JPS6350628B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cooling device such as a refrigerator having a plurality of cold storage chambers with different temperatures, and its purpose is to improve the coefficient of performance of a compressor and improve the operating efficiency of the cooling device. At the point.

Conventionally, a typical example of a system in which a single refrigeration unit cools multiple cold storage compartments with different temperatures is the cooling system for a household refrigerator-freezer.
The cooling system shown in the figure is used.

In Fig. 1, 1 is a compressor, and this compressor 1
The refrigerant liquid discharged from the condenser 2 and liquefied in the condenser 2 is
The pressure is reduced in the first capillary tube 3, and a portion of the liquid is evaporated in a refrigerating evaporator 5 disposed within the refrigerating compartment 4, at which time the refrigerating compartment 4 is cooled. The gas-liquid two-phase refrigerant that has exited the refrigeration evaporator 5 is depressurized again in the second capillary 6, and the remainder is evaporated in the refrigeration evaporator 8 disposed in the freezing compartment 7. 7. Cool. The refrigerant gas exiting the refrigeration evaporator 8 is sucked into the compressor 1 via the accumulator 9. The temperature inside each refrigerator is controlled by starting and stopping the compressor 1 using a temperature controller (not shown) disposed in either the refrigerator compartment 4 or the freezer compartment 7.

In the refrigerator-freezer configured as described above, the suction pressure of the compressor 1 is very low pressure in the refrigeration evaporator 8.
Therefore, no matter how high the evaporation pressure of the refrigeration evaporator 5 is, the coefficient of performance of the compressor 1 is extremely poor, and the cooling system is forced to operate inefficiently. . Moreover, as mentioned above, since the temperature inside the refrigerator must be adjusted depending on the temperature inside one of the refrigerators, there is a drawback that the temperature inside the other refrigerator remains unchanged.

On the other hand, in order to enable independent control of the temperature inside each refrigerator, one evaporator 8 is installed in the freezer compartment 7, and the refrigerator compartment 4 controls the indoor temperature by damper control. A cooling system in which the temperature of the chamber 7 is controlled by turning on and off the compressor 1 has become common in recent years. Although this method allows independent control of the temperature in both chambers, the evaporation temperature of the evaporator 8 still depends on the temperature of the freezer compartment 7, so the suction pressure of the compressor 1 is low and the efficiency of the cooling system is extremely low. Bad things don't change. Furthermore, when this method is used, the refrigerator compartment 4 is communicated with the freezer compartment 7 via a damper, which causes the problem of excessive dryness inside the refrigerator compartment 4, and furthermore, the amount of dew condensation on the evaporator 8 is large. However, there were disadvantages such as the need for frequent defrosting.

The present invention has been made in order to improve the various drawbacks of the above-mentioned conventional devices.Evaporators for cooling each cooling chamber are provided in a plurality of cooling chambers having different cold storage temperatures, and the evaporators are connected in parallel. The coefficient of performance of the compressor is improved by setting different times for the refrigerant to flow into each evaporator so that they do not flow at the same time, and at the same time, the refrigerant liquid that cannot be evaporated in the low-temperature side evaporator is completely evaporated in the high-temperature side evaporator. In addition, the refrigerant gas from the low-temperature side evaporator is superheated by the high-temperature side evaporator, and the heat of the refrigerant that has passed through the low-temperature evaporator is recovered, thereby increasing the operating efficiency of the entire cooling system.

The details of the present invention will be explained below using a household refrigerator-freezer as an example.

FIG. 2 is a cooling system diagram showing an embodiment of the present invention, in which 1 is a compressor, 2 is a condenser, 4 is a refrigerating compartment, 5 is a refrigerating evaporator disposed in the refrigerating compartment 4, 7 is a freezing chamber, 8 is a freezing evaporator disposed within the freezing chamber 7, and 9 is an accumulator. 3
6 is a first capillary tube as a first pressure reducer disposed upstream of the refrigerant passage of the refrigeration evaporator 5, and 6 is a second pressure reducer disposed upstream of the refrigerant passage of the refrigeration evaporator 8. 10 is a first on-off valve disposed upstream of the refrigerant passage of the first capillary 3; 11 is a three-way valve as a refrigerant control valve disposed downstream of the freezing evaporator 8; and this three-way valve 1
1 is in communication with the refrigerant suction flow path of the compressor 1 (shown as a→b in FIG. 2), and the other is in communication with the upstream side of the refrigerating evaporator 5 via the check valve 12 (see FIG. 2). Middle a →
(indicated by c).

The series refrigerant circuit of the first on-off valve 10, the first capillary tube 3, and the refrigeration evaporator 5 and the series refrigerant circuit of the second capillary tube 6, the refrigeration evaporator 8, and the three-way valve 11 are connected in parallel to the condenser. 2 and the above accumulator 9
is connected between.

The embodiment shown in FIG. 2 is similar to a conventional parallel evaporator cooling system, but is fundamentally different.

First, in order to match the evaporation pressures of evaporators at different temperature levels to the same suction pressure, the present invention eliminates the need for a pressure adjustment section that was provided after the high temperature side evaporator in the conventional device. In other words, the characteristic operation of the present invention is that refrigerant is not allowed to flow into both evaporators 5 and 8 at the same time. More specifically, the low temperature side, that is, the freezing refrigerant circuit, is composed of the second capillary 6, the refrigeration evaporator 8, and the three-way valve 11, and the first on-off valve 10, the first capillary 3, and the refrigeration evaporator 5. A refrigerating evaporator for cooling the refrigerating compartment 4 by distributing the refrigerant liquid exiting the condenser 2 to the high temperature side, that is, the refrigerating refrigerant circuit, in time series according to the temperature change situation in both rooms. By maintaining the evaporation pressure of 5 high, the coefficient of performance of the compressor 1 is improved, and the refrigerant liquid that cannot be completely evaporated in the refrigeration evaporator 8 is completely evaporated in the refrigeration evaporator 5, By superheating the refrigerant gas coming out of the refrigeration evaporator 8 in the refrigeration evaporator 5, heat recovery of the refrigerant that has passed through the refrigeration evaporator 8 is performed in the refrigeration evaporator 5,
Together with the former, this increases the operating efficiency of the entire cooling system.

FIG. 3 is an operation control block diagram of the domestic refrigerator-freezer shown in FIG. is the temperature controller for the refrigerator compartment, and the detected value from the temperature detection sensor 13 is the temperature controller for the refrigerator compartment 4.
When the temperature is higher than a predetermined upper limit value, the ON signal is output, when the temperature is lower than the predetermined lower limit value, the first OFF signal is output, and when the temperature value is slightly higher than the predetermined lower limit value, that is, the second predetermined lower limit value, the second OFF signal is output. Output. Note that the output signal line a of this temperature controller 15 is an ON signal, and the first OFF signal
signal, outputs the second OFF signal, and connects the output signal line b
outputs the first OFF signal. Reference numeral 16 is a temperature controller for the freezer compartment, which outputs an ON signal when the detected value from the temperature detection sensor 14 is equal to or higher than a predetermined upper limit value for the freezer compartment 7.
When it is below the predetermined lower limit value, an OFF signal is output. 1
7 outputs an ON signal based on the ON signal of this temperature controller 16 and the first OFF signal of the temperature detector 15. AND circuits such as AND gates, 18
1 is an OR gate that outputs an ON signal based on either the ON signal of this AND gate 17 and the ON signal of the temperature controller 15, and 1 is the ON signal of this OR gate 18.
A compressor driven by a signal, 10 is a first opening/closing valve that opens when the temperature controller 15 turns ON and closes when the second OFF signal is turned on, and 11 turns ON the AND gate 17.
It is a three-way valve that switches the flow path from a to b with a signal, and from a to c at other times.

In the configuration as described above, when the temperature of the refrigerator compartment 4 is higher than the predetermined upper limit temperature, the temperature controller 15 outputs a signal from the temperature detection sensor 13.
Since the ON signal is output, the first on-off valve 10 is opened, the three-way valve is changed from a to c, and the compressor 1 is driven via the OR gate 18. Therefore, the refrigerant passes through the first capillary tube 3 and only through the refrigerating evaporator 5 to cool the inside of the refrigerating compartment 4. When the refrigerator compartment 4 is cooled and becomes lower than the predetermined upper limit temperature and slightly higher than the lower limit temperature, that is, when it is below the second predetermined lower limit value and the freezing compartment 7 is higher than the predetermined upper limit temperature, the detected value from the temperature detection sensor 13 Accordingly, the three-way valve 11 changes the flow path from a to c according to the signal from the temperature controller 15, and closes the first on-off valve 10. Then, the refrigerant passes through the second capillary tube 6 and the refrigeration evaporator 8, and cools the inside of the freezer compartment 7. Furthermore, it passes through the three-way valve 11 from a to c and the check valve 12 and enters the refrigerating evaporator 5, where the heat of the low-temperature refrigerant is recovered.At the same time, the refrigerant evaporated at low temperature is superheated and the refrigerating compartment 4 is slightly cooled. be done. At this time, when the inside of the refrigerator compartment 4 is cooled to a predetermined lower limit temperature or less, and the freezer compartment 7 is still at a predetermined lower limit temperature or higher, a signal from the temperature detection sensor 13 is sent to the temperature controller 15, and a three-way valve 11 a
→ Switch to b to prevent refrigerant from flowing into the refrigeration evaporator 5.

When the refrigerator compartment 4 and the freezer compartment 7, which are both cooling compartments, are below the predetermined lower limit temperature, the temperature detection centers 13 and 1
4, the operation of the compressor 1 is stopped via the AND gate 17 and the OR gate 18 in response to the signals from the temperature controllers 15 and 16.

FIG. 4 is a cooling system diagram showing another embodiment of the present invention, and 20 is a three-way valve 1 in FIG.
This is a second on-off valve installed downstream of the refrigerant branch path to the check valve 12 instead of the check valve 12. In this second on-off valve 20, the flow path of the three-way valve 11 in FIG.
Open when the change is from a to c, closed when the first on-off valve 10 is closed, and closed when the first on-off valve 10 is closed. It opens and closes depending on the temperature situation. Even if configured in this way, it has the same function and the same effect.

In the above embodiment, a capillary tube is used as a pressure reducer, but it goes without saying that an expansion valve or the like may also be used, and even in the case of multiple systems with two or more load sides, the pressure reduction device is adapted to each temperature level. The present invention can be applied to multiple systems by setting a refrigerant control valve for each system and setting refrigerant control valves for multiple systems.

As described above, the present invention can improve the operating efficiency of the compressor and the cooling system as a whole by distributing refrigerant to evaporators with different evaporation pressures in time series. Since independent control is possible and the cooling of the high-temperature side cold storage chamber is performed at an appropriately high evaporation temperature, problems such as drying of the high-temperature side cold storage chamber do not occur.

Furthermore, in a conventional refrigeration system in which evaporators are connected in parallel, refrigerant flows through both evaporators at the same time. Although this was necessary later, this is no longer necessary in the present invention, and moreover, the refrigerant sucked into the compressor is sufficiently superheated during the low-temperature side cooling operation, and efficiency can be improved from this aspect as well.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the cooling system of a conventional refrigerator-freezer for domestic use, Fig. 2 is a diagram of the cooling system of a refrigerator-freezer for domestic use showing an embodiment of the present invention, Fig. 3 is a block diagram of its operation control, and Fig. 4 is a diagram of the cooling system of a conventional refrigerator-freezer for domestic use. It is a cooling system diagram showing another example of the present invention. The same symbols in the figures indicate the same or corresponding parts, 1
is a compressor, 2 is a condenser, 3 is a first capillary, 4 is a refrigerator compartment, 5 is a refrigeration evaporator, 6 is a second capillary, 7 is a freezing compartment, 8 is a freezing evaporator, 10 is a first On-off valve, 11 is a three-way valve, 12 is a check valve, 13 and 14 are temperature detection sensors, 15 and 16 are temperature controllers, 1
7 is an AND gate, and 18 is an OR gate.

Claims (1)

[Claims] 1. A plurality of cooling chambers with different cold storage temperatures, an on-off valve and a pressure reducer connected in series in the direction of refrigerant flow to individually cool each cooling chamber, and an evaporator to cool the cooling chambers. Refrigerant circuit, each refrigerant circuit is connected in parallel and connected in series to one compressor and condenser, detects the temperature of each cooling chamber, controls the on-off valve of each refrigerant circuit, and controls the above. A temperature controller for selectively flowing a refrigerant into one of the refrigerant circuits, and a refrigerant control valve provided downstream of the low-temperature side evaporator of the refrigerant circuit, and downstream of the low-temperature side evaporator. and the upstream side of the high-temperature side evaporator are connected via a check valve, and when the high-temperature side cooling chamber is within a predetermined temperature range, the refrigerant exiting the low-temperature side evaporator is passed through the check valve by the refrigerant control valve. A cooling device characterized in that the air flows to a high-temperature side evaporator through the cooling device. 2. Cooling according to claim 1, characterized in that when the cooling chamber consists of two chambers, the pressure reducer is constituted by a capillary tube, and an on-off valve is provided only on the upstream side of the pressure reducer in the high temperature side refrigerant circuit. Device. 3. The cooling device according to claim 1 or 2, characterized in that the refrigerant control valve is a three-way valve.