Refrigeration – Plural paired different function refrigeration producing...
Reexamination Certificate
2001-01-19
2002-05-28
Bennett, Henry (Department: 3744)
Refrigeration
Plural paired different function refrigeration producing...
C062S278000
Reexamination Certificate
active
06393858
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a refrigeration system. Particularly, the present invention relates to an improvement of a refrigeration system which is provided in facilities which require a plurality of types of temperature environment, for example, a supermarket, or the like.
BACKGROUND ART
Refrigerated showcases which are provided in a supermarket, or the like, are known in the prior art. A showcase of this type is disclosed in, for example, Japanese Laid-Open Patent Publication No. 62-94785. The showcase includes a refrigerant circuit which is comprised of a compressor, a condenser, an expansion valve and an evaporator which are connected together by a refrigerant pipe. The show case also includes a food display space and an air passageway for producing a cold air.
The evaporator is arranged in the air passageway. A refrigerant which has been discharged from the compressor and condensed in the condenser is depressurized through the expansion valve, and then evaporated by the evaporator while exchanging heat with the air in the air passageway, thereby cooling the air. The cooled air is supplied from the air passageway to the display space to keep the food at a predetermined low temperature. Thus, the freshness of the food is maintained.
The inventors of the present invention have also proposed a refrigeration system which realizes the production of a cold air in a plurality of showcases and general air conditioning in a supermarket store, etc., with a single refrigerating system (Japanese Patent Application No. 9-89164).
The refrigeration system includes a plurality of showcases and an air conditioner for general air conditioning which are connected to a single heat source side unit in parallel to one another. The heat source side unit and each showcase are provided as a secondary refrigerant system. Thus, the above refrigeration system includes a heat source side refrigerant circuit which is comprised of a vapor compression type refrigerating cycle. Each showcase is provided with a user-side refrigerant circuit having a refrigerant heat exchanger for exchanging heat with a refrigerant of the heat source side refrigerant circuit. On the other hand, an evaporator of the heat source side refrigerant circuit is arranged in the general air conditioned room.
Thus, in each showcase, a cold heat of a relatively low temperature (for example, −20° C.) is obtained, whereby the freshness of the food can be maintained. On the other hand, in the general air conditioned room, a cold heat of a temperature higher than that in the showcase (for example, 25° C.) is obtained, whereby the inside of the store can be cooled.
PROBLEMS TO BE SOLVED
The present inventors conducted an in-depth study on how to improve the practicability of a refrigeration system as described above which realizes the production of a cold air in a plurality of showcases with a single refrigerating system. The operations required by each individual showcase include those shown below, and the present inventors gave consideration on how to accommodate those operations with a single refrigerating system.
Specifically, the operations required for a showcase include not only the cooling of the air in the showcase but also a defrost operation for melting frost which is performed when the evaporator is frosted. In the prior art, an electric heater is attached to the evaporator, and the defrosting of the showcase is performed by powering the electric heater.
However, in terms of the energy saving property, so-called “hot gas defrosting”, wherein a refrigerant discharged from the compressor is supplied to the evaporator, is preferred over the defrosting with the electric heater. As described above, each individual showcase may require a cold heat in some cases or may require a hot heat in other cases.
However, where some showcases require a cold heat while the other showcases require a hot heat, these requirements could not be satisfied with prior art circuit configurations.
The present invention has an objective of providing a refrigeration system for performing a so-called “multi-stage cascade refrigerating cycle” as described above, wherein when a plurality of user-side units individually require a hot heat and a cold heat, these requirements can be accommodated with a single refrigerating system.
DISCLOSURE OF THE INVENTION
In order to achieve the above-described object, the first solution includes a plurality of refrigerant heat exchangers for exchanging heat between a heat source side refrigerant and a user-side refrigerant of a multi-stage cascade refrigerating cycle. Each individual refrigerant heat exchanger can be selectively communicated to a high pressure gas pipe, a low pressure gas pipe and a liquid pipe. By selecting the communication state of these pipes, it is possible to individually obtain a heat exchange state for each individual refrigerant heat exchanger.
Specifically, as illustrated in
FIG. 1
, it includes a heat source side refrigerant circuit (
70
) having a plurality of refrigerant heat exchangers (
50
,
60
), and a plurality of user-side refrigerant circuits (
11
,
21
) corresponding to the respective refrigerant heat exchangers (
50
,
60
).
The heat source side refrigerant circuit (
70
) includes compressors (
41
,
42
), first switching means (
43
,
44
), and heat source side heat exchangers (
45
,
46
) which are respectively switched by the first switching means (
43
,
44
) between a state where they are communicated to the discharge side of the compressors (
41
,
42
) and another state where they are communicated to the suction side thereof.
One end of a high pressure gas pipe (LG-H) is connected between the discharge side of the compressors (
41
,
42
) and the first switching means (
43
,
44
). One end of a low pressure gas pipe (LG-L) is connected between the suction side of the compressors (
41
,
42
) and the first switching means (
43
,
44
). One end of a liquid pipe (LL) is connected to the liquid side of the heat source side heat exchangers (
45
,
46
).
The pipes (LG-H, LG-L, LL) at the other end are branched into branch pipes (LG-H
1
, LG-H
2
, LG-L
1
, LG-L
2
, LL
1
, LL
2
), respectively.
One end side of the refrigerant heat exchanger (
50
) of one of the plurality of user-side refrigerant circuits (
11
,
21
) is connected to one of the branch pipes (LL
1
, LL
2
) of the liquid pipe (LL). One end side of the refrigerant heat exchanger (
60
) of the other one of the plurality of user-side refrigerant circuits (
11
,
21
) is connected to the other one of the branch pipes (LL
1
, LL
2
) of the liquid pipe (LL).
The other end side of the one refrigerant heat exchanger (
50
) is configured so as to be switched by second switching means (
52
) between a state where it is communicated to one of the branch pipes (LG-H
1
, LG-H
2
) of the high pressure gas pipe (LG-H) and another state where it is communicated to one of the branch pipes (LG-L
1
, LG-L
2
) of the low pressure gas pipe (LG-L).
On the other hand, the other end side of the other one refrigerant heat exchanger (
60
) is configured so as to be switched by second switching means (
62
) between a state where it is communicated to the other one of the branch pipes (LG-H
1
, LG-H
2
) of the high pressure gas pipe (LG-H) and another state where it i s communicated to the other one of the branch pipes (LG-L
1
, LG-L
2
) of the low pressure gas pipe (LG-L).
In addition, the heat source side refrigerant circuit (
70
) and the user-side refrigerant circuits (
11
,
21
) are configured so that the heat source side refrigerant circulating through the heat source side refrigerant circuit (
70
) and the user-side refrigerants circulating through the user-side refrigerant circuits (
11
,
21
) exchange heat with each other at the refrigerant heat exchangers (
50
,
60
), thereby performing at multi-stage cascade refrigerating cycle.
By this specific element, the heat exchange state at the respective refrigerant heat exchangers (
50
,
60
) can be desirably changed through a switching operation of the first switch
Mezaki Takenori
Ueno Akitoshi
Ali Mohammad M
Bennett Henry
Daikin Industries Ltd.
Nixon & Peabody LLP
Studebaker Donald R.
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