Refrigeration unit

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a cooling device that combines an ammonia refrigeration circuit and a carbon dioxide refrigeration circuit.

【0002】

[Conventional technology]

Conventionally, this type of cooling device is provided with an ammonia refrigeration circuit in which an ammonia refrigerant circulates, a carbon dioxide refrigeration circuit in which a carbon dioxide refrigerant circulates, and a cascade condenser that exchanges heat between the ammonia refrigerant and the carbon dioxide refrigerant. It has been known. The ammonia refrigeration circuit has a compressor, a condenser, an ammonia receiver, an expansion valve, and a cascade condenser in this order, and the carbon dioxide refrigeration circuit has a cascade condenser, a carbon dioxide receiver, and an evaporator in this order. There is. This cooling device is installed in stores such as convenience stores and supermarkets, and has a condensing unit outside the store in which an ammonia refrigeration circuit, a carbon dioxide refrigeration circuit excluding an evaporator, and a cascade condenser are arranged. In addition, the evaporator of the carbon dioxide refrigeration circuit is connected to the condensin unit via a refrigerant pipe and is installed in a showcase or the like indoors of a store, whereby the inside of the showcase or the like is cooled. There is. According to this cooling device, the compressor provided in the ammonia refrigeration circuit is operated to circulate the ammonia refrigerant, the heat of the carbon dioxide refrigerant is taken by the cascade condenser and liquefied, and the liquefied carbon dioxide refrigerant is the evaporator. When it flows into the water, it vaporizes, and the carbon dioxide refrigerant is naturally circulated by liquefaction and vaporization.

【0003】

[Problems to be Solved by the Invention]

However, in the cooling device, when heat exchange is not performed by the cascade condenser, for example, when the pump of the ammonia refrigeration circuit fails, the pressure of the carbon dioxide refrigerant rises excessively and the carbon dioxide refrigeration circuit is overloaded. In this case, it was necessary to ensure the safety.

【0004】

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cooling device for improving safety when the pressure of a carbon dioxide refrigerant rises.

【0005】

[Means for solving problems]

In order to achieve the above object, in claim 1, the present invention performs heat exchange between an ammonia refrigerating circuit in which an ammonia refrigerant circulates, a carbon dioxide refrigerating circuit in which a carbon dioxide refrigerant circulates, and an ammonia refrigerant and a carbon dioxide refrigerant. In a cooling device provided with a cascade condenser and naturally circulating the carbon dioxide refrigerant by liquefaction and vaporization of the carbon dioxide refrigerant, the vaporized carbon dioxide can be released to the outside of the circuit to the portion where the vaporized carbon dioxide circulates in the carbon dioxide refrigeration circuit. A relief valve is provided.

【0006】

As a result, for example, if the relief valve is configured to open when the carbon dioxide refrigerant exceeds a predetermined pressure, the vaporized carbon dioxide is out of the circuit when the pressure of the carbon dioxide refrigerant in the carbon dioxide refrigeration circuit rises excessively. Is released to.

【0007】

Further, in claim 2, in the cooling device according to claim 1, the carbon dioxide refrigeration circuit has an evaporator arranged in a cooling device such as a showcase installed indoors, and the relief valve is provided. Is placed outdoors.

【0008】

As a result, in addition to the action of claim 1, when the vaporized carbon dioxide is released from the relief valve, the vaporized carbon dioxide is released to the outside.

【0009】

Further, according to claim 3, in the cooling device according to claim 2, the condensin unit in which the ammonia refrigeration circuit and the cascade condenser are arranged is provided outdoors, and the relief valve is attached to the condensing unit. It is arranged.

【0010】

As a result, in addition to the operation of claim 2, the relief valve is arranged in the condensin unit together with the ammonia refrigeration circuit and the cascade condenser, so that the ammonia refrigeration circuit, the cascade condenser and the relief valve can be handled integrally.

【0011】

BEST MODE FOR CARRYING OUT THE INVENTION

1 to 3 show an embodiment of the cooling device of the present invention, FIG. 1 is a schematic perspective explanatory view of a store provided with a cooling device showing an embodiment of the present invention, and FIG. 2 is a schematic perspective explanatory view of the cooling device. The schematic circuit diagram and FIG. 3 are schematic explanatory views showing the installation state of the cooling device.

【0012】

As shown in FIG. 1, this cooling device cools the insides of a plurality of showcases S installed indoors of stores such as convenience stores and supermarkets.

【0013】

As shown in FIG. 2, the cooling device 1 has an ammonia refrigerating circuit 2 in which an ammonia refrigerant circulates and a carbon dioxide refrigerating circuit 3 in which a carbon dioxide refrigerant circulates. Further, the ammonia refrigeration circuit 2 and the carbon dioxide refrigeration circuit 3 are provided with a cascade capacitor 4 that exchanges heat between the refrigerants.

【0014】

The ammonia refrigeration circuit 2 has a cascade condenser 4, a compressor 5, a condenser 6, an ammonia receiver 7, and an expansion valve 8 connected in this order by an ammonia refrigerant pipe 9.

【0015】

The carbon dioxide refrigeration circuit 3 has a cascade condenser 4, a carbon dioxide receiver 10, an evaporator 11, and a relief valve 12 connected in this order by a carbon dioxide refrigerant pipe 13. Here, in the circuit diagram of FIG. 2, the carbon dioxide refrigeration circuit 3 is provided with one evaporator 11, but this is a configuration for explanation, and is actually each show. An evaporator 11 is provided for each case S, and each evaporator 11 is connected in parallel.

【0016】

Further, the cascade condenser 4, the compressor 5, the condenser 6, the ammonia receiver 7, the expansion valve 8, the carbon dioxide receiver 10, the relief valve 12, etc. are arranged in the box-shaped condensin unit C. As shown in FIG. 3, this condensin unit C is installed on the roof of the store, and the cascade condenser 4, the carbon dioxide receiver 10, the relief valve 12, etc. are arranged so as to be higher than each evaporator 11. .. That is, in the cooling device of the present embodiment, the carbon dioxide refrigerant vaporizes in the evaporator 11 of the carbon dioxide refrigeration circuit 3 and moves upward, and the carbon dioxide refrigerant liquefies and moves downward in the cascade condenser 4. As a result, the carbon dioxide refrigerant naturally circulates in the refrigeration circuit 3. The carbon dioxide refrigerant inflow side of each evaporator 11 in the carbon dioxide refrigeration circuit 3, that is, the carbon dioxide receiver 10 side is provided with solenoid valves 14 for controlling the flow rate of the refrigerant.

【0017】

The relief valve 12 is provided in a portion where vaporized carbon dioxide circulates in the refrigerating circuit 3 during normal operation of the cooling device 1. In the present embodiment, the relief valve 12 discharges the carbon dioxide refrigerant to the outside of the circuit when the carbon dioxide refrigerant exceeds a predetermined set pressure, and this set pressure is set higher than the pressure during normal operation. There is.

【0018】

In the cooling device configured as described above, if heat exchange is not performed in the cascade condenser 4 due to, for example, the compressor 5 of the ammonia refrigeration circuit 2 failing, the carbon dioxide refrigerant in the carbon dioxide refrigeration circuit 3 The pressure rises. Here, when the pressure of the carbon dioxide refrigerant near the relief valve 12 in the carbon dioxide refrigeration circuit 3 exceeds the set pressure, the carbon dioxide refrigerant is discharged from the relief valve 12 to the outside of the circuit, that is, to the outside.

【0019】

As described above, according to the cooling device of the present embodiment, when the pressure of the carbon dioxide refrigerant rises beyond the set pressure, the vaporized carbon dioxide is released from the relief valve 12 to the outside of the circuit. Even if the pressure rises excessively, an excessive load is not applied to the carbon dioxide refrigeration circuit 3, and it is possible to improve the safety when the pressure of the carbon dioxide refrigerant rises. Moreover, since the vaporized carbon dioxide is released to the outside, the carbon dioxide does not fill the room indoors.

【0020】

Further, since the relief valve 12 is arranged in the condensin unit C together with the ammonia refrigeration circuit 2, the cascade condenser 4, etc., the ammonia refrigeration circuit 2, the cascade condenser 4, the relief valve 12, etc. can be handled integrally, and in practical use. It is extremely advantageous.

【0021】

Further, since the ammonia refrigeration circuit 2 and the cascade condenser 4 are provided outdoors, there is no possibility that ammonia will fill the room indoors in the unlikely event that the ammonia refrigerant leaks from the ammonia refrigeration circuit 2.

【0022】

In the above embodiment, the relief valve 12 is arranged in the condensin unit C, but if the relief valve 12 is arranged in the portion where vaporized carbon dioxide circulates in the carbon dioxide refrigeration circuit, the relief valve is arranged in the condensin unit. It may be placed outside the.

【0023】

Further, in the above-described embodiment, the cooling device 1 is used for cooling the inside of each showcase S, but this cooling device can also be used for other cooling devices such as a cold storage. .. Furthermore, if other cooling equipment such as a cool box is installed together with the showcase in the store, the showcase and other cooling equipment can be connected in parallel by connecting the evaporator of the showcase and the evaporator of other cooling equipment in parallel. It is possible to give a cooling function to the cooling equipment of the above at the same time.

【0024】

[Effect of the invention]

As described above, according to the cooling device according to claim 1, when the pressure of the carbon dioxide refrigerant rises excessively, the vaporized carbon dioxide is released to the outside of the circuit. However, an excessive load is not applied to the carbon dioxide refrigerating circuit even if the amount rises excessively, and it is possible to improve the safety when the pressure of the carbon dioxide refrigerant rises.

【0025】

Further, according to the cooling device according to the second aspect, in addition to the effect of the first aspect, when the vaporized carbon dioxide is released from the relief valve, the vaporized carbon dioxide is released to the outside. Does not fill indoors.

【0026】

Further, according to the cooling device according to claim 3, in addition to the effect of claim 2, the ammonia refrigeration circuit, the cascade condenser and the relief valve can be handled integrally, which is extremely advantageous in practical use.

[Simple explanation of drawings]

[Figure 1]

Schematic perspective view of a store provided with a cooling device showing an embodiment of the present invention. [Figure 2]

Schematic circuit diagram of the cooling device [Fig. 3]

Schematic explanatory view showing the installation state of the cooling device [Explanation of symbols]

1 ... Cooling device, 2 ... Ammonia refrigeration circuit, 3 ... Carbon dioxide refrigeration circuit, 4 ... Cascade capacitor, 11 ... Evaporator, 12 ... Relief valve, S ... Show Case.