Refrigeration system

Details Refrigeration system Refrigeration system

1999-01-21

2001-04-10

Tapolcal, William E. (Department: 3744)

Refrigeration

Plural paired different function refrigeration producing...

Reexamination Certificate

active

06212898

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a refrigeration system employing a primary refrigerant circuit and a secondary refrigerant circuit for the purpose of transferring heat between the primary and secondary refrigerant circuits. This invention particularly pertains to a refrigeration system having a plurality of heat exchangers on the side where refrigerant heat is utilized.
BACKGROUND ART
Various refrigeration systems have been known. One such example of a refrigeration system is disclosed in Japanese Patent Application Kokai (not examined) Gazette No. 5-5567. The apparatus shown in the 5-5567 patent utilizes a binary refrigeration cycle and includes a primary refrigerant circuit through which a primary refrigerant passes and a secondary refrigerant circuit through which a secondary refrigerant passes. The exchanging of heat between the primary refrigerant and the secondary refrigerant takes place in a refrigerant heat exchanger. Such a refrigerant heat exchanger is called a cascade heat exchanger.
Some of refrigeration systems of the above-described type employ multiple secondary refrigerant circuits with respect to one primary refrigerant circuit with a view to providing a great deal of flexibility. This sole primary refrigerant circuit is shared as a source of heat among multiple heat exchangers disposed on the side where refrigerant heat is utilized.
Such a conventional refrigeration system employs a structure comprising a plurality of cooling units disposed on the indoor side. Each cooling unit is provided with an individual secondary refrigerant circuit. In other words, the primary refrigerant circuit includes liquid and gas flow lines which are branched out into liquid and gas flow branch lines. These branch lines are guided to individual cooling units. In each cooling unit, heat is exchanged between primary and secondary refrigerants in the refrigerant heat exchanger.
Each of the cooling units is arranged in series with the liquid flow line of the primary refrigerant circuit. As a result of such arrangement, the primary refrigerant passes through the cooling units in sequence. In each of the cooling units, a heat exchange takes place between primary and secondary refrigerants.
PROBLEMS THAT THE INVENTION INTENDS TO SOLVE
In conventional refrigeration systems, each cooling unit is required to contain an individual refrigerant heat exchanger when a single primary refrigerant circuit is shared as a source of heat among multiple heat exchangers disposed on the side where refrigeration is utilized. This results in the requirement that the same number of refrigerant heat exchangers as the number of secondary refrigerant circuits be prepared.
In addition to the above, each cooling unit is required to individually include a secondary, closed refrigerant circuit made up of a compressor, a condenser, an expansion valve, and a vaporizer. This results in an entire circuit configuration suffering an increased complexity.
Such a conventional refrigeration system is only applicable to refrigerator units each having an individual, closed loop of the above-described type. For instance, in the case the foregoing refrigeration system is applied to frozen display cases, the frozen display cases are provided with their respective cooling units and are coupled to a sole outdoor unit. This means that each frozen display case requires the provision of a refrigerant heat exchanger and a secondary closed refrigerant circuit.
Display cases are generally classified into two categories, namely (a) frozen display cases each containing therein an individual freeze loop and (b) refrigerated display cases each containing therein only a heat exchanger (vaporizer) of a unary refrigeration cycle.
Conventional refrigeration systems can find applications in only frozen display cases completed with freeze loops. This produces the problem that conventional refrigeration systems are inapplicable to cases where multiple display cases requiring different cooling temperatures are employed.
In view of the above-described problems with the prior art techniques, the present invention was made. Accordingly, an object of the present invention is to provide a novel technique capable of providing simplified circuit structures to refrigeration systems each containing a single primary refrigerant circuit that is shared as a source of heat among multiple heat exchangers disposed on the side where refrigerant heat is utilized and of allowing the heat exchangers to be used in various application manners.
DISCLOSURE OF THE INVENTION
In accordance with the present invention, a refrigerant heat exchanger is disposed in only a particular one of cooling units. In addition, a closed loop is composed of the refrigerant heat exchanger and a heat exchanger disposed on the side where refrigeration (produced by the refrigeration system) is utilized.
The present invention provides a first solving means (shown in
FIGS. 3 and 6
) for solving the foregoing problems associated with the prior art techniques. The first solving means of the present invention is directed to a refrigeration system comprising a primary refrigerant circuit (
10
), a secondary refrigerant circuit (
20
), and a refrigerant heat exchanger (
5
) for the exchanging of heat between refrigerant which circulates through the primary refrigerant circuit (
10
) and refrigerant which circulates through the secondary refrigerant circuit (
20
), for the purpose of transferring heat between the primary refrigerant circuit (
10
) and the secondary refrigerant circuit (
20
).
The first solving means of the present invention is characterized in that (a) the secondary refrigerant circuit (
20
) includes heat exchangers (
11
b
,
3
a
) disposed on the side where refrigerant heat is utilized and refrigerant circulates between each of the heat exchangers (
11
b
,
3
c
) and the refrigerant heat exchanger (
5
), (b) the heat exchanger (
11
b
) and the refrigerant heat exchanger (
5
) are placed in a unit (
2
a
), and (c) the heat exchangers (
3
c
) is connected to the refrigerant heat exchanger (
5
) by refrigerant lines (LL-A, GL-A) extending from the unit (
2
a
).
In the first solving means of the present invention, heat is exchanged between the primary refrigerant of the primary refrigerant circuit (
10
) and the secondary refrigerant of the secondary refrigerant circuit (
20
) in the refrigerant heat exchanger (
5
) mounted in the unit (
2
a
). Refrigerant circulates between the heat exchanger (
11
b
) and the refrigerant heat exchanger (
5
) both of which are housed in the unit (
2
a
). At the same time, refrigerant circulates between the other heat exchanger (
3
c
) and the refrigerant heat exchanger (
5
) by way of the refrigerant lines (LL-A, GL-A). The heat exchangers (
11
b
,
3
c
) perform their respective cooling operations.
The heat exchanger (
3
c
), which is located exterior to the unit (
2
a
), uses the refrigerant heat exchanger (
5
) as a source of heat. The refrigerant heat exchanger (
5
) is disposed in the unit (
2
a
).
The present invention provides a second solving means (shown in
FIG. 3
) for solving the foregoing problems associated with the prior art techniques. The second solving means of the present invention is directed to a refrigeration system comprising a primary refrigerant circuit (
10
), secondary refrigerant circuits (
11
,
12
), and a refrigerant heat exchanger (
5
) for the exchanging of heat between refrigerant which circulates through the primary refrigerant circuit (
10
) and refrigerant which circulates through each of the secondary refrigerant circuits (
11
,
12
), for the purpose of transferring heat between the primary refrigerant circuit (
10
) and each of the secondary refrigerant circuits (
11
,
12
).
The second solving means of the present invention is characterized in that: (a) a plurality of the secondary refrigerant circuits (
11
) are provided, a plurality of the secondary refrigerant circuits (
12
) are provided, the secondary refrigerant circuits (
11
) include individual heat exchangers (
11
b
) disposed on the

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