JPS63231154A - Refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a refrigeration system used for showcases, etc., and in particular, the present invention relates to a refrigeration system used for showcases, etc., and in particular, it is provided with a plurality of coolers, and the defrosting of the cooler 7J is performed by one cooler. This relates to a refrigeration system that performs operations alternately or sequentially.

(Prior art) Refrigeration equipment used for cooling showcases, etc.
In order to prevent the temperature in the cooling space from rising during defrosting to remove frost adhering to the container, install multiple coolers and defrost one by one alternately or sequentially. to other cold 2Jl
The temperature of the space to be cooled is maintained at the same temperature as during cooling by the full cooler, or slightly higher than that temperature.

Figures 4 to 6 show examples of oven-type showcases. The air passes through a duct 3 behind the duct 3, and is rectified and discharged from a discharge port 4 toward the bottom of the showcase 1 as an air curtain. The cool air is then sent from the cold air suction port 5 through the bottom of the showcase 1 to the coolers 2a and 2b by the fan 6.

Further, a damper 7 is provided in the passage leading from both coolers to the duct to open and close the passage.

When defrosting one of the coolers 2a, the damper 7 is rotated as shown in FIG.
a, so that only cold air from the side of the cooler 2b that is not being defrosted is sent to the duct 3, and when defrosting the other cooler 2b, the damper 7 is closed as shown in FIG. times f
f1lJL, block the passage 3b on the side of the cooler 2b during defrosting.

Another example is a system in which each cooler is provided with a dedicated fan motor, and the fan motor that circulates cold air to the cooler during defrosting is stopped or decelerated, while the other fan speeds up. .

FIGS. 7 and 8 show an example of a refrigeration cycle of a refrigeration system used in the above-mentioned showcase, etc., and the bold lines in the figures indicate the flow of refrigerant.

The refrigeration device 8 is installed inside a showcase, etc. 2
The compressors 17 and 39, which are installed on the outside of the base coolers 2a and 2b, and supply refrigerant to the coolers 2a and 2b, the condenser 10, the liquid receiver 11, and the piping and various valves that connect them. It is configured.

During normal cooling operation, J: sea urchin shown in bold line in Figure 7,
The liquid refrigerant from the liquid receiver 11 is supplied to the coolers 2a, 2b through the check valves 15a, 15b and the expansion valves 16a, 16b by checking the valves 12, 13, 14, and is evaporated to generate cold. The refrigerant evaporated in the coolers 2a and 2b is transferred to the valve 13.
．． 14, is sucked into the compressor t19, is compressed, and is sent to the condenser 10 and receiver 11 for circulation.

When moving from normal operation to defrosting one of the coolers 2a, the valve 17a is opened and the valves 12 and 13 are closed. That is, the eighth
As shown in the figure, the liquid refrigerant from the liquid receiver 11 is introduced into the cooler 2al through the valve 17a without expansion.
The coolant of the liquid refrigerant removes the frost from the cooler 2a. Since the valve 13 is closed, the liquid refrigerant after defrosting passes through the check valve 18a to the check valve 15b and expansion valve 16 on the other cooler 2b side.
Cold through b! It enters the 111 vessel 2b, evaporates, and reaches the compression n9 through the valve 14. When defrosting the cold yJl unit 2b,
By closing the other valves 12, 14, and 17a with a time interval of 4J, the refrigerant flows through the valve 17b, the cooler 2b, and the check valve 18.
k), check valve 15a, expansion valve 16a, cold 7JIi2a through valve 13 and pressure 1? i Reach R9.

[Problem that the invention seeks to solve]

However, since the sensible heat of the liquid refrigerant is used to defrost the refrigerator, the amount of heat is small. In most cases, it may not be possible to completely defrost the cold N1 container if the temperature around the showcase is low, such as in cold regions or during winter. As the defrosting time of the cooler becomes longer, the cooling time becomes longer with only one cooler, the temperature of the space to be cooled tends to reach an upper limit, and the efficiency of the refrigerator cannot be fully utilized, resulting in higher electricity bills. In addition, complicated piping and multiple valves are required, making the structure complex and requiring a large space to install them within the showcase, reducing the volume of product rows in the showcase and reducing the number of valves. Maintenance of the showcase shade was difficult.

Also, at the start of cooling operation after defrosting, the cold that is heated for defrosting! Circulating cold air was sent to the J1 unit to warm it up, sometimes raising the temperature in the non-cooled space.

Furthermore, the liquid refrigerant used for defrosting is rapidly sucked into the compressor without being decompressed or expanded by an expansion valve or the like, causing a condition called liquid hammer, which may damage the compressor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a refrigeration system that can improve cooling efficiency by shortening the defrosting time of a cooler and can smoothly start up a cooling operation after defrosting.

[Means for solving problems]

In order to achieve the above object, the present invention provides a refrigeration cycle with a plurality of coolers, and the cooling l! In a refrigeration system that defrosts an I-cooler in alternating current or sequential order, the refrigeration cycle is provided with a defrosting heat source circuit that supplies high-pressure side superheated refrigerant vapor or saturated refrigerant vapor to the cooler, and the defrosting heat source It is characterized in that a refrigerant recovery circuit is connected to the circuit to recover the refrigerant after the defrosting of the cooler is completed.

(Function) Therefore, since the latent heat of condensation of the cold tofu can be used to defrost the cooler, the defrosting heat source becomes larger, the cooler can be defrosted in a shorter time, and the upper temperature limit of the space to be cooled can be suppressed. At the same time, the refrigerant inside the cooler that has been heated for defrosting can be recovered, allowing the cooler to cool down and start up the cooling operation more smoothly.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 3.

The refrigeration system 20 includes two cooling units 21a and 21b installed in a space to be cooled such as a showcase, a compressor 22 installed outside the space to be cooled and supplying refrigerant to the coolers 21a and 21b, It is composed of a condenser 23, a liquid receiver 24, piping connecting them, and various valves.

During normal cooling operation, as shown by the thick line in Fig. 1, the refrigerant gas compressed by the compressor 22 to a high temperature and high pressure is radiated by the condenser 23, and most of it is liquefied and sent to the liquid receiver 24. . The liquefied liquid refrigerant passes from the liquid receiver 24 through the valve 25, and then passes through both the coolers 218 (front valves 25a, 26t) and the expansion valves 27a, 27b or the refrigerant flow control valve to the cooler 21a.

21b, where it evaporates and generates refrigeration.

The evaporated refrigerant gas is circulated back to the compressor 22 through the three-way valves 28a, 28b.

In addition, a hot gas bypass valve 29 is provided which connects the compressor 122 and the liquid receiver 24 to adjust the pressure within the refrigeration cycle.
Refrigerant gas is sent from 122 to receiver 24 to maintain the pressure of the refrigerant at an appropriate value.

Furthermore, both coolers 21a and 2 are used for defrosting operation to be described later.
1b inlet side valves 26a, 26b and expansion valves 27a, 27
Bypass circuits 31a, 3 equipped with check valves 3Qa, 30b that bypass the refrigerant and flow the refrigerant only in the direction opposite to the normal operation.
1b, a defrosting heat source circuit 32 and a refrigerant recovery circuit 33 are provided.

The defrosting heat source circuit 32 connects the upper part of the liquid receiver 24 and the Sanno valves 28a and 28b, and connects the cooler 21a or the cooling 7
When defrosting the JI device 21b, the high-pressure side superheated refrigerant vapor or saturated refrigerant vapor in the upper part of the liquid receiver 24 is transferred to the coolers 21a and 21b.
A valve 34 is provided in the middle. Further, the refrigerant recovery circuit 33 connects the compressor 22 to the piping 35 between the valve 34 provided in the defrosting heat source circuit 32 and the three-way valves 28a and 28b, and connects the compressor 22.
A thin tube 36 and a valve 37 are provided to recover the high-pressure side overheated refrigerant vapor, the saturated refrigerant vapor, or the refrigerant in which both vapors are condensed after the defrosting process is completed in a and 21b.

The thick line in FIG. 2 shows the case where one of the coolers 21a is defrosted, in which the valve 25 is closed and the pressure reducing valve 38 lowers the pressure of the liquid refrigerant on the cold IJl units 21a and 21b side. , operate one of the three-way valves 28a to transfer the refrigerant gas in the upper part of the liquid receiver 24 from the defrosting heat source circuit 32 to the three-way valve 28a.
It is supplied from the opposite direction of the cold comb 1 container 21a.

This refrigerant gas is either saturated refrigerant vapor that has not been condensed in the condenser 23 or is transferred from the compressor 22 to the hot gas bypass valve 2.
The high-pressure side superheated refrigerant vapor passes through the liquid refrigerant 9 and enters the liquid receiver 24, and has a larger enthalpy than conventionally used liquid refrigerants, and can finish defrosting within the range 115.

The liquid refrigerant that melts the frost on the outer surface and undergoes heat exchange in the Reigetsu 1 unit 21a and condenses passes through the bypass circuit 31a and is then passed through the check valve 3.
0a, passes through the valve 26b and the expansion valve 27b, enters the other cooler 21b, evaporates, generates cold, and cools the other cooler 21b.
Even when 1a is being defrosted, the temperature of the IJI space to be cooled does not rise. The refrigerant gas after evaporation is sucked into the compressor 22 through the three-way valve 28b in the same manner as in the normal operation.

In addition, since the refrigerant gas condenses in the cooler 2Ia, the pressure in the receiver 24 decreases, and the superheated refrigerant vapor on the high pressure side is compressed 12
2 through the hot gas bypass valve 29 to the receiver 24
Defrosting can be performed more efficiently.

Note that defrosting can be performed without any problem even if the valve 26a is left open.

At the end of defrosting, most of the refrigerant used for defrosting the cooler 21a is liquefied, and some remains in the gaseous state in the cooler 2Ia, and the cooler 21a is Temperature α is rising due to frost.

Therefore, when the defrosting of the cooler riI device 21a is completed, the valve 34 of the defrosting heat source circuit 32 is left open, and the valve 25 and the refrigerant recovery circuit 3 are left open.
3. Open valve 37. Also, if the valve 26a is open,
Valve 26a is also closed.

FIG. 3 shows the flow of refrigerant to the above-mentioned state.
b and expansion valve 27b to the cold 7jl unit 21b, evaporate to generate cold, and pass through the three-way valve 28b to the compressor 2.
2 is inhaled. On the other hand, the refrigerant remaining in the cooling lJj chamber 1a flows backward through the defrosting heat source circuit 32 through the three-way valves 28a and 7Js, and is gradually sucked into the compressor 22 through the thin tube 36 of the refrigerant recovery circuit 33. . Furthermore, the cold 741 vessel 21a, which was being heated at the same time, is gradually cooled down to the ambient temperature.

Then, after an appropriate period of time has elapsed or by a command specific to the temperature sensor, each valve is turned off and the normal cooling 1 operation shown in FIG. 1 is returned to.

In this way, in the refrigeration system 20 of the present invention, the cooling 1
Since the high-pressure side superheated refrigerant vapor or saturated refrigerant vapor, which has a large amount of heat, is used as the heat source for defrosting the cooling device 21a, the defrosting time can be shortened to about the conventional 11b, and only one cooling B21b is required. Since the operating time is reduced, the temperature of the space to be cooled -tJ7 can be suppressed, and two coolers 2
1a and 21b, the efficiency of the refrigeration system 20 can be fully utilized, and operating costs such as electricity costs can be reduced.Furthermore, the refrigerant used for defrosting can be recovered and then cooled.
! Since S21a is in the cooling state, the refrigerant liquefied during defrosting evaporates in the cooler 21a during recovery, lowering the thirst of the cooler 21a that was being heated for defrosting, and reducing the temperature of the cooling operation. The cold air that circulates during startup does not heat up.
Liquid cooling 7J] There is no need to increase the temperature of the space.

When defrosting the other cooler 21b, the three-way valve 28
If the other three-way valve 28b is operated in place of the three-way valve a, the same bonding as the defrosting of the cooler 21a can be obtained.

As in the embodiment, by gradually recovering the refrigerant used for defrosting through the thin tube 36 of the refrigerant recovery circuit 33, liquid hammer does not occur and damage to the compressor 22 can be prevented.

In addition, in this embodiment, the flow of refrigerant near the coolers 21a and 21b is simplified, and the space required for installing piping and valves is small, making it easy to install in a showcase, and to facilitate maintenance and other work. Sexuality also improves.

Note that switching can be performed by combining ordinary valves without using a three-way valve, and ordinary valves can be used as check valves as well. Alternatively, the refrigerant may be gradually recovered using a valve or the like without using a capillary.

Also, depending on the size of the showcase, three or more coolers may be arranged as a set, and each cooler may be defrosted in sequence. In addition, each valve used in the refrigeration cycle is
Normally, a solenoid valve is used, and the defrosting operation is controlled by a timer, computer, etc.

〔Effect of the invention〕

As described above, the present invention provides a defrosting heat source circuit that supplies high-pressure side superheated refrigerant vapor or saturated refrigerant vapor to a cooler in a refrigeration cycle, and provides a cooling fJl in the defrosting heat source circuit.
Since a refrigerant recovery circuit is connected to recover the refrigerant after the defrosting of the cooler is completed, the defrosting heat source circuit allows the high-pressure side superheated refrigerant vapor or saturated refrigerant vapor, which has a large defrosting heat source, to be used for defrosting the cooler. With this, the refrigerant can be completely defrosted in a short period of time, reducing the temperature rise in the space to be cooled, and the refrigerant recovery circuit can recover the refrigerant in the cooler before cooling operation, making it possible to defrost the cooler in a short time and completely. cold 7J warmed by]
The steam can be cooled and the start-up of the cooling operation can be made smoother.

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention. Figure 1 is a circuit diagram showing the flow of refrigerant during normal cold fJ1 operation of the refrigerated l-Nicle, and Figure 2 is during defrosting operation. Figure 3 is a circuit diagram showing the flow of refrigerant at the end of the defrosting operation at 7 o'clock, and Figures 4 to 8 show conventional examples. The figure does not show the internal structure of the showcase, but is a top view, and FIGS. 7 and 8 are circuit diagrams of the refrigeration cycle.

Claims (1)

[Claims] 1. In a refrigeration system that includes a plurality of coolers in a refrigeration cycle and defrosts the coolers alternately or sequentially, a defrosting device that supplies high-pressure side superheated refrigerant vapor or saturated refrigerant vapor to the cooler in the refrigeration cycle. A refrigeration system comprising a heat source circuit and a refrigerant recovery circuit for recovering refrigerant after defrosting of a cooler is connected to the defrosting heat source circuit.