant, thereby cooling the external refrigerant. And a switching means for selectively switching the inflow path of the condensed refrigerant to either the second heat exchanger or the third heat exchanger. Heat pump device. 2. A liquid-filled structure is adopted in at least the second and third heat exchangers of the first, second and third heat exchangers. 2. The heat pump device according to 1. 3. A connecting pipe for communicating a refrigerant space of the first heat exchanger with a refrigerant space of the second heat exchanger, and an opening / closing means for opening and closing the connecting pipe. Item 3. The heat pump device according to item 1 or 2. 4. A detecting device for detecting a state inside the second heat exchanger, and a control unit for controlling driving of the opening / closing device based on a detection result of the detecting device. Item 4. The heat pump device according to item 3. 5. The heat pump device according to claim 1, further comprising a liquid level detecting means for detecting a liquid level of the refrigerant inside the second heat exchanger. 6. A flow path of the heat medium and a flow path of the heat source are shared by the first heat exchanger, and the respective flow paths are switched so as to secure one of them as necessary. 6. The heat pump device according to claim 1, further comprising a switching unit.