JPH0233110Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an air-cooled heat pump type air conditioner.

(Prior Art) An example of a conventional air-cooled heat pump type air conditioner is shown in FIGS. 3 and 4, FIG. 3 is a refrigerant circuit diagram thereof, and FIG. 4 is an electrical control circuit diagram thereof.

During heating operation, the refrigerant flows through the compressor 1, four-way switching valve 2, indoor heat exchanger 3, check valve 5, heating throttle 7, outdoor heat exchanger 9,
It passes through the four-way switching valve 2 and the accumulator 11 in this order and returns to the compressor 1.

During cooling operation, the refrigerant flows through the compressor 1, the four-way switching valve 2, the outdoor heat exchanger 9, the check valve 8, the cooling throttle 6, the indoor heat exchanger 3, and the four-way switching valve as shown by the broken line arrow in FIG. It passes through the valve 2 and the accumulator 11 in this order and returns to the compressor 1. 4 is an indoor fan, 1
0 is an outdoor fan, 12 is a high-pressure switch that detects the pressure inside the high-pressure gas refrigerant circuit and is activated to stop the air conditioner when the pressure exceeds a predetermined value, and 13 is a defrosting thermostat. During the heating operation, frost forms on the outdoor heat exchanger 9, and the circuit is closed when the temperature of the refrigerant flowing through it falls below a predetermined value. 14 is a defrosting controller, which includes a defrosting relay 114 and its contact 1.
14A, 114B, a timer 115 and its contacts 115A. When the time set in the timer 115 has elapsed during heating operation, the contact 1
15A is closed, when the defrosting thermometer 13 is closed, the defrosting relay 114 is energized, and its contacts 114A and 114B are switched in the opposite direction to that shown in the figure, and the four-way switching valve solenoid 2A and the outdoor fan relay 110 are switched. By degaussing, the four-way switching valve 2 is switched to the cooling operation state, and the outdoor fan 10 is stopped to perform the defrost operation, and the refrigerant is circulated as shown by the broken line arrow in FIG. 3 in the same way as during the cooling operation. By flowing high temperature refrigerant gas into the outdoor heat exchanger 9, frost adhering thereto is melted. As a result of the defrost operation, when the defrost thermostat 13 opens, the defrost relay 114
is demagnetized and its contacts 114A and 114B are switched back to the state shown. Along with this,
At the same time as the four-way switching valve 2 is switched to the heating operation state, the outdoor fan 10 is activated and the timer 115 is reset. Reference numeral 15 denotes a cold air prevention thermostat, which closes when the temperature of the refrigerant flowing through the indoor heat exchanger 3 is below a predetermined value during defrost operation. 16
is the cold wind prevention controller and the cold wind prevention relay 1.
16 and its contact 116A. When the cold air prevention thermometer 15 closes, the cold air prevention relay 116 is energized and its contacts 116
The indoor fan 4 is stopped by opening the circuit A and demagnetizing the indoor fan relay 104. In FIG. 4, 130 is a start switch, 131 is a cooling/heating switch, and 101 is a compressor relay.

(Problems to be solved by the invention) In the conventional air conditioner described above, during high load operation such as when the room temperature or outside temperature rises, the refrigerant pressure in the refrigerant circuit increases, so the high pressure switch 12 is closed. The air conditioner will stop operating. Furthermore, in this case, the temperature of the refrigerant in the circuit also rises, causing deterioration of the refrigerating machine oil and causing damage to the compressor 1.

Additionally, if the indoor fan 4 is stopped during defrost operation, there is almost no heat absorption from the indoor heat exchanger 3, and the amount of refrigerant circulated is reduced, so the time required for defrosting becomes longer, and the air is sucked into the compressor 1 during defrost operation. A problem arises in that the refrigerant pressure applied becomes negative pressure and the performance of the compressor 1 is deteriorated.

(Means for Solving the Problems) The present invention was proposed to solve the above-mentioned conventional problems, and its gist is a compressor, a four-way switching valve, an indoor heat exchanger, an air conditioner, and an air conditioner. In an air-cooled heat pump air conditioner comprising a refrigerant circuit incorporating a heating diaphragm, an outdoor heat exchanger, and an accumulator, between the high-pressure liquid refrigerant circuit of the refrigerant circuit and the inlet side of the accumulator. a bypass refrigerant circuit having a solenoid valve and a throttle, and a control circuit that opens the solenoid valve during overload operation and defrost operation, and disables the defrost control circuit when the solenoid valve is opened during overload operation. The air-cooled heat pump type air conditioner is characterized by the following features:

(Embodiment) An embodiment of the present proposal is shown in FIGS. 1 and 2, where FIG. 1 is a refrigerant circuit diagram and FIG. 2 is an electrical control circuit diagram. In FIGS. 1 and 2, the same equipment as in FIGS. 3 and 4 is given the same reference numeral.

A high-pressure liquid refrigerant circuit 30, that is, a bypass between the refrigerant pipe connecting the cooling throttle 6 and the heating throttle 7 through which high-pressure liquid refrigerant flows during cooling operation, heating operation, and defrosting operation, and the inlet side of the accumulator 11 They are connected through a refrigerant circuit 31, and this bypass refrigerant circuit 31 is provided with a solenoid valve 19 and a throttle 20. 17 is a discharge refrigerant gas temperature detection thermometer connected to the discharge pipe of the compressor 1; 18 is a high pressure detector;
21 is a controller that includes a bypass relay 121, its normally open contact 121A, and its normally closed contact 121B.
It is equipped with And bypass relay 121
is connected in series with the discharge refrigerant gas detection thermo 17 and the high pressure pressure detector 18, and the normally open contact 121A is in parallel with the contact 114C of the defrosting relay 114, and
It is connected in series with the coil 19A for the electromagnetic valve 19, and the normally closed contact 121B is connected in series with the defrosting relay 114.

During heating operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 as shown by the solid arrow in FIG. It exchanges heat with air and condenses to become a high-pressure liquid refrigerant, passes through a check valve 5, is depressurized by a throttle 7, and becomes a two-phase flow of low-pressure liquid gas.
The outdoor heat exchanger 9 exchanges heat with the outside air sent in from the outdoor fan 10 and vaporizes it to become a low-pressure gas refrigerant, which passes through the four-way valve 2 and returns to the compressor 1 via the accumulator 11.

During cooling operation, the refrigerant flows from the compressor 1 to the four-way valve 2, to the outdoor heat exchanger 9, to the check valve 8, to the cooling throttle 6, to the indoor heat exchanger 3, to the four-way valve 2, as shown by the broken line arrow in FIG. It passes through the accumulator 11 in this order and returns to the compressor 1.

During the defrost operation, the refrigerant flows as shown by the broken line arrow in FIG. 1, similar to the above-mentioned cooling operation.

During heating operation, when the room temperature or outside temperature is high, the pressure inside the refrigerant circuit from the outlet of the compressor 1 to the inlet of the heating throttle 7 and the temperature of the refrigerant gas discharged from the compressor 1 become high. Therefore, the high-pressure pressure detector 18 and the discharge gas temperature detection thermometer 17 are closed to excite the bypass relay 121, and at the same time, the normally open contact 121A is closed and the normally closed contact 121B is opened. When the normally open contact 121A closes, the solenoid valve coil 19A is excited and the solenoid valve 19 opens.
Thus, the high-pressure liquid refrigerant in the high-pressure refrigerant circuit 30 flows into the accumulator 11 through the solenoid valve 19 and throttle 20 of the bypass refrigerant circuit 31, where it is temporarily held and then gradually returns to the compressor 1. . When the liquid refrigerant is held in the accumulator 11, the amount of refrigerant circulating in the refrigerant circuit decreases, and the refrigerant pressure in the refrigerant circuit decreases, causing the defrosting thermostat 13 to decrease.
The temperature of the refrigerant piping to which it is installed also decreases, but
Since the normally closed contact 121B is open, the defrost operation will not start even if the defrosting thermostat 13 is closed.

During cooling operation, the attachment pipe of the high-pressure pressure detector 18 becomes a low-pressure line, and the high-pressure pressure detector 18 is closed, so that the electromagnetic valve 19 is opened and closed by opening and closing only the discharge gas temperature detection thermometer 17. During the defrost operation, the contact 114C of the defrost relay 114 is closed, so the bypass solenoid valve 19 is also opened during the defrost operation.

By selecting the operating pressure of the high-pressure pressure detector 18 to be lower than the operating pressure of the high-pressure pressure switch 12, the high-pressure pressure switch 12 is activated, and before the compressor 1 stops operating, the solenoid valve 19 is opened and the accumulator 11
This reduces the amount of refrigerant circulating in the refrigerant circuit by temporarily holding liquid refrigerant in the refrigerant circuit.

In addition, even if the discharged refrigerant gas temperature is below the operating pressure of the high-pressure pressure switch 12, the discharged refrigerant gas temperature may exceed the usage limit of the compressor 1, so the operating value of the discharged gas temperature detection thermometer 17 is set as the discharged gas temperature usage limit of the compressor 1. The solenoid valve 19 is activated before the discharge refrigerant gas temperature exceeds the usage limit of the compressor 1.
is opened, the liquid refrigerant is temporarily held in the accumulator 11, and the liquid refrigerant is gradually returned to the compressor 1.

Furthermore, since the solenoid valve 19 is opened during defrosting, the amount of refrigerant sucked into the compressor 1 increases.

However, in the conventional air conditioners shown in FIGS. 3 and 4, when the outside temperature rises during heating operation,
The amount of heat absorbed by the outdoor heat exchanger 9 increases, and the evaporation pressure of the refrigerant increases, and the compressor 1 sucks and compresses this refrigerant gas, so that the high pressure increases. On the other hand, when the indoor temperature rises, the condensation temperature of the refrigerant rises, so the high pressure increases. That is, the high pressure increases regardless of whether the room temperature or the outside temperature rises, and when the high pressure switch 12 is activated, the operation of the air conditioner is stopped.

On the other hand, in the air conditioners shown in FIGS. 1 and 2, when the high-pressure pressure detector 18 is activated due to a rise in outside temperature or room temperature, the solenoid valve 19 opens and liquid refrigerant flows into the accumulator 11. The compressor 1 gradually returns to the compressor 1. Therefore, by reducing the amount of refrigerant circulating in the refrigerant circuit, the high pressure is lowered and the high pressure switch 12 can be prevented from operating, and the range of outside temperature and room temperature that can be operated is expanded than before. can. Thereafter, when the room temperature or outside temperature drops and the high-pressure pressure sensor 18 returns to normal, the solenoid valve 19 closes and the refrigerant in the accumulator 11 circulates through the refrigerant circuit again.

In addition, during cooling operation and heating operation, when the temperature of the discharged refrigerant gas rises, the discharged gas temperature detection thermometer 17 is activated, the solenoid valve 19 is opened, and a portion of the liquid refrigerant returns to the compressor 1. By lowering the temperature of the coil winding of the compressor 1, it contributes to improving the reliability of the compressor 1.Afterwards, when the room temperature or outside temperature drops and the temperature of the discharged refrigerant gas decreases, the discharged gas temperature detection thermometer 17 returns and the solenoid valve 19 closes. Also,
During defrost operation, in the conventional air conditioner shown in FIGS. 3 and 4, the frosted outdoor heat exchanger 9 functions as a condenser and the high pressure becomes extremely low. Therefore, the flow rate of refrigerant passing through the cooling throttle 6 decreases, and at the same time the indoor fan 4 stops, and there is no heat exchange in the indoor heat exchanger 3, and the amount of refrigerant circulating becomes very small, so there is a shortage of refrigerant sucked into the compressor 1. However, because the suction pressure of the compressor 1 becomes a negative pressure and the amount of refrigerant circulated is small, it takes a long time to melt the frost on the outdoor heat exchanger 9. However, in the air conditioners shown in FIGS. 1 and 2, the defrosting relay 114 is
The solenoid valve 19 is opened using the contact point 114C, and the refrigerant is forcibly returned to the compressor 1.
The amount of refrigerant flowing into the compressor increases, the time required for defrosting can be shortened, and the problem of negative suction pressure of the compressor 1 can be solved.

(Operations and effects of the invention) Although the embodiments have been specifically explained above, the present invention includes a compressor, a four-way switching valve, an indoor heat exchanger, a cooling diaphragm, a heating diaphragm, an outdoor heat exchanger, and an accumulator. In an air-cooled heat pump type air conditioner having a refrigerant circuit incorporating a The valve is opened during overload operation and defrost operation, and a control circuit is provided that disables the defrost control circuit when the solenoid valve is opened during overload operation. Or, when the room temperature rises, or when the temperature of the discharged refrigerant gas rises during heating or cooling operation, open the solenoid valve and let the liquid refrigerant in the high-pressure liquid refrigerant circuit pass through the solenoid valve and the throttle into the accumulator. By temporarily holding the refrigerant inside the refrigerant circuit and reducing the amount of refrigerant circulating within the refrigerant circuit, the high-pressure switch is prevented from operating, expanding the operating range of the air conditioner and at the same time lowering the compressor temperature. The reliability of the compressor can be improved. Also, during defrost operation, by opening the solenoid valve and forcibly guiding a portion of the refrigerant into the compressor, the amount of refrigerant flowing into the compressor can be increased, thereby shortening the time required for defrosting. can prevent the suction pressure from becoming negative pressure. Further, since a control circuit is provided that disables the defrost control circuit when the solenoid valve is opened during overload operation, it is possible to prevent the defrost operation from being started when the defrost operation is not required.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention,
FIG. 1 is a refrigerant circuit diagram, and FIG. 2 is an electrical control circuit diagram. 3 and 4 show an example of a conventional air-cooled heat pump type air conditioner, FIG. 3 is a refrigerant circuit diagram, and FIG. 4 is an electric control circuit diagram. Compressor...1, Four-way switching valve...2, Indoor heat exchanger...3, Cooling throttle...6, Heating throttle...
7. Outdoor heat exchanger...9. Accumulator...
11, High pressure liquid refrigerant circuit...30, Bypass refrigerant circuit...31, Solenoid valve...19, Throttle...20,
Defrost thermostat...13, Defrost controller...
14, Defrosting relay...114, Defrosting relay contacts...114A, 114B, 114C, Solenoid valve coil...19A, Bypass relay...12
1. Bypass relay contact...121A, 12
1B.

Claims (1)

[Scope of utility model registration request] In an air-cooled heat pump air conditioner equipped with a refrigerant circuit incorporating a compressor, a four-way switching valve, an indoor heat exchanger, a cooling diaphragm, a heating diaphragm, an outdoor heat exchanger, and an accumulator, the high-pressure liquid in the refrigerant circuit A bypass refrigerant circuit having a solenoid valve and a throttle is provided between the refrigerant circuit and the inlet side of the accumulator, and the solenoid valve is opened during overload operation and defrost operation, and the solenoid valve is opened during overload operation. An air-cooled heat pump type air conditioner characterized by being provided with a control circuit that disables a defrost control circuit when the defrost control circuit is disabled.