JPH0120711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a high-pressure vessel type compressor, such as a rotary compressor, which is not equipped with an intake valve as a compressor constituting a cooling system, and turns the compressor on and off using a thermostat. This invention relates to an improvement in a refrigeration device such as a refrigerator that performs OFF operation to control the internal temperature and performs defrost operation using a heater.

Conventionally, in this type of refrigerator, the temperature inside the refrigerator has been controlled by turning on and off the operation of a compressor forming a cooling system using a temperature detection thermostat installed inside the refrigerator.

As is well known, a cooling system consists of a compressor, condenser, pressure reducing device, and evaporator connected in sequence.When the compressor is operating, high temperature, high pressure refrigerant is in the condenser and compressor, and low temperature in the evaporator. , and low-pressure refrigerants are present, respectively.

The thermostat detects that the temperature inside the refrigerator has reached a predetermined temperature, and the compressor stops operating. At the same time, the high-temperature, high-pressure refrigerant in the condenser flows through the pressure reducing device and into the evaporator. do. At this time, since the compressor is stopped, the pressure reducing device functions simply as a pressure equalizing pipe, and the refrigerant flowing into the evaporator remains at a high temperature, creating a large heat load on the interior of the refrigerator.

Furthermore, since high-pressure vessel type compressors are not equipped with suction valves, the high and low pressures in the mechanical parts of the compressor are kept airtight by oil during operation, but this oil-tightness is broken as soon as the compressor is stopped. ,
Refrigerant flows backward from the high pressure side to the low pressure side within the compression mechanism. The inside of this type of high-pressure vessel type compressor is hotter than the condenser, so backflow occurs within the compression mechanism.
The high-temperature, high-pressure refrigerant flowing into the evaporator from the compressor suction port has a larger heat load than the high-temperature, high-pressure refrigerant flowing from the condenser into the evaporator through the pressure reducing device.

The above drawbacks can be improved by applying a method of installing a refrigerant control valve, which has traditionally been used for other purposes. A defrost operation is required to remove the frost, and the condition of the cooling system during defrosting is also very important.

The present invention focuses on this type of problem, and includes a first refrigerant control valve between the condenser outlet and the pressure reducing device inlet.
A second refrigerant control valve is provided between the evaporator outlet and the compressor inlet, and the two refrigerant control valves are synchronized with the compressor operation during steady operation, and the first refrigerant control valve is synchronized with the compressor operation during defrosting. This has been improved to allow the most efficient operation, including during steady operation and during defrost, by only opening the circuit.

An embodiment in which the present invention is applied to a refrigerator will be described below with reference to the accompanying drawings.

In the figure, reference numeral 1 denotes a refrigerator body, which consists of an outer box 2, an inner box 3, and a heat insulating wall 4 formed between the boxes 2 and 3. The interior of the main body 1 is divided into two compartments, an upper freezing compartment 6 and a lower refrigerating compartment 7, by a partition wall 5, and each compartment 6, 7 is provided with a freezing compartment door 8 and a refrigerating compartment door 9, respectively. In the cooling chamber within the partition wall 4, an evaporator 10 forming part of a cooling system and a blower fan 11 for circulating cold air from the evaporator are arranged. In addition, a ventilation duct 12 is formed between the rear part of the inner box 2 and the heat insulating wall 4, and the cold air cooled by the evaporator 10 is passed through the ventilation fan 11 to the freezer compartment ventilation opening 13 of the freezer compartment 6, and to the refrigerator compartment. Room air outlet 14
It is sent to each room via.

The refrigerating air outlet 14 is equipped with a damper thermostat 15 to control the air volume so that the refrigerating chamber 7 reaches a predetermined temperature. Further, a thermostat 16 is provided on the upper wall of the freezer compartment 6, and thermostat contacts 16a and 16b are operated so that the interior of the freezer compartment 6 is opened when the temperature is below a predetermined temperature and closed when the temperature is above a predetermined temperature.

The evaporator 5 is equipped with a defrost heater 17, which is used during defrost operation by a timer 19 that switches contacts 19a-19b to contacts 19a-19b depending on the cumulative operating time of the compressor 18, which will be described later. Contact 19a-1
9c) is energized.

A machine room 20 is formed at the bottom of the main body 1,
Inside this chamber 20, there is a high-pressure container type compressor 18 that forms part of a well-known cooling system, an evaporation tray 21 for evaporating defrosting water during defrosting, and an evaporation tray 21.
An auxiliary condenser 22 etc. for heating is provided.
A main condenser 24 is provided at the rear of the main body 1 so as to form a heat radiation duct 23 between it and the rear wall 3a of the outer box 3. A recess 4 is provided in the heat insulating wall 4 at the top of the machine room 20.
A is formed in the recess 4a, and the main condenser 2 is installed in the recess 4a.
A first refrigerant control valve 26 provided between the outlet 24a of the evaporator 10 and the pressure reducing device 25, and a second refrigerant control valve 27 provided between the outlet 10a of the evaporator 10 and the compressor suction port 18a are housed. The two refrigerant control valves 26 and 27 are isolated from the outside air by a heat insulating lid 28. The two refrigerant control valves 26 and 27 open their respective refrigerant passages when the respective solenoid coils 26a and 27a are energized.
Of the first and second refrigerant control valves 26 and 27, the first refrigerant control valve 26 is connected in the forward direction of the refrigerant flow, but the second refrigerant control valve 27 is connected in the opposite direction. ing. That is, the second refrigerant control valve 2
7 has its inlet side connected to the suction port 18a of the compressor 18, and its outlet side connected to the outlet side 10a of the evaporator 10. Furthermore, the first refrigerant control valve 26
A pressure reducing device 25 (here, a capillary tube) extending from the evaporator outlet 10a to the evaporator 10 is connected to the second evaporator outlet 10a.
The suction pipe 29 leading to the refrigerant control valve 27 is wrapped and glued for heat exchange.
These are arranged so as to penetrate through the heat insulating wall 4.

The above-mentioned cooling system consists of compressor 18 → auxiliary condenser 22 → main condenser 24 → first refrigerant control valve 26
A refrigerant circulation cycle is formed by → pressure reducing device 25 → evaporator 10 → suction pipe 29 → second refrigerant control valve 27 → compressor 18.

As shown in FIG. 2, the electric circuit diagram of the above configuration shows that the motor 18b for the compressor 18, the solenoid coil 27a of the second refrigerant control valve 27, and the blower fan 6 are connected in parallel, and the timer contact 19a
-19b is connected in series. Also, timer terminal 19b and thermostat contacts 16a-16b
are connected in series. On the other hand, one end of the solenoid coil 26a of the first refrigerant control valve 26 is connected to the timer terminal 19a and the thermostat contact 16.
b, and is formed in parallel with the timer 19 circuit. Timer contact 19a-
The defrost heater 17 is connected to 19c.

Next, the operation of the above configuration will be explained. When the temperature in the freezer compartment 2 is higher than the set temperature of the thermostat 16, the thermostat contacts 16a and 16b are closed. At this time, the timer 19 is connected to contact 19a-1.
9b is closed, the compressor motor 18b, the blower fan 11, and the first and second refrigerant control valves 26 and 27 are energized to open the valves and allow the refrigerant to flow through the system, thereby performing steady cooling operation. The refrigerator compartment 7 is cooled to a predetermined temperature by adjusting the amount of air from the refrigerator compartment air outlet 14 by the damper thermometer 15. The freezer compartment 6 continues to be cooled to a set temperature by the thermostat 16, and after being cooled to the set temperature, the thermostat contacts 16a-16b are opened.

At this time, a large amount of high-temperature, high-pressure refrigerant remains in the condensers 22 and 24 and in the compressor 8, but the first and second refrigerant control valve solenoid coils 26
Since the power supply to a and 27a is stopped and each refrigerant passage is closed, the high-temperature, high-pressure refrigerant flows into the evaporator 5 from the main condenser outlet 24a and the compressor suction port 18a. is completely excluded. In particular, since the second refrigerant control valve 27 is provided opposite to the refrigerant flow direction during normal cooling operation, the high temperature,
It is possible to prevent the high-pressure refrigerant from flowing into the refrigerator 1, and to eliminate the heat load that causes an increase in power consumption inside the refrigerator 1.

When the cumulative operating time of the cooling operation reaches the set time of the timer 19, the timer contacts 19a-19b are closed.
When the temperature changes from 19a to 19c and the thermostat contacts 16a to 16b close, the steady cooling operation switches to the defrost operation. At this time, the compressor 18, the blower fan 11, and the coil 27a of the second refrigerant control valve 27 are de-energized;
The coil 26a of the refrigerant control valve 26 remains energized and open. That is, during defrosting, refrigerant is allowed to flow from the condenser 24 to the evaporator 10 via the pressure reducing device 25. More specifically, in the above circuit, the thermostat contact 16a
- Since the switch to defrost operation is only performed while 16b is closed, that is, during steady cooling operation,
At the moment when the defrost heater 17 is energized, a large amount of high-temperature, high-pressure refrigerant remains in the condensers 22, 24 and the compressor 18. Therefore, when the defrost operation is started, the high-temperature, high-pressure refrigerant flows into the evaporator 10 through the pressure reducing device 25, and serves as an auxiliary heat source for heating the evaporator 10. As a result, the defrost time is shortened and the defrost heater 19
This makes it possible to reduce power consumption.

A cooling system using this type of high-pressure container type compressor 18 has a larger amount of high-temperature, high-pressure refrigerant flowing into the evaporator 10 during cooling operation than a cooling system using a conventional low-pressure container type compressor. Because it is a very large heat source after
During the defrost operation, the amount of heat generated is greater than the electrical input that energizes the first refrigerant control valve solenoid coil 26a. Furthermore, during defrost operation, evaporator 1
The pressure in the evaporator 10 may be higher than that in the condensers 22 and 24, but since the first refrigerant control valve 26 is open, the refrigerant in the evaporator 10 flows back through the pressure reducing device 25 and returns to the condenser 22. , 24. Naturally, the condensers 22 and 24 have a large heat dissipation capacity, so the high temperature, high pressure refrigerant flowing from the evaporator 5 easily dissipates heat, and the cooling system as a whole is balanced to the saturation pressure at the lowest temperature point. Therefore, under these conditions, the input to the compressor 18 during restart can be kept lower than when the refrigerant control valves 26 and 27 are closed, balanced with the saturation pressure of the outside air temperature. .

Although the above embodiment has been described as an example applied to a refrigerator, it goes without saying that the present invention can also be applied to a case or the like that requires a refrigeration load and performs defrosting.

As is clear from the above description, the refrigeration system according to the present invention is configured by sequentially connecting a high-pressure container type compressor, a condenser, a pressure reducing device, and an evaporator, and a thermostat that senses the internal temperature. In the refrigeration system that defrosts the evaporator by operating the compressor ON-OFF, energizing the defrost heater, and stopping energizing the compressor, a first A second refrigerant control valve is provided between the evaporator outlet and the compressor inlet.
A refrigerant control valve is provided, and the first and second refrigerant control valves are configured to open the refrigerant passage when the solenoid coil is energized, and close the refrigerant passage when the solenoid coil is de-energized, A solenoid coil of a second refrigerant control valve is connected to a power source via the thermostat, and a solenoid coil of the second refrigerant control valve is connected in series with the thermostat via a timer contact that is opened during defrosting together with the compressor. Since the defrost heater is connected to the timer contact which is connected and closed during defrosting, the first and second refrigerant control valves control the condenser and compressor when the compressor is stopped during steady cooling operation. This not only reduces electricity costs by removing the heat load caused by the high-temperature, high-pressure refrigerant inside the machine flowing into the evaporator, but also reduces defrost time and heater power by using high-temperature, high-pressure refrigerant during defrosting. Moreover, it is possible to suppress the pressure in the cooling system to the minimum after defrosting, and the input (electricity cost) at the time of restart can be kept low, so the electricity cost can be reduced significantly.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a refrigerator equipped with a refrigeration system according to an embodiment of the present invention, and FIG. 2 is an electrical circuit diagram of the refrigerator. 10...Evaporator, 16...Thermostat, 1
7... (defrost) heater, 18... high pressure container type compressor, 22, 24... condenser, 25...
Pressure reducing device, 26... first refrigerant control valve, 27...
a second refrigerant control valve;

Claims (1)

[Claims] 1 A high-pressure container type compressor, a condenser, a pressure reducer, and an evaporator are connected in sequence, and the compressor is turned on by a thermostat that senses the temperature inside the refrigerator.
In the refrigeration system that defrosts the evaporator by operating in the OFF state, energizing the defrost heater, and stopping energizing the compressor, a first refrigerant control valve is provided between the condenser outlet and the evaporator inlet. , a second refrigerant control valve is provided between the evaporator outlet and the compressor inlet, and when the solenoid coil is energized, the first and second refrigerant control valves open the refrigerant passage and pass the refrigerant to the solenoid coil. The solenoid coil of the first refrigerant control valve is connected to a power source via the thermostat, and the solenoid coil of the second refrigerant control valve is connected to the compressor together with the solenoid coil of the first refrigerant control valve. A refrigeration system characterized in that the defrost heater is connected in series with the thermostat via a timer contact that is opened during defrosting, and the defrost heater is connected to a timer contact that is closed during defrost.