JPH0933116A - Heat pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the abnormality of a compressor surely and prevent the damage of the compressor due to overheating while maintaining the operating condition of the same. SOLUTION: Upon heating operation, a refrigerant circuit 30 is constituted so that refrigerant, discharged out of a compressor 20, is supplied to indoor heat exchangers 43a-43d to effect indoor heating there by radiating the condensation heat of the refrigerant in the heat exchangers and, thereafter, the refrigerant is heated in outdoor heat exchangers 38a, 38b and a double-tube heat exchanger 55 to return it into the compressor 20. On the other hand, a compressor temperature sensor 78 and a bypass line 48, returning the low-temperature refrigerant after dissipating heat in the outdoor heat exchangers 38a, 38b into the compressor 20 detouring the outdoor heat exchangers 38a, 38b and the double-tube heat exchanger 55, are provided while the bypass line 48 is provided with a control valve 49, regulating the amount of bypassing refrigerant based on the detecting temperature of the compressor temperature sensor 78.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a compressor, a condenser,
The present invention relates to a heat pump device configured to perform cooling / heating or freezing by radiating heat in the condenser or absorbing heat in the evaporator while circulating a refrigerant in a closed circuit including an expansion valve and an evaporator.

[0002]

2. Description of the Related Art Conventionally, this type of heat pump device is generally well known, and includes, for example, indoor and outdoor heat exchangers as a condenser and an evaporator, and includes a compressor and the indoor and outdoor heat exchangers. An air conditioning technology for heating and cooling by circulating a refrigerant in a refrigerant circuit is known, and recently, by changing the circulation direction of the refrigerant in this circuit, cooling and heating are performed by one device. A heat pump type air conditioner is frequently used.

In such a heat pump type air conditioner, when heating is performed, a high-temperature, high-pressure gaseous refrigerant compressed by a compressor is sent to an indoor heat exchanger, where it releases condensation heat. While being liquefied, the heat of condensation at this time heats the indoor air. Then, the refrigerant that has released the heat of condensation is decompressed by an expansion valve provided immediately downstream of the indoor heat exchanger into a low-temperature low-pressure atomized refrigerant, and then sent to the outdoor heat exchanger where it is evaporated. It takes heat, vaporizes it, and is taken into the compressor.

On the other hand, when cooling is performed, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor is sent to the outdoor heat exchanger where it is cooled and condensed by the outside air, and then the expansion valve. Is sent to the indoor heat exchanger via. That is, the indoor valve is cooled by rapidly reducing the pressure in the expansion valve into a low-temperature low-pressure atomized refrigerant, and depriving the indoor air of latent heat required for evaporation of the refrigerant at this time. Then, the vaporized refrigerant is then sucked into the compressor.

[0005]

SUMMARY OF THE INVENTION In such a device,
Conventionally, a temperature sensor is attached to the piping of the refrigerant circuit in the vicinity of the discharge port of the compressor, and the temperature of the refrigerant discharged from the compressor is detected to detect an excessive increase in the refrigerant temperature. It is designed to prevent the compressor from overheating. For example, when the temperature of the refrigerant reaches or exceeds a predetermined temperature, the output of the compressor is reduced or the compressor is stopped to suppress the temperature rise of the compressor.

However, as will be described in detail in the embodiment described later, the refrigerant stays in the circuit depending on the operating state,
Alternatively, when the circuit is damaged and the refrigerant leaks, and the amount of the circulating refrigerant is insufficient, the refrigerant returning to the compressor is reduced as shown in FIG. When the load decreases, the rotation speed of the compressor rises, and the frictional heat etc. raises the temperature of the compressor, while the amount of circulating refrigerant decreases, so the temperature detected by the temperature sensor is too low. The phenomenon of not rising may occur. In such a case, there is a possibility that a situation may occur in which the abnormality of the compressor is delayed and the device fails.

Therefore, the occurrence of such a situation is avoided,
It is desirable to detect abnormalities due to overheating of the compressor at an early stage and reliably to prevent damage to the compressor.

In order to prevent an abnormal situation,
It may be possible to set the upper limit of the compressor speed to a low level in advance, but in this case, the air conditioning function will be reduced even during normal operation, and it will be impossible to maintain a comfortable indoor space. Therefore, it is preferable that the temperature rise of the compressor can be suppressed while avoiding such deterioration of the function.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat pump device capable of reliably detecting an abnormality due to overheating of a compressor to prevent damage to the compressor. I am trying.

[0010]

A heat pump device according to a first aspect of the present invention comprises a compressor, a heat radiating portion having a condenser, an expansion valve, and a heat absorbing portion having an evaporating portion, and is discharged from the compressor. In a heat pump device in which a refrigerant circuit is configured so that the refrigerant is returned to the compressor through the heat radiating portion, the expansion valve, and the heat absorbing portion, the compressor is provided with temperature detecting means for detecting its temperature, and this temperature detection is performed. A suppressing means for suppressing the temperature rise of the compressor is provided based on the detection result of the means.

In this heat pump device, the refrigerant discharged from the compressor is circulated so as to return to the compressor through the condenser, the expansion valve, and the evaporating portion, so that cooling or heating by heat radiation or endothermic action or refrigeration is performed. Done. During operation, the temperature of the compressor is detected by the temperature detecting means, and if the temperature of the compressor rises abnormally, the temperature suppression action of the compressor works based on the temperature detection to prevent overheating of the compressor. .

A heat pump device according to a second aspect is the heat pump device according to the first aspect, wherein the suppressing means bypasses the refrigerant having passed through the heat radiating portion to at least a part of the heat absorbing portion and returns it to the compressor. It has a passage and a bypass amount adjusting means for adjusting the bypass amount of the refrigerant in the bypass passage based on the temperature detected by the temperature detecting means.

According to this heat pump device, when the compressor temperature detected by the temperature detecting means becomes high, the bypass passage is opened so that a part or all of the refrigerant cooled in the heat radiating portion bypasses the heat absorbing portion. Returned to the compressor. Therefore, the relatively low-temperature refrigerant is returned to the compressor to exert a cooling effect on the compressor, effectively suppressing the temperature of the compressor.

A heat pump device according to a third aspect is the heat pump device according to the second aspect, wherein the bypass amount adjusting means increases the flow rate of the refrigerant in the bypass passage as the temperature of the compressor rises. It will be.

According to this heat pump device, it is possible to return to the compressor an appropriate amount of refrigerant that effectively exhibits the cooling action, depending on the temperature of the compressor.

A heat pump device according to a fourth aspect is the heat pump device according to any one of the first to third aspects, wherein the suppressing means has a control means for controlling the drive of the compressor. The control means is configured to limit the number of revolutions of the compressor to a predetermined value or less when the temperature detected by the temperature detecting means becomes a predetermined value or more.

According to this heat pump device, the increase in the number of revolutions of the compressor is limited when the detected temperature is high, so that heat generation in the compressor is suppressed.

[0018]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing an air conditioner using a heat pump device according to the present invention. As shown in this figure, an air conditioner 1 (hereinafter abbreviated as air conditioner 1)
Includes a water-cooled gas engine 2 (hereinafter abbreviated as engine 2), a compressor 20 driven by the gas engine 2, a refrigerant circuit 30 for circulating a refrigerant such as CFC, and the engine 2
And a cooling water circuit 50 for cooling the.

In the engine 2 and the compressor 20, the belt 5 is mounted over the pulley 4 attached to the output shaft 3 of the engine 2 and the pulley 22 attached to the input shaft 21 of the compressor 20. Engine 2
The rotation generated in (1) is transmitted to the compressor 20 via the belt 5 so that the compressor 20 is driven.

An intake pipe 6 is connected to the engine 2 as an intake system, and an air cleaner 7 and a mixer 8 are connected to the intake pipe 6. In the mixer 8,
A fuel supply pipe 9 connected to a fuel gas supply source (not shown) is connected, and a fuel gas electromagnetic valve 10 and a zero governor 11 for adjusting the pressure reduction of the fuel gas are connected to the fuel supply pipe 9.

An oil tank 13 is connected to the crank chamber of the engine 2 via an oil supply pipe. Also,
A breather pipe 14 is led out from the engine 2, an oil separator 15 is connected to the breather pipe 14, and the gas line 1 is connected from the oil separator 15 to the gas line 1.
6 and the oil line 17 are respectively led out, the gas line 16 is connected to the upstream side of the mixer 8 of the intake pipe 6, while the oil line 17 is connected to the crank chamber of the engine 2. That is, the breather gas discharged from the engine 2 has its oil content removed by the oil separator 15 and returned to the intake pipe 6, while the removed oil is returned to the crank chamber of the engine 2.

The engine 2 is provided with an exhaust pipe 18 as an exhaust system, and an exhaust gas heat exchanger 19 is provided in the exhaust pipe 18.

The refrigerant circuit 30 includes a heat radiating portion having a condenser, an expansion valve, and a heat absorbing portion having an evaporator. The refrigerant discharged from the compressor 20 passes through the heat radiating portion, the expansion valve, and the evaporation portion. A closed circuit for circulating the pressure so as to return it to the compressor 20 is configured.

In this embodiment, four indoor heat exchangers 43 are used.
a to 43d and the expansion valves 42 respectively provided therein
The two outdoor heat exchangers 38a and 38b, the double heat exchanger 55, and the like are incorporated in the refrigerant circuit 30, and the four-way valve 33 that switches the refrigerant circulation direction is provided, so that the indoor heat The exchangers 43a to 43d are condensers, the outdoor heat exchangers 38a and 38b are evaporators, and at the time of cooling,
The indoor heat exchangers 43a to 43d are an evaporator and the outdoor heat exchanger 3
8a and 38b are configured to be condensers.

More specifically, the line 31a is led out from the discharge side of the compressor 20 and is connected to the first port 33a of the four-way valve 33 via the oil separator 32. In the four-way valve 33, a line 31b is led out from the third port 33c.
Is introduced into the suction side of the compressor 20 via the liquid gas heat exchanger 34, the silencer 35, and the accumulator 36, and the oil return line 45 derived from the oil separator 32 is on the downstream side of the accumulator 36. Further, it is connected to this line 31b on the downstream side of the connecting portion of a bypass line 48 described later. Incidentally, 45a is a capillary tube provided in the oil return line 45.

A return line 46, which branches from the line 31a to reach the silencer 35, is provided on the downstream side of the oil separator 32 in the line 31a, and a control valve 47 for adjusting the flow rate is provided in the return line 46. Are connected.

In the four-way valve 33, the second port 33
A line 31c is derived from b, and this line 3c
1c through the strainer 44 each indoor heat exchanger 43a ~
It has reached 43d.

The indoor heat exchangers 43a to 43d are arranged in parallel with each other as shown in the figure, and the input / output portions on one side (the lower side in the figure) are connected to the line 31c. The input / output portions on the other side (upper side in the figure) are connected to the line 31d via the expansion valves 42, respectively.

The line 31d reaches the liquid gas heat exchanger 34 via the strainer 41, the sight glass 40 and the dryer 39, and is connected to the outdoor heat exchanger 38a via the liquid gas heat exchanger 34. A line 31g is led out from the outdoor heat exchanger 38a, and this line 31g is connected to the fourth port 33d of the four-way valve 33 via the double heat exchanger 55 of the cooling water circuit 50 which will be described later in detail. .

From the line 31d to the line 31
e is branched, and this line 31e is connected to the outdoor heat exchanger 3
8b, a line 31f is led out from the outdoor heat exchanger 38b, and this line 31f is connected to the line 31g between the outdoor heat exchanger 38a and the double heat exchanger 55.

Further, a bypass line 48 (bypass passage) branched from the line 31d is provided between the liquid gas heat exchanger 34 and the branched portion of the line 31e in the line 31d.
8 is connected to the line 31b on the downstream side of the accumulator 36, and the bypass line 4
A control valve 49 (bypass amount adjusting means) for adjusting the flow rate is connected to 8.

The specific structure of the compressor 20 applied to the refrigerant circuit 30 is not particularly limited in the present invention, but in the present embodiment, the compressor 20 is shown in FIGS. Such a multi-type compressor is applied.

The compressor 20 has a case 61 as shown in these figures, and in this case 61, two left and right (right and left in FIG. 4) compressor main bodies 62 and a common compressor main body 62. And an oil sump 63 as a lubricating oil supply source.

In this compressor 20, as shown by the white arrow in FIG. 3, the refrigerant flowing back from the refrigerant circuit 30 is sucked and compressed by each compressor body 62 from the line 31b to form a high temperature, high pressure gaseous state. The refrigerant is discharged into the oil sump 63 via the oil separator 64 and is supplied to the refrigerant circuit 30 from the line 31a connected to the ceiling of the oil sump 63.

Further, as shown by the arrow in FIG. 3, the lubricating oil is sucked up from the oil supply port 67 opened in the oil sump 63 and circulated through the sliding portion of each compressor body 62. . The lubricating oil is mixed with the gaseous refrigerant in each compressor body 62, but is separated and returned to the oil sump 63 when discharged together with the gaseous refrigerant to the oil sump 63 via the oil separator 64. ing.

As shown in FIG. 5, the compressor body 62 includes a casing 70, a drive shaft 71 connected to the input shaft 21 via clutch means, a rotor 72 rotating integrally with the drive shaft 71, and an ellipse. And a cylinder 74 having a shaped inner wall.

The rotor 72 is provided with a plurality of vanes 73 that are urged in the radial direction and have their tip ends slidably contacting the inner wall of the cylinder 74, whereby two compression spaces that change with the rotation of the rotor 72 are provided. It is formed in the cylinder 74. Further, the cylinder 74 is provided with a communication passage 75 corresponding to each compression space, and a discharge port 76 having a plate valve 77. And each compressor body 6
2, when the rotor 72 is rotationally driven, the refrigerant that has recirculated from the refrigerant circuit 30 is sucked from the intake port on one side of the rotor 72 and the intake port on the other side through each communication passage 75, and the compression of each compression After being compressed in space, each discharge port 76
Is discharged from the oil separator 64 through the discharge passage 79.
Be led to.

Further, as shown in FIG. 5, a compressor temperature sensor 78 is attached to the casing 70 of the compressor 20, so that the temperature of the compressor 20 is detected at any time and the circuit controller 82 (see FIG. 6). Output). By detecting the temperature change of the compressor 20 in this way, the control valve 49 is opened and closed in the refrigerant return control described later.

In the cooling water circuit 50, as shown in FIG. 1, a cooling line 51a is led out from the discharge side of the pump 52, and the cooling line 51a cools the engine 2 via the exhaust gas heat exchanger 19. The cooling line 51b is connected to the water inlet and is connected to the cooling water outlet of the engine 2.
Is derived and is connected to the switching valve 53.

From the switching valve 53, cooling lines 51c, 51
e is derived respectively, and the cooling line 51c is connected to the input side of the radiator 54. Radiator 54
The cooling line 51d is led out from the output side of the cooling line 51d is connected to the suction side of the pump 52, and the cooling line 51e is connected to the cooling line 51d via the double tube heat exchanger 55. It is connected to the.

Here, the switching valve 53 has the cooling lines 51c and 5 by the action of a built-in thermostat.
The flow rate of the cooling water to 1e is adjusted. Specifically, as shown in FIG. 2, when the cooling water temperature is 78 ° C. or lower, the cooling line 51c is fully closed, the cooling line 51e is fully opened, and the cooling water is sent only to the cooling line 51e. When the temperature exceeds 78 ° C, the cooling line 51c starts to be opened and the cooling water is sent to the cooling line 51c, while the cooling line 51e is started to be closed to suppress the cooling water to be sent to the cooling line 51c, and the cooling water temperature is 86 °.
When it exceeds C, the cooling line 51e is fully closed, the cooling line 51c is fully opened, and the cooling water is sent only to the cooling line 51c.

Further, in the cooling water circuit 50, a cooling water supply line 51f branched from the cooling line 51d is provided between the connecting portion of the cooling line 51e and the radiator 54. This cooling water supply line is provided. 51
f is connected to the water tank 56. In the figure, 51g indicates an air vent passage, and 57 indicates a throttle.

Next, the air conditioner 1 configured as described above
The control system will be briefly described with reference to the block diagram of FIG. In this figure, only the configuration of the control system mainly relating to the refrigerant circuit 30 is shown.

As shown in the figure, the air conditioner 1 includes:
A main controller 80 that controls the air conditioning operation in a centralized manner, and an indoor unit controller 81 and an outdoor unit controller 82 that are connected to the main controller 80 are provided.

The indoor unit controller 81 has indoor units 100a to 100d for accommodating the indoor heat exchangers 43a to 43d.
Are connected, and the indoor heat exchangers 43a to 43d are comprehensively controlled by the indoor unit control device 81. Each of the indoor units 100a to 100d has fans 84a to 84d for blowing air and indoor heat exchangers 43a to 4d.
Inlet refrigerant temperature sensor 8 for detecting the inlet refrigerant temperature of 3d
5a to 85d, outlet refrigerant temperature sensors 101a to 101d that detect the outlet refrigerant temperature, operation units 86a to 86d that include an on / off switch and a temperature setting key, and indoor temperature sensors 102a to 102d that detect each indoor temperature. It is provided. Then, for example, when a desired temperature is input through the operation unit 86a of the indoor unit 100a, the indoor temperature is detected by the indoor temperature sensor 102a in the indoor unit control device 81, and the difference between this temperature and the desired temperature is detected. The output of the fan 84a is controlled by the main controller 80 via the indoor unit controller 81 in order to reduce the temperature difference.

The outdoor unit controller 82 includes an engine 2, a compressor temperature sensor 78, control valves 47 and 49, a four-way valve 33, and outdoor heat exchangers 38a and 38b, as shown in FIG.
The discharge refrigerant temperature sensor 120 and the like are also connected.
The outdoor unit control device 82 controls the four-way valve 33 to switch the circulation direction of the refrigerant in the refrigerant circuit 30 in accordance with the heating / cooling switching of the indoor units 100a to 100d, and the engine to reduce the temperature difference as described above. 2 is controlled to adjust the output of the compressor 20. Further, the opening degree of the control valve 47 is controlled according to the operating conditions of the indoor units 100a to 100d, that is, the number of operating indoor units 100a to 100d, and the amount of the refrigerant flowing through the return line 46 is adjusted. Specifically, as the number of operated indoor heat exchangers 43a to 43d decreases, the opening degree of each control valve 47 increases and the amount of refrigerant flowing through the return line 46 increases. It is like this. Further, during the heating operation, the outdoor unit control device 82 sets the refrigerant temperature before heat dissipation detected by the inlet refrigerant temperature sensors 85a to 85d and the refrigerant temperature after heat dissipation detected by the outlet refrigerant temperature sensors 101a to 101d. Based on the temperature difference, the opening degree of each expansion valve 42a to 42d, and the pressure difference between the high-pressure side and the low-pressure side, each indoor heat exchanger 4 described later.
3a to 43d are calculated, and the control valve 49 is controlled to open and close the bypass line 48 based on the calculated heat radiation amount and the temperature detected by the suction refrigerant temperature sensor 87. As shown in FIG. 8, the heat radiation amount is not an accurate heat radiation amount, that is, a heat radiation amount obtained by converting the rated heat exchange amount of each indoor unit in the operating state (see FIG. 8).
Step S3) and the temperature of the compressor itself by the compressor temperature sensor 78 instead of the refrigerant temperature on the suction side of the compressor (see FIG. 8).
The control valve 49 is controlled by steps S5 and S9). In FIG. 1, 110 is a high pressure side pressure sensor, and 111 is a low pressure side pressure sensor.

Next, the air conditioner 1 configured as described above
The operation of will be described.

First, the case where the air conditioner 1 is operated for heating will be described. First, the compressor 20 is operated in response to the driving of the engine 2, and the high-temperature and high-pressure gaseous refrigerant is discharged to the line 31 a and sent to the first port 33 a of the four-way valve 33 via the oil separator 32. As the refrigerant passes through the oil separator 32 in this way, the oil component is removed and reaches the four-way valve 33. Note that the removed oil component is the oil return line 45 and the line 3
It is returned to the compressor 20 via 1b. In addition, the control valve 47
Is completely closed, so that all the refrigerant is sent to the four-way valve 33.

The four-way valve 33 is in a state in which the first port 33a and the second port 33b communicate with each other during heating. Therefore, the refrigerant sent to the four-way valve 33 is sent to the line 31c via the four-way valve 33. After reaching the indoor heat exchangers 43a to 43d through the strainer 44, the heat of condensation is released and liquefied. That is, at this time, the indoor heat is heated by the condensation heat released in each of the indoor heat exchangers 43a to 43d.

The refrigerant liquefied by releasing the heat of condensation is decompressed by the expansion valve 42 and sent to the line 31d, where the strainer 41, the sight glass 40, and the dryer 39 are provided.
After passing through the liquid gas heat exchanger 34, the outdoor heat exchanger 38a
And 38b, where the heat of evaporation from the outside air is absorbed and vaporized, and then sent to the line 31g to be transferred to the double-tube heat exchanger 55.
At this point, heat is absorbed from the cooling water flowing through the cooling water circuit 50 and then sent to the four-way valve 33. And the control valve 49
When is completely closed, all the refrigerant flowing through the line 31c is sent to the outdoor heat exchangers 38a and 38b.

In the four-way valve 33, the third port 33c and the fourth port 33c
Therefore, the refrigerant is sent to the line 31b through the four-way valve 33, and the liquid gas heat exchanger 3 is connected to the port 33d.
4. It reaches the accumulator 36 through the silencer 35. Then, after the refrigerant is separated into a gas and a liquid here, only the gaseous refrigerant is sent to the compressor 20 through the line 31b, and thereafter, the refrigerant is circulated in the refrigerant circuit 30 in the same manner.

By the way, when some of the indoor heat exchangers 43a to 43d are operated,
The amount of heat radiated in the heat radiating portion (indoor heat exchanger) is smaller than the amount of heat radiating in the heat absorbing portion (outdoor heat exchanger and double heat exchanger), and the heat transfer balance of the refrigerant tends to be out of balance.
As a result, the temperature of the refrigerant rises and the compressor 20 is easily overheated.

That is, during the normal heating operation, as shown in the Ph diagram of FIG. 7, the pressure P and the enthalpy h
Is a (P ₁ , h ₁ ) → b (P ₂ , h ₂ ) → e (P ₂ , h ₀ ).
→ f (P ₁ , h ₀ ) → a (P ₁ , h ₁ ), that is, the gaseous refrigerant compressed by the compressor (a → b) changes due to heat dissipation in the indoor heat exchanger. It is changed from gas (b → c) → gas-liquid mixture (c → d) → liquid (d → e), and after that, when completely liquefied, it is expanded into a mist-like refrigerant (e → f). , For example, when the number of indoor heat exchangers to be operated is small, the amount of heat radiated in the indoor heat exchanger is smaller than the amount of heat absorbed in the outdoor heat exchanger, which causes the refrigerant in the indoor heat exchanger to It may not be completely liquefied (c →
d '). When the refrigerant is expanded in such a state that the refrigerant is not sufficiently liquefied (d '→
f '), the weight of the vapor phase refrigerant is reduced. Therefore, a part of the refrigerant discharged from the compressor and sent to the indoor heat exchanger cannot pass through the expansion valve and stays in the indoor heat exchanger, particularly in the stopped indoor heat exchanger. This reduces the amount of refrigerant returning to the compressor. On the other hand, the refrigerant that has passed through the expansion valve absorbs heat sufficiently in the outdoor heat exchanger, so that the refrigerant pressure on the low pressure side between the expansion valve and the suction port of the compressor rises. The pressure is reduced, which also causes the weight of the refrigerant passing through the expansion valve to decrease, increasing the amount of refrigerant stagnated in the indoor heat exchanger that is stopped. As the load on the compressor decreases as a result, the rotation speed of the compressor rises, and in addition to the rise in temperature on the suction side of the compressor due to heat absorption, the temperature of the compressor itself rises due to frictional heat and the like. Become. Moreover, even when the circulating refrigerant is insufficient as described above, the heat radiated in the outdoor heat exchanger, etc. is sufficiently absorbed compared to the heat radiation in the indoor heat exchanger, so that the circulating refrigerant remains. The temperature of the refrigerant that returns to the compressor while decreasing more increases further, which also increases the temperature of the compressor.

When a part of the indoor units is operated as described above, the compressor driving force by the engine 2 is controlled and the control valve 47 is opened to open the line 31a.
By returning a part of the refrigerant flowing through the compressor 20 to the compressor 20 via the return line 46, the indoor units 100a-100
The supply amount of the refrigerant to the indoor heat exchanger is adjusted according to the number of operating d. However, when the number of operating indoor heat exchangers is small, the capacity of the heat radiating portion becomes smaller, whereas the capacity of the heat absorbing portion becomes smaller. Since it is still large, it is difficult to eliminate the imbalance in heat transfer simply by adjusting the refrigerant supply amount according to the number of operating indoor units. The air conditioner 1 can be used for a long time in a state where the balance of heat transfer is unbalanced.
Is continuously operated, the refrigerant circulation amount is gradually decreased, heat is accumulated in the refrigerant, and the temperature is gradually increased, which may cause the compressor 20 to be overheated as described above.

Therefore, based on the temperature detection by the compressor temperature sensor 78 provided in the compressor 20, when the compressor temperature rises due to the above phenomenon, this is directly detected and the compression is performed accordingly. Control is performed to suppress the rise in machine temperature. Particularly, in this embodiment, when the compressor temperature is equal to or higher than a predetermined value, the control valve 49 of the bypass line 48 is opened to compress the relatively low temperature refrigerant after releasing the heat of condensation in each of the indoor heat exchangers 43a to 43d. The temperature of the refrigerant sucked into the compressor 20 is lowered, and the compressor 20 is cooled. By doing so, the compressor 20 that has been overheated due to the imbalance of heat transfer between the refrigerants is cooled and its damage is prevented, while heating of the refrigerant is suppressed and the balance of heat transfer between the refrigerants is eliminated. ing.

The control based on the temperature detection of the compressor 20 by the compressor temperature sensor 78 as described above will be described with reference to the flowchart of FIG.

In this control, it is first determined whether or not the engine 2 is in operation, and if it is in operation, it is further determined whether or not the air conditioner 1 is in heating operation (steps S1 and S2). ). Here, when the air conditioner 1 is in heating operation, it is determined whether or not the operating indoor unit capacities of the indoor heat exchangers 43a to 43d are smaller than a predetermined comparison value Q, and if the capacities are large, The process moves to step S10 and returns to step S1 without opening the control valve 49 (step S3).

Here, the operating indoor unit capacity corresponds to the heat radiation amount of the indoor heat exchanger, and is, for example, the rated capacity obtained for each of the operating indoor heat exchangers 43a to 43d. Is the sum of At this time, the amount of heat dissipation increases as the output of the automatically controlled fan increases,
Since the difference between the inlet refrigerant temperature and the outlet refrigerant temperature increases accordingly, the temperature difference may be multiplied by the expansion valve opening degree, the pressure difference, and a predetermined coefficient to determine the capacity of each indoor unit. . Further, if the difference between the desired temperature and the indoor temperature set by the operating section becomes large, the output of the fan is increased and the amount of heat radiation increases, so the capacity is obtained by multiplying the difference between the desired temperature and the indoor temperature by a constant. You may do it.

When the above-mentioned capacity becomes small, it becomes difficult to sufficiently radiate heat, so that the balance of the heat exchange of the refrigerant (heat radiation in the indoor unit and heat absorption in the outdoor unit) tends to be lost. Therefore, step S3 is provided, and control is performed according to the approximate balance of heat transfer. That is, a boundary with the operating state that theoretically or experimentally ensures the balance of heat transfer of the refrigerant can be obtained from the above capacity point (comparative value Q), and the actual state during the operation is described above. When the capacity is larger than the predetermined value Q, it is determined that the balance of heat exchange of the refrigerant is properly maintained, and the control valve 4
9 is closed, or the process proceeds to step S10 described later in order to maintain the closed state.

On the other hand, when the operating indoor unit capacity is smaller than the comparison value Q, the amount of heat radiation is small, and it is determined that the operating state is such that the balance of heat exchange of the refrigerant is likely to be disturbed, and the process proceeds to step S4. Here, it is determined whether or not the control valve 49 has already been opened. If the control valve 49 has not been opened, the process proceeds to step S5, and the compressor temperature sensor 78
It is determined whether or not the detected temperature is 105 ° C or higher, that is, whether or not the compressor 20 is overheated. Here, when the detected temperature is 105 ° C. or higher, it is determined that the balance of heat exchange of the refrigerant is unbalanced, the control valve 49 is opened, and the refrigerant flowing through the line 31d is compressed via the bypass line 48. It is returned to the machine 20, and thereby the above-described action by the refrigerant return control is exhibited (step S6). At this time, it is desirable to control the control valve opening in multiple stages or steplessly so that the opening of the control valve 49 increases as the detected temperature increases.

On the other hand, in steps S1 and S2, YE
In the case of S, the process proceeds to step S7, and it is determined whether or not the temperature detected by the compressor temperature sensor 78 is 105 ° C or higher. If the detected temperature is 105 ° C or higher, step S6 is performed. The control valve 49 is opened in the same manner as above. An example of such a case is when the compressor 20 is in an overheated state immediately after the air conditioner 1 is stopped, and even in such a case, the residual refrigerant in the line 31d is returned to the compressor 20 and compressed. A cooling action for the machine 20 is exerted.

In the case of NO in step S7, it is determined in step S8 whether or not the control valve 49 is already open. If the control valve 49 is not open here, the control valve 49 is not opened. Is maintained in the closed state and the process returns to step S1.

If YES in step S8, it is determined whether the temperature detected by the compressor temperature sensor 78 is 70 ° C. or lower, that is, whether the compressor 20 is maintained at the ideal operating temperature. When the detected temperature is 70 ° C. or less, there is no need to perform the refrigerant return control, so the control valve 49 is closed and the process returns to step S1 (steps S9 and 10). On the other hand, when the detected temperature is 70 ° C. or higher in step S9, the process proceeds to step S6, and the process returns to step S1 while the control valve 49 remains open. In other words, when the temperature rises, the control valve 49 opens at 105 ° C or higher, while when the temperature falls thereafter,
Control with hysteresis is performed so that the open state is maintained up to C, and the temperature is sufficiently lowered.

As described above, according to the air conditioner 1, even when the temperature of the compressor 20 rises due to the imbalance of heat exchange between the refrigerants, the compressor temperature sensor 7
Based on the temperature detection of the compressor 20 by 8, the above-described refrigerant return control is performed to return the low temperature refrigerant passing through the line 31d to the line 31b via the bypass line 48 when the temperature reaches a predetermined temperature. Since the cooling of the refrigerant is suppressed by bypassing the outdoor heat exchangers 38a, 38b and the double-tube heat exchanger 55 while cooling, the compressor 20 is cooled immediately and its damage is prevented. This can be prevented in advance, and the balance of heat exchange of the refrigerant can be eliminated. Moreover,
In the liquid return control, the output of the compressor 20 is not lowered or the compressor 20 is not stopped, so that the temperature rise of the compressor 20 is suppressed while the heat is normally radiated in the indoor heat exchangers 43a to 43d. can do. Therefore, the temperature rise of the compressor 20 can be effectively suppressed without lowering or stopping the air conditioning function.

Further, since the refrigerant return control is performed based on the temperature detection of the compressor 20 by the compressor temperature sensor 78, the compressor generated due to the imbalance of the heat transfer of the refrigerant as described above. Not only in the case of 20 overheating,
For example, when the pipe is damaged and the refrigerant leaks, and the refrigerant returning to the compressor 20 decreases, the rotation speed of the compressor 20 increases and the compressor 20 is overheated. Refrigerant return control is performed and the compressor 20 is cooled. Therefore, regardless of the cause, the abnormal temperature rise of the compressor 20 can be reliably detected and damage due to overheating can be prevented, thereby improving the durability of the compressor 20.

However, in the case of refrigerant leakage, the circulating refrigerant gradually decreases, and therefore it is not possible to completely eliminate the overheat of the compressor 20 by the refrigerant return control. Therefore,
When the overheated state of the compressor 20 continues to be eliminated based on the time-dependent change of the temperature of the compressor 20, for example, the air conditioner 1 is forcibly stopped or a warning light or the like is provided. It is desirable to do so.

By the way, the above is the case where the air conditioner 1 is operated for heating, but when it is operated for cooling, the circulation of the refrigerant is performed as follows.

That is, during the cooling operation, the first port 33a and the third port 33d of the four-way valve 33 and the second port 33b and the third port 33c of the four-way valve 33 in the refrigerant circuit 30 are in communication with each other. The discharged refrigerant reaches the outdoor heat exchangers 38a and 38b through the lines 31a and 31g. The control valve 47 is closed, so that all the refrigerant is sent to the outdoor heat exchangers 38a and 38b.

The refrigerant in the outdoor heat exchangers 38a, 38b is cooled and condensed here by the outside air to become a high-pressure liquid refrigerant, passing through the lines 31e, 31f, 31d, the liquid-gas heat exchanger 34, the dryer 39, and Each expansion valve 42 is reached through the sight glass 40. The control valve 48 is closed, so that all the refrigerant is sent to the expansion valve 42 side.

The refrigerant sent to each expansion valve 42 is decompressed here and sent to each indoor heat exchanger 43a to 43d, and absorbs latent heat of vaporization from the indoor air to evaporate (vaporize). That is, the interior of the room is cooled by absorbing the latent heat of vaporization inside the room in this way.

The vaporized refrigerant is supplied to the line 31c and the four-way valve 3
3 to the line 31b, the liquid gas heat exchanger 34,
It reaches the compressor 20 via a silencer 35 and an accumulator 36. Then, after the refrigerant is separated into a gas and a liquid here, only the gaseous refrigerant is sent to the compressor 20 through the line 31b, and thereafter, in the same manner, the refrigerant circuit 30.
The refrigerant is circulated.

In the cooling operation as well, as in the heating operation, when some of the indoor heat exchangers 43a to 43d are operated, the control valve 47 is set in accordance with the number. When opened, an appropriate amount of refrigerant is supplied to the indoor heat exchangers 43a to 43d.

By the way, in such a cooling operation, for example, the outside air temperature is high, and all the indoor heat exchangers 43a are
In an environment where ~ 43d is operated, the heat of the refrigerant is not sufficiently dissipated in the outdoor heat exchangers 38a and 38b, and thus the refrigerant of the outdoor heat exchanger may not be completely liquefied. In such a case, as in the case where some of the indoor heat exchangers are operated during the heating operation, the amount of heat absorbed by the indoor heat exchangers 43a to 43d is large, so that the refrigerant temperature on the suction side of the compressor 20 is increased. As the pressure rises, the pressure difference between the expansion valves 42a to 42d decreases, and the refrigerant flows into the refrigerant circuit 30.
The amount of the refrigerant that stays inside and returns to the compressor 20 gradually decreases. Then, due to the rise in the suction refrigerant temperature and the rise in the rotation speed due to the reduction of the load on the compressor, the compressor 2
It will induce a temperature rise of zero.

However, even in such a case, the control valve 49 is opened and a part of the refrigerant flowing through the line 31d is returned to the compressor 20 via the bypass line 48, whereby the refrigerant return control is performed. Thus, the cooling action on the compressor 20 is exerted and damage to the compressor 20 is prevented. However, in such a refrigerant return control during the cooling operation, the refrigerant before reaching the indoor heat exchangers 43a to 43d is returned to the compressor 20 via the bypass line 48, so that the indoor heat exchangers 43a to 43d are returned. Since the supply amount of the refrigerant is insufficient, the cooling capacity of the indoor heat exchangers 43a to 43d is reduced.

The air conditioner 1 of the above embodiment is an example of an air conditioner using the heat pump device according to the present invention, and its specific circuit configuration and the like may be appropriately changed without departing from the gist of the present invention. It can be changed. For example, in the above embodiment, the bypass line 48 once is connected to the line 31b on the downstream side of the accumulator 36, but may be connected to the line 31b on the upstream side of the accumulator 36, for example. With such a configuration, the liquid refrigerant can be reliably removed in the accumulator 36 and only the gaseous refrigerant can be returned to the compressor 20, which is desirable in terms of protection of the compressor 20.

Further, when the balance of heat transfer is lost and the compressor temperature rises, in addition to the control for bypassing the refrigerant as in the above embodiment, the engine output is controlled so as to suppress the increase in the rotational speed of the compressor. You may. For example, in step S6 in FIG. 7, in addition to the control of the control valve 49, the engine output is decreased as the temperature rises, and at 120 ° C. or higher, the engine output is controlled to the minimum (fully closed throttle). . In this way, the temperature rise of the compressor 20 can be prevented more reliably.

Further, although not particularly described in the above embodiment, the refrigerant circuit 30 is used for controlling the output of the compressor 20 and the like.
When it is necessary to detect the temperature of the refrigerant circulating in the
A sensor (a discharge refrigerant temperature sensor 120 indicated by a broken line in FIGS. 1, 3 and 6) may be provided near the discharge port of the compressor 20 to detect the temperature of the discharge refrigerant. That is, when the discharge refrigerant temperature detected by the discharge refrigerant temperature sensor 120 is high, the opening degree of the control valve 49 may be correspondingly increased or the rotation speed of the compressor 20 may be limited to a predetermined value or less. Good. However, under the proper operating condition, as shown in FIG.
As shown in 0, there is a correlation between the temperature of the compressor 20 and the discharge refrigerant temperature. Therefore, such a correlation is experimentally or theoretically obtained in advance, and the correlation is determined based on the refrigerant temperature. Such control may be performed based on the detected value of the compressor 20 by the compressor temperature sensor 78. According to this, one sensor can cover the temperature detection of the compressor 20 and the refrigerant temperature detection, which is advantageous in the configuration.

[0079]

As described above, the heat pump device of the present invention includes the compressor, the heat radiating portion having the condenser, the expansion valve, and the heat absorbing portion having the evaporating portion in the refrigerant circuit. Since the temperature detecting means for detecting the temperature of the compressor is provided and the suppressing means suppresses the temperature rise of the compressor based on the detected temperature, it is possible to reliably detect the overheating of the compressor in operation and damage the compressor. Can be prevented.

Particularly, in this heat pump device, a bypass passage for returning the refrigerant passing through the heat radiating portion to the compressor by bypassing at least a part of the heat absorbing portion is provided, and the bypass amount of the refrigerant in the bypass passage is adjusted according to the detected temperature. If the suppressing means is configured to be adjusted, the relatively low-temperature refrigerant cooled in the heat radiating portion can be returned to the compressor without passing through the heat absorbing portion. Therefore, damage due to overheating of the compressor can be prevented more reliably. Moreover, since the compressor can be cooled in the normal operating state without lowering the output of the compressor, it is possible to suppress the temperature rise of the compressor without lowering the air conditioning function.

Further, if the flow rate of the refrigerant in the bypass passage is increased as the temperature of the compressor rises, an appropriate amount of the refrigerant corresponding to the temperature of the compressor is returned to the compressor to efficiently raise the temperature of the compressor. Can be suppressed.

Furthermore, if the number of revolutions of the compressor is limited to a predetermined value or less when the temperature detected by the temperature detecting means exceeds a predetermined value, overheating of the compressor may occur due to insufficient refrigerant. By limiting the increase in the rotation speed of the compressor, heat generation in the compressor is effectively suppressed.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an air conditioner to which a heat pump device according to the present invention is applied.

FIG. 2 is a graph showing a control method of a switching valve in a cooling water circuit.

3 is a cross-sectional view showing the structure of a compressor applied to the apparatus of FIG.

FIG. 4 is a view (partially cutaway view) of FIG. 3 showing the structure of the compressor.

5 is a sectional view taken along line VV of FIG. 3 showing the structure of the compressor.

FIG. 6 is a block diagram showing a control system of the air conditioner shown in FIG. 1.

FIG. 7 is a Ph diagram of a refrigerant cycle.

8 is a flowchart showing refrigerant return control in the air conditioner shown in FIG.

FIG. 9 is a diagram showing a relationship between a compressor temperature and a discharged refrigerant temperature (when the temperature rises).

FIG. 10 is a diagram showing the relationship between the temperature of the compressor and the temperature of the discharged refrigerant (when the temperature drops).

FIG. 11 is a diagram showing an example of the relationship between the compressor temperature and the refrigerant temperature when the circulating refrigerant is insufficient in the conventional apparatus.

[Explanation of symbols]

1 Air Conditioner 2 Water Cooled Gas Engine 20 Compressor 30 Refrigerant Circuit 31a, 31b, 31c, 31d, 31e, 31f, 3
1g Line 33 Four-way valve 43a-43d Indoor heat exchanger 38a, 38b Outdoor heat exchanger 46 Return line 48 Bypass line 47,49 Control valve 50 Cooling water circuit 55 Double pipe heat exchanger

Claims (4)

[Claims] 1. A compressor, a heat radiation section having a condenser, an expansion valve, and a heat absorption section having an evaporation section, wherein refrigerant discharged from the compressor causes the heat radiation section, the expansion valve, and the heat absorption section to In the heat pump device in which the refrigerant circuit is configured to be returned to the compressor, the compressor is provided with temperature detecting means for detecting its temperature, and the temperature rise of the compressor is detected based on the detection result of the temperature detecting means. A heat pump device, characterized in that a suppression means for suppressing is provided. 2. The bypass means for returning the refrigerant that has passed through the heat radiating portion to the compressor by bypassing at least a part of the heat absorbing portion, and the bypass amount of the refrigerant in the bypass passage, the bypass amount of the refrigerant in the bypass passage. The heat pump device according to claim 1, further comprising a bypass amount adjusting unit that adjusts based on a temperature detected by the unit. 3. The bypass amount adjusting means is configured to increase the flow rate of the refrigerant in the bypass passage as the temperature of the compressor rises.
The heat pump device as described in the above. 4. The suppressing means has a control means for controlling the driving of the compressor, and the control means controls the compressor when the temperature detected by the temperature detecting means becomes a predetermined value or more. The heat pump device according to any one of claims 1 to 3, wherein the heat pump device is configured to limit the rotation speed to a predetermined value or less.