JP2002228283A - Cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device for reducing manufacturing costs and operating costs. SOLUTION: By installing a condensing unit C having a cascade condenser on the housetop of a shop, the cascade condenser is arranged at a higher position than an evaporator 11 in each showcase S. As a result, a carbon dioxide refrigerant in a carbon dioxide circuit is naturally circulated by liquefying and vaporizing the dioxide carbon refrigerant, thus eliminating the need for providing a driving means such as a pump at the carbon dioxide circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device combining an ammonia refrigeration circuit and a carbon dioxide refrigeration circuit.

[0002]

2. Description of the Related Art Conventionally, as this type of cooling device, an ammonia refrigeration circuit for circulating an ammonia refrigerant, a carbon dioxide refrigeration circuit for circulating a carbon dioxide refrigerant, and a cascade condenser for exchanging heat between the ammonia refrigerant and the carbon dioxide refrigerant. And those with The ammonia refrigeration circuit has a cascade condenser, a compressor, a condenser, an ammonia receiver, and an expansion valve in this order, and the carbon dioxide refrigeration circuit has a cascade condenser, a carbon dioxide receiver, a pump, and an evaporator in this order. . The evaporator of the carbon dioxide refrigeration circuit is arranged in a showcase installed in a convenience store or the like, and cools the inside of the showcase storage by the evaporator. In this cooling device, the compressor provided in the ammonia refrigeration circuit is operated to circulate the ammonia refrigerant, and the heat of the vaporized carbon dioxide is removed by the cascade condenser into liquefied carbon dioxide. Given to become vaporized carbon dioxide.

[0003]

However, in the cooling device, since a pump for circulating the carbon dioxide refrigerant is provided in the carbon dioxide refrigeration circuit, not only the number of parts is increased and the manufacturing cost of the device is increased, but also the pump is not used. There is a problem that the operation cost of the device increases because power or the like is consumed at the time of driving.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a cooling device that can reduce the manufacturing cost and the operating cost.

[0005]

In order to achieve the above object, according to the present invention, there is provided an ammonia refrigeration circuit in which an ammonia refrigerant circulates, and a carbon dioxide refrigeration circuit in which a carbon dioxide refrigerant circulates and has an evaporator. A cascade condenser for exchanging heat between an ammonia refrigerant and a carbon dioxide refrigerant, wherein the evaporator is arranged in a cooling device installed indoors, and the cooling device naturally circulates the carbon dioxide refrigerant by liquefaction and vaporization of the carbon dioxide refrigerant. In the apparatus, the cascade condenser is provided at a position higher than the evaporator.

Accordingly, the carbon dioxide refrigerant is liquefied by the cascade condenser and moves downward, and is vaporized by the evaporator and moves upward. Therefore, the carbon dioxide refrigerant can be naturally circulated without providing a refrigerant transport means such as a pump in the carbon dioxide refrigeration circuit.

According to a second aspect of the present invention, in the cooling device according to the first aspect, the carbon dioxide refrigeration circuit has a liquid receiver, and the ammonia refrigeration circuit and the liquid receiver of the carbon dioxide refrigeration circuit are provided. And the cascade condenser are provided, and a condensing unit connected to the evaporator by a refrigerant pipe is provided.

Thus, in addition to the function of the first aspect, in the assembly of the cooling device to a store or the like, the condensing unit is installed at an arbitrary place, and the condensing unit is connected to an evaporator provided in a showcase or the like by piping. It is done by doing.

According to a third aspect of the present invention, in the cooling device according to the second aspect, the condensing unit is provided outdoors.

Thus, in addition to the function of claim 2, even if the ammonia refrigerant leaks from the ammonia refrigeration circuit, the ammonia flows out to the outside.

[0011]

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

As shown in FIG. 1, this cooling device cools a plurality of showcases S installed indoors of a store such as a convenience store or a supermarket.

As shown in FIG. 2, the cooling device 1 has an ammonia refrigeration circuit 2 in which an ammonia refrigerant circulates, and a carbon dioxide refrigeration circuit 3 in which a carbon dioxide refrigerant circulates. The ammonia refrigeration circuit 2 and the carbon dioxide refrigeration circuit 3 are provided with a cascade condenser 4 for exchanging heat between the refrigerants.

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

The carbon dioxide refrigeration circuit 3 has a cascade condenser 4, a carbon dioxide receiver 10, and an evaporator 11 connected in this order by a carbon dioxide refrigerant pipe 12.
Here, in the circuit diagram of FIG. 2, the one in which one evaporator 11 is provided in the carbon dioxide refrigeration circuit 3 is illustrated, but this is a configuration for explanation, and in actuality, each showcase Each evaporator 11 is provided, and the evaporators 11 are connected in parallel.

The cascade condenser 4, the compressor 5, the condenser 6, the ammonia receiver 7, the expansion valve 8, the carbon dioxide receiver 10 and the like are installed in a box-shaped condensing unit C. As shown in FIG. 3, the condensing unit C is installed on the roof of a store, and the cascade condenser 4, the carbon dioxide receiver 10, and the like are arranged at a higher position than each evaporator 11. An electromagnetic valve 13 for controlling the refrigerant flow rate is provided on the carbon dioxide refrigerant inflow side of each evaporator 11 in the carbon dioxide refrigeration circuit 3, that is, on the carbon dioxide receiver 10 side.

In the cooling device configured as described above, when cooling each showcase S, the compressor 5 of the ammonia refrigeration circuit 2 is operated to operate the cascade condenser 4.
The heat of the carbon dioxide refrigerant is removed to liquefy the carbon dioxide refrigerant, and the carbon dioxide refrigerant is circulated to the evaporator 11 by its own weight.
When the liquefied carbon dioxide refrigerant flows into the evaporator 11 and is given heat, the carbon dioxide refrigerant is vaporized and rises to the cascade condenser 4 side.

As described above, according to the cooling device of the present embodiment, the cascade condenser 4 is provided at a position higher than the evaporator 11, so that the carbon dioxide refrigerant is liquefied and vaporized.
The carbon dioxide refrigerant in the carbon dioxide refrigeration circuit 3 can be naturally circulated. Therefore, it is not necessary to provide a driving means such as a pump in the carbon dioxide refrigeration circuit 3 as in the conventional case, and to circulate the carbon dioxide refrigerant forcibly. Therefore, the number of parts can be reduced and the manufacturing cost can be reduced. In addition, since electric power or the like for driving the pump or the like is not required, the operating cost can be reduced.

Further, according to the cooling device of this embodiment, the ammonia refrigeration circuit 2 is installed in the condensing unit C.
And each part of the carbon dioxide refrigeration circuit 3 except for the evaporator 11 are installed and integrally configured. Therefore, when the cooling device is installed in the store, the condensing unit C may be installed at an arbitrary place in the store and connected to the showcase S having the evaporator 11 therein by piping. It can be dramatically improved. Furthermore, since the condensing unit C is provided outdoors, there is no possibility that the inside of the room will be filled with ammonia if the ammonia refrigerant leaks from the ammonia refrigeration circuit 2.

In the above embodiment, the condensing unit C is provided on the roof of a store.
If the cascade condenser 4 is located at a position higher than each evaporator 11, the same operation and effect as in the previous embodiment can be obtained even if it is provided on the side of the store.

In the above embodiment, the cooling device 1 is used for cooling the inside of each showcase S. However, this cooling device is used for other cooling devices such as a cool box. You can also. Furthermore, when other cooling equipment such as a cool box is installed together with the showcase in the store, the showcase and other cooling equipment are connected in parallel to form the showcase and other cooling equipment. Cooling device can be provided with a cooling function at the same time.

Further, in the above embodiment, one cooling device 1 is provided with a plurality of evaporators 11, but it is needless to say that one cooling device 1 may be provided with one evaporator. is there.

[0023]

As described above, according to the cooling device of the first aspect, the carbon dioxide refrigerant can be naturally circulated without providing a pump or the like in the carbon dioxide refrigeration circuit. As described above, it is not necessary to provide a driving means such as a pump in the carbon dioxide refrigeration circuit, and it is not necessary to forcibly circulate the carbon dioxide refrigerant, so that the number of parts can be reduced and the production cost can be reduced. In addition, since electric power or the like for driving the pump or the like is not required, the operating cost can be reduced.

According to the cooling device of the second aspect,
In addition to the effect of claim 1, the installation of the cooling device in stores and the like,
The condensing unit is installed at an arbitrary location such as a store, and is connected by piping to a showcase or the like that has a built-in evaporator, so that the cooling device can be easily assembled to the store, etc. Adhesion can be dramatically improved.

According to the cooling device of the third aspect,
In addition to the effect of the second aspect, since the condensing unit is provided outdoors, there is no possibility that the inside of the room will be filled with ammonia if the ammonia refrigerant leaks from the ammonia refrigeration circuit.

[Brief description of the drawings]

FIG. 1 is a schematic perspective explanatory view of a store provided with a cooling device according to an embodiment of the present invention.

FIG. 2 is a schematic circuit diagram of a cooling device.

FIG. 3 is a schematic explanatory view showing an installation state of a cooling device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cooling apparatus, 2 ... Ammonia refrigeration circuit, 3 ... Carbon dioxide refrigeration circuit, 4 ... Cascade condenser, 10 ... Carbon dioxide receiver, 11 ... Evaporator, S ... Showcase.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norio Kojima 3584-1, southern Hongo, Miyazaki-shi, Miyazaki Pref.

Claims (3)

[Claims] An ammonia refrigeration circuit for circulating an ammonia refrigerant, a carbon dioxide refrigeration circuit for circulating a carbon dioxide refrigerant and having an evaporator, and a cascade condenser for exchanging heat between the ammonia refrigerant and the carbon dioxide refrigerant, An evaporator is disposed in a cooling device installed indoors, and in a cooling device that naturally circulates the carbon dioxide refrigerant by liquefaction and vaporization of the carbon dioxide refrigerant, the cascade condenser is provided at a position higher than the evaporator. And cooling device. 2. The carbon dioxide refrigeration circuit has a receiver, wherein the ammonia refrigeration circuit, the receiver of the carbon dioxide refrigeration circuit, and the cascade condenser are installed, and the evaporator is The cooling device according to claim 1, further comprising a condensing unit connected by a refrigerant pipe. 3. The cooling device according to claim 1, wherein the condensing unit is provided outdoors.