JPH11182953A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the effectiveness of energy without making a refrigerator larger in scale and increasing the production cost in such a refrigerator as to utilize two-dimensional refrigerating cycle. SOLUTION: This refrigerator utilizing dual refrigerating cycle is provided with a heat-source side refrigerant circuit A and a usage side refrigerant circuit B which are connected with each other in such a manner as to be heat- exchanged through a cascade heat exchanger 4. A heat transfer tube for condensing refrigerant integrated with an outdoor heat exchanger 2 is provided on the upstream side of the cascade heat exchanger 4 in the usage side refrigerant circuit B. In the usage side refrigerant circuit B, the usage-side refrigerant discharged from a compressor 11 is condensed by an outdoor heat exchanger 2 and then it is sent to the cascade heat exchanger 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a heat source-side refrigerant circuit (high-stage circuit) and a use-side refrigerant circuit (low-stage circuit). The present invention relates to a so-called secondary refrigerant system that performs the above-described method, and particularly to a measure for improving the energy efficiency.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 5-5567, a heat source side refrigerant circuit and a use side refrigerant circuit are provided, and heat can be transferred between the two. A secondary refrigerant system that performs a primary refrigeration cycle is known. Hereinafter, this type of system will be described. FIG.
As shown in the figure, the heat source side refrigerant circuit (a) includes a compressor (b), an outdoor heat exchanger (c) in which an outdoor fan (c1) is arranged in proximity, and an expansion valve.
(d), the heat source side heat transfer section (e1) of the cascade heat exchanger (e) is connected to the heat source side refrigerant by a refrigerant pipe so that the heat source side refrigerant can be circulated. On the other hand, the use side refrigerant circuit (f) includes a compressor (g), a use side heat transfer section (e2) of the cascade heat exchanger (e), an expansion valve (h, h), and an indoor fan (i1, i1). The indoor heat exchangers (i, i) disposed in close proximity to each other are connected by a refrigerant pipe so that the use-side refrigerant can circulate.

During operation of this system, the heat source side refrigerant circuit (a)
In the heat source side refrigerant compressed by the compressor (b) and condensed in the outdoor heat exchanger (c), the pressure is reduced by the expansion valve (d), and the heat source side heat transfer section (e1) of the cascade heat exchanger (e) After evaporating by heat exchange with the use-side refrigerant flowing through the use-side heat transfer section (e2) in the compressor (b)
Perform a circulating operation such as returning to. On the other hand, the use side refrigerant circuit
In (f), the cascade heat exchanger (e) compressed by the compressor (g)
The use-side refrigerant condensed by exchanging heat with the heat-source-side refrigerant in the use-side heat transfer section (e2) of the indoor heat exchanger (i,
After evaporating by heat exchange with room air in i), the compressor
A circulation operation such as returning to (g) is performed. This cools the room (for example, inside the freezer).

In this system, the use-side refrigerant circuit is provided.
(f), the heat source side heat transfer section (e1) of the cascade heat exchanger (e) and the expansion valve (d) of the heat source side refrigerant circuit (a) are assembled in advance in a factory, and the heat source side refrigerant circuit (a ) Compressor
(b) and the outdoor heat exchanger (c). That is, FIG.
Each unit enclosed by a dashed line is manufactured as a unit, and shut-off valves (j, j) are installed at the pipe ends, and the compressor (b) and outdoor heat exchange of the heat source side refrigerant circuit (a) are installed on site. After connecting the container (c), installation work such as opening the shut-off valve (j, j) is performed.

[0005]

By the way, in such a system, all of the condensing capacity of the use side refrigerant circuit (f) is covered by the evaporation capacity of the heat source side refrigerant circuit (a). FIG. 5 shows a Mollier diagram in the present system. (I) of this figure shows a refrigeration cycle of the heat source side refrigerant circuit (a), and (II) shows a refrigeration cycle of the use side refrigerant circuit (f). Also, Q
_EH indicates the evaporation capacity of the heat source side refrigerant circuit (a), and Q _CL indicates the condensation capacity of the use side refrigerant circuit (f). In this system, since all of the heat released when the gas refrigerant in the use side refrigerant circuit (f) condenses is recovered by the refrigerant in the heat source side refrigerant circuit (a), the evaporation of the heat source side refrigerant circuit (a) is always performed. Ability Q _EH
Must be maintained higher than the condensing capacity Q _CL of the use side refrigerant circuit (f). For this reason, the heat source side refrigerant circuit (a) requires a high evaporation ability. In order to increase the evaporation capacity, it is necessary to increase the input power of the heat source side refrigerant circuit (a) to the compressor (b), and there is a limit in improving the energy effective ratio (EER).

In addition, a large-sized compressor (b) having a high capacity may be employed as the compressor (b) of the heat source side refrigerant circuit (a), or the heat exchange between the circuits (a, f) may be increased by increasing the size of the cascade heat exchanger (e). Although it is conceivable to increase the amount of replacement, it is not practical because it increases the size of the system and increases the cost.

[0007] The present invention has been made in view of the above points, and an object thereof is to provide a refrigeration system that performs a binary refrigeration cycle without increasing the size of the system or increasing the manufacturing cost. The purpose is to improve the effective energy rate.

[0008]

In order to achieve the above object, the present invention radiates a part of the heat of a use side refrigerant circulating in a use side refrigerant circuit directly to air, and recovers the heat source side refrigerant circuit. The amount of heat of the use side refrigerant has been reduced. Further, the configuration is simplified by sharing the air passage for heat radiation of the heat source side refrigerant and the air passage for heat radiation of the use side refrigerant.

Specifically, the invention according to claim 1 includes a heat source side compressor (1), an air-cooled heat source side heat exchange means (2A), a pressure reducing mechanism.
(3) a heat source side refrigerant circuit (A) having a heat source side heat transfer part (4A) of the cascade heat exchanger (4) and capable of circulating the heat source side refrigerant
And the use side compressor (11), the use side heat transfer part (4B) of the cascade heat exchanger (4), the pressure reduction mechanism (12, 12), the use side heat exchanger (13, 1
3) having a use-side refrigerant circuit (B) in which the circulation of the use-side refrigerant is made possible by heat exchange in the cascade heat exchanger (4) between the refrigerants circulating in each circuit (A, B). It is assumed that the refrigerating apparatus is configured to apply cold heat from the heat source side refrigerant circuit (A) to the use side refrigerant circuit (B). The above use side refrigerant circuit
(B), after condensing the use-side refrigerant discharged from the use-side compressor (11), the use-side heat transfer section (4B) of the cascade heat exchanger (4)
An air-cooled use side condensing means (2B) for supplying the air to the apparatus is provided.
Further, the utilization side condensation means (2B) is arranged in the same air passage as the heat source side heat exchange means (2A) of the heat source side refrigerant circuit (A).

According to this specific matter, a part of the heat radiation when the use-side refrigerant discharged from the use-side compressor (11) condenses is collected by the use-side condensation means (2B) by air (for example, outside air). Is recovered by the heat-source-side refrigerant of the heat-source-side refrigerant circuit (A). For this reason, the evaporation capacity of the heat-source-side refrigerant circuit (A) is only required to be able to recover the heat release amount of the use-side refrigerant circuit (B) to the heat-source-side refrigerant circuit (A), and the use-side refrigerant circuit (B) It is not necessary to keep it constantly higher than the total condensation capacity. Therefore, it is not necessary to increase the input power to the compressor (1) of the heat source side refrigerant circuit (A) in order to increase the evaporation capacity of the heat source side refrigerant circuit (A) as in the related art.

According to a second aspect of the present invention, the heat source side heat exchange means (2A) and the use side condensation means (2B) having a common air passage.
Is a concrete example of the configuration described above. That is, the refrigeration apparatus according to claim 1 includes an air-cooled heat exchanger (2) having a plurality of heat transfer tubes (21, 22, 23) assembled to the radiation fins (20, 20, ...). And the heat source side heat exchange means (2) through a part of the plurality of paths (21, 22) of the heat exchanger (2).
A), and use-side condensation means (2B) by another path (23)
Is composed.

According to this specific matter, the effect of the invention according to claim 1 described above is improved only by improving the path for flowing the refrigerant of each circuit (A, B) with respect to the heat exchanger having substantially the same configuration as the conventional one. A device that can be played is obtained. That is, the conventional 2
The input power to the compressor (1) of the heat source side refrigerant circuit (A) is reduced by simple improvements such as allowing the use side refrigerant to flow in some paths of the outdoor heat exchanger provided in the secondary refrigerant system It becomes possible. Further, since the amount of heat radiation in the entire apparatus does not change from that of the conventional apparatus, even if the path is changed in this way, it is not necessary to make the heat exchanger (2) itself large.

According to a third aspect of the present invention, in the refrigeration system according to the first or second aspect, the heat source side refrigerant circuit (A), the use side compressor (11), the use side condensing means (2B), and the cascade heat exchange. The use side heat transfer section (4B) of the vessel (4) is unitized as a heat source unit (C). At the installation site, refrigeration is performed by connecting the decompression mechanism (12, 12) and the use side heat exchanger (13, 13) of the use side refrigerant circuit (B) to the refrigerant pipe (14) of the use side refrigerant circuit (B). The device is configured.

According to this specific matter, most of the refrigeration apparatus according to the present invention can be manufactured in a factory, most of the apparatus can be manufactured under high quality control, and installation work can be simplified. I can do it.

According to the fourth aspect of the present invention, the use-side refrigerant can be condensed by air cooling, so that the energy effective rate can be further improved. Specifically, in the refrigeration apparatus according to claim 1, the heat source side compressor (1) and the use side compressor (11)
Pressure detection means (PS1, PS2) for detecting each discharge refrigerant pressure
And a comparison means (31) for receiving a detection signal from the pressure detection means (PS1, PS2) and comparing each discharge refrigerant pressure, and issuing a stop signal when a difference between the pressures becomes a predetermined value or less. means
Stop means (32) capable of receiving the stop signal of (31) and stopping the heat source side compressor (1) when the stop signal is received.
Are provided.

In particular, when the outside air temperature is relatively low, the difference between the discharge gas pressures of the compressors (1, 11) becomes small. However, in such a situation, the use side heat exchange can be performed without performing the binary refrigeration cycle. The evaporating temperature of the vessel (13) can be reduced to the target temperature. Therefore, when the outside air temperature is relatively low, it is recognized by detecting the difference between the discharge gas pressures of the compressors (1, 11), and when it is not necessary to perform the binary refrigeration cycle, the heat source side is used. Stop compressor (1) and use refrigerant circuit
The refrigerant is circulated only to (B). In this circulation operation, heat exchange in the cascade heat exchanger (4) is not performed, but the use-side refrigerant is condensed in the air-cooled use-side condensing means (2B). At low outside air, a sufficient amount of refrigerant condensed at this time can be obtained, and the evaporation temperature of the use-side heat exchanger (13) drops to the target temperature.

[0017]

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

Description of Circuit Configuration As shown in FIG. 1, the refrigeration apparatus according to the present embodiment includes a heat source side refrigerant circuit (A) and a use side refrigerant circuit (B), and both circuits (A, B)
A so-called secondary refrigerant system that cools the freezer by exchanging heat between refrigerants circulating in the refrigerator.

First, the heat source side refrigerant circuit (A) will be described. This circuit (A) includes a compressor (1), an outdoor heat exchanger (2), an electric expansion valve (3) as a pressure reducing mechanism, and a cascade heat exchanger (4).
The heat source side heat transfer tube (4A) is connected by a refrigerant pipe (5) so that the heat source side refrigerant can circulate. The outdoor heat exchanger (2) is an air-cooled type that exchanges heat with the outside air, and has an outdoor fan (6) arranged in close proximity. Cascade heat exchanger
The heat source side heat transfer tube (4A) of (4) gives cold heat to the use side refrigerant of the use side refrigerant circuit (B).

Thus, the heat source side refrigerant discharged from the compressor (1) is condensed in the outdoor heat exchanger (2) and decompressed by the electric expansion valve (3), and then the heat source of the cascade heat exchanger (4) The heat transfer pipe (4A) absorbs heat from the use-side refrigerant circuit (B) and evaporates.

Next, the use side refrigerant circuit (B) will be described. This circuit (B) consists of a compressor (11), a cascade heat exchanger
(4) Use side heat transfer tube (4B), electric expansion valve as pressure reducing mechanism
(12,12), Internal heat exchanger (13,13) as user-side heat exchanger
It has. And as a feature of this use side refrigerant circuit (B), the discharge side of the compressor (11) is connected to the outdoor heat exchanger (2). The outlet side of the outdoor heat exchanger (2) is connected to the use side heat transfer tube (4B) of the cascade heat exchanger (4). In other words, this use-side refrigerant circuit (B)
(11), outdoor heat exchanger (2), use side heat transfer tube (4B) of cascade heat exchanger (4), electric expansion valve (12,12), indoor heat exchanger (13,1
3) is connected by a refrigerant pipe (14) so that the use-side refrigerant can circulate. The in-compartment heat exchangers (13, 13) exchange heat with in-compartment air, and the in-compartment fans (15, 15) are arranged in close proximity. The use side heat transfer tube (4B) of the cascade heat exchanger (4) receives cold heat from the refrigerant in the heat source side refrigerant circuit (A).

As a result, the use-side refrigerant discharged from the compressor (11) is condensed in the outdoor heat exchanger (2) and becomes supercooled in the use-side heat transfer tube (4B) of the cascade heat exchanger (4). After the pressure is reduced by the electric expansion valve (12, 12), the internal heat exchanger (1
In 3,13), it exchanges heat with the air in the refrigerator and evaporates.

Next, the specific structure of the outdoor heat exchanger (2) will be described. FIG. 2 is a perspective view showing a part of the outdoor heat exchanger (2) according to the present embodiment. As shown in this figure, outdoor heat exchanger (2)
Consists of a plate fin tube type heat exchanger. In other words, the U-tubes (21a, 22a, 23a) are provided at the edges with respect to the plurality of radiation fins (20, 20,...) Arranged in parallel at a predetermined interval.
A heat transfer tube (21, 22, 23) provided with a through hole extends in the orthogonal direction.
An outdoor heat exchanger (2) is provided with a plurality of heat transfer tubes (21, 22, 23) having such a shape. This embodiment is provided with three paths arranged side by side in the horizontal direction, and a first path heat transfer tube (21) and a second path heat transfer tube in order from the downstream side in the air flow direction (see the arrow in FIG. 2). (22), 3rd pass heat transfer tube (2
3).

The discharge side of the compressor (1) of the heat source side refrigerant circuit (A) communicates with the first pass heat transfer tube (21) and the second pass heat transfer tube (22), and the use side refrigerant circuit (B) The discharge side of the compressor (11) communicates with the third-pass heat transfer tube (23). In FIG. 2, (21b) is a refrigerant introduction tube for the first-pass heat transfer tube (21), and (23b) is a refrigerant introduction tube for the third-pass heat transfer tube (23). Refrigerant introduction tube for the first-pass heat transfer tube (21)
(21b) is connected to a refrigerant introduction pipe (not shown) for the second-pass heat transfer pipe (22) by a header, and each refrigerant introduction pipe is connected to the compressor (1) of the heat source side refrigerant circuit (A) through the header. ).

Thus, the first-pass heat transfer tube (21) and the second-pass heat transfer tube (22) for condensing the heat-source-side refrigerant in the heat-source-side refrigerant circuit (A) and the use-side refrigerant in the use-side refrigerant circuit (B) Heat exchanger with a third pass heat transfer tube (23) to condense
The heat transfer tubes (21, 22, 23) are integrated into (2) and arranged on the same air passage.

That is, the heat-source-side refrigerant discharged from the compressor (1) of the heat-source-side refrigerant circuit (A) flows through the first-pass heat transfer tube (21) and the second-pass heat transfer tube (22) and flows between the outside air and the outside. While performing heat exchange,
The usage-side refrigerant discharged from the compressor (11) of the usage-side refrigerant circuit (B) flows through the third-pass heat transfer tube (23) and exchanges heat with the outside air. With such a configuration, the first-pass heat transfer tube (21) and the second-pass heat transfer tube (22) allow the heat-source-side heat exchange means (2A) of the present invention to function as a third-pass heat transfer tube.
The use side condensing means (2B) according to the present invention is constituted by (23).

Further, the present apparatus is provided with a controller (30) for controlling each device. This controller
(30) determines the operating capacity of the compressor (1,11), the number of revolutions of the fan (6,15), and the degree of opening of the electric expansion valve (3,12) according to the internal temperature, the internal target temperature, etc. It is to adjust.

A pressure sensor (PS1, PS2) for detecting a discharge gas pressure is provided on the discharge side of each compressor (1, 11), and the controller (30) is provided with the pressure sensors (PS1, PS1). PS
The pressure signal can be received from 2).

Further, the controller (30) includes a comparing means (31) and a stopping means (32). The comparing means (31) can receive pressure signals from the pressure sensors (PS1, PS2), compare the pressure signals, and issue a stop signal when the pressure difference is equal to or less than a predetermined value. Has become. The stop means (32) can receive a stop signal from the comparison means (31), and when the stop signal is received, the heat source side refrigerant circuit
The compressor (1) of (A) is stopped. That is,
In the state where the outside air temperature is relatively low, the difference between the discharge gas pressures of the compressors (1, 11) becomes small, but in such a situation, the internal temperature is reduced to the target temperature without performing the binary refrigeration cycle. It becomes possible. Therefore, when the outside air temperature is relatively low, it is recognized by detecting the difference between the discharge gas pressures of the compressors (1, 11). (1) is stopped and the refrigerant is circulated only to the use-side refrigerant circuit (B) to cool the inside of the refrigerator.

Further, in this device, the heat source side refrigerant circuit (A), the use side heat transfer tube (4B) of the cascade heat exchanger (4) and the compressor (11) of the use side refrigerant circuit (B) are pre-set at the factory. At the installation site, the electric expansion valve (1
2,12) and the internal heat exchanger (13,13). That is, as shown by the dashed line in FIG. 1, each device is unitized and produced as a heat source unit (C), a shutoff valve (25, 25) is attached to a pipe end, and the heat source unit (C) is installed on site. After connecting the electric expansion valves (12, 12) and the in-compartment heat exchangers (13, 13) of the use-side refrigerant circuit (B) to the storage side, an installation operation such as opening the closing valves (25, 25) is performed.

-Explanation of Refrigerant Circulation Operation- During operation of the refrigeration system configured as described above, in the heat source side refrigerant circuit (A), the compressor (1) and the outdoor fan (6) are driven, and the electric expansion valve ( 3) is adjusted to a predetermined opening. As a result, as shown by the solid arrow in FIG. 1, the heat-source-side refrigerant discharged from the compressor (1) is supplied to the first-pass heat transfer tube (21) of the outdoor heat exchanger (2).
And heat exchange with the outside air in the second-pass heat transfer tube (22) to condense and reduce the pressure with the electric expansion valve (3), and then the heat source side heat transfer tube (4A) of the cascade heat exchanger (4) User-side refrigerant circuit (B)
The cooling medium is evaporated by applying cold to the utilization side refrigerant, and is collected on the suction side of the compressor (1). Such a refrigerant circulation operation is performed in the heat source side refrigerant circuit (A).

On the other hand, in the use side refrigerant circuit (B), the compressor (1
1) and the internal fan (15, 15) are driven, and the electric expansion valve (12, 12)
Is adjusted to a predetermined opening. As a result, the use-side refrigerant discharged from the compressor (11) transfers heat to the outside air in the third-pass heat transfer tube (23) of the outdoor heat exchanger (2), as indicated by the broken arrow in FIG. Exchange and condense, cascade heat exchanger
After being supercooled by the use-side heat transfer tube (4B) in (4) and depressurized by the electric expansion valves (12, 12), heat exchange was performed with the air in the refrigerator using the heat exchangers (13, 13) in the refrigerator. It evaporates and is collected on the suction side of the compressor (11). Such a refrigerant circulation operation is the utilization side refrigerant circuit (B)
It is performed in. Thereby, the inside of the refrigerator is cooled to the predetermined temperature.

FIG. 3 shows a Mollier diagram in the present system. (I) of this figure shows a refrigeration cycle of the heat source side refrigerant circuit (A), and (II) shows a refrigeration cycle of the use side refrigerant circuit (B). Q _EH indicates the evaporation capacity of the heat source side refrigerant circuit (A), and Q _CL indicates the condensation capacity of the use side refrigerant circuit (B). In this system, the use side refrigerant circuit
A part of the amount of heat released when the gas refrigerant of (B) is condensed is recovered to the outside air in the outdoor heat exchanger (2), and the other is recovered by the refrigerant of the heat source side refrigerant circuit (A). In FIG. 3, Q _CL1 indicates the amount of heat released from the use side refrigerant circuit (B) to the outside air, and Q _CL2 indicates the amount of heat released from the use side refrigerant circuit (B) to the heat source side refrigerant circuit (A). Therefore, the evaporation capacity Q _EH of the heat-source-side refrigerant circuit (A) is equal to the heat release amount of the use-side refrigerant circuit (B) to the heat-source-side refrigerant circuit (A), that is, as long as it is capable of recovering Q _CL2 in FIG. Frequently, it is not necessary to keep the total condensing capacity Q _{CL of} the use side refrigerant circuit (B) always higher than the total condensing capacity Q _CL . Therefore, as in the conventional case, the heat source side refrigerant circuit (A)
It is not necessary to increase the input power to the compressor (1) of the heat source side refrigerant circuit (A) in order to increase the evaporation capacity of the heat source, and the effective energy rate can be improved. The compressor (1) of the heat source side refrigerant circuit (A) may be a large-sized compressor with high capacity, or the cascade heat exchanger (4) may be increased in size.
Since there is no need to increase the amount of heat exchange between (A, B), there is no increase in the size and cost of the system. Also,
Since the total heat release of each refrigerant in the entire apparatus is the same as that of the conventional apparatus (one in which the use-side refrigerant circuit is not provided with an air condenser), the outdoor heat exchanger (2) does not become large. That is, conventionally, the heat source side refrigerant is the outdoor heat exchanger (2)
In the present embodiment, the heat of the use-side refrigerant is partially radiated to the outside air through the heat-source-side refrigerant.
According to (2), the heat is directly radiated to the outside air, and the remaining heat is radiated to the outside air via the heat source side refrigerant. Therefore, there is no change in the amount of heat radiation as compared with the conventional one, and it is not necessary to increase the heat radiation capacity of the outdoor heat exchanger (2). Therefore, the outdoor heat exchanger
(2) does not need to be large.

In the above-described refrigerant circulation operation,
Discharge gas pressure of each compressor (1,11) is pressure sensor (PS1, PS2)
The pressure signal is detected by the comparing means (31).
Has been sent to. The comparing means (31) recognizes the difference between the discharge gas pressures of the compressors (1, 11) based on the received pressure signal. Then, when the difference becomes equal to or smaller than the predetermined value, a stop signal is issued to the stopping means (32). Stop means (32) receiving this stop signal is the compressor (1) of the heat source side refrigerant circuit (A).
To stop. Thereby, the refrigerant circulation operation is performed only in the use-side refrigerant circuit (B). In other words, the use side refrigerant circuit
The refrigerant circulating in (B) is the third-pass heat transfer tube of the outdoor heat exchanger (2)
In (23), heat is radiated to the outside air. As described above, when the difference between the discharge gas pressures of the compressors (1, 11) becomes equal to or less than a predetermined value, the outside air temperature is relatively low, so that the use-side refrigerant is used without performing a two-way refrigeration cycle. By merely radiating the refrigerant in the circuit (B) to the outside air in the third pass heat transfer tube (23) of the outdoor heat exchanger (2), it is possible to cool the inside of the refrigerator to a predetermined target temperature. Therefore, the compressor of the heat source side refrigerant circuit (A)
Unnecessary driving of (1) is avoided, and this can also improve the energy efficiency.

In the present embodiment, the case where the present invention is applied to a refrigeration system for cooling the inside of a refrigerator to a predetermined refrigeration temperature has been described. However, the present invention is not limited to this. It is also applicable to

In this embodiment, the difference in the pressure of the discharged gas from each of the compressors (1, 11) is detected to recognize that the outside air temperature is relatively low. The compressor (1) of the heat source side refrigerant circuit (A) may be stopped when the outside air temperature is directly detected and becomes equal to or lower than a predetermined value.

[0037]

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

According to the first aspect of the present invention, the use-side refrigerant circuit is provided.
Part of the heat of the use-side refrigerant circulating in (B) is directly radiated to the air to reduce the amount of heat of the use-side refrigerant collected by the heat-source-side refrigerant circuit (A). For this reason, the evaporation capacity of the heat-source-side refrigerant circuit (A) is only required to be able to recover the heat release amount of the use-side refrigerant circuit (B) to the heat-source-side refrigerant circuit (A), and the use-side refrigerant circuit (B) It is not necessary to keep it constantly higher than the total condensation capacity. Therefore, the heat source side refrigerant circuit
There is no need to increase the input power to the compressor (1) of the heat source side refrigerant circuit (A) in order to increase the evaporation capacity of (A), and the energy efficiency can be improved. In addition, use a large-sized compressor with high capacity as the compressor (1) of the heat source side refrigerant circuit (A), or increase the size of the cascade heat exchanger (4) to reduce the amount of heat exchange between the circuits (A, B). Since there is no need to increase the size, there is no increase in the size and cost of the system. Further, a heat source side heat exchange means for radiating the heat source side refrigerant.
(2A) and the use-side condensation means (2B) for radiating the use-side refrigerant are arranged in the same air passage, so that it is not necessary to form individual air passages, and the structure of the device is complicated. Without the above, the above-mentioned effects can be exhibited.

According to the second aspect of the present invention, an air-cooled heat exchanger (2) having a plurality of heat transfer tubes (21, 22, 23) is provided. Some paths (21,2
The heat source side heat exchange means (2A) is configured by (2), and the other paths (2
The use side condensing means (2B) was constituted by 3). As a result, the compressor (1) of the heat source side refrigerant circuit (A) can be easily improved by making the use side refrigerant flow through a part of the path of the outdoor heat exchanger provided in the conventional secondary refrigerant system. , It is possible to reduce the input power to improve the energy efficiency. In addition, since the amount of heat radiation in the entire device does not change from that of the conventional device, even if the path is changed in this way, the heat exchanger (2) itself does not have to be enlarged, and the device becomes larger. Without this, the energy efficiency can be improved.

In the invention according to claim 3, the heat source side refrigerant circuit
(A), the use side compressor (11), the use side condensing means (2B) and the use side heat transfer section (4B) of the cascade heat exchanger (4)
Unitized as (C). Therefore, most of the apparatus can be manufactured in the factory, and most of the apparatus can be manufactured under high quality control, and the reliability of the apparatus can be improved. At the time of installation, it is only necessary to connect the pressure reducing mechanism (12, 12) and the use-side heat exchanger (13, 13) of the use-side refrigerant circuit (B) to this heat source unit (C). It can also be simplified.

According to the fourth aspect of the present invention, the heat source side compressor
Recognize the difference between the discharge refrigerant pressures of (1) and the use side compressor (11), and when the difference becomes less than a predetermined value, the heat source side compressor
(1) was stopped. That is, each compressor (1,11)
When the difference between the discharge gas pressures is equal to or less than a predetermined value, the outside air temperature is relatively low, so that the refrigerant in the use-side refrigerant circuit (B) is used without using the binary refrigeration cycle. In (2B), it is possible to lower the evaporation temperature of the use side heat exchanger (13) to a predetermined target temperature only by radiating heat to the air (outside air). Therefore, unnecessary driving of the compressor (1) of the heat source-side refrigerant circuit (A) is avoided, and the energy efficiency can also be improved.

[Brief description of the drawings]

FIG. 1 is a refrigerant piping system diagram of a refrigeration apparatus according to an embodiment.

FIG. 2 is a perspective view showing a part of the outdoor heat exchanger.

FIG. 3 is a Mollier diagram according to the embodiment.

FIG. 4 is a refrigerant piping system diagram in a conventional example.

FIG. 5 is a Mollier diagram according to a conventional example.

[Explanation of symbols]

 (1,11) Compressor (2A) Heat source side heat exchange means (2B) User side condensation means (3,12) Electric expansion valve (decompression mechanism) (4) Cascade heat exchanger (4A) Heat source side heat transfer tube (4B ) Usage side heat transfer tube (13) Internal heat exchanger (use side heat exchanger) (20) Radiation fin (31) Comparison means (32) Stopping means (PS1, PS2) Pressure sensor (pressure detecting means) (A) Heat source side refrigerant circuit (B) User side refrigerant circuit (C) Heat source unit

Claims (4)

[Claims] 1. A heat source side compressor (1), an air-cooled heat source side heat exchange means (2A), a pressure reducing mechanism (3), and a heat source side heat transfer section (4A) of a cascade heat exchanger (4). The heat-source-side refrigerant circuit (A) enabling circulation of the heat-source-side refrigerant, the use-side compressor (11), the use-side heat transfer section (4B) of the cascade heat exchanger (4), and the pressure reduction mechanism (12, 12) ), A use-side refrigerant circuit (B) having a use-side heat exchanger (13, 13) and capable of circulating the use-side refrigerant, and a cascade of refrigerants circulating in each circuit (A, B). In a refrigeration apparatus configured to apply cold heat from the heat source side refrigerant circuit (A) to the use side refrigerant circuit (B) by heat exchange in the heat exchanger (4), the use side refrigerant circuit (B) includes: After condensing the use side refrigerant discharged from the compressor (11), the cascade heat exchanger
An air-cooled use-side condensing means (2B) for supplying to the use-side heat transfer section (4B) of (4) is provided, and the use-side condensing means (2B) exchanges heat on the heat source side of the heat source-side refrigerant circuit (A). A refrigeration apparatus characterized by being disposed in the same air passage as the means (2A). 2. The refrigeration apparatus according to claim 1, wherein the heat transfer tubes (2, 2) are mounted on the radiation fins (20, 20,...).
1,22,23) with an air-cooled heat exchanger (2),
Some of the paths (21, 22) of the plurality of paths of the heat exchanger (2) constitute the heat source side heat exchange means (2A), and the other path (23) constitutes the use side condensation means (2B). A refrigeration apparatus characterized by comprising. 3. The refrigeration apparatus according to claim 1, wherein the heat source side refrigerant circuit (A), the use side compressor (11), the use side condensing means (2B), and the use side of the cascade heat exchanger (4). Heat transfer section (4B)
Is unitized as a heat source unit (C), and at the installation site, the pressure reduction mechanism of the user-side refrigerant circuit (B)
(12,12) and the use side heat exchanger (13,13) are the use side refrigerant circuit
A refrigeration apparatus characterized by being connected to the refrigerant pipe (14) of (B). 4. The refrigerating apparatus according to claim 1, wherein the pressure detecting means (PS1, PS2) for detecting a refrigerant pressure discharged from each of the heat source side compressor (1) and the utilization side compressor (11). A comparison means (31) for receiving a detection signal from the pressure detection means (PS1, PS2), comparing each of the discharged refrigerant pressures, and issuing a stop signal when a difference between the pressures becomes equal to or less than a predetermined value; A refrigerating apparatus characterized by comprising a stop means (32) capable of receiving the stop signal of (31) and stopping the heat source side compressor (1) when receiving the stop signal.