JP3324420B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system for injecting intermediate-pressure refrigerant into a compressor, and more particularly to defrosting a heat exchanger of a refrigeration system.

[0002]

2. Description of the Related Art Conventionally, there has been known a refrigerating apparatus for injecting an intermediate-pressure gas refrigerant into a compressor for the purpose of improving the capacity of a condenser.

[0003] For example, Japanese Patent Application Laid-Open No. 4-177062 discloses a refrigeration apparatus as shown in FIG. In this device, the refrigerant circulates in the direction indicated by the arrow during heating.
The refrigerant discharged from the compressor (a) is condensed in the indoor heat exchanger (c) and reduced in pressure from the high pressure to the intermediate pressure in the decompressors (g1) and (g3), and then the gas-liquid separator (d) And is separated into a gas refrigerant and a liquid refrigerant. The liquid refrigerant passes through the check valve (i2) and is reduced in pressure from the intermediate pressure to a low pressure by the pressure reducer (g2). Then, the low-pressure refrigerant evaporates in the outdoor heat exchanger (e) and is then sucked into the compressor (a). on the other hand,
The gas refrigerant in the gas-liquid separator (d) passes through the outlet pipe (h) to the compressor.
Inhaled in (a). As a result, the circulation amount of the gas refrigerant flowing through the indoor heat exchanger (c) increases, and the heating capacity is improved.

In recent years, in view of global environmental problems such as depletion of the ozone layer, a transition from a conventional refrigerant such as R22 to an alternative refrigerant has been made. At present, a refrigerant called R410A is particularly attracting attention as an alternative refrigerant. R410A has a characteristic that the amount of change in latent heat due to a temperature change is larger than that of R22. Therefore, when the condensation temperature increases, it becomes difficult to secure a necessary enthalpy difference in the condenser. In that case,
There is a need to increase the amount of refrigerant circulating through the condenser. Therefore, it is considered that a necessary heating capacity can be secured by using the injection refrigeration apparatus as described above.

[0005]

In the above refrigeration system,
When the refrigerant is used under the condition where the evaporation temperature is below the freezing point, frost is formed on the outdoor heat exchanger (c). However, the above-mentioned refrigerating apparatus is not provided with a means (defrost means) for melting frost attached to the outdoor heat exchanger (c). Therefore, it is necessary to separately provide defrost means such as that used in a normal refrigeration apparatus other than the injection refrigeration apparatus to perform the defrost operation, or to reverse the circulation direction of the refrigerant to perform a so-called reverse cycle defrost operation. .

[0006] The reverse cycle defrost operation has the advantage that it can be performed without providing extra equipment, but the low temperature refrigerant flows through the indoor heat exchanger (c). It will cool down. Further, a sound is generated in the indoor heat exchanger (c) during the defrost operation. Therefore, there is a problem that indoor comfort is impaired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make effective use of an injection passage in an injection refrigeration apparatus without causing a refrigerant to flow through a use side heat exchanger. It is to provide a defrost means.

[0008]

In order to achieve the above-mentioned object, the present invention provides a high-temperature refrigerant discharged from a compressor (1) through a heat source side heat exchanger (7) during a defrost operation. And the high-temperature refrigerant in which the frost was melted was sucked into the compressor (1) through the injection passage (11).

More specifically, the means implemented by the first aspect of the present invention includes a compressor (1), a use side heat exchanger (3), a first pressure reducing mechanism (4), and a second pressure reducing mechanism. (5) and a refrigerant circuit (25) in which a heat source side heat exchanger (7) is connected in order, and a first pressure reducing mechanism (4)
A refrigerating apparatus having an injection passage (11) for supplying an intermediate-pressure refrigerant to the compressor (1) between the compressor (1) and the second pressure reducing mechanism (5). )
A bypass passage (30) communicating with the suction side of the low-pressure refrigerant is connected to the heat source-side heat exchanger (7). During the first defrost operation of the heat source-side heat exchanger (7), the high-temperature refrigerant discharged from the compressor (1) The refrigerant supplied to the heat exchanger (7) and passed through the heat source side heat exchanger (7) is passed through the injection passage (11) and the bypass passage.
Defrost control means (4) returning to the compressor (1 ) through the passage (30).
0) is provided.

According to the above-mentioned invention, the use side heat exchanger
(3) It is possible to realize an injection refrigeration apparatus capable of performing a defrost operation by effectively utilizing the injection passage (11) without circulating a refrigerant through (3).

[0011] means invention is taken as claimed in claim 2, in the refrigerating apparatus according to claim 1, the refrigerant circuit (25),
Gas-liquid separator (6) connected to the injection passage (11)
Is provided between the first pressure reducing mechanism (4) and the second pressure reducing mechanism (5), and an opening / closing means ( On the other hand, the injection passage (11) is provided with opening / closing means (SV-2) for opening and closing the injection passage (11), and the defrost control means (40) is provided with a refrigerant during the first defrost operation. The opening and closing means (SV-2) of the injection passage (11) and the opening and closing means (4) of the refrigerant circuit (25) are controlled to be fully closed so that the refrigerant returns to the compressor (1) through the bypass passage (30). Things.

According to the present invention, during the defrost operation, the refrigerant can be sucked only from the low-pressure refrigerant suction port (1b) of the compressor (1) through the bypass passage (30) to increase the circulation amount of the refrigerant. .

According to a third aspect of the present invention, there is provided the refrigeration apparatus according to the first aspect , wherein the defrost control means is provided.
(40) returns a part of the refrigerant to the compressor (1) through the bypass passage (30) and returns another refrigerant to the compressor (1) through the injection passage (11) during the second defrost operation.
The configuration is as follows.

According to the above-mentioned invention specific matter, the circulation amount of the refrigerant can be further increased.

According to a fourth aspect of the present invention, in the refrigeration apparatus according to the first aspect, the refrigerant circuit (25) includes:
A gas-liquid separator between the first pressure reducing mechanism (4) and the second pressure reducing mechanism (5)
(6) is provided, the gas-liquid separator (6) and the compressor (1),
It is configured to be integrally wrapped with a soundproofing material (35) having heat insulation.

According to the above-mentioned invention, the high-temperature gas refrigerant in the gas-liquid separator (6) is heated during the defrost operation.
It is sucked into the compressor (1). Therefore, the temperature of the high-temperature refrigerant gas discharged from the compressor (1) also increases. As a result, the frost of the heat source-side heat exchanger (7) is melted by the higher-temperature high-temperature refrigerant gas, so that the defrost time is reduced.

According to a fifth aspect of the present invention, in the refrigeration system according to the first aspect, the intermediate-pressure liquid refrigerant which is reduced in pressure and flows into the heat source side heat exchanger (7) is generated during the defrost operation. A cooling means (37) for cooling by heat exchange with the drain (W) is provided.

[0018] According to the above-mentioned invention specific matter, the enthalpy of the refrigerant flowing into the heat source side heat exchanger (7) during the heating operation is reduced. Therefore, the enthalpy change amount of the refrigerant in the heat source side heat exchanger (7) increases. Therefore, the circulation amount of the refrigerant flowing through the heat source side heat exchanger (7) can be reduced, and the pressure loss of the refrigerant can be reduced.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

-Configuration of Air Conditioner (22)-As shown in FIG. 1, the refrigeration apparatus according to Reference Example 1 is a heat pump type air conditioner (22), which is mainly an outdoor unit.
(20) and an indoor unit (21). The outdoor unit (20) includes a compressor (1), a four-way switching valve (2), a first electric valve (4) which is a first expansion valve whose opening is adjustable, and a second expansion valve whose opening is adjustable. Certain second motor-operated valve (5), gas-liquid separator (6), outdoor heat exchanger (7) as heat source side heat exchanger, accumulator
(8) An injection passage (11) provided with a second solenoid valve (SV-2) and a bypass passage (10) provided with a first solenoid valve (SV-1). On the other hand, the indoor unit (21) includes an indoor heat exchanger (3) that is a use-side heat exchanger. By connecting such an outdoor unit (20) and an indoor unit (21) by a refrigerant pipe, the following refrigerant circuit (2)
An air conditioner (22) having 5) is configured.

The air conditioner (22) is configured such that an injection passage (11) and a bypass passage (10) are provided in a main refrigerant circuit.

The main refrigerant circuit includes a compressor (1) and a four-way switching valve (2).
And an indoor heat exchanger (3), a first motor-operated valve (4), a gas-liquid separator (6), a second motor-operated valve (5), and an outdoor heat exchanger (7). . An accumulator (8) is provided in a suction pipe (15) disposed between the four-way switching valve (2) and the compressor (1). One end of the suction pipe (15) is connected to a low-pressure refrigerant suction port (1b) of the compressor (1).

The injection passage (11) has a gas-liquid separator
A second solenoid valve (SV-2) is provided between the compressor (6) and the compressor (1) and is an on-off valve. Injection passage (1
1) is connected to the injection port (1c) of the compressor (1), and is configured to allow the refrigerant in the gas-liquid separator (6) to be sucked into the compressor (1) from the injection port (1c). .

The bypass passage (10) includes a pipe (16) between the indoor heat exchanger (3) and the first motor-operated valve (4), a gas-liquid separator (6) and a second motor-operated valve (5). And a pipe (17) between the two. The bypass passage (10) is provided with a first solenoid valve (SV-1) as an on-off valve.

In the refrigerant circuit (25), the refrigerant R4 having the characteristic that the amount of change in latent heat with respect to the temperature change is large.
10A is enclosed.

Each of the electric valves (4) and (5) and the solenoid valve (SV-
1) and (SV-2) are connected to the controller (40). The controller (40) controls the degree of opening of each of the electric valves (4) and (5), and controls the opening and closing of the solenoid valves (SV-1) and (SV-2). The controller (40) controls the first motor-operated valve (4) and the first solenoid valve (SV-1) to be fully closed during the defrost operation, and the second motor-operated valve (5) and the second solenoid valve (SV-2). ) Fully open and hot gas
It constitutes defrost control means for supplying from (1) to the outdoor heat exchanger (7).

-Operation of air conditioner (22)-In the air conditioner (22), non-injection heating operation,
Four types of normal operations, an injection heating operation, a non-injection cooling operation, and an injection cooling operation, are possible, and a defrost operation is also possible. Hereinafter, each operation will be described.

-Non-Injection Heating Operation- During non-injection heating operation, the first solenoid valve
(SV-1) is open, the second solenoid valve (SV-2) is closed,
The motor-operated valve (4) is set to a fully closed state. The degree of opening of the second motor-operated valve (5) is set to be slightly throttled so that high-pressure refrigerant is converted to low-pressure refrigerant. The four-way switching valve (2) is switched to the broken line side shown in FIG.

As indicated by the dashed arrows, the high-pressure refrigerant discharged from the compressor (1) flows into the indoor heat exchanger (3) after passing through the four-way switching valve (2). The high-pressure refrigerant is condensed in the indoor heat exchanger (3) and heats indoor air. The condensed liquid refrigerant flows out of the indoor heat exchanger (3) and then flows through the bypass passage (10). At this time, since the first electric valve (4) is closed, the refrigerant does not flow through the first electric valve (4). And the bypass passage
The refrigerant that has passed through (10) is reduced in pressure from high pressure to low pressure by the second electric valve (5), and becomes a low-pressure two-phase refrigerant. The low-pressure two-phase refrigerant evaporates in the outdoor heat exchanger (7). After passing through the four-way switching valve (2), the low-pressure refrigerant flows into the accumulator (8). Then, the refrigerant in the accumulator (8) is sucked into the compressor (1) through the suction port (1b). As described above, the refrigerant circulates through the refrigerant circuit (25), and the room is heated.

-Injection heating operation-During the injection heating operation, the first solenoid valve (S
V-1) is set to the closed state, and the second solenoid valve (SV-2) is set to the open state. The opening of the first motor-operated valve (4) is set slightly open so as to reduce the high-pressure refrigerant to a predetermined intermediate pressure.
The opening degree of (5) is set slightly open so that the intermediate-pressure refrigerant has a low pressure. The four-way switching valve (2) is set on the broken line side shown in FIG.

As indicated by the dashed arrows, the high-pressure refrigerant discharged from the compressor (1) flows into the indoor heat exchanger (3) after passing through the four-way switching valve (2). The high-pressure refrigerant is condensed in the indoor heat exchanger (3) and heats indoor air. After flowing out of the indoor heat exchanger (3), the condensed liquid refrigerant passes through the first electric valve (4) without passing through the bypass passage (10). At this time, the first
The pressure is reduced from a high pressure to a predetermined intermediate pressure by a motor-operated valve (4),
It becomes an intermediate-pressure two-phase refrigerant. The intermediate-pressure two-phase refrigerant flows into the gas-liquid separator (6), and is separated into an intermediate-pressure gas refrigerant and a liquid refrigerant.

The intermediate-pressure liquid refrigerant is reduced from the intermediate pressure to a low pressure by passing through the second motor-operated valve (5), and becomes a low-pressure two-phase refrigerant. Then, the low-pressure two-phase refrigerant evaporates in the outdoor heat exchanger (7). The low-pressure refrigerant flowing out of the outdoor heat exchanger (7) passes through the four-way switching valve (2), passes through the accumulator (8), and is drawn into the compressor (1) from the suction port (1b).

On the other hand, the intermediate-pressure gas refrigerant in the gas-liquid separator (6) passes through the injection passage (11) and is sucked into the compressor (1) from the injection port (1c).

The intermediate-pressure gas refrigerant sucked into the compressor (1) is mixed and compressed with the low-pressure gas refrigerant, becomes a high-pressure gas refrigerant, and is discharged from the discharge port (1a) of the compressor (1).

As described above, the refrigerant circulates through the refrigerant circuit (25) to heat the room. In the injection heating operation, an intermediate-pressure gas refrigerant is injected into the compressor (1), thereby increasing the amount of refrigerant circulating in the condenser and improving the condensing capacity.

-Non-Injection Cooling Operation- Next, the cooling operation will be described. The cooling operation is performed by switching the four-way switching valve (2) to reverse the circulation direction of the refrigerant. First, the non-injection cooling operation will be described.

During the non-injection cooling operation, the first solenoid valve (SV-1) is open, the second solenoid valve (SV-2) is closed, and the first motor-operated valve (4) is fully closed. Is set to The degree of opening of the second motor-operated valve (5) is set to be slightly throttled so that high-pressure refrigerant is converted to low-pressure refrigerant. The four-way switching valve (2) is switched to the solid line side shown in FIG.

As shown by the solid arrows in FIG. 1, the compressor (1)
The high-pressure refrigerant discharged from is passed through the four-way switching valve (2),
It flows into the outdoor heat exchanger (7). The high-pressure refrigerant is condensed in the outdoor heat exchanger (7). After the condensed high-pressure liquid refrigerant flows out of the outdoor heat exchanger (7), the second electric valve (5) decompresses the high-pressure liquid refrigerant from a high pressure to a low pressure to become a low-pressure two-phase refrigerant. And
The low-pressure two-phase refrigerant passes through the bypass passage (10) without passing through the gas-liquid separator (6), evaporates in the indoor heat exchanger (3),
Cool indoor air. After the low-pressure refrigerant flowing out of the indoor heat exchanger (3) passes through the four-way switching valve (2), the accumulator (8)
Flows into. Then, the refrigerant in the accumulator (8) is sucked into the compressor (1) through the suction port (1b). As described above, the refrigerant circulates through the refrigerant circuit (25), and indoor cooling is performed.

-Injection Cooling Operation- During the injection cooling operation, the first solenoid valve (S
V-1) is set to the closed state, and the second solenoid valve (SV-2) is set to the open state. The opening of the second motor-operated valve (5) is set slightly open so as to reduce the high-pressure refrigerant to a predetermined intermediate pressure.
The opening degree of (4) is also set slightly open so as to reduce the pressure of the intermediate-pressure refrigerant. The four-way switching valve (2) is set on the solid line side shown in FIG.

The high-pressure refrigerant discharged from the compressor (1) passes through the four-way switching valve (2) and is condensed in the outdoor heat exchanger (7). After flowing out of the outdoor heat exchanger (7), the condensed high-pressure liquid refrigerant is reduced in pressure from a high pressure to a predetermined intermediate pressure by the second electric valve (5), and becomes an intermediate-pressure two-phase refrigerant. The intermediate-pressure two-phase refrigerant flows into the gas-liquid separator (6) without passing through the bypass passage (10), and is separated into an intermediate-pressure gas refrigerant and a liquid refrigerant.

The intermediate-pressure liquid refrigerant in the gas-liquid separator (6) is reduced from the intermediate pressure to a low pressure when passing through the first motor-operated valve (4), and becomes a low-pressure two-phase refrigerant. Then, the low-pressure two-phase refrigerant flows into the indoor heat exchanger (3). The low-pressure two-phase refrigerant evaporates in the indoor heat exchanger (3) and cools indoor air. The low-pressure refrigerant flowing out of the indoor heat exchanger (3) passes through the four-way switching valve (2), passes through the accumulator (8), and is sucked into the compressor (1) from the suction port (1b). You.

On the other hand, the intermediate-pressure gas refrigerant in the gas-liquid separator (6) passes through the injection passage (11) and is sucked into the compressor (1) from the injection port (1c).

As described above, the refrigerant circulates through the refrigerant circuit (25) to cool the room. In the injection cooling operation, the medium-pressure gas refrigerant is injected into the compressor (1), thereby increasing the amount of refrigerant circulating in the outdoor heat exchanger (7), which is the heat source-side heat exchanger, resulting in insufficient heat absorption on the heat source side. Has been eliminated. Further, since the circulation amount of the refrigerant flowing through the indoor heat exchanger (3) decreases, the pressure loss of the refrigerant in the indoor heat exchanger (3) decreases.

In the non-injection heating operation or the injection heating operation, the outdoor heat exchanger (7)
Is used as an evaporator. Therefore, the evaporation temperature is 0 ° C
In the following cases, frost may be formed on the outdoor heat exchanger (7). Therefore, the amount of heat exchange in the outdoor heat exchanger (7) may decrease, and the performance of the air conditioner (22) may decrease. Therefore, when the performance of the air conditioner (22) decreases by a predetermined amount, a defrost operation for melting frost of the outdoor heat exchanger (7) as described below is performed.

-Defrosting Operation-During the defrosting operation, the first solenoid valve (SV-1) is set to a closed state, and the second solenoid valve (SV-2) is set to an open state. The degree of opening of the second motor-operated valve (5) is set to a fully open state so that the high-temperature gas refrigerant passes as it is. First motor-operated valve (4)
Is set to a fully closed state so that this gas refrigerant does not flow into the indoor heat exchanger (3). The four-way switching valve (2) is shown in FIG.
Are set on the solid line side shown in FIG.

The high-temperature gas refrigerant discharged from the compressor (1) passes through the four-way switching valve (2) and then flows into the frosted outdoor heat exchanger (7). The high-temperature gas refrigerant melts the frost in the outdoor heat exchanger (7), passes through the second electric valve (5), and flows into the gas-liquid separator (6) as the gas refrigerant. The gas refrigerant in the gas-liquid separator (6) passes through the injection passage (11), and is sucked into the compressor (1) from the injection port (1c). The gas refrigerant sucked into the compressor (1) is compressed again,
It is discharged from the discharge port (1a) as a discharge gas.

As described above, in the air conditioner (22), in the normal operation, not only the heating operation or the cooling operation can be arbitrarily selected and performed, but also For each of the heating operation and the cooling operation, either the injection operation or the non-injection operation can be arbitrarily performed.
Further, a defrost operation having the following effects is also possible.

In the air conditioner (22), the defrost operation can be performed without providing extra equipment for defrost by using the injection passage (11) as it is.

Further, unlike the so-called reverse cycle defrost operation in which the four-way switching valve (2) is switched, the refrigerant does not flow through the indoor heat exchanger (3), so that the indoor comfort is not impaired. In addition, the sound generated during the defrost operation indoors is not generated.

Unlike the reverse cycle defrost, since the indoor heat exchanger (3) is not cooled during the defrost operation, the time until the operation is stabilized in the heating operation after the end of the defrost operation is short.

[0051] - configuration of the air conditioner (22b) - as shown in FIG. 2, the refrigeration system of Embodiment 1, Reference Example 1
An air conditioner (22b) in which a hot gas bypass passage (30) is added to the air conditioner (22).

The hot gas bypass passage (30) has one end connected to a pipe between the four-way switching valve (2) and the indoor heat exchanger (3), and the other end connected to the gas-liquid separator (6). The solenoid valve (SV-2) is connected to an injection passage (11). The hot gas bypass passage (30) is provided with a third solenoid valve (SV-3). The third solenoid valve (SV-3) is connected to the controller (40).

-Operation of Air Conditioner (22b)-In the air conditioner (22b) according to Embodiment 1 , in addition to the normal operation described in Reference Example 1 , a defrost operation described below can be performed.

The defrost operation of the air conditioner (22b) is such that the high-temperature refrigerant gas discharged from the compressor (1), ie, the so-called hot gas, is injected into the injection passage (11).
The operation is such that the gas does not flow into the compressor (1) from the injection port (1c) through the hot gas bypass passage (30) but flows into the compressor (1) from the suction port (1b).

In this defrost operation, the first solenoid valve (SV-1)
Is set to the closed state, and the second solenoid valve (SV-2) is also set to the closed state.
The third solenoid valve (SV-3) is set to the open state. 2nd motorized valve
(5) is set to the fully open state so that the hot gas is passed as it is. The first motor-operated valve (4) is set to a fully closed state so that hot gas does not flow into the indoor heat exchanger (3). The four-way switching valve (2) is set on the solid line side shown in FIG.

The hot gas discharged from the compressor (1)
After passing through the four-way switching valve (2), the frosted outdoor heat exchanger (7)
Flows into. After melting the frost in the outdoor heat exchanger (7), the hot gas passes through the second motor-operated valve (5) and flows into the gas-liquid separator (6) as a gas refrigerant. The hot gas in the gas-liquid separator (6) passes through the hot gas bypass passage (30) and
It is sucked into the compressor (1) from (1b). The gas refrigerant sucked into the compressor (1) is compressed again and becomes hot gas.
Discharged from (1).

[0057] - The effect of the air conditioner (22b) - in the defrosting operation of the air conditioner (22b), so that inhalation of hot gas to the suction port of the low-pressure refrigerant of the compressor (1) (1b), Reference Compressor (1) compared to the air conditioner (22) of Example 1
Volumetric efficiency is improved. Therefore, the circulation amount of the hot gas can be increased. As a result, the defrost time is reduced.

Further, since the refrigerant does not flow through the indoor heat exchanger (3), the indoor comfort is not impaired.

-Other Embodiments- In the air conditioner (22b) of the first embodiment, in addition to the above-described defrost operation (hereinafter, referred to as a first defrost operation),
The following defrost operation (hereinafter, referred to as a second defrost operation) is possible. The second defrost operation is mainly performed when rapid defrost is required.

In the second defrost operation, the hot gas is diverted in the injection passage (11), and a part of the hot gas flows from the injection passage (11) into the injection port (1c) of the compressor (1), and the other gas flows. The part is an operation of passing through the hot gas bypass passage (30) and flowing into the suction port (1b).

In the second defrost operation, the first solenoid valve (SV-
1) is set to a closed state, and the second solenoid valve (SV-2) and the third solenoid valve (SV-3) are set to an open state. The opening of the first motor-operated valve (4) and the second motor-operated valve (5) and the setting of the four-way switching valve (2) are the same as in the first defrost operation.

The hot gas discharged from the compressor (1)
Like the first defrost operation, the frost in the outdoor heat exchanger (7) is thawed, and then flows into the gas-liquid separator (6). Gas-liquid separator (6)
The gas refrigerant inside is divided in the injection passage (11) as shown by the dashed arrow in FIG. That is, a part of the gas refrigerant passes through the injection passage (11) and flows into the compressor (1) from the injection port (1c). Another part of the gas refrigerant passes through the hot gas bypass passage (30). The gas refrigerant that has passed through the hot gas bypass passage (30) passes through the four-way switching valve (2) and the accumulator (8), and is then drawn into the compressor (1) from the suction port (1b). The gas refrigerant sucked from the low-pressure refrigerant suction port (1b) and the injection port (1c) is mixed and compressed, and is discharged from the discharge port (1a) of the compressor (1) as hot gas.

-Effect of Second Defrosting Operation- In the second defrosting operation, the hot gas is sucked into both the suction port (1b) and the injection port (1c) of the compressor (1). ) The amount of hot gas inhaled increases. Therefore, the circulation amount of the hot gas can be further increased, and the defrost time can be further reduced.

Also, in the second defrost operation, since the refrigerant does not flow through the indoor heat exchanger (3), the indoor comfort is not impaired.

As shown in FIG. 3, the refrigeration apparatus according to the second embodiment is obtained by changing the position of the hot gas bypass passage (30) of the air conditioner (22b) according to the first embodiment.

-Configuration of Air Conditioner (22c)-In the air conditioner (22c) according to Embodiment 2 , one end of the hot gas bypass passage (30) has a four-way switching valve (2) and an accumulator (8). The other end is connected to an injection passage (11) between the gas-liquid separator (6) and the second solenoid valve (SV-2). Similarly to the first embodiment, the third solenoid valve (SV-3) is provided in the hot gas bypass passage (30).
Is provided.

-Operation of Air Conditioner (22c)-In the refrigeration apparatus of the second embodiment, the first defrost operation or the second defrost operation is performed in the same manner as the refrigeration apparatus of the first embodiment. Various motorized valves (4), (5), solenoid valves (SV-
1), (SV-2), (SV-3), and the operation method of the defrost operation such as the setting of the four-way switching valve (2) and the circulation path of the refrigerant are described in Embodiment 1.
Therefore, the description is omitted.

-Effects of Air Conditioner (22c)-In the air conditioner (22c), unlike the air conditioner (22b) according to the first embodiment, one end of the hot gas bypass passage (30) is connected to the four-way switching valve ( It is connected between 2) and the accumulator (8). Therefore, the hot gas flowing out of the gas-liquid separator (6) directly flows into the accumulator (8) without passing through the four-way switching valve (2). As a result, the pressure loss of the hot gas is reduced, and the circulation amount is increased. Therefore, the defrost time is shortened in combination with the effect described in the first embodiment.

[0069] the refrigeration apparatus of the third embodiment, the embodiment 1-2
In the air conditioners (22), (22b), and (22c), the compressor (1)
And the gas-liquid separator (6) are integrally wrapped with the soundproof material (35) of the compressor (1).

Specifically, as shown in FIG. 4, the gas-liquid separator (6) is juxtaposed near the compressor (1) and the accumulator (8). The gas-liquid separator (6), the compressor (1), and the accumulator (8) are integrally wrapped by a sound insulating material (35) having heat insulation. Since the soundproofing material (35) generally used for the compressor (1) has heat insulation properties, the soundproofing material (35) of the compressor (1) can be used as it is.

Therefore, the heat generated in the compressor (1) is hardly released to the outside of the space surrounded by the soundproofing material (35).
It is not wasted as heat loss. Therefore, the gas-liquid separator (6) is efficiently heated by the heat generated in the compressor (1).

As a result, the refrigeration apparatus of Embodiment 3 has the following effects during the defrost operation.

The refrigerant gas that has melted the frost in the outdoor heat exchanger (7) is heated in the gas-liquid separator (6), and its enthalpy rises. Therefore, since the enthalpy of the refrigerant gas sucked into the compressor (1) is high, the enthalpy of the hot gas after compression also increases accordingly. Therefore, the temperature of the hot gas can be increased without increasing the input of the compressor (1). As a result, a higher temperature hot gas can be supplied to the outdoor heat exchanger (7), so that the defrost time can be reduced.

That is, in the refrigerating apparatus of the third embodiment, the heat of the compressor (1), which was conventionally wasted as heat loss, is recovered and effectively used as a part of the defrost heat source. As a result, the defrost time is reduced without increasing the input of the compressor (1).

The refrigeration apparatus of Reference Example 2 is different from the air conditioner (22) of Reference Example 1 in that the drain generated by the defrost operation
This is an air conditioner (22d) that effectively utilizes (W) during normal operation.

—Configuration of Air Conditioner (22d) — As shown in FIG. 5, the air conditioner (22d) includes a drain pan disposed below the outdoor heat exchanger (7) in the air conditioner (22). (36) and a heat exchange section (37) as cooling means provided in the drain pan (36). Heat exchange unit (37)
Is a part for cooling the saturated liquid refrigerant by exchanging heat between the intermediate-pressure saturated liquid refrigerant separated by the gas-liquid separator (6) and the drain (W). The heat exchange part (37) is composed of the second motor-operated valve (5) and the gas-liquid separator
A heat transfer tube (38) provided between the heat transfer tube (6) and the heat transfer tube (6) is arranged to be in contact with the drain (W). This air conditioner (22d)
5, the heat transfer tube (38) is configured to be immersed in the drain (W) stored in the drain pan (36).

-Operation of Air Conditioner (22d)-In the air conditioner (22d), defrost operation is performed in the same manner as in the air conditioner (22). In the present air conditioner (22d), the drain (W) formed by melting the frost attached to the outdoor heat exchanger (7) during the defrost operation is stored in the drain pan (36).

Thereafter, after performing the defrost operation for a predetermined time, the air conditioner (22d) starts the normal heating operation again. Hereinafter, the injection heating operation after the defrost operation will be described.

In the injection heating operation after the defrost operation, the first solenoid valve (SV-1) is closed and the second solenoid valve (SV-1) is closed.
V-2) is set to the open state. The opening of the first motor-operated valve (4) is
The high-pressure refrigerant is set slightly open so as to reduce the pressure to a predetermined intermediate pressure, and the opening degree of the second electric valve (5) is set slightly open so that the intermediate pressure refrigerant is set at a low pressure. Four-way switching valve
(2) is set on the broken line side shown in FIG.

Next, the circulation route and state of the refrigerant will be described with reference to FIGS. As indicated by the dashed arrow, the high-pressure refrigerant (E) discharged from the compressor (1) flows into the indoor heat exchanger (3) after passing through the four-way switching valve (2). The high-pressure refrigerant is condensed in the indoor heat exchanger (3) and heats indoor air. After the condensed liquid refrigerant (F) flows out of the indoor heat exchanger (3), it does not pass through the bypass passage (10), and the first electric valve
Go through (4). At this time, the pressure is reduced from a high pressure to a predetermined intermediate pressure by the first motor-operated valve (4), and the refrigerant becomes an intermediate-pressure two-phase refrigerant (G). The intermediate-pressure two-phase refrigerant (G) flows into the gas-liquid separator (6), and is separated into an intermediate-pressure saturated gas refrigerant (C) and a saturated liquid refrigerant (H). Up to this point, the operation is the same as the injection heating operation of Reference Example 1 .

The intermediate-pressure saturated liquid refrigerant (H) flowing out of the gas-liquid separator (6) flows into the heat transfer pipe (38) of the heat exchange section (37).
The intermediate-pressure saturated liquid refrigerant (H) flowing in the heat transfer tube (38) exchanges heat with the drain (W) outside the heat transfer tube (38) and is cooled. Therefore, the intermediate-pressure saturated liquid refrigerant (H) is an intermediate-pressure supercooled liquid refrigerant.
(I), and the enthalpy decreases from Ih to Ii. The intermediate-pressure supercooled liquid refrigerant (I) is reduced in pressure from the intermediate pressure to a low pressure by the second electric valve (5) to become a low-pressure two-phase refrigerant (J). Then, the low-pressure two-phase refrigerant (J) flows into the outdoor heat exchanger (7). At this time, as shown in FIG.
(J) is an outdoor heat exchanger in which the enthalpy is smaller by ΔI compared to the injection heating operation of Reference Example 1 .
(7). Low-pressure two-phase refrigerant (J) is an outdoor heat exchanger (7)
To evaporate to become a low-pressure gas refrigerant (A). At this time, the amount of change in the enthalpy of the refrigerant is larger by ΔI than in the injection heating operation of Reference Example 1 . The low-pressure gas refrigerant (A) flowing out of the outdoor heat exchanger (7) is
After passing through (2), it passes through the accumulator (8), and the compressor (1)
Inhaled.

On the other hand, the intermediate-pressure saturated gas refrigerant (C) in the gas-liquid separator (6) is sucked into the compressor (1) from the injection port (1c) through the injection passage (11).

The medium-pressure gas refrigerant sucked into the compressor (1) is mixed and compressed with the low-pressure gas refrigerant, and is mixed with the high-pressure gas refrigerant (E).
And discharged from the compressor (1).

-Effects of Air Conditioner (22d)-As described above, in the air conditioner (22d), in the injection heating operation after the defrost operation, the enthalpy of the refrigerant in the evaporator, that is, the outdoor heat exchanger (7). The amount of change can be increased. Therefore, the amount of circulating refrigerant required to obtain the same evaporation capacity is reduced. Therefore, the pressure loss of the refrigerant in the outdoor heat exchanger (7) decreases. As a result, the load on the compressor (1) is reduced, and the air conditioner (22d)
Abilities improve.

[0085]

As described above, according to the present invention, the following effects are exhibited.

According to the first aspect of the present invention, it is possible to realize a refrigeration apparatus capable of performing a defrost operation by effectively utilizing an injection passage without flowing a refrigerant through a use-side heat exchanger.

According to the second aspect of the present invention, by circulating the high-temperature refrigerant from the low-pressure refrigerant suction port of the compressor, the circulation amount of the high-temperature refrigerant can be increased. As a result, the defrost time is reduced.

According to the third aspect of the present invention, the high-temperature refrigerant is sucked into the compressor through both the injection passage and the hot gas bypass passage, so that the circulation amount of the high-temperature refrigerant can be further increased. As a result, the defrost time is further reduced.

[0089] According to the invention described in claim 4, during the defrosting operation, the refrigerant gas in the gas-liquid separator is heated, the temperature of the refrigerant gas to be sucked into the compressor is increased. Therefore, the temperature of the hot gas also increases. Therefore, since the frost of the heat source side heat exchanger can be melted by the hot gas having a higher temperature, the defrost time is reduced.

According to the fifth aspect of the invention, during the injection heating operation after the defrost operation, the enthalpy of the refrigerant flowing into the heat source side heat exchanger decreases. Therefore, the enthalpy change amount of the refrigerant in the heat source side heat exchanger increases, and the circulation amount of the refrigerant can be reduced. Therefore, the pressure loss of the refrigerant decreases.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of an air conditioner according to Reference Example 1 .

FIG. 2 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 1 .

FIG. 3 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 2 .

FIG. 4 is a plan view showing an arrangement of a compressor and a gas-liquid separator.

FIG. 5 is a refrigerant circuit diagram of an air conditioner according to Reference Example 2 .

FIG. 6 is a Mollier diagram.

FIG. 7 is a refrigerant circuit diagram of a conventional refrigeration apparatus.

[Explanation of symbols]

 (1) Compressor (1a) Discharge port (1b) Suction port (1c) Injection port (2) Four-way switching valve (3) Indoor heat exchanger (6) Gas-liquid separator (7) Outdoor heat exchanger (11 ) Injection passage (30) Hot gas bypass passage (35) Sound insulation material (36) Drain pan (37) Heat exchange part (40) Controller

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-261 (JP, A) JP-A-59-196992 (JP, A) JP-A-59-52160 (JP, A) 126440 (JP, A) Japanese Utility Model 1984-142-673 (JP, U) Japanese Utility Model Application Hei 3-57363 (JP, U) Japanese Utility Model Application Utility Model 2-38061 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F25B 47/02 550

Claims (5)

(57) [Claims] 1. A compressor (1), a use side heat exchanger (3), a first pressure reducing mechanism (4), a second pressure reducing mechanism (5), and a heat source side heat exchanger.
(7) and a refrigerant circuit (25) connected in sequence to the intermediate pressure refrigerant between the first pressure reducing mechanism (4) and the second pressure reducing mechanism (5).
A refrigerating apparatus having an injection passage (11) for supplying to the (1), wherein the injection passage (11) is connected to a bypass passage (30) communicating with a low-pressure refrigerant suction side of the compressor (1). During the first defrost operation of the heat source side heat exchanger (7), the high temperature refrigerant discharged from the compressor (1) is transferred to the heat source side heat exchanger.
(7), the refrigerant having passed through the heat source side heat exchanger (7) is subjected to the injection passage (11) and the bypass passage (30).
A refrigeration apparatus comprising a defrost control means (40) for returning to the compressor (1) through the compressor. 2. The refrigeration apparatus according to claim 1 , wherein the refrigerant circuit (25) includes a gas-liquid separator (6) connected to the injection passage (11) and the first pressure reducing mechanism (4) and the second pressure reducing mechanism (4). Decompression mechanism
(5), and an opening / closing means (4) for opening and closing between the gas-liquid separator (6) and the use side heat exchanger (3) is provided, while the injection passage (11) is provided in the injection passage (11). on-off means (SV-2) is provided for opening and closing the injection passageway (11), defrost control means (40), the first defrosting operation,
Controlling the opening and closing means (SV-2) of the injection passage (11) and the opening and closing means (4) of the refrigerant circuit (25) to be fully closed so that the refrigerant returns to the compressor (1) through the bypass passage (30). Characterized refrigeration equipment. 3. The refrigeration apparatus according to claim 1 , wherein the defrost control means (40) operates during the second defrost operation.
With return to the compressor (1) through the bypass passage (30) a part of the refrigerant, the refrigeration apparatus, characterized in that to return to the compressor (1) through the other refrigerant injection passageway (11). 4. The refrigeration apparatus according to claim 1, wherein the refrigerant circuit (25) includes a first pressure reducing mechanism (4) and a second pressure reducing mechanism (5).
And a gas-liquid separator (6) is provided between the gas-liquid separator (6) and the compressor (1). A refrigeration apparatus characterized by the above-mentioned. 5. The refrigeration apparatus according to claim 1, wherein the intermediate-pressure liquid refrigerant that has been depressurized and flows into the heat-source-side heat exchanger (7) is heat-exchanged with a drain (W) generated during a defrost operation. A refrigeration apparatus comprising a cooling means (37) for cooling.