JPH048704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump type air conditioner such as a separate air conditioner having an indoor side unit and an outdoor side unit.

Conventionally, there has been an air conditioner as shown in FIG. 1 as described above.

In Fig. 1, 1 is a compressor, 2 is a four-way valve, and 3 is a compressor.
is an outdoor heat exchanger, 4 is a distributor, and 5 is an outdoor heat exchanger.
is an expansion valve, 6 is a connecting pipe, 7 is an indoor heat exchanger,
8 is a connection pipe, 9 is an accumulator, and in a separate air conditioner, at least the indoor heat exchanger 7
are provided in the indoor unit, and each member not provided in the indoor unit is provided in the outdoor unit.

In such an air conditioner, during cooling operation, high-temperature, high-pressure refrigerant discharged from the compressor 1 and lubricating refrigerating machine oil mixed with this refrigerant pass through the four-way valve 2 and reach the outdoor heat exchanger 3, where they are The liquid refrigerant undergoes heat exchange and becomes a high-temperature, high-pressure liquid refrigerant. This liquid refrigerant passes through the distributor 4, is depressurized by the expansion valve 5, passes through the connecting pipe 6, reaches the indoor heat exchanger 7, and evaporates there and is transferred to the connecting pipe. 8, the four-way valve 2, the accumulator 9, and is sucked into the compressor 1 again, forming a circulation cycle.

However, in such an air conditioner, the compressor 1
When the refrigerant is started, the refrigerant that has been mixed into the refrigerating machine oil and is in a so-called sleeping state causes forming, and a large amount of refrigerating machine oil is discharged.The discharged refrigerating machine oil circulates through the refrigeration cycle and flows to the suction side of the compressor 1. However, if the connecting pipes 6 and 8 become long, it will take time for the discharged refrigerating machine oil to circulate and return to the compressor 1, and the refrigerating machine oil in the compressor 1 will decrease. This has the drawback of causing poor lubrication of the compressor and seizure of sliding parts. Moreover, such drawbacks also occur during heating operation.

Furthermore, when performing compressor capacity control operation or low-load operation, the amount of refrigerant circulated decreases and the speed of refrigerant flowing in the piping decreases, making it difficult for the refrigerant oil to return to the compressor. However, there is a drawback that lubrication failure of the compressor similar to that mentioned above occurs.

This invention aims to eliminate the above-mentioned drawbacks of the conventional ones, and includes an oil separator provided between the discharge side of the compressor and the four-way valve, and the oil separator and accumulator are connected via a solenoid valve. The solenoid valve is opened by the control device for a certain period of time from the start of the compressor and the refrigerating machine oil is returned to the accumulator from the bypass path, thereby preventing compressor lubrication failure due to lack of refrigerating machine oil. The present invention provides an air conditioner that is capable of preventing air-conditioning capacity from decreasing and causing damage to the compressor by continuously returning part of the refrigerant to the compressor via a bypass path during operation of the compressor. is intended to provide.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, parts that are the same as those in FIG. 1 are given the same reference numerals, and their explanation will be omitted. Reference numeral 10 denotes an oil separator, and the oil separator 10 is provided between the discharge side of the compressor 1 and the four-way valve 2 of the refrigeration cycle, with the upper portion connected thereto. 11 is a bypass path connecting the lower part of the oil separator 10 and the accumulator 9, and 12 is a solenoid valve provided in the middle of the bypass path 11.

FIG. 3 shows the electrical circuit of the control device according to this embodiment. In Fig. 3, CM is the electric motor for the compressor 1, F ₁ M is the electric blower motor for blowing air to the outdoor heat exchanger 3, and F ₂ M is the electric blower motor for blowing air to the indoor heat exchanger 7. , SW ₁ is an operation switch, SW ₂ is an air conditioning/heating switch, and 23W is an indoor temperature thermoswitch.When the indoor temperature is higher than the set value, the contact of the thermoswitch 23W is (c)-
In (a), when the value is lower than the set value, the contact is switched between (b) and (c). 52F is a contactor coil for the blower motor F ₂ M, and when this coil 52F is energized and energized, its contact 52f is closed, and the blower motor F ₂ M is energized and operated, and deenergized and deenergized. Then, the contact 52f is opened and the blower electric motor F ₂ M is stopped. Also,
52C is the compressor motor CM and blower motor
F ₁ M contactor coil, this coil 52
When C is energized and excited, its contact 52c is closed, and the compressor motor CM and blower motor
When F ₁ M is operated and deenergized, contact 52
c is opened, and the compressor motor CM and blower motor F ₁ M are stopped. 21C is a coil of the electromagnetic valve 12. When the coil 21C is energized and excited, the electromagnetic valve 12 is opened, and when the coil 21C is deenergized and deenergized, the electromagnetic valve 12 is closed. _21S4 is the coil of the four-way valve 2, and when this coil _21S4 is energized and excited, the second
The four-way valve 2 is switched so that the heating operation is performed in which the refrigerant flows as shown by the broken line arrow in the figure, and the cooling operation (or defrost operation) is performed in which the refrigerant flows as shown in the solid line arrow in FIG. 2 when deenergized and demagnetized. TM
is a timer motor, and this motor TM rotates when energized and stops rotating when de-energized. tm is a timer contact, and the set time (tm ₁ +
tm ₂ ), the timer motor rotates once, and at this time, the contact tm is open for the set time tm ₁ , and the next set time tm ₂
The contact tm is closed during this period, and this process is repeated. Y is a time-limited relay, and when this time-limited relay Y is energized, its contact y is closed for a fixed time _tm3 ,
After that, contact y remains open as long as the current is applied.
Then, the coil 52C of the contactor, the coil 21C of the solenoid valve 12, the timer motor TM, and the time-limiting relay Y.
is connected in parallel to the contact (c) of the indoor temperature thermoswitch 23W. 26S is a contact point of a thermostat attached to the suction pipe, which closes when the temperature falls below a certain set value and opens when the temperature rises above the set value. _26D1 is a contact point of the defrost start thermostat, which closes when the temperature falls below the set value and opens when the temperature rises above the set value.

_26D2 is a contact point of the defrost end thermostat, which closes when the temperature falls below the set value and opens when the temperature rises above the set value. Note that the set value of the defrost start thermostat is lower than the set value of the defrost end thermostat. X2 is an auxiliary relay coil connected in series with thermostats 26D ₁ and 26D ₂ ;
When energized and excited, the contact 2χa closes and the contact 2χb,
2χc, 2χd, 2χe open, and when demagnetized, contact 2χa opens and contacts 2χb, 2χc, 2χd, 2χe close. X3 is a coil of an auxiliary relay connected in series with the contact 26S of the thermostat, and when energized and energized, the contact 3χa closes, and when deenergized and deenergized, the contact 3χa opens. X1 is the coil of the auxiliary relay, and the contact point 26D ₁ of the thermostat,
It is connected in series with 26D ₂ and in parallel with the coil X2 of the auxiliary relay, and when it is energized and energized, its contact 1χa closes, and when it is deenergized and deenergized, its contact 1χa is opened. Also, the timer contact is connected to the coil 21C of the solenoid valve 12.
tm, contact y of time-limited relay Y, and contacts 2χa and 3χa of auxiliary relays X2 and X3 are connected in parallel.

When the indoor temperature is higher than the set value of the thermo switch 23W during cooling, when the operation switch SW ₁ is turned on, the coil 52F of the contactor is energized and the contact 52f is closed, and the blower motor F of the indoor heat exchanger is turned on. ₂ M is activated and the heating/cooling switch is turned on.
Since SW ₂ is on the cooling side (d) and the contacts (a) and (c) of the thermo switch 23W are connected, the contactor coil 52C is energized and the contact 52c is closed, and the compressor motor CM is turned on. The compressor 1 starts to drive.

In addition, since the time-limited relay Y is also energized, the contact y
is closed, the coil 21C of the solenoid valve is excited, the solenoid valve 12 is opened, and the bypass path 11 is opened. Further, after the set time tm ₃ has elapsed, the time-limited relay Y is demagnetized, the contact y is opened, the coil 21C of the solenoid valve is demagnetized, the solenoid valve 12 is closed, and the bypass path 11 is closed. Note that this also applies to startup during heating. The timer motor TM is energized and continues to rotate, and when the set time tm ₁ has elapsed, the contact tm closes and the solenoid valve coil 21C
is excited, the solenoid valve 12 is opened, and the set time
After tm ₂ has elapsed, the contact tm is opened, the coil 21C is demagnetized, the solenoid valve 12 is closed, and the above-described operation is repeated thereafter. Note that this also applies during heating.

During heating, when the room temperature is lower than the set value of the thermo switch 23W, when the operation switch SW ₁ is turned on, the contactor coil 52F is energized and the contact 52 is turned on.
f is closed, and the blower motor for the indoor heat exchanger
F ₂ M is started, the air conditioning/heating changeover switch SW ₂ is set to the heating side (E), the coil 21S ₄ of the four-way valve 2 is excited and the heating operation is started, and the contacts (B) and (C) of the thermo switch 23W are connected. Therefore, the coil 52C of the contactor is excited, the contact 52c is closed, and the compressor 1 is started.

Since the time-limited relay Y is also energized, the contact y is closed and the coil 21C of the solenoid valve is energized, and the solenoid valve 12 is opened and the bypass path 11 is formed. Furthermore, after the set time _tm3 , the time-limited relay Y is demagnetized, the contact y is opened, the coil 21C is demagnetized, the solenoid valve 12 is closed, and the bypass path 11 is closed.

The timer motor TM is energized and continues to rotate.
As in the case of cooling described above, the coil 21C is energized after the set time tm ₁ has elapsed, and demagnetized after the set time tm ₂ has elapsed, and the operation of opening and closing the solenoid valve 12 is repeated.

Also, when the temperature of the thermostat attached to the suction pipe falls below the set value during low-temperature heating, its contact 26S closes, the auxiliary relay coil X3 is energized, the contact 3χa closes, and the solenoid valve coil 21C When excited, the solenoid valve 12 is opened and the bypass path 11 is opened.

Furthermore, in defrosting, first, when the set temperature falls below the set value of the higher defrost end thermostat, that contact _26D2 closes, and then when the set temperature falls below the set value of the defrost start thermostat, that contact closes. 26D ₁ is closed and the auxiliary relay coil X2
is excited and the contact 2χc is opened, so the coil 21S ₄ of the four-way valve 2 is demagnetized and defrosting begins.
At the same time, contact 2χb, 2 of coil X2 of auxiliary relay
When χd and 2χe are opened, the motor F ₂ M of the indoor heat exchanger 7 and the motor F ₂ M of the outdoor heat exchanger 3 are stopped, and the contact 2χa is closed, and the coil 21 of the solenoid valve is closed.
C is excited, the solenoid valve 12 is opened, and the bypass path 11 is opened. Further, the coil X1 of the auxiliary relay is energized, the contact 1χa is closed, and the coil _X1 of the auxiliary relay is connected in parallel with the contact 26D1 of the defrosting start thermostat.
When defrosting starts, the temperature immediately rises above the set value of the defrost start thermostat and its contact 26
D ₁ is open, and the defrosting end thermostat contact 26D ₂ , contact 1χa, auxiliary relay coil X2,
A circuit of X1 is formed. When the temperature rises above the set value of the defrost thermostat, its contact 26
D ₂ is open, and the auxiliary relay coils X2 and X1
is demagnetized and defrosting is completed.

Next, the operation of the refrigeration cycle shown in FIG. 2 will be explained. In Figure 2, the solid arrows indicate the flow of refrigerant during cooling and defrosting operations, and the dashed arrows indicate the flow of refrigerant during heating.
The dashed dotted line indicates the flow of refrigerant and refrigerating machine oil in the bypass path.

During cooling operation, high-temperature, high-pressure refrigerant gas and refrigerating machine oil discharged from the compressor 1 enter the oil separator 10 from above, and the refrigerating machine oil is separated from the refrigerant gas and accumulated at the bottom of the oil separator 10. The refrigerant gas separated from the refrigeration oil exits from the upper part of the oil separator 10, passes through the four-way valve 2, reaches the outdoor heat exchanger 3, where it exchanges heat and becomes a high-temperature, high-pressure refrigerant liquid, which passes through the distributor 4. It is depressurized by the expansion valve 5, evaporated in the indoor heat exchanger 7 via the connecting pipe 6, and then returns to the compressor via the connecting pipe 8, the four-way valve 2, and the accumulator 9.

During this operation, the solenoid valve 12 located in the middle of the bypass path 11 is closed, but when refrigerating machine oil accumulates in the oil separator 10, the solenoid valve 12 is opened by a signal and the oil accumulates in the lower part of the oil separator 10. The refrigerating machine oil passes through the bypass path 11, is returned to the accumulator 9 via the solenoid valve 12, and is returned to the compressor 1 together with the low-temperature, low-pressure refrigerant gas that has returned from the indoor heat exchanger 7. This greatly shortens the refrigerating machine oil circulation circuit. This operation is almost the same during heating operation.

Therefore, even if the indoor unit and outdoor unit of the air conditioner are far apart, that is, even if the connecting pipes 6 and 8 are long, the refrigerating machine oil circulation circuit is short and passes through the bypass path 11, so the compression There is no possibility of a shortage of refrigerating machine oil in machine 1. In addition, when the compressor 1 is of the capacity control type, even when the circulating amount of refrigerant discharged from the compressor is significantly reduced and becomes small, that is, when the speed at which the refrigerant moves in the piping becomes low, Since the distance of the circuit through which the refrigerating machine oil circulates is short, there is no possibility of insufficient return of the refrigerating machine oil.

When the compressor 1 is started, the time-limited relay Y
Therefore, the solenoid valve 12 is kept open for a certain period of time tm ₃ after the compressor 1 is started, so that the refrigerant that has been mixed in the refrigerating machine oil when the compressor 1 is stopped will form when the compressor starts. Even if a large amount of refrigerating machine oil is discharged from the compressor 1 compared to during normal continuous operation, the refrigerating machine oil separated from the refrigerant by the oil separator 10 passes through the bypass path 11 and passes through the open electromagnetic It returns to the accumulator 9 via the valve 12 and returns to the compressor 1 together with the low-pressure gas, making it possible to compensate for a shortage of refrigerating machine oil in the compressor in a short time.

Furthermore, when the heating operation changes to the defrosting operation, the auxiliary relay coil X2 is energized, contact 2χa is closed, and the solenoid valve coil 21C is energized,
2 opens, and at the same time, the four-way valve 2 is switched.
Therefore, the high-temperature, high-pressure refrigerant gas compressed by the compressor 1 passes through the oil separator 10, the four-way valve 2, and reaches the outdoor heat exchanger 3, and after defrosting it, the distributor 4 The pressure is reduced by the expansion valve 5, and the connection pipe 6, the indoor heat exchanger 7, and the connection pipe 8
It passes through the four-way valve 2 and returns to the accumulator 9. At the same time, a portion of the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 is returned to the accumulator 9 from the lower part of the oil separator 10 via the bypass passage 11 and through the electromagnetic valve 12 . In the accumulator 9, the low-temperature, low-pressure refrigerant gas that has passed through the indoor heat exchanger 7, which functions as an evaporator, is mixed with the high-temperature, high-pressure refrigerant gas that has passed through the bypass path 11. The pressure increases and returns to the compressor 1. As a result, it is possible to create a state in which the refrigerant gas has a small specific volume and a large circulation amount, and therefore the outdoor heat exchanger 3
Frost that adheres to the surface can be melted and removed in a short time.

When the heating temperature is low, there is a risk of frost forming on the outdoor heat exchanger 3 immediately, so when the temperature falls below the set value of the thermostat attached to the suction pipe, its contact 26S closes, and the coil X3 of the auxiliary relay closes.
is excited, its contact 3χa closes, the coil 21C of the solenoid valve is energized, the solenoid valve 12 is opened, and a part of the high temperature and high pressure refrigerant gas discharged from the compressor 1 passes through the oil separator 10 and the bypass path 11. The air is bypassed and returned to the accumulator 9, thereby increasing the heating capacity at low heating temperatures.

When a variable capacity compressor 1 is used, the above-mentioned solenoid valve 1 for defrosting and heating at low temperatures is used.
By operating the compressor at its maximum capacity while 2 is open, it is more effective to increase the defrosting capacity and heating capacity.

During cooling or heating operation, after starting the compressor 1, continuous operation is performed for a certain period of time tm ₁ , and then the contact tm of the timer motor TM closes, and the timer motor TM
continues to rotate, the coil 21C is energized for a set time tm ₃ at set time intervals tm ₂ and the solenoid valve 12 is opened, so that the refrigeration oil stored in the oil separator 10 is bypassed from the oil separator 10. Road 11
via the solenoid valve 12 to the accumulator 9
The refrigerating machine oil is returned to the compressor 1 along with the low-temperature, low-pressure refrigerant gas returned from the heat exchanger serving as the evaporator, and the compressor is replenished with refrigerating machine oil, so there is no shortage of refrigerating machine oil.

Furthermore, since this embodiment is configured as described above, even if the refrigerant accumulated in the connecting pipe 8 returns to the discharge port side of the compressor 1 due to its own weight when the air conditioner is stopped, the oil It is possible to prevent the liquid from being accumulated in the separator 10 and entering the discharge port of the compressor 1, and therefore to prevent the valve of the compressor 1 from being damaged during startup.

In the above embodiment, a split-type air conditioner in which the compressor is located outside the room has been described, but the present invention can also be applied to a remote-type air conditioner in which the compressor is located inside the room. Further, in the above embodiment, an expansion valve was used as the throttle device, but in the present invention, a throttle device such as a capillary tube, an electric expansion valve, or an orifice can be used, and the mounting position of the throttle device is also on the indoor side. It may be placed anywhere between the heat exchanger and the outdoor heat exchanger.

As explained above, according to the present invention, an oil separator is provided between the discharge side of the compressor and the four-way valve, and the oil separator and the accumulator are connected via a bypass path via a solenoid valve. By opening the solenoid valve, the refrigerating machine oil and high-temperature, high-pressure refrigerant gas are returned to the accumulator via the bypass path, which prevents damage to the valve and poor lubrication that would occur if the refrigerating machine oil was returned directly to the compressor. In addition to preventing seizure accidents of sliding parts, it is easy to increase the installation distance between indoor and outdoor units, that is, the connecting piping, and when using a variable capacity compressor, the refrigerant discharge amount can be reduced. Even during operation where the refrigerating machine oil is significantly reduced, the refrigerating machine oil can be easily and sufficiently returned to the compressor.In particular, the control device is equipped with a means to open the solenoid valve when the compressor is started and close it after a certain period of time, so that the refrigerating machine oil can be easily and sufficiently returned to the compressor. Sometimes, the refrigerant trapped in the compressor oil forms when the compressor is started, and even if a larger amount of refrigerant oil is discharged from the compressor than during normal continuous operation, the refrigerant oil can be transferred to the compressor in a short time. It can be easily restored and during normal continuous operation,
Closing the solenoid valve prevents a portion of the refrigerant from returning to compression via the bypass path, so air conditioning performance is not reduced. Therefore, it is possible to provide an air conditioner with high comfort, high reliability, and high precision in a heat pump with a simple configuration and at a low cost.

[Brief explanation of drawings]

Figure 1 is a configuration explanatory diagram showing a conventional air conditioner;
FIG. 2 is a configuration explanatory diagram showing an air conditioner according to an embodiment of the invention, and FIG. 3 is an electric circuit diagram of a control device according to an embodiment of the invention. 1... Compressor, 2... Four-way valve, 3... Outdoor heat exchanger, 4... Distributor, 5... Expansion valve, 6, 8... Connection piping, 7... Outdoor heat exchanger , 9...Accumulator, 10...Oil separator, 11...Bypass path, 12...Solenoid valve, CM
...Compressor motor, F ₁ M, F ₂ M...Outdoor side,
Indoor heat exchanger blower electric motor, SW ₁ ...operation switch, SW ₂ ...air conditioning/heating selector switch, 23W
...Indoor temperature thermo switch, 52C, 52F...
...Contactor coil, 21C...Solenoid valve coil,
21S ₄ ...Four-way valve coil, TM...Time motor, Y...Time relay, 26D ₁ , 26D ₂ ...
Defrost start, defrost end thermostat contact, 26
S...Thermostat contacts, X1, X2, X3
...Auxiliary relay coil. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In an air conditioner having a refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, a throttling device, an indoor heat exchanger, and an accumulator are connected in a ring, the air conditioner is installed between the discharge side of the compressor and the four-way valve. a bypass path connecting the oil separator and the accumulator via a solenoid valve, and a solenoid valve for returning refrigerating machine oil from the oil separator to the accumulator when the compressor is started An air conditioner characterized by comprising: a control device having means for opening and closing after a certain period of time.