JPH0664071U - Multi-source refrigerator - Google Patents

Abstract

(57) [Summary] [Objective] To provide a multi-source refrigeration system capable of enhancing refrigeration efficiency. [Structure] In a multi-source refrigeration system in which a plurality of refrigerators are connected in multiple stages by a cascade condenser forming a condenser, a discharge pipe extending from a compressor 1 on the highest source side is connected to a condenser 2, and an outlet of the condenser 2 The suction side heat exchanger 16 with the pipe line at the lowest side
And the outlet pipe of the suction side heat exchanger 16 is connected via the expansion valve 4 to the condenser coil 5 of the middle cascade condenser 5.
a, the outlet of the condensing coil 5a is connected to the suction side of the compressor 1 on the highest source side by a suction pipe, and the discharge pipe extending from the compressor 10 on the lowest source is connected to the low source cascade condenser 9
To the cooling coil 13a of the cooler 13 via the expansion valve 12, and the outlet of the cooling coil 13a to the heat radiation coil 16a of the suction side heat exchanger 16. Connect this heat dissipation coil 16
The outlet of a was connected to the suction side of the lowest compressor 15 by a suction pipe.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a multi-source refrigerating device used in an ultra-low temperature device for cooling to -100 ° C. or lower, and more particularly to a multi-source refrigerating device improved to enhance the refrigerating effect of a high-grade refrigerator.

[0002]

[Prior art]

 In a multi-source refrigeration system, the condenser of the high-side refrigerator is cooled by cooling water, and this high-side cooling coil condenses the refrigerant gas discharged from the compressor of the low-side refrigerator. It is possible to cool the cooler on the low side to a very low temperature by connecting it to the condenser and connecting multiple refrigerators with a heat exchanger.

FIG. 3 shows the configuration of this conventionally known multi-source refrigeration system. In this figure, the discharge pipe extending from the high pressure compressor 1 is connected to a high temperature condenser 2 to which cooling water is externally supplied to a coil 2a, and the outlet of this condenser 2 is a high temperature intermediate cooler 3, It is connected via the expansion valve 4 to the inlet of the evaporation coil 5a of the medium cascade condenser 5. The outlet of the evaporation coil 5a is connected to the suction side of the high-pressure compressor 1 by a suction pipe.

The discharge pipe of the middle-source compressor 6 is connected to the middle-source cascade condenser 5, and the outlet of the cascade condenser 5 passes through the middle-source intake heat exchanger 7 and the expansion valve 8 to the low-source cascade condenser 9 Is connected to the inlet of the evaporation coil 9a. The outlet of the evaporation coil 9a passes through the heat radiating coil 7a of the medium intake heat exchanger 7 and is connected to the intake side of the medium compressor 6 by an intake pipe.

Further, the discharge pipe of the low-source compressor 10 is connected to the low-source cascade condenser 9, and the outlet of the cascade condenser 9 cools the cooler 13 via the low-source intake heat exchanger 11 and the expansion valve 12. It is connected to the inlet of the coil 13a. The outlet of the cooling coil 13a passes through the heat dissipation coil 11a of the low-source intake heat exchanger 11 and is connected to the intake side of the low-source compressor 10 by an intake pipe. In the figure, 14 and 15 are pressure protection containers.

In the multi-source refrigeration system configured as described above, the gas refrigerant from the high-grade compressor 1 is condensed by the cooling water in the high-grade condenser 2 during the refrigeration operation, and the liquid refrigerant exiting from the condenser 2 is condensed. By being sent to the coil 5a of the medium cascade capacitor 5 via the expansion valve 4, the vapor is evaporated in the coil 5a. Due to this evaporation action, the gas refrigerant from the middle compressor 6 is condensed, and the liquefied refrigerant is sent to the coil 9a of the low-stage cascade condenser 9 through the expansion valve 8 to be evaporated in the coil 9a. By this evaporating action, the gas refrigerant from the low-pressure compressor 10 is condensed, and the liquid refrigerant is sent to the cooling coil 13a via the expansion valve 12, whereby the cooler 13 cools the heat load of the freezer or the like. Be done.

In addition, in the suction heat exchangers 7 and 11 provided on the low side and the medium side, the refrigerating effect is enhanced by exchanging heat between the suction gas and the liquid refrigerant, respectively.

In such a multi-source refrigerator, the heat taken by the low-end refrigerator becomes the heat load of the middle-source refrigerator, and the heat load of the middle-source refrigerator becomes the heat load of the high-source refrigerator, It is possible to set the cooling temperature by the cooler 13 on the low-source refrigerator side to an ultra-low temperature.

[0009]

[Problems to be solved by the device]

 By the way, the evaporation temperature of the refrigerant in the cooler 13 on the low temperature side is as low as −100 ° C. or lower, and if such a low temperature refrigerant is directly returned to the low temperature compressor 10, it causes malfunction of the compressor 10. From the viewpoint of protecting the compressor 10, it is necessary to heat the refrigerant to about -60 ° C.

Therefore, in the conventional multi-source refrigeration system, in addition to exchanging heat of the low-side refrigerant with the liquid refrigerant in the suction heat exchanger 11, heat is radiated in the middle of the pipe connected to the suction port of the compressor 10, and the refrigerant is cooled. Was returned to the compressor 10 after the temperature was raised.

Therefore, there arises a problem that the refrigeration efficiency is reduced by the amount of heat released from the refrigerant in the middle of the piping.

FIG. 4 shows a Mollier diagram in the conventional multi-source refrigeration system. In the figure, Δi3 is the enthalpy for radiating and raising the temperature during pipe distribution, and Δi1 (= Δi2) is the enthalpy for the supercooling that radiates heat in the heat exchanger 11.

The present invention has been proposed in order to solve the problems of the conventional techniques, and an object of the present invention is to provide a multi-source refrigeration system capable of enhancing refrigeration efficiency.

[0014]

[Means for Solving the Problems]

 In order to achieve this object, the present invention is a multi-source refrigeration system in which multiple refrigerators are connected in multiple stages with a cascading condenser forming a condenser, and the discharge pipe extending from the compressor on the highest source side is connected to the condenser. Then, connect the outlet line of this condenser to the lowest inlet side heat exchanger, and connect the outlet line of this inlet side heat exchanger to the evaporation coil of the first cascade condenser via the expansion valve. , The outlet of this evaporation coil is connected to the suction side of the compressor on the top side by a suction pipe, and the discharge pipe extending from the compressor of the lowest side is connected to the second cascade condenser. The outlet pipe is connected to the cooling coil of the cooler via the expansion valve, the outlet of this cooling coil is connected to the heat radiation coil of the suction side heat exchanger, and the outlet of the heat radiation coil is connected to the lowest source side by the suction pipe. Inhalation of compressor There is a configuration in which to connect to.

When this multi-source refrigerating device forms a three-way refrigerating device in which a low-source refrigerating machine, a middle-source refrigerating machine, and a high-source refrigerating machine are connected, the compressor on the highest source side corresponds to the high-source compressor, and The cascading capacitor of corresponds to the Nakamoto cascade capacitor. Also, the lowest original compressor corresponds to the low original compressor, and the second cascade capacitor corresponds to the low original cascade capacitor.

[0016]

With the above-described configuration, the suction gas of the lowest element and the liquid refrigerant of the highest element can be exchanged by the suction side heat exchanger provided on the lowest element side, and the refrigerating effect on the highest element side can be increased.

[0017]

【Example】

 Hereinafter, specific embodiments of the multi-source refrigeration system according to the present invention will be described in detail with reference to the drawings. In the description, the same parts as those in the conventional example are designated by the same reference numerals and the description of the overlapping parts will be omitted.

An example of this multi-source refrigeration system is shown in the system diagram of FIG. In this figure, in addition to the low-source intake heat exchanger 11, the intake-side heat exchanger 11 is provided in the middle of the pipeline connecting the outlet of the cooling coil 13a of the low-source cooler 13 and the intake port of the low-source compressor 10. A low-source intake / high-source liquid heat exchanger 16 is provided, and the intake gas discharged from the cooling coil 13a passes through the heat radiation coils 11a and 16a of the heat exchangers 11 and 16 to the low-source compressor. Inhaled to 10.

The pipe extending from the outlet of the high-source side condenser 2 is connected to the inlet of the low-source intake / high-source liquid heat exchanger 16 via the high-source intercooler 3 and the outlet of the heat exchanger 16 Is connected to the inlet of the evaporation coil 5a of the middle cascade condenser 5 via the expansion valve 4 by a pipe line. The outlet of the evaporation coil 5a is connected to the high-pressure compressor 1 by a suction pipe.

In the multi-source refrigeration system configured as described above, the suction gas on the low-source side and the liquid refrigerant on the high-source side are heat-exchanged by the heat exchanger 16, and the suction gas that has been conventionally discarded by heat radiation in the suction pipe line. The amount of heat generated by the high-end refrigerator can be recovered. Therefore, as shown in the Mollier diagram of this multi-source refrigeration system in FIG. 2, the enthalpy of the high-grade liquid refrigerant is small, and the refrigerating effect of the high-grade refrigerator is increased as indicated by Y1. In the figure, Δi3 corresponds to the enthalpy of the supercooled portion that is heat-exchanged with the high-grade liquid refrigerant in the heat exchanger 16. Note that Y2 indicates the refrigerating effect in the conventional device. As a result, the refrigerant circulation amount of the high-end refrigerator is reduced and the piston displacement amount of the compressor 1 is reduced, so that the compressor 1 can be downsized and energy can be saved.

In the above-mentioned embodiment, the three-source single-stage refrigerating device is described as an example, but the present invention can be applied to a high-source system having a two-stage cycle.

[0022]

[Effect of device]

 As described above, according to the present invention, since the lowest source intake gas and the high-source side liquid refrigerant are heat-exchanged, the enthalpy of the high-source liquid refrigerant becomes small, and the refrigerating effect of the high-source refrigerator is reduced. Can increase. As a result, the high-end refrigerator can be downsized by about 5 to 10% and energy can be saved. Further, the refrigeration efficiency of the entire multi-source refrigeration system can be improved.

[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 Mollier diagram of the multi-source refrigeration system shown in FIG.

FIG. 3 is a system diagram showing a conventional multi-source refrigeration system.

FIG. 4 is a Mollier diagram showing a conventional multi-source refrigeration system.

[Explanation of symbols]

 1 High-source compressor 2 High-source condenser 3 High-source intercooler 4, 8, 12 Expansion valve 5 Middle-source cascade condenser 6 Middle-source compressor 7 Middle-source intake heat exchanger 9 Low-source cascade condenser 10 Low-source compressor 11 Low-source intake heat exchanger 13 Coolers 14 and 15 Pressure protection container 16 Low-source intake / high-source liquid heat exchanger

Claims (1)

[Scope of utility model registration request] 1. In a multi-source refrigeration system in which a plurality of refrigerators and a cascade condenser forming a condenser are connected in multiple stages, a discharge pipe extending from a compressor on the highest source side is connected to the condenser, and an outlet pipe of the condenser. The line is connected to the heat exchanger on the suction side of the lowest source side, the outlet line of this heat exchanger on the suction side is connected to the condenser coil of the first cascade condenser via the expansion valve, and the outlet of this condenser coil is sucked. Connected to the suction side of the compressor of the highest source side by a pipe, connect the discharge pipe extending from the compressor of the lowest source to the second cascade condenser, and the outlet line of this second cascade condenser through the expansion valve. Connected to the cooling coil of the cooler, connected the outlet of this cooling coil to the radiation coil of the suction side heat exchanger, and connected the outlet of this radiation coil to the suction side of the lowest compressor by the suction pipe. Characterized by Stage refrigeration apparatus.