JPH0264365A - Cooling and heating apparatus - Google Patents

Abstract

PURPOSE:To keep a required amount of oil in a compressor by making oil in a refrigerant heater flow from the top of an outdoor refrigerant condenser into the condenser, and also returning oil from the bottom of an outdoor air condenser through an accumulator into the compressor after heating operation is stopped. CONSTITUTION:After heating operation is stopped, a first and a third solenoid valves 36 and 41 are opened and a compressor is put into operation by a control circuit 48. When the third solenoid valve 41 is opened, the oil retained in a refrigerant heater 28 passes through an oil drain refrigerant pipeline 44 with refrigerant, and flows into an outdoor heat exchanger 37 through a sixth check valve 45. The oil and refrigerant flowing from the top of the outdoor heat exchanger 45 are sucked from the bottom of outdoor heat exchanger 37 into a compressor 33 through a second solenoid valve 36, a four-way valve 35, and an accumulator 47. The refrigerant is released in an indoor heat exchanger 46. At this time, the oil is retained in the compressor 33. A timer starts counting at the same time the compressor is started, and when a specified time has passed, the third solenoid valve is closed first to stop the oil flowing into the outdoor heat exchanger 37, and then the oil and refrigerant retained in the outdoor heat exchanger 37 are pumped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an apparatus for performing air conditioning and heating by connecting indoor and outdoor units with refrigerant piping, and in particular to an air conditioning and heating apparatus that heats a refrigerant with a burner or the like and transfers heat to an indoor unit for heating. It is related to the device.

2. Description of the Related Art As shown in FIG. 3, in a conventional heating and cooling system of this type, during heating operation, the refrigerant heated and vaporized by a refrigerant heater 1 is transferred to a gas-liquid separator 2 and a first solenoid valve 3 in an open state. through the indoor heat exchanger 4, condenses and liquefies due to heat radiation, and passes through the first check valve 5.
The liquid flows into the liquid receiver 6 through the liquid receiver 6. At this time, the second solenoid valve 7,
The third solenoid valve 8 and the fourth solenoid valve 9 are in an open state. Receiver 6
When the liquid refrigerant accumulates in the tank, the on-off valve 10 opens, and the liquid refrigerant flows from the liquid receiver 6 disposed above the refrigerant heater 1 under its own weight to the second tank.
The refrigerant flows into the refrigerant heater 1 via the check valve 11 . At this time, the pressures in the refrigerant heater I and the liquid receiver 6 are equalized, and liquid refrigerant does not flow into the liquid receiver 6 from the indoor heat exchanger 4. Next, the liquid receiver 6
When the liquid refrigerant inside runs out, the on-off valve 10 becomes closed, and the condensed liquid refrigerant accumulates in the liquid receiver 6 again. At this time, the second check valve 11 prevents the liquid refrigerant flowing into the liquid receiver 6 from flowing into the refrigerant heater.

As described above, by repeatedly opening and closing the on-off valve 10, liquid refrigerant is intermittently supplied from the liquid receiver 6 to the refrigerant heater 1, and the refrigerant evaporated and gasified in the refrigerant heater 1 is sent under pressure to the indoor heat exchanger 4. This cycle is repeated during heating operation.

Although the second solenoid valve 7, the third solenoid valve 8, the fourth solenoid valve 9, the third check valve 12, and the fourth check valve 13 are in the closed state during heating operation, if the operation is continued for a long time, the second solenoid valve ~4th solenoid valve 7
．． 8.9 Due to refrigerant leakage from the third and fourth check valves 12°I3, refrigerant gradually accumulates in the compressor 14, accumulator 15, and outdoor refrigerant condenser 16, and the amount of refrigerant during the heating operation cycle decreases. As a result, the temperature of the refrigerant in the refrigerant heater 1 rises, reducing the thermal stability of the refrigerant and thus the reliability of the system.

In order to prevent such problems, the combustion of the refrigerant heater 1 is stopped, the fourth solenoid valve 9 is opened, and the compressor 14 is operated for a certain period of time (hereinafter referred to as pump-down operation). E5 and the refrigerant accumulated in the outdoor refrigerant condenser IG are returned to the heating cycle.

Next, during cooling operation, the second solenoid valve 7 and the third solenoid valve 8 are open, the on-off valve 10, the first solenoid valve 3, and the fourth solenoid valve 9 are closed, and the high temperature discharged from the compressor 14 is The high-pressure gas refrigerant enters the outdoor refrigerant condenser 16 from the fourth check valve 13 via the refrigerant heater 1 and the second solenoid valve 7, and after being condensed by heat radiation,
It is depressurized and expanded in a pressure reducing device 17 via a check valve 12 and a liquid receiver 6, and enters an indoor heat exchanger 4. After being evaporated and gasified in the indoor heat exchanger 4, it returns to the compressor 14 via the third electromagnetic valve 8 and the accumulator 15. Cooling is performed through this cycle.

(Japanese Patent Application No. 61-128623) Problems to be Solved by the Invention However, in the above-described configuration, when the compressor 4 is driving the heating pump in down operation and during cooling operation, the oil in the compressor 4 flows into the refrigerant heater. l. Oil is released into the outdoor refrigerant condenser 16, liquid receiver 6, indoor heat exchanger 4, etc., so if the number of times the compressor 4 is operated increases, oil will flow into the refrigerant heater 1, which contains refrigerant liquid, during heating operation. If the oil accumulates in the compressor 4, the temperature distribution inside the refrigerant heater 1 will become uneven, causing a local increase in the refrigerant temperature, reducing the thermal stability of the refrigerant, or reducing the amount of oil in the compressor 4, causing the drive of the compressor 4 to become difficult. There were issues with the reliability of the system, such as a decline in the lubrication performance of the compressor m4 and failure of the compressor m4.

The present invention solves these problems and aims to ensure system reliability.

Means for Solving the Problems In order to solve the above problems, the air conditioning system of the present invention opens the third solenoid valve for a certain period of time after stopping the heating operation, and drains the oil in the refrigerant heater outdoors through the sixth check valve. From the top of the refrigerant condenser,
The oil in the condenser is caused to flow into the condenser, and at the same time, the compressor is driven to return the oil in the condenser from the lower part of the outdoor air condenser to the compressor via an accumulator.

Effect of the Invention With the above configuration, the present invention can ensure the necessary amount of oil in the compressor when the compressor is driven, and the amount of oil in the refrigerant heater is reduced.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 1 shows the overall configuration of a heating and cooling system according to the present invention, where I8 is an outdoor unit, I9 is an indoor unit, 20.
21 is a refrigerant pipe connecting the outdoor unit 8 and the indoor unit 19. Reference numeral 22 denotes a heat transfer heating block used during heating, which is provided with an on-off valve 23, a liquid receiver 24, a first check valve 25, and a gas-liquid separator 26 in order from the top, and has a combustion section 27 at the bottom. There is a heater 28, a conduit 29 connecting the refrigerant heater 28 and the lowest part of the gas-liquid separator 26, a pressure equalizing pipe 30 provided between the refrigerant heater 28, the upper part of the gas-liquid separator 26, and the on-off valve 23, and the on-off valve 23. The main components are a return pipe 31 into which the refrigerant flows between the liquid receiver 24 and the liquid receiver 24, and a second check valve 32 provided in the return pipe 31. 33 is a compressor;
4 is a third check valve provided between the compressor 33 and the four-way valve 35;
A second electromagnetic valve 6 is provided between the four-way valve 35 and the lower part of the outdoor heat exchanger 37.

Further, 38 is a first solenoid valve provided between the upper part of the outdoor heat exchanger 37 and the upper part of the liquid receiver 24, and 39 is a first solenoid valve provided between the upper part of the outdoor heat exchanger 37 and the upper part of the liquid receiver 24.
A fifth check valve 40 is provided in the heating pipeline between the upper part, the four-way valve 35, and the third check valve 34. 41 is a third solenoid valve provided between the refrigerant heater 28 and the pressure reducing device 42;
43 is a fourth check valve provided between the third solenoid valve 41 and the pressure reducing device 42. Reference numeral 44 denotes an oil-draining refrigerant pipe branching from between the third solenoid valve 41 and the fourth check valve 43 and reaching between the first solenoid valve 38 and the upper part of the outdoor heat exchanger 37; and 45, the refrigerant pipe 44 This is the sixth check valve provided in the.

In addition, the pressure reducing device 42 and the indoor heat exchanger 4 in the indoor unit 9
6 are communicated by a refrigerant pipe 21, and a return pipe 31 is branched from the middle of the pipe 21. On the other hand, four-way valve 35
The indoor heat exchanger 46 in the indoor unit 19 is connected to the refrigerant pipe 2.
It is communicated with 0. 47 is an accumulator provided on the suction side of the four-way valve 35 and the compressor 33, and 48 is a control device that controls the second solenoid valve 36, third solenoid valve 41, and compressor 33 when heating is stopped; is as shown in Figure 2.

In the above configuration, during cooling operation, the four-way valve 35 is in the on state (dotted line in the figure), and the first... Second. third solenoid valve 3B,
36.41 is open, the on-off valve 23 is closed, and the compressor 3
The high temperature and high pressure gas refrigerant discharged from the third check valve 3
4. It passes through the four-way valve 35 and the second solenoid valve 36 and enters the outdoor heat exchanger 37. After heat radiation and condensation in the outdoor heat exchanger 37, the first
It passes through the tfff valve 38, the liquid receiver 24, the first check valve 25, the gas-liquid separator 26, the conduit 29, the refrigerant heater 28, and the third electromagnetic valve 41. The refrigerant is depressurized and expanded in the decompression device 42 via the fourth reverse valve 43 and enters the indoor heat exchanger 46 from the refrigerant pipe 21 .

After being evaporated into gas in the indoor heat exchanger 46, the refrigerant pipe 20,
It returns to the compressor 33 via the four-way valve 35 and the accumulator 47. Here, the refrigerant does not flow into the oil drain refrigerant pipe 44 due to the sixth check valve 45 . This cycle carries out the refrigerant.

On the other hand, during heating operation, the four-way valve 35 is in the off state (solid line in the figure) and the first four-way valve 35 is in the off state (solid line in the figure). Second. The third electromagnetic valve 38, 36, 41 is in a closed state, and at the same time as combustion in the combustion section 27 starts, the on-off valve 23 repeats the opening and closing operation.

Here, the liquid refrigerant accumulated in the liquid receiver 24 passes through the first reverse valve 25 and the gas-liquid separator 26 and is supplied to the refrigerant heater 28 from the conduit 29. The refrigerant heated by the heat of combustion in the refrigerant heater 28 passes through the pressure equalization pipe 30, the gas-liquid separator 26, only the gas refrigerant passes through the heating pipe 39, passes through the fifth check valve 40, the four-way valve 35, and then enters the refrigerant pipe. 20 to the indoor heat exchanger 46 where it is condensed and liquefied. If the on-off valve 23 is in the closed state at this time, the condensed and liquefied refrigerant is transferred to the refrigerant pipe 21 and to the liquid receiver 24, which is located higher than the refrigerant heater 28 and the gas-liquid separator 26. The liquid refrigerant flows in through the pipe 31 and the second check valve 32, and when the liquid refrigerant is completely stored in the liquid receiver 24, the on-off valve 23 is opened and the refrigerant in the liquid receiver 24 flows into the first It flows from the check valve 25 to the gas-liquid separator 26, and the gas-liquid separator 26
The refrigerant enters the refrigerant heater 28 via a conduit 29 . When the on-off valve 23 is in the open state, no condensed liquid refrigerant flows into the receiver 24 . The above operations are repeated during heating operation, and liquid refrigerant is intermittently supplied to the refrigerant heater 28, and gas refrigerant is pressure-fed to the indoor heat exchanger 46.

Next, when the heating operation is stopped, the control circuit 48 controls the second. Third solenoid valve 36.41
is opened and the compressor 33 is operated. When the third electromagnetic valve 41 is opened, the oil accumulated in the refrigerant heater 28 enters the oil removal refrigerant pipe 44 together with the refrigerant, and passes through the sixth check valve 45 to the upper part of the outdoor heat exchanger 37. Inflow. The oil and refrigerant flowing from the upper part of the outdoor heat exchanger 37 are sucked into the compressor 33 from the lower part of the outdoor heat exchanger 37 via the second electromagnetic valve 36, the four-way valve 35, and the accumulator 47.

Most of the refrigerant sucked into the compressor 33 passes through the third check valve 34 , the four-way valve 35 , and the refrigerant pipe line 20 to the indoor heat exchanger 4
released into G.

At this time, oil accumulates in the compressor 33.

Also, from FIG. 2, the timer is counted at the same time as the compressor 33 is operated, and when a certain period of time is exceeded, the third solenoid valve closes, cutting off the refrigerant oil from flowing into the outdoor heat exchanger 37. When the oil and refrigerant accumulated in the outdoor heat exchanger 37 are pumped up and the timer reaches the set time, the second solenoid valve 36
, the compressor 33 stops.

This ensures that any oil released into the heating circuit is recovered. Furthermore, oil can be recovered in a short time by sucking oil into the compressor 33 from the lower part of the outdoor heat exchanger 37.

Effects of the Invention As described above, according to the air conditioning system of the present invention, after the heating operation is stopped, the third solenoid valve is opened for a certain period of time, and the oil in the refrigerant heater is exchanged for outdoor heat via the sixth check valve. By making the oil flow into the outdoor exchanger from the upper part of the heat exchanger and driving the compressor, the oil is returned to the compressor from the lower part of the outdoor heat exchanger via the accumulator, so that when the heating pump is down or during cooling operation, Since the oil discharged from the compressor can be recovered to the compressor reliably and in a short time, it is possible to prevent local refrigerant temperature rises in the refrigerant heater due to oil and deterioration of the lubrication performance of the compressor drive part due to oil loss, and prevent refrigerant It is possible to improve the reliability of the entire air-conditioning system, such as the thermal stability of the air conditioner and the prevention of compressor failure.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant circuit configuration diagram of an air conditioning system according to an embodiment of the present invention, FIG. 2 is a flowchart of a control circuit after heating is stopped, and FIG. 3 is a refrigerant circuit configuration diagram of a conventional air conditioning system. 22... Heat transfer heating block, 23...
・Opening/closing valve, 24...Liquid receiver, 25...
First check valve, 26... Gas-liquid separator, 28...
... Refrigerant heater, 31 ... Refrigerant pipe line (return pipe), 32 ... Second check valve, 33 ... Compressor, 34 ... ...Third check valve, 35...
Four-way valve, 36...Second solenoid valve, 37...
・Outdoor heat exchanger (outdoor refrigerant condenser), 38...
First solenoid valve, 39... Refrigerant pipe line (heating pipe line),
40... Fifth check valve, 41... Third solenoid valve, 42... Pressure reducing device, 43... Fourth check valve, 44... ... Refrigerant pipe line (oil removal refrigerant pipe line), 45 ... Sixth check valve, 46 ...
・Indoor heat exchanger, 47... Accumulator,
48...Control device. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 2 Figure 1

Claims (2)

[Claims] (1) A heat transfer heating block consisting of an on-off valve, a liquid receiver, a first check valve, a gas-liquid separator, a refrigerant heater, and a second check valve, and a first solenoid valve from the liquid receiver. A second solenoid valve, a four-way valve, an accumulator compressor, a third check valve, an indoor heat exchanger, a pressure reducing device, a fourth check valve, and a third check valve are connected to the outdoor heat exchanger through the outdoor heat exchanger. A refrigerant pipe passes through the electromagnetic valves in sequence, and between the gas-liquid separator, the four-way valve, and the third check valve,
A refrigerant pipe line provided with a fifth check valve is connected, a refrigerant pipe line from between the indoor heat exchanger and the pressure reducing device to the second check valve is connected, and a fourth check valve and a third check valve are connected. An air-conditioning/heating device in which a refrigerant pipeline is branched from between the solenoid valves and provided between the outdoor heat exchanger and the first solenoid valve via a sixth check valve. (2) After the heating operation is stopped, the third solenoid valve is opened for a certain period of time, the second solenoid valve is opened, the compressor is operated, and after the third solenoid valve is closed, the second solenoid valve is closed with a delay. The heating and cooling device according to claim 1, further comprising a control device for stopping the compressor.