JPH04263742A - Refrigerator - Google Patents

Abstract

PURPOSE:To restrict rising of suction pressure of a compressor to prevent increasing of refrigerator oil discharged from the compressor by a method wherein when a volume of heat transfer is reduced by opening a condenser bypass solenoid valve, a subsidiary throttle device bypass solenoid valve is closed to operate a subsidiary throttle device. CONSTITUTION:A refrigeration cycle is constituted of a compressor 1, a condenser 2, a throttle device 3, a vaporizer 4 and a refrigerant piping 6. A condenser bypass solenoid valve 5 is connected between the compressor 1 and the vaporizer 4. The solenoid valve 5 is closed during a normal operation, while it is opened during a capacity-controlling operation of heat transfer so as to bypass a part of refrigerant discharged from the compressor 1 to the condenser 2. In a front part or a rear part of the throttle device 3, a subsidiary throttle device 9 is provided. Further, a subsidiary throttle device bypass solenoid valve 10 is connected in parallel to the subsidiary throttle device 9, so that during the normal operation, the solenoid valve 10 is opened to bypass the refrigerant to the subsidiary throttle device 9, while during the capacity- controlling operation, it is closed to make the refrigerant flow to the subsidiary throttle device 9.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention provides an auxiliary throttle device and an auxiliary throttle device bypass at the front or rear part of the throttle device.
The present invention relates to a refrigeration system that can prevent damage to a compressor and suppress an increase in power consumption due to increased discharge of refrigerating machine oil, and expand the capacity control range.

0002

2. Description of the Related Art FIG. 4 is a refrigerant circuit diagram of a conventional refrigeration system. In FIG. 4, 1 is a compressor, 2 is a condenser, 3 is a throttle device, 4 is an evaporator, 5 is a condenser bypass solenoid valve, and 6 is a refrigerant pipe that connects the compressor 1, condenser 2,
A diaphragm device 3, an evaporator 4, and a condenser bypass solenoid valve 5 are connected to form a refrigeration cycle. 7 and 8 indicate the flow direction of the refrigerant.

Next, the operation will be explained. In FIG. 4, normally, the refrigerant is compressed by the compressor 1 and becomes a high-temperature, high-pressure gas state (for example, 70°C, 15 kg/cm2), and the refrigerant is compressed by the condenser 2.
to go into. During condensation, the refrigerant releases heat to the cooling fluid (e.g., outside air), condenses and becomes a high-pressure liquid refrigerant (e.g., 15 kg/cm2), and is further depressurized by the expansion device 3 to become a low-temperature, low-pressure liquid refrigerant. It is sent to evaporator 4.

[0004] Here, the refrigerant evaporates by absorbing heat from the heat source fluid (for example, room air), becomes a low-temperature, low-pressure gas refrigerant (for example, 5° C., 4 kg/cm 2 ), and returns to the compressor 1 . At this time, the condenser bypass solenoid valve 5 is closed.
The refrigerant does not flow in the refrigerant flow direction 8, but all flows in the refrigerant flow direction 7.

Next, the capacity control will be explained. The refrigerant is compressed by the compressor 1 and becomes a high-temperature, high-pressure gas state. At this time, the condenser bypass solenoid valve 5 is open, and some of the high temperature and high pressure gas refrigerant flows into the condenser bypass solenoid valve 5 via the refrigerant flow direction 8 .

The remaining high-temperature, high-pressure gas refrigerant flows in the refrigerant flow direction 7.
It enters the condenser 2, where it releases heat to the cooling fluid, condenses and becomes a high-pressure liquid refrigerant, and then enters the throttling device 3.
The pressure is reduced and it becomes a low-temperature, low-pressure liquid refrigerant. This low-pressure low-temperature liquid refrigerant merges with the high-temperature high-pressure liquid refrigerant flowing from the condenser bypass solenoid valve 5, thereby absorbing heat and increasing the pressure (eg, 10° C., 6 kg/cm 2 ). This refrigerant is sent to the evaporator 4, where it is evaporated as the heat source stream absorbs more heat, and a low-temperature, low-pressure gas refrigerant (for example, 15°C, 6°C) is evaporated.
kg/cm2) and returns to the compressor 1.

At this time, compared to normal operation, the temperature of the refrigerant at the inlet of the evaporator 4 has increased, and since the amount of refrigerant flowing in the flow direction 7 to the condenser 2 has decreased, the amount of refrigerant flowing from the evaporator 4 to the condenser 2 has decreased. The capacity for heat to be transferred is reduced.

By repeating the above cycle, the refrigeration system configured as described above can transfer heat from the heat source fluid to the cooling fluid, and by controlling the condenser bypass solenoid valve 5, the transferred heat can be transferred. capacity can be controlled.

[0009]

[Problems to be Solved by the Invention] Since the conventional refrigeration system is constructed as described above, the condenser bypass solenoid valve 5
If it is opened, the amount of refrigerant circulating increases due to the increase in pressure in the compressor suction, and the amount of refrigerating machine oil discharged from the compressor 1 increases, so the amount of refrigerating machine oil inside the compressor becomes insufficient,
The compressor 1 may be damaged.

[0010] Furthermore, since the amount of refrigerant circulation increases despite the decrease in heat transfer capacity, the power consumption of the compressor also increases, resulting in poor energy consumption efficiency. As an approximation technique, '90 Mitsubishi Electric Corporation, Cooling and Heating Handbook,
Package air conditioner edition P1221. There is a description of the PWT-B type.

Furthermore, due to the above-mentioned problem, the amount of refrigerant in the condenser bypass is also reduced so as not to increase the amount of refrigerant circulated too much, resulting in a problem that the range in which the heat transfer capacity is restricted becomes smaller.

[0012] The present invention was made to solve the above-mentioned problems, and it is possible to increase the reliability of the compressor, improve energy consumption efficiency, and widen the range in which heat transfer capacity can be controlled. The purpose is to obtain refrigeration equipment.

[0013]

[Means for Solving the Problems] A refrigeration system according to the present invention has an auxiliary throttle device and an auxiliary throttle device bypass solenoid valve connected in parallel to the front or rear part of the throttle device.

[0014]

[Operation] The refrigeration system according to the present invention reduces the compressor suction pressure by closing the auxiliary throttling device bypass solenoid valve and operating the auxiliary throttling device when the condenser bypass solenoid valve is opened to reduce the heat transfer capacity. By suppressing the increase in the amount of refrigerant and reducing the amount of refrigerant circulation, the amount of refrigerating machine oil discharged from the compressor is prevented from increasing.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the refrigeration system of the present invention will be described below with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of an embodiment of the present invention, and FIG. 2 shows its electrical connection diagram. First, the refrigerant circuit shown in FIG. 1 will be described. In FIG. 1, parts that are the same as those in the conventional example shown in FIG. 4 are given the same reference numerals, and repeated explanation thereof will be omitted, and the parts different from those in FIG. 4 will be mainly described. In this FIG. 1, the parts indicated by numerals 1 to 8 are the same as those in FIG. 4, and the parts indicated after 9 are newly added in the embodiment of FIG. The auxiliary throttle device 10 is an auxiliary throttle device bypass solenoid valve that bypasses the auxiliary throttle device 9, and both are connected in parallel. 11 is the flow direction of the refrigerant flowing through the auxiliary throttle device 9, and 12 is the flow direction of the refrigerant flowing through the auxiliary throttle device bypass solenoid valve 10.

Next, the control circuit diagram shown in FIG. 2 will be explained. In FIG. 2, an operation switch 14 and a compressor electromagnetic contactor 13 are connected in series between the two poles of the power source E, and a capacity control switch 15 is connected in parallel to the compressor electromagnetic contactor 13. A series circuit of terminal c, fixed terminal b, and condenser bypass solenoid valve 5 is connected, and further between fixed terminal a of capacity control switch 15 and one electrode of power source E,
An auxiliary throttle device bypass solenoid valve 10 is connected.

Next, the operation will be explained. In FIG. 1, during normal operation, the refrigerant is compressed by the compressor 1, becomes a high temperature, high pressure gas state (for example, 70° C., 15 kg/cm 2 ), and enters the condenser 2. The refrigerant condenses by giving up heat to the cooling fluid (e.g. outside air), and the high pressure liquid refrigerant (e.g. 15 kg
/cm2).

At this time, the auxiliary throttle device bypass solenoid valve 1
0 is open and has very little resistance compared to the auxiliary throttle device 9, so most of the high-pressure liquid refrigerant passes through the auxiliary throttle device bypass solenoid valve 10, and the auxiliary throttle device 9 does not operate.

This high-pressure liquid refrigerant is then depressurized by the expansion device 3 to become a low-temperature, low-pressure liquid refrigerant (for example, 0° C., 4 kg/cm 2 ), and then sent to the evaporator 4 . Here, the refrigerant evaporates by absorbing heat from the heat source fluid (e.g., indoor air), and is a low-temperature, low-pressure gas refrigerant (e.g., 5°C, 4kg/cm2).
Then, the process returns to compressor 1. At this time, the condenser bypass solenoid valve 5 is closed, and the refrigerant does not flow in the refrigerant flow direction 8, but all refrigerant flows in the refrigerant flow direction 7.

Next, a description will be given of controlling the heat transfer capacity. The refrigerant is compressed by the compressor 1 and becomes a high-temperature, high-pressure gas state. At this time, the condenser bypass solenoid valve 5 is open, and some of the high temperature and high pressure gas refrigerant flows into the condenser bypass solenoid valve 5 via the refrigerant flow direction 8 . The remaining high temperature and high pressure gas refrigerant enters the condenser 2 through the refrigerant flow direction 7 and condenses into high pressure liquid refrigerant by releasing heat to the cooling fluid.

At this time, the auxiliary throttle device bypass solenoid valve 1
0 is closed, and the high-pressure liquid refrigerant is depressurized by the auxiliary expansion device 9 and further depressurized by the expansion device 3, becoming a low-temperature, low-pressure liquid refrigerant with a smaller flow rate than during normal operation. This low-pressure, low-temperature liquid refrigerant absorbs heat by merging with the high-pressure, high-temperature gas refrigerant flowing from the condenser bypass electromagnetic valve 5, and its pressure increases (eg, 0° C., 4 kg/cm 2 ). This refrigerant is sent to the evaporator 4, where it is evaporated by absorbing heat from the heat source fluid.
m2) and returns to compressor 1.

At this time, if the amount of throttling by the auxiliary throttling device 9 is increased, the pressure of the refrigerant sucked into the compressor 1 decreases, and the capacity of heat transferred from the evaporator 4 to the condenser 2 also decreases. Conversely, if the amount of throttling by the auxiliary throttling device 9 is reduced, the pressure of the refrigerant sucked into the compressor 1 will increase, and the capacity of heat transferred from the evaporator 4 to the condenser 2 will increase.

On the other hand, if the amount of refrigerant flowing through the condenser bypass solenoid valve 5 is increased, the pressure of the refrigerant sucked into the compressor 1 increases, and the capacity of heat transferred from the evaporator 4 to the condenser 2 decreases. Conversely, if the amount of refrigerant flowing through the condenser bypass electromagnetic valve 5 is reduced, the suction refrigerant pressure of the compressor 1 will decrease, and the capacity of heat transferred from the evaporator 4 to the condenser 2 will increase.

In the compressor 1, the amount of refrigerant circulated, the amount of refrigerant discharged from the compressor 1, the power consumption of the compressor 1, and the refrigerant temperature at the inlet of the evaporator 4 change depending on the suction refrigerant pressure. By determining the suction refrigerant pressure of 1 and determining the required capacity of heat to be transferred from the evaporator 4 to the condenser 2, the amount of throttling by the auxiliary throttling device 9 and the amount of refrigerant flowing to the condenser bypass solenoid valve 5 can be determined.

Next, the operation of the control circuit shown in FIG. 2 will be explained. By closing the operation switch 14, the compressor electromagnetic contactor 13 is activated, and the compressor 1 in FIG. 1 is operated.
Heat transfer begins from the heat source fluid to the cooling fluid. At this time, if the movable terminal c of the capacity control switch 15 is connected to the fixed terminal a side, the auxiliary throttle device bypass solenoid valve 10 is opened, the condenser bypass solenoid valve 5 is closed, and normal operation is performed. Furthermore, the movable terminal c of the capacity control switch 15 is connected to the fixed terminal b.
If connected to the auxiliary throttle device bypass solenoid valve 10
and open the condenser bypass solenoid valve 5 to reduce the heat transfer capacity.

Next, by opening the operation switch 14, the compressor 1 shown in FIG. 1 is stopped, and the heat transfer from the heat source fluid to the cooling fluid is completed.

By repeating the above cycle, the refrigeration system configured as described above can transfer heat from the heat source fluid to the cooling fluid. By opening and closing the valve 5 and starting and stopping the compressor 1, the capacity of heat transferred from the heat source fluid to the cooling fluid can be adjusted.

In the above embodiment, the auxiliary throttle device 9 and the auxiliary throttle device bypass solenoid valve 1 are provided at the front of the throttle device 3.
0 is shown, but as shown in FIG.
An auxiliary throttling device 9 and an auxiliary throttling device bypass solenoid valve 10 may be provided at the rear of the auxiliary throttling device 9 and in parallel therewith.

[0029]

As described above, according to the present invention, an auxiliary throttle device and an auxiliary throttle device bypass solenoid valve for bypassing the auxiliary throttle device are provided at the front or rear part of the throttle device,
When the condenser bypass solenoid valve opens, the auxiliary throttling device bypass solenoid valve is configured to close, so when controlling the heat transfer capacity, it is possible to prevent compression due to insufficient refrigerating machine oil inside the compressor due to increased refrigerant circulation. This prevents machine damage and does not increase compressor power consumption, improving energy consumption efficiency. Furthermore, since the amount of refrigerant in the condenser bypass can be increased, the range in which the capacity of heat transferred from the heat source fluid to the cooling fluid can be controlled can be increased.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant circuit diagram of a refrigeration system according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a control circuit of the refrigeration system in FIG. 1;

FIG. 3 is a refrigerant circuit diagram of a refrigeration system according to another embodiment of the present invention.

FIG. 4 is a refrigerant circuit diagram of a conventional refrigeration system.

[Explanation of symbols]

1 Compressor 2 Condenser 3 Squeezing device 4 Evaporator 5 Condenser bypass solenoid valve 6 Refrigerant piping 9 Auxiliary diaphragm device 10 Auxiliary throttling device bypass solenoid valve

Claims (1)

[Claims] [Claim 1] Compressor, condenser, throttling device, evaporator,
A refrigeration cycle constituted by refrigerant piping, and a refrigerant connected between the outlet side of the compressor and the inlet side of the evaporator, closed during normal operation, and opened during heat transfer capacity control operation to be discharged from the compressor. a condenser bypass solenoid valve that bypasses a part of the condenser to the condenser; an auxiliary throttle device provided at the front or rear of the throttle device; A refrigeration system comprising: an auxiliary throttling device bypass solenoid valve that bypasses the refrigerant to the auxiliary throttling device and closes during the capacity control operation to allow the refrigerant to flow to the auxiliary throttling device.