JP2513165Y2 - Multi-source refrigerator - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-source refrigerating device in which a plurality of refrigerators are connected in multiple stages, and more particularly to an improved one for performing efficient defrosting.

[0002]

2. Description of the Related Art Recently, the freezing storage temperature of fresh fish such as tuna has been as low as -60 to -70 ° C, and when cooling a fresh fish storage to such a low temperature, a multi-source freezing device is used. Used. In this multi-source refrigeration system, while cooling the condenser of the high-side refrigerator with cooling water, this high-side cooling coil is used as a condenser for condensing the refrigerant gas discharged from the compressor of the low-side refrigerator. By connecting and connecting a plurality of refrigerators by a heat exchanger, the heat load of the freezer or the like can be cooled to a low temperature by the cooler on the lower side.

By the way, in such a multi-source refrigeration system, defrosting of the cooler is mainly performed by an electric heater or water sprinkling defrost, and even when hot gas defrost is used, the low-temperature side that contributes to cooling. Was performed only by the heat source of the refrigerant.

[0004]

By the way, if defrosting is performed only by the heat source of the low-side refrigerant (CFC 13, CFC 23, or other refrigerant), the refrigerant on the low-source side has the nature of the refrigerant. Since only the sensible heat portion can be used, problems such as defrost failure and long defrost time occur particularly in an apparatus using a large-sized cooler.

This is because of the following reasons. As shown in the Mollier diagram in the dual refrigeration system using the low-source side refrigerator and the high-source side refrigerator in FIG. 3, a portion of the low-source side refrigerant state that can be used as a heat source for defrost (shown by a chain line) ) Is a portion A to B on the diagram, and it can be seen that only the sensible heat portion of the total amount of heat of condensation of the refrigerant is shown. This is because, for example, when Freon 23 (R-23) is used as the low temperature side refrigerant, the condensation temperature is −26 ° C. and the melting temperature of frost is 0.
Since it is lower than ° C, points A and below in the figure cannot be used.

Further, even if the design is made to utilize the sensible heat of the refrigerant up to the point A (+ 10 ° C.), the point A may be shifted to the point F side due to load fluctuations such as the degree of frost, and Becomes negative, it becomes easy to cause a defrost defect.

Further, the total amount I1 (6
18% of heat of condensation I2 (1 Kcal / kg) (11 Kcal / kg)
Since only kg) is available, the defrost time will be long.

The present invention has been proposed in order to solve the problems of the prior art as described above, and an object thereof is to provide a multi-source refrigeration system capable of efficiently performing defrosting in a short time. To do.

[0009]

In order to achieve this object, the multi-source refrigeration system according to the present invention has a discharge of a high-side compressor.
By the hot gas supply pipe with a solenoid valve in the middle of the side
Connect to the drain pan heating coil of the cooler on the lowest
Connect the outlet of the coil to the heating coil of the cooler, and
The outlet of the heat coil is connected to the high side through the defrost heat exchanger.
Connected to the suction side of the compressor, the lowest discharge side of the compressor
With a hot gas supply pipe equipped with a solenoid valve in the middle
Connected to the cooling coil inlet of the cooler, the lowest source and the higher source side
Defrosting the cooler by hot gas discharged from the compressor
It is configured so that

[0010]

[0011]

When the heat source of the high temperature side refrigerant is used for defrosting, all the heat of condensation from point a to point d can be used as shown in the Mollier diagram of FIG. For example, when Freon 502 (R-502) is used as the refrigerant,
The refrigerant condensation heat quantity I3 of 33 Kcal / kg can be used.

Although the ratio of the refrigerant circulation amount on the low side to the high side varies depending on the operating state and the size of the cascade condenser, the ratio of the refrigerant circulation amount in the state of FIG. 3 is approximately as follows. . High source side: Low source side = 265: 100 Compared to the case where only the low heat source side refrigerant heat amount is used, when the high heat source side refrigerant heat amount is used for defrosting, about 7.9.
If the heat quantity of the low-side refrigerant is doubled, the heat quantity of about 8.9 times can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the multi-source refrigerating apparatus according to the present invention will be described below in detail with reference to the drawings. An example of a multi-source refrigeration system configured as a dual refrigeration system is shown in the system diagram of FIG. In this figure, the discharge pipe extending from the high-pressure side compressor 1 is connected to a water-cooled condenser 2, and the outlet of this condenser 2 is connected to an evaporation coil 4 a of a cascade condenser 4 via an expansion valve 3. It The outlet of the evaporation coil 4a is connected to the high-pressure compressor 1 by a suction pipe.

Further, the discharge pipe of the low side compressor 5 on the low side is
It is connected to the cascade condenser 4 via the oil separator 6, and the outlet of this condenser 4 is connected to the cooling coil 8 a of the cooler 8 via the expansion valve 7. This cooling coil 8a
The outlet of is connected to the low-grade compressor 5 via a liquid separator 9 and a suction pressure adjusting valve 10 by a suction pipe. Note that 11, 1
2 is a pressure protection container.

Next, a connection system for defrost will be described. The discharge port of the high-grade compressor 1 has a high-grade hot gas supply pipe 14 provided with a high-grade hot gas supply solenoid valve 13 in the middle thereof.
Is connected to the drain pan temperature raising coil 15a installed in the drain pan 15 of the cooler 8.
The outlet of a is connected to the heating coil 16 installed in the cooler 8 so as to wrap the cooling coil 8a. The outlet of the heating coil 16 is connected to a defrost air heat exchanger 18 via a refrigerant flow rate adjusting valve 17. The outlet of this heat exchanger 18 is connected to the suction pipe of the high-pressure compressor 1. Heat exchanger 1
8 may be configured by other methods than the pneumatic method.

Also, the oil separator 6 on the discharge side of the low-pressure compressor 5
The outlet of is connected to the inlet of the cooling coil 8a by a low-side hot gas supply pipe 20 provided with a low-side hot gas supply solenoid valve 19 in the middle.

In the multi-source refrigerating apparatus U1 thus constructed, the gas refrigerant from the high-pressure compressor 1 is condensed by the cooling water in the condenser 2 during the refrigerating operation, and the liquid refrigerant discharged from the condenser 2 is expanded by the expansion valve. It is sent to the coil 4a of the cascade condenser 4 via 3 and evaporated in the coil 4a.
By this evaporation action, the gas refrigerant from the low-pressure compressor 5 is condensed, and the liquefied refrigerant passes through the expansion valve 7 and the cooling coil 8a.
By being sent to, the cooling device 8 cools the heat load of the freezer warehouse N and the like.

On the other hand, at the time of defrosting, the hot gas refrigerant that has flowed out of the high-pressure compressor 1 as shown by the arrow of the refrigerant flows through the solenoid valve 13 and the hot gas supply pipe 14 into the drain pan temperature raising coil 15a. After warming 15, it is sent to the heating coil 16. As a result, these parts are usually heated from 10 ° C. to 15 ° C. and defrosted. The refrigerant liquid condensed at the time of defrosting is decompressed by the refrigerant flow rate adjusting valve 17 after exiting the heating coil 16, and is supplied to the defrost air heat exchanger 18. The refrigerant evaporated and gasified in the heat exchanger 18 is returned to the high-pressure compressor 1 by the suction pipe.

The hot gas refrigerant discharged from the low-pressure compressor 5 is sent to the cooling coil 8a through the solenoid valve 19 and the hot gas supply pipe 20. As a result, this cooling coil 8a
The part is warmed up to about 10 ° C. and defrosted. The refrigerant discharged from the cooling coil 8a is returned to the low-grade compressor 5 via the liquid separator 9.

Here, 15 times per defrost cycle
If about a minute of time is allotted, the hot gas refrigerant from the high-pressure compressor 1 is sent to the cooler 8 for defrosting in about 10 minutes in the first half, and the low-pressure compressor 5 in the latter half for about 5 minutes.
By sending the hot gas refrigerant from the high-pressure compressor 1 to the cooler 8 and performing defrosting, the defrosting of the cooler 8 can be performed efficiently in a short time.

Next, another embodiment shown in FIG. 2 will be described. In this embodiment, the cooler 8 is defrosted only with the hot gas from the high-source compressor 1, and the hot gas supply pipe 20 connecting the low-source compressor 5 and the cooling coil 8a is omitted. Has been.

The present invention is not limited to the two-way refrigerator, but can be applied to a three-way refrigerator composed of a low-source refrigerator, a middle-source refrigerator and a high-source refrigerator.

[0023]

As described above, according to the present invention, since the heat source of the high-side refrigerant whose condensation temperature is high (for example, + 40 ° C.) can be used for the defrost, the defrost failure does not occur, and the cooler is excellent. Can defrost. In addition, by utilizing the heat quantity of the high-source side refrigerant and using the sensible heat part of the condensation heat quantity of the low-source side refrigerant together, a larger heat quantity can be secured compared to the conventional one, and the defrost time can be greatly shortened. You can

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a multi-source refrigeration system according to the present invention.

FIG. 2 is a system diagram showing a multi-source refrigeration system of another embodiment.

FIG. 3 is a Mollier diagram showing a refrigerant state in the dual refrigeration system.

[Explanation of symbols]

 1 High-source compressor 2 Water-cooled condenser 3, 7 Expansion valve 4 Cascade condenser 4a Evaporation coil 5 Low-source compressor 6 Oil separator 8 Cooler 8a Cooling coil 9 Liquid separator 10 Suction pressure control valve 11, 12 Pressure protection container 13 High Side Hot Gas Supply Solenoid Valve 14 High Side Hot Gas Supply Pipe 15 Drain Pan 15a Drain Pan Temperature Coil 16 Heating Coil 17 Refrigerant Flow Rate Control Valve 18 Defrost Air Heat Exchanger 19 Low Side Hot Gas Supply Solenoid Valve 20 Low source hot gas supply pipe

Claims (1)

(57) [Scope of utility model registration request] 1. A multiple refrigeration devices coupled in multiple stages in cascade condenser which forms a a plurality of the refrigerator condenser, the discharge side of the compressor of the high-stage-side, the hot gas feed pipe provided with a solenoid valve in the middle part By the lowest source side of the cooler drain pan rise
Connect it to the hot coil and connect the outlet of this coil to the heating coil of the cooler.
And the defrost heat exchanger at the outlet of this heating coil.
Connect it to the suction side of the compressor on the high
The discharge side of the compressor is a hot gas with a solenoid valve in the middle.
Connected to the cooling coil inlet of the cooler by
A multi-source refrigeration system characterized in that the cooler can be defrosted by hot gas discharged from the low-source and high-source compressors.