JPH0138228B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cooling device such as a refrigerator-freezer having a plurality of cold storage compartments with different temperatures, and in particular improves the coefficient of performance of a pressure reducer and improves the operating efficiency of the cooling device. It is something.

Conventionally, a household refrigerator-freezer is a typical example of a device that cools multiple cold storage compartments with different temperatures using a single refrigeration unit, and it basically employs the cooling system shown in Figure 1. .

In FIG. 1, 1 is a compressor, and the refrigerant liquid discharged from the compressor 1 and liquefied in a condenser 2 is depressurized in a first capillary tube 3, and is stored in a refrigerator compartment 4. A portion of the liquid is evaporated in the evaporator 5, and at that time a cooling effect is performed in the refrigerator compartment 4.

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.

In addition, 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 in the refrigerator compartment 4, and furthermore, the amount of frost on the evaporator 8 increases. There were disadvantages such as the large size and the need for frequent defrosting.

This invention was made in order to improve the above-mentioned conventional drawbacks, and involves disposing an evaporator for cooling each cooling chamber in a plurality of cooling chambers for keeping cool at different temperatures, and connecting these evaporators in parallel. At the same time, the priority order for flowing refrigerant to each evaporator is determined, and the refrigerant is flowed according to this priority order, and by not flowing at the same time, the coefficient of performance of the compressor is improved, and the operating efficiency of the entire cooling system is increased. It is an object of the present invention to provide a cooling device in which the priority order can be changed by a switch, and each evaporator can be operated with an appropriate amount of refrigerant.

Hereinafter, details of an embodiment of the cooling device of the present invention will be described 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, Reference numeral 7 denotes a freezing chamber, 8 a freezing evaporator disposed within the freezing chamber 7, and 9 an accumulator, which are the same as those in the conventional apparatus.

3 is a first unit that reduces the pressure of the refrigerant liquid exiting the condenser 2;
A first capillary tube as a pressure reducer, 10 a first electromagnetic valve as a first opening/closing valve disposed on the downstream side of the refrigerant passage of the refrigeration evaporator 5, and 6 an upstream side of the refrigerant passage of the refrigeration evaporator 8 A second capillary tube 11 serves as a second pressure reducer disposed in the second capillary tube 6, and a second capillary tube 11 serves as a second on-off valve disposed on the upstream side of the refrigerant passage of the second capillary tube 6.
The electromagnetic valve 12 is a check valve provided on the downstream side of the refrigerant passage of the freezing evaporator 8.

Note that the first capillary tube 3, the refrigerating evaporator 5, and the first
A series refrigerant circuit of the solenoid valve 10 and the first solenoid valve 10
The series refrigerant circuit of the second electromagnetic valve 11, the second capillary tube 6, the freezing evaporator 8, and the check valve 12 are connected in parallel to form the condenser 2 and the accumulator 9.
is connected between.

FIG. 3 is an operation control block diagram of the domestic refrigerator-freezer shown in FIG. 15 is the temperature detection sensor 1 mentioned above.
This is a temperature controller for a refrigerator compartment that outputs an ON signal when the detected value from 3 is equal to or higher than a predetermined upper limit temperature value of the refrigerator compartment 4, and outputs an OFF signal when the detected value is equal to or lower than a predetermined lower limit value.

16 indicates that the detected value from the temperature sensor 14 is in the freezer compartment 7.
A temperature controller 17 for the freezer compartment outputs an on signal when the temperature is above a predetermined upper limit temperature value, and an off signal when the temperature is below a predetermined lower limit value; This is an AND circuit such as an AND gate that is established by a signal and outputs an ON signal.

18, 19 are first inverters that invert the signals from the temperature controllers 15, 16, respectively; 20,
21 is a second inverter that inverts the signal from the AND circuit 17; 22 and 23 are established by ON signals from the second inverters 20 and 21, respectively, and pass the outputs of the temperature controllers 15 and 16; 1 three-state gates 24 and 25 are respectively established by the ON signal of the AND circuit 17, and are second three-state gates that allow the outputs of the temperature controllers 15 and 16 or the outputs of the first inverters 18 and 19 to pass through. It is.

Reference numeral 26 denotes an OR gate, etc., which is established by an ON signal of any one of the first and second three-state gates 22, 24 for the refrigerator compartment, and the first and second three-state gates 23, 25 for the freezer compartment, and outputs an ON signal. This is an OR circuit.

27 is a delay circuit that is activated when the off signal is output from the OR circuit 26; 28 is a delay circuit that is activated to input a signal to the second three-state gates 24 and 25; output and the first refrigeration inverter 19
This is an interlocking changeover switch that switches between the output of the temperature controller 16 and the output of the temperature controller 16. And the above logical sum circuit 2
The compressor 1 is driven by the ON signal of 6, and the ON signal of the first and second three-state gates 22 and 24 for refrigeration turns on the first solenoid valve 10 and the first and second three-state gates 23 and 25 for refrigeration. The second solenoid valve 11 is opened by the signal.

Further, the AND circuit 17, the first inverter 18,
19, second inverters 20, 21, first three-state gates 22, 23, second three-state gates 24, 25, and OR circuit 26 constitute a refrigerant circuit controller.

In the household refrigerator-freezer configured as described above, the changeover switch 2 is set to give priority to the refrigerator compartment 4.
As shown in FIG. 3, the second three-state gates 24 and 25 are switched by inputting the output of the temperature controller 15 and the output of the first inverter 19, which is an inverted version of the output of the temperature controller 16.

The temperatures in both rooms detected by temperature detection sensors 13 and 14 are input to temperature controllers 15 and 16.

At this time, if the temperature of the refrigerator compartment 4 is higher than the predetermined upper limit and the temperature of the freezer compartment 7 is lower than the predetermined lower limit, the freezing temperature controller 16 outputs an off signal,
Refrigeration temperature controller 15 outputs an on signal.

The output of this temperature controller 15 is input to an AND circuit 17 and a first three-state gate 22. However, since the AND circuit 17 does not hold, an OFF signal is output, and this signal is sent to the second refrigeration inverter 2.
0 is input to the second three-state gate 24 for refrigeration.

Here, the signal input to the second inverter 20 is inverted, becomes an on signal, and is input to the first three-state gate 22 for refrigeration, so the on signal from the temperature controller 15 for refrigeration is transmitted to the first three-state gate for refrigeration. It passes through the state gate 22, opens the first solenoid valve 10, and connects the compressor 1 through the OR circuit 26.
to drive.

Therefore, a cooling operation for the refrigerator compartment 4 is performed. During this cooling operation of the refrigerator compartment 4, when the temperature in the freezer compartment 7 also becomes higher than the predetermined upper limit value and an ON signal is output from the temperature controller 16, the AND circuit 17 is established, but the first three-state gate for freezing 23 is the AND circuit 17
The second refrigeration inverter 21 inverts the output from
Also, the second three-state gate 25 is not established due to the off signal from the first refrigeration inverter 19, which is an inversion of the on signal from the temperature controller 16.
is not cooled.

When the cooling operation of the refrigerator compartment 4 reaches a predetermined lower limit value, the refrigerator temperature controller 16 outputs an off signal,
The first solenoid valve 19 is closed. At that time, freezer compartment 7
If the internal temperature is high and the ON signal is output from the refrigeration temperature controller 16, the AND circuit 17 will not be established between this ON signal and the OFF signal from the refrigeration temperature controller 15, so an OFF signal will be output. , this OFF signal is inverted by the second refrigeration inverter 21 and becomes an ON signal, so that the refrigeration first three-state gate 23
is established, the compressor 1 continues to operate through the logical sum circuit 26, the second electromagnetic valve 11 is also opened, and the freezer compartment 7 is cooled.

If the temperature inside the refrigerator compartment 4 rises above the predetermined upper limit value again during this cooling operation of the freezer compartment 7, an ON signal from the refrigeration temperature controller 15 is sent to start the cooling operation of the refrigerator compartment 4 as described above. Switch to .

When the internal temperatures of both chambers become below the predetermined lower limit, both temperature controllers 15 and 16 close the solenoid valves 10 and 11, stop the compressor 1, and issue an off signal.

As a result, the solenoid valves 11 and 12 are closed, but due to the action of the delay control circuit 27, the compressor 1
continues to operate for a while, and the refrigerant in the refrigeration circuit can be stored in the refrigeration evaporator 5.

When cooling the inside of the freezer compartment 7 by circulating refrigerant through the refrigeration evaporator 8 side, the amount of refrigerant in the refrigeration circuit is lower than when cooling the refrigerator compartment 4 by circulating the refrigerant through the refrigeration evaporator 5. Since it is possible to operate more efficiently by reducing the amount, the operation is performed in which the freezing compartment 7 side is cooled by the combination of this delay circuit 27 and the solenoid valve 10 provided on the downstream side of the refrigeration evaporator 5. Even in mode, the amount of refrigerant can be adjusted to an appropriate amount.

This adjustment is possible by changing the setting of the delay time using the delay circuit 27. Note that when there are a plurality of evaporators, it is obvious that the refrigerant should be stored in the evaporator with the highest temperature.

The effects of the present invention described above will be explained using specific numerical values. Normally, the temperature of the freezer compartment of a household refrigerator-freezer is around -18°C, and to achieve that temperature, an evaporation temperature of -25 to -30°C is required.

On the other hand, the temperature of the refrigerator compartment is about 5°C, and the evaporation temperature of about 0 to -5°C is sufficient. Further, the cooling load ratio between the two is about 4:6, with the load on the refrigerator compartment being larger.

In addition, the compressor's coefficient of performance, or operating efficiency, is -
When comparing both evaporation temperatures of 25 to -30°C and 0 to -5°C, the latter is 2 to 2.5 times the former. That is,
In this embodiment, the cooling operation of the refrigerator compartment, which accounts for 60% of the cooling load, can be performed with the operating efficiency of the compressor more than twice that of the conventional compressor, and a large energy saving effect can be expected.

In addition, although the above explanation has been given regarding the case where priority is given to the cooling operation of the refrigerator compartment 4, the changeover switch 28
By switching, priority is given to the cooling operation of the freezer compartment 7.

In addition, in the above embodiment, the switching operation was performed using two on-off valves to simplify the explanation, but a three-way valve may also be used, and if a capillary tube is used as the pressure reducer, Since the flow resistance of the capillary tube section of the refrigerant circuit for the freezer compartment is significantly greater than that for the refrigerator compartment, it may be possible to make it unnecessary by making it also serve as the opening/closing valve of the refrigerant circuit for the freezer.

Further, although the above embodiment has been described for a household refrigerator-freezer, it goes without saying that it can be applied to other systems as well, and can easily be applied to loads with more than two systems on the load side.

As described above, the present invention provides cooling using an evaporator each equipped with a plurality of cooling chambers with different cold storage temperatures, a single compressor, and a condenser, and the refrigerant is transferred to the evaporators with different evaporation pressures at the same time. Serial distribution can improve the operating efficiency of the compressor and cooling system as a whole.

Furthermore, the temperature of the cooling chamber, which has a high priority, can always be maintained at an appropriate value.

In addition, it is possible to independently control the temperature of each cooling room.
The amount of refrigerant in the refrigerant circuit can be adjusted appropriately, and there is no need for a regulating valve to adjust the pressure of the refrigerant after evaporation.

Since the evaporation temperature of the evaporator in the cooling chamber is kept at a relatively high temperature, problems such as dryness do not occur. Furthermore, since it has a changeover switch that can change the priority order for cooling a plurality of cold storage chambers, it can be freely selected depending on the time of use, improving usability.

[Brief explanation of drawings]

Fig. 1 is a diagram of the cooling system of a conventional domestic refrigerator-freezer, Fig. 2 is a diagram of the cooling system of a refrigerator-freezer for domestic use showing an embodiment of the cooling device of the present invention, and Fig. 3 is a diagram of the cooling system of a conventional refrigerator-freezer for domestic use. FIG. 3 is an operation control block diagram that performs operation control. 1... Compressor, 2... Condenser, 3... First capillary, 4
...refrigeration room, 5...refrigeration evaporator, 6...second capillary tube,
7... Freezer compartment, 8... Refrigeration evaporator, 10... First solenoid valve, 11... Second solenoid valve, 12... Check valve, 13, 1
4... Temperature detection sensor, 15, 16... Temperature controller,
17...AND circuit, 18-21...Inverter, 2
2 to 25... Three-state gate, 26... OR circuit, 27... Delay circuit, 28... Changeover switch. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1 A cold storage system in which a plurality of refrigerant circuits each having a pressure reducer and an evaporator connected in series are connected in parallel and connected in series to a single compressor and a condenser, and each evaporator has a different temperature. In a cooling system that cools a room, the evaporator that maintains the temperature at the highest temperature is connected in series with the pressure reducer, evaporator, and refrigerant control valve, and the other evaporators are connected in series with the refrigerant control valve, pressure reducer, and evaporator. ,
A plurality of temperature controllers are connected in series in the order of check valves, detect the temperature in each of the above-mentioned cold storage chambers, and output an on signal when the temperature is above a predetermined value, and an off signal when it is below a predetermined value; The compressor is driven by the ON signal from the temperature controller, and the refrigerant is sent only to the corresponding refrigerant circuit, and when ON signals are output from multiple temperature controllers, the refrigerant is sent to the refrigerant circuit with the highest priority. A cooling device comprising: the refrigerant control valve and refrigerant circuit controller that allow only the refrigerant to flow; a changeover switch that can change the priority order of the refrigerant circuit; and a delay circuit that delays the stop of the compressor in response to the off signal. . 2. The refrigerant control valve is an on-off valve provided in each of the series refrigerant circuits, the pressure reducer is configured with a capillary tube, and the capillary tube also serves as the on-off valve of the refrigerant circuit corresponding to the cold storage chamber that is kept cool at the lowest temperature. A cooling device according to claim 1. 3 There are two cold storage chambers, an AND circuit established by the ON signals of both temperature controllers, each second three-state gate established by the ON signal of this AND circuit, and the above AND a second inverter that respectively inverts the output of the circuit; a first three-state gate that is respectively established by an on signal of the second inverter; a first inverter that inverts the output of the temperature controller, respectively; an OR circuit that is established by an ON signal of either the first three-state gate or the second three-state gate and drives the compressor, and the logical sum circuit is configured to drive the compressor, and the logical sum circuit is established by an ON signal of either the first three-state gate or the second three-state gate and drives the compressor, and 3. The cooling device according to claim 2, wherein the cooling device is a refrigerant circuit controller configured to open a corresponding opening/closing valve with an output of .