JPH0727430A - Compression type heat pump - Google Patents

Abstract

PURPOSE:To effectively prevent suction of recovery liquid refrigerant of a compressor by providing pressure introducing means for switching a discharge side positive pressure of the compressor to a positive pressure applied state for applying it to a liquid refrigerant tank or to a negative pressure applied state for applying a suction side negative pressure of the compressor to the tank. CONSTITUTION:Pressure introducing means X operable to switch a liquid refrigerant tank T to a positive pressure applied state for applying a discharge side positive pressure of a compressor Co to the tank T or a negative pressure applied state for applying a suction side negative pressure of the compressor Co to the tank T is provided. That is, a pressure regulating valve vp is so opened to the positive pressure applied state as to introduce a positive pressure to overcome an applied negative pressure through a capillary tube ct from a low pressure side pressure guide passage p2 from a high pressure side pressure guide passage p1. The vale vp is closed to set it to a negative pressure applied state by an applied negative pressure from the passage p2 through the tube ct. Thus, danger of suction of recovery liquid refrigerant by the compressor Co can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression heat pump, and more specifically, it is provided with a target heat exchanger interposed between a liquid refrigerant passage communicating with another heat exchanger and a gas refrigerant discharge passage of the compressor for condensation. The refrigerant circuit is switched between a condensation switching state in which the target heat exchanger is operated and an evaporation switching state in which the target heat exchanger is interposed between the liquid refrigerant path and the gas refrigerant suction path of the compressor to operate as an evaporator. The present invention relates to a compressible heat pump configured as possible.

[0002]

2. Description of the Related Art Conventionally, in a compression heat pump as described above, a target heat exchanger is switched from a condensation switching state in which the target heat exchanger acts as a condenser, for example, for starting a defrosting operation or switching between heating and cooling. In order to switch the refrigerant circuit to the evaporation switching state in which the
18 to FIG. 19, the target heat exchanger NA is switched from the connection state of the compressor Co to the gas refrigerant discharge path Go to the connection state of the gas refrigerant suction path Gs with the valve being stopped as shown in FIGS. 18 to 19. As a result, the target heat exchanger NA that has been acting as a condenser and the liquid refrigerant (indicated by the thick line with hatching in the figure) remaining in the connection passage in the vicinity of the target heat exchanger NA are discharged to the compressor suction side and the compressor discharge side. Due to the residual pressure difference between the side of the compressor and the side of the compressor, the accumulator Ac installed on the suction side of the compressor collects and stores the gas via the gas refrigerant suction path Gs.

Following this, by restarting the operation of the compressor Co, the large amount of recovered liquid refrigerant R stored in the accumulator Ac is gradually evaporated and vaporized by the work of the compressor and is sent to the gas refrigerant discharge passage Go. While returning to the refrigerant circuit, the liquid refrigerant from the heat exchanger NB that acts as another condenser is supplied to the target heat exchanger NA that acts as an evaporator through the liquid refrigerant path L and the expansion valve exA, Further, the low-pressure gas refrigerant (shown by a white thick line in the figure) evaporated in the target heat exchanger NA is compressed by the compressor Co via the gas refrigerant suction passage Gs.
Was returned to the suction side, and with this, the transition to the evaporation switching state was completed.

[0004]

However, in the conventional switching mode as described above, the following drawbacks (a), (b) and (c), that is, (a) a process of recovering the residual liquid refrigerant to the accumulator Ac. In order to avoid sucking the liquid refrigerant of the compressor Co, it is necessary to temporarily stop the operation of the compressor Co, and therefore, the time for interrupting the original operation of the heat pump such as cooling and heating and heating / cooling of articles becomes long, The service life of the compressor Co decreases as the number of times the compressor Co starts and stops increases.

(B) If the amount of residual liquid refrigerant becomes large for some reason and the accumulator capacity becomes insufficient, the liquid refrigerant suction of the compressor Co occurs when the operation of the compressor Co is restarted, and so-called liquid There is a risk of causing a compressed state, which may damage the compressor Co.

(C) Since the liquid refrigerant R collected in the accumulator Ac is vaporized by the work of the compressor and returned to the refrigerant circuit, the work of the compressor causes energy loss from the original operation of the heat pump. Energy efficiency is low.

An object of the present invention is to effectively solve the above problems by a rational liquid refrigerant recovery structure.

[0008]

[Means for Solving the Problems]

[First characteristic configuration] A first characteristic configuration of a compression heat pump according to the present invention is that a target heat exchanger is interposed between a liquid refrigerant passage communicating with another heat exchanger and a gas refrigerant discharge passage of a compressor. The refrigerant circuit is switched between a condensation switching state in which the condenser operates and an evaporation switching state in which the target heat exchanger is interposed between the liquid refrigerant passage and the gas refrigerant suction passage of the compressor to cause the evaporator to operate. In contrast to the switchable configuration, in the liquid refrigerant path, while connecting the liquid refrigerant tank to the side of the other heat exchanger than the expansion valve for the target heat exchanger, the connection point of the liquid refrigerant tank A liquid refrigerant passage opening / closing valve between the expansion valve and the expansion valve, and a positive pressure application state in which a positive pressure on the discharge side of the compressor is applied to the liquid refrigerant tank, and a negative pressure on the suction side of the compressor Switch to the state of applying negative pressure to the liquid refrigerant tank. For example lies in the provision of the operation can be Shirube圧 means.

[Second Characteristic Configuration] A second characteristic configuration of the compression heat pump according to the present invention is to identify a preferable configuration in the implementation of the first characteristic configuration described above. In switching the refrigerant circuit to the switching state for evaporation, the following operations (a) to (d),
That is, (a) the pressure guiding means is switched to a negative pressure application state, (b) the liquid refrigerant passage opening / closing valve is closed, and (c) the target heat exchanger is connected to the gas refrigerant discharge passage from the gas refrigerant. Switch to the connection state for the suction path,
(D) A switching control means is provided for automatically opening the liquid refrigerant passage opening / closing valve and switching the pressure guiding means to a positive pressure application state in that order.

[0010]

[Action]

[Operation of First Characteristic Configuration] That is, in the first characteristic structure, when switching from the condensation switching state to the evaporation switching state, first, the pressure guiding means is switched to the negative pressure application state, whereby the condenser operation is performed. The liquid refrigerant generated in the target heat exchanger is sucked and collected in the liquid refrigerant tank connected to the liquid refrigerant path, and the liquid refrigerant is retracted toward the liquid refrigerant tank side from the expansion valve or the liquid refrigerant path opening / closing valve in the liquid refrigerant path.

Then, in this liquid refrigerant withdrawal state, the liquid refrigerant passage opening / closing valve is closed, and then the target heat exchanger is connected from the gas refrigerant discharge passage of the compressor to the gas refrigerant suction passage of the compressor. Switch to.

By this switching, the suction action of the compressor is exerted on the target heat exchanger via the gas refrigerant suction passage, whereby the liquid refrigerant remaining in a small amount in the target heat exchanger and the like evaporates and the wetness of the liquid is reduced. The high-pressure low-pressure gas refrigerant is sucked into the compressor suction side through the gas refrigerant suction passage, but the recovered liquid refrigerant is subjected to the suction action of the compressor, and then the compressor through the target heat exchanger and the gas refrigerant suction passage. The liquid refrigerant passage open / close valve in the closed state prevents the liquid refrigerant from being sucked into the suction side.

After that, when a small amount of residual liquid refrigerant is removed and the compressor sucks low-pressure low-pressure gas refrigerant, the liquid refrigerant passage opening / closing valve is opened and the target heat exchange is performed from the liquid refrigerant passage through the expansion valve. The liquid refrigerant is supplied to the heat exchanger, which causes the target heat exchanger to act as an evaporator.

Further, when the liquid refrigerant passage opening / closing valve is opened, the pressure guiding means is switched to a positive pressure application state to discharge the stored liquid refrigerant in the liquid refrigerant tank to the liquid refrigerant passage, and the discharged liquid refrigerant acts as an evaporator. The target heat exchanger to be operated or another heat exchanger which is in communication with the liquid refrigerant passage and acts as an evaporator is evaporated.

[Operation of Second Characteristic Configuration] In the second characteristic configuration, the pressure guiding means, the liquid refrigerant passage opening / closing valve, the gas refrigerant discharge passage,
The switching control means automatically performs switching from the condensation switching state to the evaporation switching state, which is performed by switching each of the gas refrigerant suction paths in the above-described predetermined procedure.

[0016]

【The invention's effect】

[Effects of First Characteristic Configuration] That is, according to the first characteristic structure of the present invention, the liquid refrigerant condensed in the target heat exchanger is not recovered to the suction side of the compressor, but compressed against the target heat exchanger. Since the liquid refrigerant is recovered to the side of the liquid refrigerant path that is opposite to the suction side of the machine, it is possible to reliably prevent the situation where the compressor sucks the recovered liquid refrigerant as compared with the conventional recovery mode described above.

As a result, it is possible to eliminate the need to temporarily stop the compressor operation when switching from the condensation switching state to the evaporation switching state, and to shorten the interruption time of the heat pump original operation and start / stop the compressor. It is possible to avoid a decrease in service life due to an increase in the number of times.

Further, due to some reason, the amount of refrigerant condensed in the target heat exchanger becomes large, so that even if the entire amount of liquid refrigerant could not be recovered to the liquid refrigerant tank side, it is sucked into the suction side of the compressor. Since the amount of liquid refrigerant to be used is limited to a small amount by recovering the liquid refrigerant on the liquid refrigerant tank side, it is possible to more reliably prevent the occurrence of liquid compression in the compressor even with such changes in the refrigerant condensation amount. The risk of compressor damage due to compression can be reduced.

Moreover, the liquid refrigerant collected on the liquid refrigerant tank side, that is, on the liquid refrigerant path side is evaporated by heat absorption from the outside in the heat exchanger which communicates with the liquid refrigerant path and acts as an evaporator, and then the low pressure gas refrigerant. Since it is returned to the compressor as described above, the energy efficiency as a whole can be improved as compared with the case where a large amount of the recovered liquid refrigerant is evaporated and vaporized by the work of the compressor as in the conventional recovery mode described above.

[Effects of Second Characteristic Configuration] According to the second characteristic structure of the present invention, the automatic switching by the switching control means simplifies the switching from the condensation switching state to the evaporation switching state without human operation. You can do it.

[0021]

【Example】

[First Embodiment] FIG. 1 shows a separate type air conditioner using a compression heat pump, where U1 is an outdoor unit, U2 and U3.
Are first and second indoor units respectively connected to the outdoor unit U1 via the transition refrigerant pipe r.

The outdoor unit U1 has a first heat exchanger N1 for absorbing and radiating the outside air OA, and the outside air O is supplied to the first heat exchanger N1.
A first fan F1 that ventilates A, a compressor Co, an accumulator Ac, a liquid refrigerant tank T, and an electronic first expansion valve ex1 are provided.

The first indoor unit U2 has a second heat exchanger N2 for cooling and heating air, and a second heat exchanger N in the air flow direction.
A third heat exchanger N3 for reheat located downstream of 2,
A second fan F for sending out the air SA1 adjusted by the second and third heat exchangers N2, N3 to the corresponding air conditioning target area.
2 and electronic second and third expansion valves ex2, e
It is equipped with x3.

Similar to the first indoor unit U2, the second indoor unit U3 has a fourth heat exchanger N4 for cooling and heating air and a reheat located downstream of the fourth heat exchanger N4 in the air flow direction. Fifth heat exchanger N5 for use, and fourth and fifth heat exchanger N thereof
It is equipped with a third fan F3 that sends out air SA2 adjusted by 4, N5 to the corresponding air-conditioning target area, and electronic fourth and fifth expansion valves ex4, ex5.

Incidentally, the first to fifth expansion valves ex1 to e
Each x5 has a configuration that can be switched between a state in which it functions as an expansion valve and a state in which it functions as a flow rate adjusting valve. Further, v1 to v9 in the figure are electromagnetic valves for switching the flow paths, respectively.

The liquid refrigerant tank T is located on the opposite side of the heat exchangers N1 to N5 from the compressor Co in the refrigerant circuit, and in the liquid refrigerant passage L connecting the heat exchangers N1 to N5. Expansion valves ex1 to e for the heat exchangers N1 to N5
The connection path s for the liquid refrigerant path L is connected to the part between the x5 parts (that is, the part where the liquid refrigerant always exists).
The in-tank opening of is placed at the bottom of the tank so as to be positioned in the stored liquid refrigerant R.

With respect to the liquid refrigerant tank T, a positive pressure application state in which a positive pressure on the discharge side of the compressor Co is applied to the liquid refrigerant tank T and a negative pressure on the suction side of the compressor Co are applied to the liquid refrigerant tank T. A pressure guiding means X operable to switch to a negative pressure applying state.
Is equipped with a concrete structure of a compressor Co
Gas refrigerant discharge passage Go (so-called high-pressure gas passage of compression heat pump) and high-pressure side pressure passage p1 connecting liquid refrigerant tank T, and gas refrigerant suction passage Gs of compressor Co (so-called low pressure of compression heat pump). The low pressure side pressure guiding path p2 that connects the gas passage) to the liquid refrigerant tank T is provided, and the pressure adjusting valve vp that opens and closes the high pressure side pressure guiding path p1 is provided, and the capillary tube ct is provided in the low pressure side pressure guiding path p2. Is installed.

That is, the pressure adjusting valve vp is opened and operated so that the positive pressure that overcomes the negative pressure applied from the low pressure side pressure guiding path p2 via the capillary tube ct is introduced from the high pressure side pressure guiding path p1. A positive pressure is applied to the negative pressure applying state, and conversely, the pressure adjusting valve vp is closed to apply a negative pressure due to the negative pressure applied from the low pressure side pressure guiding path p2 via the capillary tube ct.

FIG. 1 shows a refrigerant flow state in the heating mode. As the refrigerant flow, a high pressure gas refrigerant (shown by a thick black line in the figure) discharged from the compressor Co flows through the gas refrigerant discharge passage Go. Through the second and fourth heat exchangers N2, N4
And condensed in the second and fourth heat exchangers N2 and N4, and the condensed liquid refrigerant sent from the second and fourth heat exchangers N2 and N4 (indicated by a thick line with hatching in the figure). (Indicated) is supplied to the first heat exchanger N1 via the liquid refrigerant passage L in which the second and fourth expansion valves ex2 and ex4 function as flow rate adjusting valves, and the first expansion valve ex1 functions as an expansion valve. The low-pressure gas refrigerant (shown by a white thick line in the figure) that has been vaporized in the first heat exchanger N1 and is sent out from the first heat exchanger N1 passes through the gas refrigerant suction passage Gs and the accumulator Ac to the compressor Co. Return to the suction side (the black valve in the figure shows the closed state).

Further, in this refrigerant flow state, the opening of the pressure adjusting valve vp is adjusted in the intermediate opening range so that the amount of the refrigerant circulated in the refrigerant circuit becomes an appropriate amount of refrigerant in the compressor operation. The liquid refrigerant storage amount of the liquid refrigerant tank T is adjusted.

Y is a control device for controlling the operation. As an example of the operation control, the control device Y causes each of the second and fourth heat exchangers N2 and N4 to act as a condenser to supply the air conditioning target area. The above heating mode (see FIG. 1) in which the heating temperatures of the air SA1 and SA2 are controlled and the heat of the first heat exchanger N1 is made to act as an evaporator to absorb heat from the outside air OA, and the first heat is used in the operation in the heating mode. When frost is formed on the exchanger N1, the second
A defrosting mode in which each of the fourth heat exchangers N2 and N4 acts as an evaporator to absorb heat from the air conditioning target area side, and the first heat exchanger N1 acts as a condenser to frost by condensation heat (Fig. 5
(See) and switch.

The switching from the heating mode to the defrosting mode is carried out when the second and fourth heat exchangers N2 and N4 are used as the target heat exchanger NA and the target heat exchanger NA is viewed.
The target heat exchanger NA (N2, N4) is replaced with another heat exchanger NB
Liquid refrigerant path L communicating with (first heat exchanger N1) and compressor C
From the switching state for condensation in which the condenser action is performed by interposing it between the gas refrigerant discharge passage Go of No. o and the target heat exchanger NA (N
2, N4) is interposed between the liquid refrigerant passage L and the gas refrigerant suction passage Gs of the compressor Co to make the evaporator act as an evaporator, and the controller Y controls the target heat exchanger. It functions as a switching control unit that automatically switches the condensation switching state for NA (N2, N4) from the evaporation switching state.

The control device Y as the switching control means switches from the heating mode to the defrosting mode,
That is, when switching from the condensation switching state to the evaporation switching state when the second and fourth heat exchangers N2 and N4 are used as the target heat exchanger NA, various operating state detection information is used as a specific control operation. Based on (a) below
The operation of (d) is automatically performed in that order.

For switching from the heating mode to the defrosting mode in the first embodiment, the second and fourth heat exchangers N2 and N4 will be referred to as the target heat exchanger NA, and the first heat exchanger N1 will be referred to below. The second and fourth expansion valves ex for the second and fourth heat exchangers N2 and N4 are also called other heat exchangers NB.
2, ex4 are referred to as expansion valves exA for the target heat exchanger NA.

(A) While the refrigerant flow state in the heating mode is as shown in FIG. 1, as shown in FIG. 2, the pressure regulating valve vp is closed to apply the negative pressure to the pressure guiding means X. And the expansion valve exA for the target heat exchanger NA that was functioning as a flow rate control valve is fully opened, so that the liquid refrigerant (thick line with hatching) generated in the target heat exchanger NA acting as the condenser is removed. The liquid refrigerant is sucked and collected in the liquid refrigerant tank T, and the liquid refrigerant is retreated in the liquid refrigerant path L toward the liquid refrigerant tank T side with respect to the expansion valve exA for the target heat exchanger NA.

(B) Next, as shown in FIG. 3, the expansion valve exA for the target heat exchanger NA is used as the liquid refrigerant passage opening / closing valve vA, and the expansion valve exA for the target heat exchanger NA is closed to close the liquid refrigerant passage. L is closed to the target heat exchanger NA.

(C) Then, among the solenoid valves v1 to v9, excluding the fourth and seventh solenoid valves v4 and v7 for reheating, the switching operation is carried out, and as shown in FIG. N
A is switched from the connected state to the gas refrigerant discharge path Go to the connected state to the gas refrigerant suction path Gs, and the other heat exchanger NB is switched from the connected state to the gas refrigerant suction path Gs to the connected state to the gas refrigerant discharge path Go. .

By this switching operation, the target heat exchanger NA
The suction action of the compressor Co is exerted via the gas refrigerant suction passage Gs, whereby a small amount of the liquid refrigerant remaining in the target heat exchanger NA and the refrigerant passage in the vicinity thereof evaporates and the low-pressure gas having a high degree of wetness is obtained. In the state of the refrigerant (white thick line), it is sucked into the compressor suction side through the gas refrigerant suction passage Gs, and accordingly,
Although the amount of liquid refrigerant stored in the accumulator Ac increases slightly,
The liquid refrigerant (thick line with hatching) collected and withdrawn to the liquid refrigerant tank T side is prevented from moving to the compressor suction side by the expansion valve exA as the liquid refrigerant passage opening / closing valve vA in the closed state. It

(D) Thereafter, as shown in FIG. 4, the removal of a small amount of residual liquid refrigerant from the target heat exchanger NA progresses, and the compressor Co comes to draw in a low-pressure gas refrigerant having a low degree of wetness (that is, (The amount of liquid refrigerant stored in the accumulator Ac decreases), and as shown in FIG. 5, the expansion valve exA as the liquid refrigerant passage opening / closing valve vA is opened and the target heat exchanger NA is caused to function as an original expansion valve. Thus, the liquid refrigerant (thick line with hatching) is supplied from the liquid refrigerant passage L to the target heat exchanger NA through the expansion valve exA to supply the target heat exchanger N.
Let A act as an evaporator.

In addition to opening the expansion valve exA as the liquid refrigerant passage opening / closing valve vA, the pressure regulating valve vp is opened to switch the pressure guiding means X to the positive pressure application state, whereby the stored liquid in the liquid refrigerant tank T is stored. The refrigerant R is discharged to the liquid refrigerant path L, and the discharged liquid refrigerant is sent to the liquid refrigerant path L from another heat exchanger NB acting as a condenser via the first expansion valve ex1 as a flow rate adjusting valve. At the same time, it is sent to the target heat exchanger NA to be vaporized in the target heat exchanger NA, and the switching from the heating mode to the defrosting mode is completed.

On the other hand, when returning from the defrosting mode to the heating mode, when the first heat exchanger N1 is used as the target heat exchanger NA and the target heat exchanger NA is viewed, the heating mode is changed from the previous heating mode to the defrosting mode. Similar to switching, target heat exchanger NA
(N1) to another heat exchanger NB (second and fourth heat exchangers N
2, N4) and the target heat exchanger NA (N1) from the condensation switching state in which the condenser action is effected by being interposed between the liquid refrigerant passage L communicating with the gas refrigerant discharge passage Go of the compressor Co. It is a switch to an evaporation switching state in which the evaporator action is effected by being interposed between L and the gas refrigerant suction path Gs of the compressor Co, and the control device Y also returns from the defrosting mode to the heating mode. Similarly, the target heat exchanger NA (N1)
Functioning as switching control means for automatically switching from the condensation switching state to the evaporation switching state.

Then, the control device Y returns from the defrosting mode to the heating mode, that is, switches from the condensation switching state to the evaporation switching state when the first heat exchanger N1 is the target heat exchanger NA. In this regard, as a specific control operation, based on various operating state detection information, the above (a)
The following operations (a ') to (d') having the same form as the operations (d) to (d) are automatically performed in that order.

Hereinafter, in returning from the defrosting mode to the heating mode in the first embodiment, the first heat exchanger N1 will be referred to as the target heat exchanger NA, and the second and fourth heat exchangers N2 and N2.
N4 is referred to as another heat exchanger NB, and the first heat exchanger N
The first expansion valve ex1 for 1 is referred to as an expansion valve exA for the target heat exchanger NA.

(A) While the refrigerant flow state in the defrosting mode is the state shown in FIG. 5, the pressure regulating valve vp is closed and the pressure guiding means X is set to a negative pressure as shown in FIG. The expansion valve exA for the target heat exchanger NA, which was switched to the applied state and functioned as the flow rate adjusting valve, was fully opened, whereby the liquid refrigerant generated in the target heat exchanger NA acting as the condenser (hatched thick line). ) Is sucked and collected in the liquid refrigerant tank T, and the liquid refrigerant is retracted to the liquid refrigerant tank T side of the expansion valve exA for the target heat exchanger NA in the liquid refrigerant passage L.

(B ') Next, as shown in FIG. 7, the expansion valve exA for the target heat exchanger NA is used as the liquid refrigerant passage opening / closing valve vA, and the expansion valve exA for the target heat exchanger NA is closed to close the liquid refrigerant. The path L is closed to the target heat exchanger NA.

(C ') Then, among the solenoid valves v1 to v9, excluding the fourth and seventh solenoid valves v4 and v7 for reheating, the switching operation is carried out, and as shown in FIG. The reactor NA is switched from the connection state for the gas refrigerant discharge path Go to the connection state for the gas refrigerant suction path Gs, and the other heat exchanger NB is changed from the connection state for the gas refrigerant suction path Gs to the connection state for the gas refrigerant discharge path Go. Switch.

(D ') After that, as shown in FIG. 8, the removal of the small amount of residual liquid refrigerant to the target heat exchanger NA proceeds, and the compressor Co comes to draw in the low-pressure gas refrigerant having low wetness (that is, , The amount of liquid refrigerant stored in the accumulator Ac decreases), and as shown in FIG. 9 (the same refrigerant flow state as in FIGS. 9 and 1), the expansion valve exA as the liquid refrigerant passage opening / closing valve vA is opened and The heat exchanger NA is caused to function as an original expansion valve, whereby the liquid refrigerant (thick line with hatching) is supplied from the liquid refrigerant path L to the target heat exchanger NA via the expansion valve exA to thereby perform the target heat exchanger. Let NA act as an evaporator.

Further, with the opening of the expansion valve exA serving as the liquid refrigerant passage opening / closing valve vA, the pressure regulating valve vp is opened to apply the positive pressure to the pressure guiding means X (that is, the amount of refrigerant circulating in the refrigerant circuit is compressed). In order to obtain an appropriate amount of refrigerant for machine operation,
The pressure adjusting valve vp is adjusted in the intermediate opening range to adjust the liquid refrigerant storage amount in the liquid refrigerant tank T),
As a result, the stored liquid refrigerant R in the liquid refrigerant tank T is discharged to the liquid refrigerant passage L, and the discharged liquid refrigerant is supplied from the other heat exchanger NB acting as a condenser to the second and fourth expansion valves as flow rate adjusting valves. The liquid refrigerant sent to the liquid refrigerant path L via ex2 and ex4 is sent to the target heat exchanger NA to be evaporated in the target heat exchanger NA, thereby completing the return from the defrost mode to the heating mode.

[Second Embodiment] In the air conditioner shown in the first embodiment, the control means Y is a second example of another operation control in the refrigerant flow state as shown in FIG.
Each of the heat exchangers N2 and N4 acts as a condenser to heat and control the temperature of the supply air SA1 and SA2 to the air-conditioned area, and the first heat exchanger N1 acts as an evaporator to absorb heat from the outside air OA. In the heating mode (FIGS. 10, 9 and 1 show the same refrigerant flow state, respectively) and the refrigerant flow state shown in FIG. 14, the second heat exchanger N2 is caused to act as an evaporator and the corresponding air conditioning target area is set. The temperature of the supply air SA1 to the corresponding air-conditioning target area by controlling the cooling temperature of the supply air SA1 to the fourth heat exchanger N4, and the first heat exchanger N1 to the evaporator. The mode is switched to the heating / cooling parallel mode in which the heating is performed and heat is absorbed from the outside air OA.

When switching from the heating mode to the above-mentioned cooling / heating parallel mode, when the second heat exchanger N2 is used as the target heat exchanger NA and the target heat exchanger NA is viewed, the target heat exchanger NA (N2) is switched. Other heat exchangers NB (first and fourth
Liquid refrigerant path L and compressor C communicating with heat exchangers N1, N4)
From the switching state for condensation in which the condenser action is performed by interposing it between the gas refrigerant discharge passage Go of No. o and the target heat exchanger NA (N
2) is the switching state for evaporation in which the liquid refrigerant passage L and the gas refrigerant suction passage Gs of the compressor Co are interposed to act as an evaporator, and the control device Y switches from this heating mode to the cooling / heating parallel mode. It functions as a switching control unit that automatically switches the target heat exchanger NA (N1) from the condensation switching state to the evaporation switching state.

Then, the control device Y switches from the heating mode to the above-mentioned cooling / heating parallel mode, that is, from the condensing switching state when the second heat exchanger N2 is the target heat exchanger NA to the evaporation switching state. When switching between
As a specific control operation, the following operations (a "to (d") of the same form as the operations (a) to (d) in the first embodiment described above are performed in that order based on various operation state detection information. It is configured to be automatically performed by.

Hereinafter, in the second embodiment showing the switching from the heating mode to the cooling / heating parallel mode, the second mode will be described.
The heat exchanger N2 is referred to as a target heat exchanger NA, and the first and the fourth
The heat exchangers N1 and N4 are referred to as other heat exchangers NB, and
The second expansion valve ex2 for the second heat exchanger N2 is referred to as an expansion valve exA for the target heat exchanger NA.

(A) While the refrigerant flow state in the heating mode is as shown in FIG. 10, as shown in FIG. 11, the pressure regulating valve vp is closed to put the pressure guiding means X in the negative pressure applying state. Switching, and fully open the expansion valve exA for the target heat exchanger NA that was functioning as a flow rate adjusting valve,
As a result, the liquid refrigerant (thick line with hatching) generated in the target heat exchanger NA acting as the condenser is sucked and recovered in the liquid refrigerant tank T, and the liquid refrigerant is expanded in the liquid refrigerant passage L to the expansion valve exA for the target heat exchanger NA. Than the liquid refrigerant tank T side.

(B) Next, as shown in FIG. 12, the expansion valve exA for the target heat exchanger NA is replaced with the liquid refrigerant passage opening / closing valve vA.
The liquid refrigerant passage L is closed to the target heat exchanger NA by closing the expansion valve exA for the target heat exchanger NA.

(C) Then, the first and second solenoid valves v
By switching between 1 and v2, as shown in FIG.
The target heat exchanger NA is switched from the connected state to the gas refrigerant discharge path Go to the connected state to the gas refrigerant suction path Gs.

(D) After that, as shown in FIG. 13, the removal of a small amount of residual liquid refrigerant in the target heat exchanger NA progresses, and the compressor Co comes to draw in a low-pressure gas refrigerant having a low degree of wetness (ie, , The amount of liquid refrigerant stored in the accumulator Ac decreases), and as shown in FIG. 14, the expansion valve exA serving as the liquid refrigerant passage opening / closing valve vA is opened and the target heat exchanger NA functions as the original expansion valve. This allows
The liquid refrigerant (thick line with hatching) is supplied from the liquid refrigerant path L to the target heat exchanger NA through the expansion valve exA to cause the target heat exchanger NA to act as an evaporator.

Further, the expansion valve exA serving as the liquid refrigerant passage opening / closing valve vA is opened, and the pressure regulating valve vp is opened to switch the pressure guiding means X to the positive pressure application state. The refrigerant R is discharged to the liquid refrigerant path L, and the discharged liquid refrigerant is discharged from the fourth heat exchanger N4 acting as a condenser among the other heat exchangers NB to a fourth expansion valve ex serving as a flow rate adjusting valve.
The first heat exchanger N1 that acts as an evaporator of the other heat exchangers NB together with the liquid refrigerant that is sent to the liquid refrigerant path L via
(Or, it is sent to the target heat exchanger NA that acts as an evaporator) to be evaporated, and thus the switching from the heating mode to the cooling / heating parallel mode is completed.

[Third Embodiment] In the first and second embodiments described above, as a switching control means for automatically switching the condensation switching state of the target heat exchanger NA from the evaporation switching state. In addition to functioning the control device Y, the control device Y is caused to switch from the dehumidifying mode of the refrigerant flow state shown in FIG. 15 to the cooling mode of the refrigerant flow state shown in FIG.

In the dehumidification mode (see FIG. 15), the second and fourth heat exchangers N2 and N4 act as evaporators to cool and dehumidify the supply air SA1 and SA2 to the air-conditioning target area first, and the third And the fifth heat exchangers N3, N5 act as a condenser to reheat the cooling and dehumidifying air SA1, SA2 by the second and fourth heat exchangers N2, N4, and condense the first heat exchanger N1. In the cooling mode (see FIG. 17), while the refrigerant supply to the third and fifth heat exchangers N3 and N5 for reheating is stopped,
The second and fourth heat exchangers N2, N4 act as evaporators to control the cooling temperatures of the supply air SA1, SA2 to the air conditioning target area, and the first heat exchanger N1 acts as a condenser to the outside air OA. Dissipate heat.

Further, in each of the dehumidifying mode and the cooling mode, the amount of the refrigerant circulated in the refrigerant circuit is set to be an appropriate amount for operating the compressor, as in the heating mode and the cooling / heating parallel mode. By adjusting the opening of the pressure adjusting valve vp in the intermediate opening range, the amount of liquid refrigerant stored in the liquid refrigerant tank T is adjusted.

Then, the control device Y is configured to automatically perform the following operations (e) to (e) as specific control operations in that order when switching from the dehumidifying mode to the cooling mode.

(E) While the refrigerant flow state in the dehumidifying mode is as shown in FIG. 15, the pressure regulating valve vp is closed and the pressure guiding means X is switched to the negative pressure applying state as shown in FIG. Also, the third and fifth expansion valves ex3, ex5, which have been functioning as flow rate adjusting valves, are fully opened, whereby the third and fifth heat exchangers N3, N5 that act as a condenser.
The liquid refrigerant (thick line with hatching) generated in 1 is sucked and collected in the liquid refrigerant tank T, and the liquid refrigerant is passed through the liquid refrigerant path L to the third position.
And the liquid refrigerant tank T side of the fifth expansion valves ex3 and ex5.

(F) Next, as shown in FIG. 17, the fourth and seventh solenoid valves v4 and v7 for reheating are closed to make the fourth.
And, the refrigerant supply to the seventh heat exchangers N4, N7 is cut off, and then the pressure regulating valve vp is opened to apply the positive pressure to the pressure guiding means X (that is, the amount of the refrigerant circulating in the refrigerant circuit depends on the compressor operation). In order to obtain an appropriate amount of refrigerant, the pressure adjusting valve vp is switched to a state in which the opening degree of the pressure adjusting valve vp is adjusted in the intermediate opening range to adjust the amount of liquid refrigerant stored in the liquid refrigerant tank T). Complete the switch to.

That is, in the operations of (e) to (f),
At the time of switching from the dehumidifying mode to the cooling mode by using the liquid refrigerant tank T and the pressure guiding means X used for switching from the condensation switching state to the evaporation switching state shown in the first and second embodiments. Heat exchangers N3, N5 for reheating
To prevent residual refrigerant from flowing into.

In the above operation (f), the fourth
It is preferable to close the third and fifth expansion valves ex3 and ex5 as liquid refrigerant passage shutoff valves together with the closing operation of the seventh and seventh solenoid valves v4 and v7.

[Other Embodiments] Next, other embodiments will be listed.

(1) In each of the above embodiments, the expansion valve exA for the target heat exchanger NA is replaced by the liquid refrigerant passage opening / closing valve vA.
The heat exchanger NA is also used as a heat exchanger.
The expansion valve exA and the liquid refrigerant passage opening / closing valve vA may be configured by different valves.

(2) A positive pressure application state in which the discharge side positive pressure of the compressor Co is applied to the liquid refrigerant tank T, and a negative pressure application state in which the suction side negative pressure of the compressor Co is applied to the liquid refrigerant tank T. The specific structure of the pressure guiding means X that can be switched can be changed in various ways. For example, a part of the high pressure gas refrigerant discharged from the compressor Co as in each of the above-described embodiments can be used for the high pressure side pressure guiding path. It is introduced into the liquid refrigerant tank T via p1 or the gas refrigerant in the liquid refrigerant tank T is passed through the low pressure side pressure guiding path p2 to the compressor C.
Instead of sucking into the suction side of o, between the compressor side and the liquid refrigerant tank T, a mode in which only the pressure is propagated while the circulation of the refrigerant itself is cut off may be adopted.

(3) The target heat exchanger NA may have any purpose and may be switched between the condensation switching state and the evaporation switching state. The compression heat pump according to the present invention has various fields. Can be used for various purposes.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 Refrigerant flow chart for heating mode

FIG. 2 is a refrigerant flow chart showing an initial stage of a switching operation to a defrost mode.

FIG. 3 is a refrigerant flow chart showing a middle stage of a defrosting mode switching operation.

FIG. 4 is a refrigerant flow chart showing a latter stage of a switching operation to a defrost mode.

FIG. 5 is a refrigerant flow chart showing a completion state of a switching operation to a defrost mode.

FIG. 6 is a refrigerant flow chart showing an initial stage of a return operation to a heating mode.

FIG. 7 is a refrigerant flow chart showing the middle stage of the operation for returning to the heating mode.

FIG. 8 is a refrigerant flow chart showing the latter stage of the operation for returning to the heating mode.

FIG. 9 is a refrigerant flow chart showing a completion state of a return operation to the heating mode.

FIG. 10: Flow chart of refrigerant in heating mode

FIG. 11 is a refrigerant flow chart showing an initial stage of a switching operation to the heating / cooling parallel mode.

FIG. 12 is a refrigerant flow chart showing the middle stage of the switching operation to the heating / cooling parallel mode.

FIG. 13 is a refrigerant flow chart showing the latter stage of the switching operation to the cooling / heating parallel mode.

FIG. 14 is a refrigerant flow chart showing the completion state of the switching operation to the cooling / heating parallel mode.

FIG. 15 is a refrigerant flow chart in dehumidification mode.

FIG. 16 is a refrigerant flow chart showing an intermediate stage of a switching operation to a cooling mode.

FIG. 17 is a refrigerant flow chart showing a completed state of a switching operation to the cooling mode.

FIG. 18 is a refrigerant flow chart showing a switching state for condensation in a conventional example.

FIG. 19 is a refrigerant flow chart showing a process of switching to a switching state for evaporation in a conventional example.

[Explanation of symbols]

 Co Compressor Go Gas refrigerant discharge path Gs Gas refrigerant suction path L Liquid refrigerant path NA Target heat exchanger NB Other heat exchanger T Liquid refrigerant tank X Pressure guiding means exA Expansion valve vA Liquid refrigerant path opening / closing valve

Claims (2)

[Claims] 1. A target heat exchanger (NA) is interposed between a liquid refrigerant passage (L) communicating with another heat exchanger (NB) and a gas refrigerant discharge passage (Go) of a compressor (Co). And a state in which the target heat exchanger (NA) is interposed between the liquid refrigerant passage (L) and the gas refrigerant suction passage (Gs) of the compressor (Co) to evaporate. A compression heat pump configured to switch a refrigerant circuit to a vaporization switching state in which the target heat exchanger (N) is connected in the liquid refrigerant path (L).
The liquid refrigerant tank (T) is connected to the other heat exchanger (NB) side of the expansion valve (exA) with respect to A), and the connection point of the liquid refrigerant tank (T) and the expansion valve (exA). ) With a liquid refrigerant passage opening / closing valve (vA) interposed therebetween, and a positive pressure application state in which a positive pressure on the discharge side of the compressor (Co) is applied to the liquid refrigerant tank (T); Co)
A compression heat pump provided with a pressure guiding means (X) that can be switched to a negative pressure application state in which the suction side negative pressure is applied to the liquid refrigerant tank (T). 2. In the refrigerant circuit switching from the condensation switching state to the evaporation switching state, the following operations (a) to (d), that is, (a) the pressure guiding means (X) is performed. Switching to a negative pressure application state, (b) closing the liquid refrigerant passage opening / closing valve (vA), (c) injecting the gas refrigerant from the connected state of the target heat exchanger (NA) to the gas refrigerant discharge passage (Go) Road (G
switching control means for automatically switching in that order (d) opening the liquid refrigerant passage opening / closing valve (vA) and switching the pressure guiding means (X) to the positive pressure application state. The compression heat pump according to claim 1, wherein Y) is provided.