Refrigeration – Plural paired different function refrigeration producing...
Reexamination Certificate
2000-08-25
2001-10-09
Tapolcai, William E. (Department: 3744)
Refrigeration
Plural paired different function refrigeration producing...
Reexamination Certificate
active
06298683
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a refrigeration system and more particularly to a technique for continuation of refrigeration operation in the event that a heat source equipment stops in a two-stage cascade refrigerating cycle refrigeration system.
BACKGROUND ART
As disclosed in Japanese Unexamined Patent Gazette No. H09-210515, there is a conventional refrigeration system which is formed into a two-stage cascade refrigerating cycle of the vapor compression type by connecting together a high temperature-side refrigerant circuit and a low temperature-side refrigerant circuit through a refrigerant heat exchanger. More specifically, the high temperature-side refrigerant circuit, on the one hand, comprises a closed circuit formed by sequential connection, established by refrigerant piping, of a compressor, a heat source-side heat exchanger, an expansion valve, and an evaporation portion of a refrigerant heat exchanger. On the other hand, the low temperature-side refrigerant circuit comprises a closed circuit formed by sequential connection, established by refrigerant piping, of a compressor, a condensation portion of the refrigerant heat exchanger, an expansion valve, and an application-side heat exchanger.
Such a two-stage cascade refrigerating cycle refrigeration system finds applications in refrigerating apparatus such as showcases for foods or the like installed at stores (e.g., super markets and convenience stores). Defined in such a showcase are a display space for frozen foods in the showcase chamber and an air passage for the circulation of air with the display space. The application-side heat exchanger, which is disposed in the air passage, is able to provide a supply of air into the showcase chamber with the aid of an air blower.
During the operation of the showcase, refrigerants are circulated in the high temperature-side refrigerant circuit and in the low temperature-side refrigerant circuit, wherein heat exchange is carried out between the refrigerants of these two refrigerant circuits in the refrigerant heat exchanger. With regard to the low temperature-side refrigerant circuit, a refrigerant discharged out of the compressor condenses in the refrigerant heat exchanger, decompresses in the expansion valve, and thereafter evaporates by heat exchange with air flowing through the air passage in the application-side heat exchanger in the showcase, whereby the air is cooled. Then, the cooled air is supplied, through the air passage, into the display space in the showcase chamber. In this way, foods are preserved at a predefined low temperature to maintain their freshness.
However, in such a conventional showcase constructed in the way described above, the operation will be brought into a stop when there occurs a failure in some equipment on the heat source side (e.g., the compressor), even though the application-side equipments are normally operating. There are some possible means of coping with such stoppage, one of which is to transfer the goods to another showcase that remains in operation. This, however, results in an increase in the load of refrigerating/cooling, therefore producing the problem of making it impossible to maintain the quality of goods at a satisfactory level. Particularly, in the case a freezing showcase stops, this produces the problem that the stored goods cannot be preserved at a satisfactory level of quality even when transferred into a cold storage showcase.
Bearing in mind the above-described problems, the present invention was made. Accordingly, an object of the present invention is to maintain the quality of goods by achieving continuation of refrigeration operation even when a heat source-side equipment stops in a two-stage cascade refrigerating cycle refrigeration system applied to a showcase or the like.
DISCLOSURE OF INVENTION
In accordance with the present invention, even when in a two-stage cascade refrigerating cycle refrigeration system an equipment on the heat source side stops, the operation can be continued by temporarily providing a supply of refrigerant from a refrigeration circuit disposed in, for example, air conditioning apparatus to a refrigerant heat exchanger of the refrigeration system.
The present invention provides first solving means comprising a first refrigeration circuit (
1
) for a refrigerating apparatus (
6
A) which is formed into a two-stage cascade refrigerating cycle by establishing connection between a high temperature-side refrigerant circuit (
3
) and a low temperature-side refrigerant circuit (
4
) through a refrigerant heat exchanger (
5
), and a second refrigeration circuit (
2
) which is formed into a refrigerating cycle different from that of the first refrigeration circuit (
1
). A liquid piping line (
15
a
) of the high temperature-side refrigerant circuit (
3
) and a liquid piping line (
36
a
) of the second refrigeration circuit (
2
) are connected together through a first connection piping line (
41
) and a suction-side gas piping line (
15
b
) of the high temperature-side refrigerant circuit (
3
) and a suction-side gas piping line (
36
b
) of the second refrigeration circuit (
2
) are connected together through a second connection piping line (
42
), and the first solving means further comprises switching means (
43
,
44
) for selective circulation of a refrigerant of the second refrigeration circuit (
2
) to the refrigerant heat exchanger (
5
) of the first refrigeration circuit (
1
) through each of the connection piping lines (
41
,
42
).
The second refrigeration circuit (
2
) is not limited to a refrigeration circuit for air conditioning apparatus. In the first solving means, any other refrigeration circuit of any refrigerating cycle provided in the facilities where a refrigeration system of the present invention is installed may be employed. However, in second solving means of the present invention, the second refrigeration circuit (
2
) is a refrigeration circuit for air conditioning apparatus.
The present invention further provides third solving means according to the first solving means, in which the refrigerant heat exchanger (
5
) is able to provide a supply of air to the chamber inside of the refrigerating apparatus (
6
A) by means of an air blower. In such a construction, the refrigerant heat exchanger (
5
) may be arranged either in the chamber inside of the refrigerating apparatus (
6
A) or in a position facing the chamber inside thereof for a direct supply of air. Alternatively, an arrangement may be made in which the refrigerant heat exchanger (
5
) is disposed exterior to the chamber of the refrigerating apparatus (
6
A) to provide a supply of air to the chamber inside through a duct or the like.
The present invention further provides fourth solving means according to the first solving means, in which the first refrigeration circuit (
1
) has an application-side heat exchanger (
19
) connected in parallel to the refrigerant heat exchanger (
5
).
The present invention further provides fifth solving means according to the first solving means, in which the second refrigeration circuit (
2
) is formed into a single-stage refrigerating cycle.
The present invention further provides sixth solving means comprising a plurality of refrigeration circuits (
1
) for refrigerating apparatus (
6
A,
6
B), wherein each of the plurality of refrigeration circuits (
1
) is formed into a two stage cascade refrigerating cycle by establishing connection between a high temperature-side refrigerant circuit (
3
) and a low temperature-side refrigerant circuit (
4
) through a refrigerant heat exchanger (
5
) and wherein the high temperature-side refrigerant circuit (
3
) has an application-side heat exchanger (
19
) connected in parallel to the refrigerant heat exchanger (
5
).
The present invention provides seventh solving means according to the sixth solving means, wherein the application-side heat exchangers (
19
) included in the high temperature-side refrigerant circuits (
3
) of the plurality of refrigeration circuits (
1
) each are able to provide a supply of air to the chamber in
Kondo Isao
Mezaki Takenori
Ueno Akitoshi
Ali Mohammad M
Daikin Industries Ltd.
Nixon & Peabody LLP
Studebaker Donald R.
Tapolcai William E.
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