JP2007218466A - Secondary refrigerant type refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary refrigerant type refrigerating device capable of smoothly and stably exerting natural circulation of a carbon dioxide refrigerant at all times without being subject to restriction of its installation place. <P>SOLUTION: This secondary refrigerant type refrigerating device wherein a carbon dioxide refrigerant gas of a secondary-side refrigerant circuit system is allowed to exchange heat with a refrigerant of a primary-side refrigerant circuit system to be condensed and liquefied, comprises liquid storing containers 43A, 43B for storing the carbon dioxide refrigerant liquefied by a cascade capacitor 7, and refrigerant circulating means 31A, 31B composed of siphon tubes 45A, 45B attached to the liquid storing containers, allowing the refrigerant liquid in the liquid storing containers to flow out when they reach a prescribed level, guiding the refrigerant liquid to gas generating portions 47A, 47B to exchange heat with the primary-side refrigerant to be heated/gasified, and applying the gas pressure to refrigerant liquid surfaces in the liquid storing containers to be pressurized, and the refrigerant liquid in the liquid storing containers is circulated to an evaporator of the secondary-side refrigerant circuit system by the refrigerant circulating means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention combines a primary side refrigerant circuit system and a secondary side refrigerant circuit system using a carbon dioxide refrigerant through a cascade capacitor, and the carbon dioxide refrigerant gas of the secondary side refrigerant circuit system is primaryly coupled by the cascade capacitor. The present invention relates to a secondary refrigerant type refrigeration apparatus in which heat is exchanged with a refrigerant in a side refrigerant circuit system to be condensed and circulated to an evaporator in a secondary side refrigerant circuit system.

Conventionally, various types of secondary refrigerant refrigeration apparatuses as described above have been proposed. As the primary refrigerant circuit system of such a secondary refrigerant type refrigeration apparatus, a refrigerant system using a CFC refrigerant such as R404A or R410A or a non-CFC refrigerant such as ammonia, propane, butane, or isobutane has been proposed. , A cascade condenser, a compressor, a condenser (condenser), a liquid receiver (receiver), and a pressure reducing means (expansion valve) are connected in this order by refrigerant piping to constitute a primary refrigerant circuit.
On the other hand, as the secondary refrigerant circuit system, in consideration of safety and reduction of chlorofluorocarbon refrigerant, there are many natural refrigerants using carbon dioxide refrigerant having a low evaporation temperature, cascade capacitors, A carbon dioxide refrigerant receiver, a liquid pump, and an evaporator (cooler) are connected in this order by refrigerant piping to constitute a secondary refrigerant circuit.

  In such a secondary refrigerant type refrigeration apparatus, the refrigerant is compressed by driving the compressor of the primary side refrigerant circuit system, circulated to the cascade condenser through the condenser, the liquid receiver, and the decompression means, and the cascade condenser The refrigerant is evaporated, the heat of vaporization cools the carbon dioxide refrigerant gas in the secondary refrigerant circuit system, condenses it, and the liquefied secondary carbon dioxide refrigerant is converted into a secondary refrigerant circuit system by a liquid pump. It is made to circulate to the evaporator of this, and a cooling effect is acquired by evaporating a carbon dioxide refrigerant with this evaporator. The secondary refrigerant type refrigeration apparatus can be widely applied to refrigeration / freezing of various refrigerators, cold storages, freezers, showcases, reach-in cases, and the like.

Therefore, in the secondary refrigerant type refrigeration apparatus, a liquid pump is required to circulate the carbon dioxide refrigerant liquid in the secondary refrigerant circuit system, which increases the components of the secondary refrigerant circuit system, This not only increases the manufacturing cost of the apparatus, but also consumes power when driving the liquid pump, and therefore includes the problem of increased running costs during operation of the apparatus.
Therefore, a condensing unit provided with a primary side refrigerant circuit system, a cascade capacitor, a carbon dioxide refrigerant receiver for the secondary side refrigerant circuit system, etc. is installed at a position higher than the evaporator of the secondary side refrigerant circuit system. There has been proposed one in which a carbon dioxide refrigerant liquid is naturally circulated by gravity without providing a refrigerant conveying means such as a liquid pump (see Patent Document 1).

  In addition, a pressurized tank (reservoir container) is provided as a refrigerant circulating means in place of the liquid pump, and the carbon dioxide refrigerant liquid condensed and liquefied by the cascade condenser is flowed into the pressurized tank, which is used as the refrigerant of the primary refrigerant circuit system. The inside of the pressurized tank is pressurized by heat exchange and heating, and a pumping means for pumping up the carbon dioxide refrigerant liquid using the pressure difference is provided, and the carbon dioxide refrigerant liquid is naturally circulated by the pumping means. The thing made to do is proposed (refer patent document 2).

JP 2002-228283 A JP 2002-48422 A

  However, in the one described in Patent Document 1, since the carbon dioxide refrigerant can be circulated naturally, a liquid pump is not required, and the initial cost and running cost of the apparatus can be greatly reduced. Must be installed at a higher position than the evaporator of the secondary refrigerant circuit system, so that these are severely restricted. In particular, this type of device often has a limited installation location due to problems such as installation space, building structure, noise, etc., and when it is difficult to install the condensing unit at a high position, it can circulate the refrigerant naturally. It has problems such as being unable to do so.

  Moreover, what is described in Patent Document 2 stores carbon dioxide refrigerant liquid in a pressurized tank, pressurizes it by heating it with a refrigerant in a primary refrigerant circuit system, and uses the pressure difference to produce carbon dioxide. Although the refrigerant liquid is naturally circulated, the refrigerant liquid flows in and out by alternately heating and cooling the pressurized tank and the refrigerant stored in the pressurized tank. It is difficult to eliminate. For this reason, the heating loss is large, and it takes time to pressurize and depressurize. To shorten the time and secure responsiveness, it is necessary to secure the circulation amount of the refrigerant by increasing the heating and cooling capacity. Disappear. Furthermore, in order to allow the refrigerant to flow into and out of the pressurized tank, switching means such as an electromagnetic valve is indispensable, and there is a problem that a controller for that purpose is required.

The present invention has been made in view of the circumstances as described above, and the problem to be solved is that the secondary side refrigerant circuit system is always smoothly and stably oxidized without being restricted by the installation location. An object of the present invention is to provide a secondary refrigerant refrigeration apparatus using a carbon dioxide refrigerant capable of naturally circulating a carbon refrigerant.
Another problem is that when carbon dioxide refrigerant in the secondary refrigerant circuit system is naturally circulated using the refrigerant in the primary refrigerant circuit system as a heat source, heat loss is reduced and responsiveness during heating and cooling is improved. Another object of the present invention is to provide a secondary refrigerant type refrigeration apparatus that can secure a sufficient amount of refrigerant circulation while keeping the heat source capacity to a minimum, and that can improve the cooling capacity of a cascade condenser.
In addition, in the above-described secondary refrigerant refrigeration apparatus, another problem can be realized by a simple configuration without providing a switching means such as a solenoid valve or a controller therefor for continuous natural circulation by batch switching of carbon dioxide refrigerant. The object is to provide a secondary refrigerant refrigeration system.
A further problem is to provide a secondary refrigerant type refrigeration apparatus capable of sufficiently ensuring the circulation amount of the carbon dioxide refrigerant in spite of changes in the outside air temperature.

In order to solve the above-described problems, the secondary refrigerant refrigeration apparatus according to the present invention employs the following means.
The first means combines a primary side refrigerant circuit system and a secondary side refrigerant circuit system using carbon dioxide refrigerant through a cascade capacitor, and the cascade capacitor causes the carbon dioxide refrigerant of the secondary side refrigerant circuit system to be combined. A secondary refrigerant refrigeration apparatus configured to heat and exchange gas with refrigerant in the primary refrigerant circuit system to condense and liquefy, a liquid reservoir for storing the carbon dioxide refrigerant liquefied by the cascade condenser, and the liquid reservoir When the refrigerant liquid in the liquid storage container reaches a predetermined level, the refrigerant liquid flows out, and the refrigerant liquid is led to the gas generation section to exchange heat with the primary side refrigerant to be heated and gasified, and its gas pressure And a siphon tube that adds pressure to the refrigerant liquid level in the liquid storage container and pressurizes the refrigerant circulation means. The refrigerant circulation means causes the refrigerant liquid in the liquid storage container to flow into the secondary refrigerant circuit. Wherein the circulating in the evaporator.

According to the above, the carbon dioxide refrigerant condensed and liquefied by the cascade condenser flows into the liquid reservoir. When the refrigerant in the liquid storage container reaches a predetermined level, it flows out to the siphon tube, and the refrigerant reaches the gas generating section where it is heated by the high-temperature primary side refrigerant and gasified. This refrigerant gas pressure is applied to the refrigerant liquid level in the liquid storage container via the siphon tube and pressurized to send out the refrigerant liquid in the liquid storage container, and the cascade condenser and the evaporator of the secondary refrigerant circuit system Regardless of the installation positional relationship, the natural circulation of the secondary refrigerant can be smoothly and stably realized.
In addition, since the carbon dioxide refrigerant flows out from the liquid storage container through the siphon tube and only the refrigerant is heated by the primary side refrigerant in the gas generation section to be gasified, the liquid storage container and all the internal refrigerant are heated. There is no heating loss due to heating, and responsiveness during heating and cooling can be improved. Accordingly, the refrigerant circulation capacity can be increased without increasing the heat source capacity.
Furthermore, since the primary side refrigerant can be supercooled by the above refrigerant heating, the cooling capacity of the cascade condenser can be increased and the efficiency can be improved.

  A second means is characterized in that, in the first means, the gas generating section is disposed in a primary refrigerant receiver provided in the primary refrigerant circuit system.

  By disposing the gas generation unit in the primary side refrigerant receiver provided in the primary side refrigerant circuit system in this way, the carbon dioxide refrigerant that has reached the gas generation unit with the primary side liquid refrigerant stored in the receiver can be reliably ensured. And since it can heat efficiently, the gas generation capability of a carbon dioxide refrigerant | coolant can be raised and the natural circulation of a refrigerant | coolant can be accelerated | stimulated.

  A third means is characterized in that, in any one of the first and second means, a plurality of sets of the refrigerant circulation means are provided in parallel in the secondary side refrigerant circuit system.

  According to the above, continuous natural circulation of carbon dioxide refrigerant can be realized by alternately switching a plurality of sets of refrigerant circulation means provided in parallel.

  A fourth means is characterized in that, in the third means, the gas generating portions in the plurality of refrigerant circulation means are respectively disposed in the primary refrigerant receiver.

  By arranging a plurality of gas generators in one refrigerant receiver in this way, one refrigerant receiver can be shared, and uniform gas generation capability can be ensured by uniform heating, so the natural circulation of the refrigerant is stable. Can be

  According to a fifth means, in any one of the third and fourth means, the carbon dioxide refrigerant liquefied by the cascade condenser is directly supplied to one of the liquid reservoirs of the plurality of refrigerant circulation means via the downflow pipe. It is made to flow down and it is made to flow down to the other liquid storage container through the branch pipe branched from the said down pipe.

  By configuring as described above, the refrigerant liquefied by the cascade condenser preferentially flows into one liquid storage container, and when a predetermined amount of refrigerant accumulates in the liquid storage container and stops flowing, another liquid storage container Therefore, there is no need for switching adjustment, and it automatically operates alternately. Therefore, an electromagnetic valve and a controller for switching are not necessary, and the configuration can be simplified.

A sixth means is characterized in that, in the fifth means, a check valve is provided in each of the downflow pipe, the branch pipe and the delivery pipe for sending the refrigerant liquid from the liquid reservoir.

  By providing the check valve as described above, the operation of the refrigerant circulating means provided in a plurality of sets can be switched more reliably.

  The seventh means provides a pressure reducing means on the primary refrigerant receiver outlet side of the primary refrigerant circuit system in any one of the second to sixth means, and the downstream refrigerant piping of the pressure reducing means is connected to the liquid refrigerant. The container cooler is arranged to be able to exchange heat with the storage container.

  According to the above, when the refrigerant liquid in the liquid storage container is sent out and the refrigerant liquid stops flowing into the siphon tube and the refrigerant supply from the liquid storage container is stopped, the gas refrigerant inside the liquid storage container is transferred into the container cooler. Therefore, the gas refrigerant can be quickly condensed and liquefied to depressurize the liquid reservoir, and the inflow of the carbon dioxide refrigerant liquid from the cascade condenser can be started. Therefore, the cooling capacity of the liquid reservoir can be improved and the responsiveness can be enhanced.

According to an eighth means, in any one of the first to seventh means, a discharge gas refrigerant bypass circuit including a discharge gas bypass valve is provided in parallel to the condenser of the primary refrigerant circuit system. It is characterized by.

  By providing a bypass circuit as described above, even if the outside air temperature changes and the refrigerant temperature of the primary refrigerant circuit system falls, the bypass valve is opened and the compressor discharge gas is bypassed by the condenser. Since the refrigerant liquid temperature in the refrigerant receiver can be maintained by flowing it, the decrease in the amount of gas generated at the gas generating part of the siphon tube is prevented, and a sufficient amount of refrigerant circulation is ensured regardless of changes in the outside air temperature. be able to.

  A ninth means uses any one of R410A, R404A, propane, butane, isobutane and ammonia or a mixture thereof as the refrigerant in the primary refrigerant circuit system in any one of the first to eighth means. It is characterized by that.

  According to the above, it is possible to provide a secondary refrigerant type refrigeration apparatus in which an optimal primary side refrigerant is selected according to the application. In particular, the use of chlorofluorocarbon refrigerant can be reduced by using propane, butane, isobutane, ammonia or the like.

  According to a tenth means, in any one of the first to ninth means, an air conditioning indoor heat exchanger for air-conditioning the building is provided in the primary refrigerant circuit system in addition to the cascade capacitor. And

  By providing an indoor heat exchanger for air conditioning in the primary side refrigerant circuit system as described above, a single secondary refrigerant refrigeration system can be used for indoor air conditioning and for refrigeration and refrigeration equipment installed indoors. It can be beneficially applied to air conditioning, freezing, and refrigeration at convenience stores.

According to the secondary refrigerant type refrigeration apparatus of the present invention, the carbon dioxide refrigerant can be naturally circulated smoothly and stably at all times regardless of the installation position relationship of the constituent devices, so that restrictions on the installation location can be eased. it can.
In addition, the refrigerant in the primary side refrigerant circuit system is used as the heat source when the carbon dioxide refrigerant is naturally circulated. However, since the heat loss is eliminated and the responsiveness during heating / cooling is improved, the heat source is increased. Without increasing the refrigerant circulation capacity, a sufficient amount of refrigerant circulation can be secured. At the same time, since the primary side refrigerant can be supercooled when the secondary side refrigerant is heated, the cooling capacity of the cascade condenser can be increased and the efficiency can be improved.

Embodiments according to the present invention will be described below with reference to the drawings.
[First embodiment]
FIG. 1 shows a refrigerant system diagram of a secondary refrigerant refrigeration apparatus 1 according to the first embodiment of the present invention.
The secondary refrigerant refrigeration apparatus 1 according to the present embodiment includes a primary refrigerant circuit system 3 that uses any one of R404A, R410A, ammonia, propane, butane, isobutane, or a mixture thereof as a refrigerant, and evaporation as a refrigerant. A secondary side refrigerant circuit system 5 using a low temperature carbon dioxide refrigerant is combined and coupled via a cascade capacitor 7.

The primary side refrigerant circuit system 3 includes a compressor 9, a condenser (condenser) 11, a primary side liquid refrigerant receiver (receiver) 13, a pressure reducing means (expansion valve) 15, a cascade capacitor 7, a carbon dioxide cylinder cooler 17, The accumulator 19 is connected in this order by the refrigerant pipe 21 to constitute a refrigerant circuit that forms a refrigeration cycle. The compressor 9, the condenser (condenser) 11, and the accumulator 19 are installed in the outdoor unit 23.

  In the primary-side refrigerant circuit system 3, the compressor 9 compresses the primary-side refrigerant gas and discharges it as a high-temperature and high-pressure gas refrigerant. The discharged gas refrigerant flows into the condenser 11, where Heat is exchanged with the outside air blown by an outdoor fan (not shown), and it is cooled, condensed and liquefied, and flows out to the liquid refrigerant receiver 13. In the liquid refrigerant receiver 13, the gas component in the refrigerant is separated, and only the liquid refrigerant is sent to the decompression means 15. The refrigerant which is adiabatically expanded by passing through the decompression means 15 and is in a low-temperature and low-pressure gas-liquid two-phase state flows into the cascade condenser 7 and is heat-exchanged with a carbon dioxide refrigerant gas which will be described later. The liquid is condensed and liquefied to evaporate itself, and after the carbon dioxide refrigerant recovered in the carbon dioxide cylinder 25 is cooled in the carbon dioxide cylinder cooler 17 provided as needed, the accumulator After 19, it is again sucked and compressed by the compressor 9.

On the other hand, the secondary refrigerant circuit system 5 connects a plurality of sets of refrigerant circulation means 31A, 31B, a plurality of flow rate adjusting valves 33A, 33B, a plurality of evaporators 35A, 35B, and a cascade condenser 7 in this order by a refrigerant pipe 37. Thus, a refrigerant circuit forming a refrigeration cycle is configured and combined and coupled so as to exchange heat with the refrigerant of the primary refrigerant circuit system 3 via a cascade capacitor 7.
As described above, the cascade capacitor 7 exchanges heat between the primary-side refrigerant and the secondary-side refrigerant and evaporates the primary-side refrigerant, so that carbon dioxide refrigerant gas, which is the secondary-side refrigerant, is generated by the heat of vaporization. It functions to condense and liquefy.

In the secondary side refrigerant circuit system 5, a plurality of sets of refrigerant circulation means 31A and 31B are arranged so as to be positioned below the cascade condenser 7, and in the downstream pipe 39 where the refrigerant condensed and liquefied by the cascade condenser 7 naturally flows down. In contrast, they are connected in parallel to each other.
The plurality of sets of refrigerant circulation means 31A, 31B have liquid reservoir containers 43A, 43B for storing liquid refrigerant flowing down from the cascade condenser 7, respectively, of which the liquid reservoir container 43A is connected via a flow down pipe 39. Thus, the liquid refrigerant is allowed to flow down directly, and to the other liquid storage container 43B via the branch pipe 41 branched from the middle of the flow down pipe 39. The flow down pipe 39 and the branch pipe 41 are inserted to the bottoms of the liquid storage containers 43A and 43B, respectively, and are opened in the containers.

  The liquid reservoirs 43A and 43B are provided with siphon tubes 45A and 45B that open at predetermined liquid level in the containers, respectively. The siphon tubes 45A and 45B are taken out downward from the liquid reservoirs 43A and 43B, and then a part thereof is coupled to the liquid refrigerant receiver 13 of the primary refrigerant circuit system 3 described above. It is arranged to exchange heat with the liquid refrigerant. The heat exchange portions are gas generating portions 47A and 47B, and the other ends of the siphon tubes 45A and 45B that have passed through the gas generating portions 47A and 47B are connected and opened to the upper portions of the liquid reservoirs 43A and 43B.

Further, the refrigerant liquid delivery pipes 49A and 49B are branched from the lower extraction portions of the siphon pipes 47A and 47B, respectively, and the delivery pipes 49A and 49B are connected to a refrigerant pipe 37 connected to the plurality of evaporators 35A and 35B. Yes.
The flow-down pipe 39, the branch pipe 41, and the delivery pipes 49A and 49B are each provided with a check valve 51 so that the refrigerant flows only in one direction of the refrigerant circulation direction.

The plurality of evaporators 35A and 35B are connected in parallel to the refrigerant pipe 37 via flow rate adjusting valves 33A and 33B, respectively, and are used for refrigeration / freezing of various refrigerators, cold storages, freezers, showcases, reach-in cases, and the like It functions as a cooler.
The carbon dioxide refrigerant gas evaporated in each of the evaporators 35A and 35B is guided to the cascade condenser 7 through the refrigerant pipe 37, where it is heat-exchanged with the primary side refrigerant, cooled, and condensed again. .

Next, the cooling operation of the secondary refrigerant refrigeration apparatus 1 will be described.
In the primary refrigerant circuit system 3, the high-temperature and high-pressure refrigerant gas compressed by the compressor 9 is discharged from the compressor 9, and then the condenser 11, the refrigerant receiver 13, the decompression means 15, the cascade condenser 7, the carbon dioxide It circulates through the cylinder cooler 17 and the accumulator 19, and during this time, it is cooled by exchanging heat with the outside air in the condenser 11 to be condensed and liquefied. The condensed and liquefied refrigerant is guided to the refrigerant receiver 13 where the gas component is separated. In the refrigerant receiver 13, as described above, the gas generators 47A and 47B of the siphon tubes 45A and 45B constituting the refrigerant circulation means 31A and 31B of the secondary refrigerant circuit system 5 are disposed. The primary side liquid refrigerant in the inside exchanges heat with the secondary side carbon dioxide refrigerant flowing out from the liquid storage containers 43A, 43B through the siphon tubes 47A, 47B to the gas generating parts 47A, 47B, and the carbon dioxide refrigerant. Is gasified by heating.

The refrigerant in the refrigerant receiver 13 then flows out from the refrigerant receiver 13, is adiabatically expanded by the decompression means 15, reaches a cascade capacitor 7 as a low-temperature low-pressure gas-liquid two-phase refrigerant. This primary side refrigerant is heat-exchanged with the carbon dioxide refrigerant circulating in the secondary side refrigerant circuit system 5 by the cascade condenser 7, and takes the heat of vaporization from the carbon dioxide refrigerant gas to evaporate itself. The carbon dioxide refrigerant gas is cooled and condensed.
The primary refrigerant evaporated and gasified by the cascade condenser 7 reaches the accumulator 19 through the carbon dioxide cylinder cooler 17, and after the liquid is separated, it is sucked into the compressor 9 and compressed again. By repeating the above circulation, the function of heating the gas generators 47A and 47B in the refrigerant receiver 13 and the function of cooling the secondary carbon dioxide refrigerant gas by the cascade condenser 7 are exhibited.

On the other hand, the secondary refrigerant circuit system 5 operates as follows.
First, the natural circulation of carbon dioxide refrigerant by a plurality of sets of refrigerant circulation means 31A and 31B will be described. The carbon dioxide refrigerant condensed and liquefied by the cascade condenser 7 flows preferentially into the liquid reservoir 43A via the flow down pipe 39. When the liquid level of the secondary side refrigerant liquid stored in the liquid storage container 43A rises and reaches the inlet level of the siphon tube 45A, the secondary side refrigerant liquid flows out into the siphon tube 45A, and the primary side refrigerant circuit system 3 The gas generation unit 47A disposed in the refrigerant receiver 13 is reached, and heat exchange is performed with the primary refrigerant liquid in the refrigerant receiver 13.

  The primary side refrigerant liquid and the secondary side carbon dioxide refrigerant liquid to be heat-exchanged here have a higher temperature of the primary side refrigerant liquid than the temperature of the carbon dioxide refrigerant liquid in the gas generation part 47A. The carbon dioxide refrigerant liquid is heated and vaporized into the liquid storage container 43A, added to the carbon dioxide refrigerant liquid level in the liquid storage container 43A, and pressurizes the liquid level. Thus, the carbon dioxide refrigerant liquid stored in the liquid storage container 43A is pressure-fed from the liquid storage container 43A to the refrigerant piping 37 through the siphon tube 45A, the refrigerant delivery tube 49A, and the check valve 51.

The refrigerant sent to the refrigerant pipe 37 as described above is adjusted in flow rate by the flow rate adjusting valves 33A and 33B and then flows into the evaporators 35A and 35B. This refrigerant is the refrigerant circulation means 31A. Therefore, regardless of the installation position of the evaporators 35A and 35B with respect to the cascade condenser 7, the refrigerant can be naturally circulated smoothly and stably without a pump. .
In addition, when the refrigerant liquid in the liquid storage container 43A is sent out, gas generation in the gas generation unit 47A disappears, and the gas in the liquid storage container 43A gradually condenses and the pressure in the liquid storage container 43A is reduced. The refrigerant liquid again flows down from the cascade condenser 7.

The secondary refrigerant that has flowed into the evaporators 35A and 35B is heat-exchanged with, for example, air in the refrigerator where the evaporator is installed, evaporates, and cools the inside of the refrigerator with the heat of vaporization. The evaporated and evaporated refrigerant is guided to the cascade condenser 7 through the refrigerant pipe 37, exchanges heat with the primary side refrigerant, and is condensed and liquefied again, and passes through either the downflow pipe 39 or the branch pipe 41, and is stored in the liquid storage containers 43A and 43B. Flow down to either.
As described above, the carbon dioxide refrigerant, which is the secondary refrigerant, naturally circulates through the secondary refrigerant circuit system 5, thereby exhibiting a cooling function in the evaporators 35A and 35B.

In the above description, when one refrigerant circulation means 31A starts sending the refrigerant liquid to the refrigerant pipe 37 through the delivery pipe 49A, the secondary side refrigerant condensed and liquefied by the cascade condenser 7 acts on the check valve 51. Flows down into the liquid reservoir 43B of the other refrigerant circulating means 31B through the branch pipe 41. When a predetermined amount of the refrigerant liquid is accumulated in the liquid reservoir 43B and reaches the inlet level of the siphon pipe 45B, the refrigerant liquid is pressurized to the refrigerant pipe 37 by the same operation as that of the refrigerant circulation means 31A.・ Press feed. Hereinafter, by repeating the same operation, the two sets of refrigerant circulation means 31A and 31B can be automatically and batch-switched alternately to continuously and naturally circulate the carbon dioxide refrigerant.

According to the secondary refrigerant type refrigeration apparatus according to the present embodiment described above, natural circulation of the secondary carbon dioxide refrigerant is always smoothly and stably regardless of the installation positions of the evaporators 35A and 35B with respect to the cascade condenser 7. Can be made. At this time, the liquid reservoirs 43A and 43B, the downflow pipe 39, the branch pipe 41, the siphon pipes 45A and 45B, the gas generation sections 47A and 47B, the delivery pipes 49A and 49B, the check valve 51, etc. Since the refrigerant circulation means 31A and 31B provided in parallel to the circuit system 5 are automatically and batch-switched alternately, the carbon dioxide refrigerant can be continuously naturally circulated.
In addition, since the refrigerant flow to the plurality of liquid storage containers 43A and 43B can be automatically switched with priority on the liquid storage container 43A, there is no need to provide switching means such as an electromagnetic valve and its controller, and the configuration It can be simplified.

Further, when the carbon dioxide refrigerant is gasified in the refrigerant circulation means 31A, 31B, only the refrigerant flowing out to the gas generating portions 47A, 47B of the siphon tubes 45A, 45B is heated and gasified by the primary refrigerant. Therefore, there is no heating loss, and the refrigerant circulation capacity can be increased by improving the responsiveness. At the same time, since the primary refrigerant can be supercooled by heating the carbon dioxide refrigerant, the cooling capacity of the cascade capacitor 7 can be increased and the efficiency can be improved.
Further, the gas generation units 47A and 47B are disposed in one primary refrigerant receiver 13 provided in the primary refrigerant circuit system 3, and the primary liquid refrigerant in the receiver 13 is shared by using one refrigerant receiver 13. Thus, since the carbon dioxide refrigerant flowing out to the gas generating portions 47A and 47B can be heated, the carbon dioxide refrigerant can be heated efficiently and evenly. Accordingly, it is possible to equalize the gas generation capacity in each of the gas generation units 47A and 47B and stabilize the refrigerant circulation.

Further, in the secondary refrigerant refrigeration apparatus 1 of the present embodiment, any one of R410A, R404A, propane, butane, isobutane, and ammonia is used as the refrigerant in the primary refrigerant circuit system 3, and the secondary refrigerant circuit. Since carbon dioxide is used as the refrigerant of the system 5, it is possible to reduce the usage amount of the chlorofluorocarbon refrigerant that is harsh on the environment.
In the secondary refrigerant refrigeration apparatus 1 of the present embodiment, a carbon dioxide cylinder cooler 17 is provided in the suction piping system of the primary refrigerant circuit system 3 so that the carbon dioxide cylinder 25 can be cooled by the suction gas refrigerant. Therefore, when the operation of the secondary refrigerant type refrigeration apparatus 1 is stopped for a while, the carbon dioxide refrigerant liquefied by the cascade condenser 7 as needed is placed in the carbon dioxide cylinder 25 via the pipe 53 and the on-off valve 55. It can be collected and stored.

[Second Embodiment]
FIG. 2 shows a refrigerant system diagram of the secondary refrigerant refrigeration apparatus 101 according to the second embodiment of the present invention.
In the present embodiment, a discharge gas refrigerant bypass circuit is provided in parallel with the condenser in the primary refrigerant circuit system with respect to the first embodiment, and the liquid storage container is cooled in the refrigerant pipe at the outlet side of the refrigerant receiver. The difference is that a container cooler is provided. Since other points are the same as those in the first embodiment, description thereof is omitted.

In the primary refrigerant circuit system 301 of the secondary refrigerant refrigeration apparatus 101 according to the present embodiment, the refrigerant gas discharged from the compressor 9 is discharged to bypass the condenser 11 and flow to the refrigerant pipe 21 on the downstream side thereof. A gas refrigerant bypass circuit 303 is provided, and a discharge gas bypass valve 305 for controlling the condensate temperature of the primary refrigerant to be a predetermined temperature or higher is provided in the discharge gas refrigerant bypass circuit 303.
Further, a pressure reducing means 307 such as an expansion valve is provided in the downstream side refrigerant pipe 21 of the liquid refrigerant receiver 13, and a liquid storage container provided in the downstream side refrigerant pipe 21 and the secondary side refrigerant circuit system 5 of the pressure reducing means 307. 43A and 43B are arranged so as to be capable of exchanging heat, and container coolers 309A and 309B for cooling the liquid storage containers 43A and 43B are configured.
As shown in the present embodiment, the delivery pipes 49A and 49B for delivering the refrigerant liquid from the liquid storage containers 43A and 43B are not configured to branch from the siphon pipes 45A and 45B as in the first embodiment, You may make it connect directly to container 43A, 43B.

In the present embodiment, the discharge gas refrigerant bypass circuit 303 and the discharge gas bypass valve 305 are provided as described above so that the discharge refrigerant gas from the compressor 9 can flow by bypassing the condenser 11. The liquid temperature of the primary side refrigerant condensed in the condenser 11 is lowered due to a decrease in temperature, the heating capacity of the gas generating units 47A and 47B by the primary side refrigerant liquid in the liquid refrigerant receiver 13 is reduced, and the secondary side refrigerant When the gasification capacity of the primary side refrigerant may be lowered, the liquid temperature of the primary-side refrigerant can be maintained at a predetermined temperature or higher by opening the discharge gas bypass valve 305 and bypassing the high-temperature discharge refrigerant gas.
Accordingly, it is possible to prevent a decrease in the gas generation amount of the secondary side refrigerant in the gas generation units 47A and 47B, and to ensure the circulation amount of the secondary side refrigerant liquid.

Further, since the container coolers 309A and 309B for cooling the liquid storage containers 43A and 43B are provided so that the liquid storage containers 43A and 43B can be cooled by the primary side refrigerant adiabatically expanded through the decompression means 307. The residual gas in the liquid reservoirs 43A and 43B that sent out the side refrigerant liquid is forcibly cooled and condensed, and the pressure in the liquid reservoirs 43A and 43B is quickly reduced, so that the refrigerant inflow from the cascade condenser 7 can be started. .
Therefore, the responsiveness of the batch switching and sending operation of the secondary side refrigerant can be improved, and the refrigerant circulation performance can be improved.

[Third embodiment]
In the first and second embodiments described above, the configurations of the primary refrigerant circuit systems 3 and 301 are both dedicated refrigerant circuit systems that cool the secondary refrigerant by the cascade condenser 7 to condense and liquefy it. However, the present invention is not limited to this. The primary refrigerant circuit system may be constituted by a refrigerant circuit system in which an air conditioning indoor heat exchanger for air-conditioning the building is arranged in parallel with the cascade capacitor 7.
By making the primary side refrigerant circuit system a refrigerant circuit system provided with the indoor heat exchanger for air conditioning as described above, one unit for indoor air conditioning and one for refrigeration / refrigeration equipment installed indoors. Since it can be covered by the secondary refrigerant type refrigeration apparatus, it can be beneficially applied to air conditioning, freezing, and refrigeration at convenience stores and the like.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the outdoor unit or the condensing unit including the cascade condenser, the refrigerant circulation means, and the like can be appropriately configured, and an appropriate number of evaporators connected to the secondary side refrigerant circuit system can be provided. Moreover, although the gas generation part is arrange | positioned in the primary side refrigerant | coolant receiver, what is necessary is just the structure which can be heat-exchanged with not only this but the primary side high pressure refrigerant | coolant liquid.

1 is a refrigerant system diagram of a secondary refrigerant refrigeration apparatus according to a first embodiment of the present invention. It is a refrigerant | coolant system | strain diagram of the secondary refrigerant | coolant type freezing apparatus concerning the 2nd Embodiment of this invention.

Explanation of symbols

1,101 Secondary refrigerant type refrigeration apparatus 3,301 Primary side refrigerant circuit system 5 Secondary side refrigerant circuit system 7 Cascade condenser 13 Primary side refrigerant receivers 31A, 31B Refrigerant circulation means 35A, 35B Evaporator 39 Downstream pipe 41 Branch pipe 43A , 43B Reservoir 45A, 45B Siphon tube 47A, 47B Gas generator 49A, 49B Delivery tube 51 Check valve 303 Discharge gas refrigerant bypass circuit 305 Discharge gas bypass valve 307 Pressure reducing means 309A, 309B Container cooler

Claims (10)

A primary side refrigerant circuit system and a secondary side refrigerant circuit system using carbon dioxide refrigerant are combined and coupled via a cascade capacitor, and carbon dioxide refrigerant gas of the secondary side refrigerant circuit system is coupled to the primary side refrigerant by the cascade capacitor. In the secondary refrigerant type refrigeration apparatus configured to be condensed and liquefied by exchanging heat with the refrigerant of the circuit system,
A liquid storage container for storing the carbon dioxide refrigerant liquefied by the cascade condenser, and attached to the liquid storage container, when the refrigerant liquid in the liquid storage container reaches a predetermined level, the liquid is discharged, and the refrigerant liquid is A refrigerant circulation means comprising: a siphon tube that is led to the generation unit and heated and gasified by heat exchange with the primary side refrigerant, and the gas pressure is added to the liquid level of the refrigerant in the liquid reservoir and pressurized.
A secondary refrigerant refrigeration apparatus, characterized in that the refrigerant liquid in the liquid reservoir is circulated to the evaporator of the secondary refrigerant circuit system by the refrigerant circulation means.   The secondary refrigerant refrigeration apparatus according to claim 1, wherein the gas generating unit is disposed in a primary refrigerant receiver provided in the primary refrigerant circuit system.   The secondary refrigerant refrigeration apparatus according to claim 1 or 2, wherein a plurality of sets of the refrigerant circulation means are provided in parallel to the secondary refrigerant circuit system.   The secondary refrigerant refrigeration apparatus according to claim 3, wherein the gas generation units in the plurality of refrigerant circulation means are respectively disposed in the primary refrigerant receiver.   The carbon dioxide refrigerant liquefied by the cascade condenser is caused to flow directly down through the flow down pipe to one of the liquid storage containers of the plurality of refrigerant circulation means, and a branch pipe branched from the flow down pipe is provided in the other liquid storage containers. 5. The secondary refrigerant refrigeration apparatus according to claim 3, wherein the secondary refrigerant refrigeration apparatus is flowed down through the refrigerant.   6. The secondary refrigerant refrigeration apparatus according to claim 5, wherein a check valve is provided in each of the flow-down pipe, the branch pipe, and a delivery pipe for delivering the refrigerant liquid from the liquid reservoir.   A pressure reducing means is provided on the primary side refrigerant receiver outlet side of the primary side refrigerant circuit system, and a downstream side refrigerant pipe of the pressure reducing means is disposed so as to be capable of exchanging heat with the liquid reservoir, thereby forming a container cooler. The secondary refrigerant refrigeration apparatus according to any one of claims 2 to 6, The secondary refrigerant type according to any one of claims 1 to 7, wherein a discharge gas refrigerant bypass circuit including a discharge gas bypass valve is provided in parallel with the condenser of the primary refrigerant circuit system. Refrigeration equipment. 9. The secondary according to claim 1, wherein any one of R410A, R404A, propane, butane, isobutane, and ammonia or a mixture thereof is used as the refrigerant in the primary refrigerant circuit system. Refrigerant type refrigeration equipment. The secondary refrigerant refrigeration apparatus according to any one of claims 1 to 9, wherein an air-conditioning indoor heat exchanger for air-conditioning a building is provided in the primary refrigerant circuit system in addition to the cascade capacitor. .