JPH09138018A - Heat pump equipment - Google Patents

Abstract

(57) Abstract: In a heat pump device such as an air conditioner using a non-azeotropic refrigerant, COP is effectively increased to improve the operation performance. A compressor 20, a four-way valve 41, indoor heat exchangers 68a to 68n, expansion valves 70a to 70n, and outdoor heat exchangers 75a and 75b are provided in a refrigerant circuit 30, and a non-azeotropic refrigerant is used as a refrigerant. In the heat pump device, the accumulators 45 and 46 are arranged in the path through which the refrigerant returns from the evaporator to the compressor 20. In addition, while controlling the rotation speed of the compressor according to the load, at the time of heating at least the sub-cool control that makes the temperature of the refrigerant near the high-pressure side expansion valve lower than the saturated liquid temperature by adjusting the opening of the expansion valve is performed. Means are provided. Further, a liquid refrigerant passage 62 that connects the lower portions of the accumulators 45 and 46 and a refrigerant circuit downstream of the accumulator is formed, and heat exchange that heats and vaporizes the liquid refrigerant in the liquid refrigerant passage 62 in the middle thereof. A container 64 is provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a compressor, a condenser,
While circulating the refrigerant in a closed circuit provided with an expansion valve and an evaporator, the heat pump device configured to perform heating and cooling, or freezing by heat dissipation in the condenser or heat absorption in the evaporator, particularly as a working refrigerant. The present invention relates to a heat pump device using a non-azeotropic refrigerant.

[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. By circulating the refrigerant in the refrigerant circuit and incorporating a four-way valve in this refrigerant circuit to switch the circulation direction of the refrigerant, a heat pump type air conditioner that performs cooling and heating by one device, or the above four-way BACKGROUND OF THE INVENTION Refrigerating devices that only perform freezing without incorporating a valve are frequently used.

In the above air conditioner, during cooling, the refrigerant circulates in the order of the compressor, the four-way valve, the outdoor heat exchanger, the expansion valve, the indoor heat exchanger, the four-way valve and the compressor, so that the outdoor heat exchanger is The condenser and the indoor heat exchanger serve as evaporators to cool the room by absorbing heat in the indoor heat exchanger, while the refrigerant is compressed by the compressor, the four-way valve, the indoor heat exchanger, the expansion valve, and the outdoor during heating. By circulating the heat exchanger, the four-way valve, and the compressor in this order, the indoor heat exchanger serves as a condenser and the outdoor heat exchanger serves as an evaporator, and the refrigerant is used to perform heating by radiating heat in the indoor heat exchanger. The circuit is configured.

Further, in the heat pump device used for such an air conditioner or a refrigerating device, the expansion valve opening degree and the like are controlled so that the refrigerant temperature near the high pressure side expansion valve is lower than the saturated liquid temperature. There is one that is designed to improve the performance by performing so-called subcool control.

In this device, an accumulator is provided in the middle of the route in which the refrigerant returns from the evaporator to the compressor, for example, in the air conditioner, between the four-way valve and the compressor suction port. Then, as the load becomes smaller, the rotation speed of the compressor is lowered, and the opening degree of the expansion valve is set to be small, so that the refrigerant temperature in the vicinity of the expansion valve on the high pressure side is lowered to the saturated liquid temperature or lower. The control is performed so that the excess refrigerant in the liquid phase generated in the refrigerant after evaporation is retained in the accumulator by the subcool control.

According to this subcool control, when a single boiling point refrigerant (for example, R22) is used as the refrigerant,
COP showing the efficiency of the refrigeration cycle as detailed later
(Coefficient of performance) can be increased.

[0007]

By the way, recently, as a refrigerant in this type of heat pump device, a plurality of kinds of refrigerants having different boiling points are mixed in order to satisfy requirements such as prevention of ozone layer depletion and improvement of refrigerant capacity. Although a non-azeotropic refrigerant has been developed, the conventional apparatus has the following problems when using this non-azeotropic refrigerant.

That is, when a non-azeotropic refrigerant is used in the device for performing the subcool control, if the supercooling degree is controlled so as to be maintained at an appropriate constant value in order to ensure the performance, the high boiling point component of the non-azeotropic refrigerant is used. Since it becomes difficult to evaporate, the high-boiling point component stays in the accumulator at a high rate over time, and the rate of the low-boiling point component in the gas-phase refrigerant sucked into the compressor becomes higher than the initial filling rate. In general, the low-boiling point component has a smaller non-volume than the high-boiling point component, so if the proportion of the low-boiling point component in the gas-phase refrigerant sucked into the compressor increases, the compression work required to increase the pressure to a predetermined pressure in the compressor. , Which reduces COP. Therefore, even if sub-cool control is performed, CO
P cannot be improved.

In view of the above circumstances, the present invention is such that when a non-azeotropic refrigerant is used, the component ratio of the refrigerant sucked and circulated in the compressor fluctuates with respect to the initial filling ratio while performing subcool control. It is an object of the present invention to provide a heat pump device capable of effectively improving COP and improving operating performance by suppressing the above.

[0010]

In order to achieve the above object, the present invention comprises a compressor, a condenser, an expansion valve and an evaporator, and the refrigerant discharged from the compressor is the condenser. A heat pump device in which a refrigerant circuit is configured to be returned to the compressor via an expansion valve and an evaporator, and a non-azeotropic refrigerant is used as the refrigerant, in which the refrigerant returns from the evaporator to the compressor. An accumulator is placed inside the subcooler that controls the rotation speed of the compressor according to the load, while adjusting the opening of the expansion valve to keep the refrigerant temperature near the high-pressure side expansion valve at a temperature lower than the saturated liquid temperature. A control means for controlling is provided, and a liquid refrigerant passage that connects the lower part of the accumulator and the refrigerant circuit downstream of the accumulator is formed, and in the middle of the liquid refrigerant passage, the liquid-phase refrigerant in the passage is heated. hand Heating means for reduction in which is provided.

According to this device, the COP is enhanced by performing the subcool control. In addition, when subcool control is performed, excess refrigerant in the liquid phase stays in the accumulator, and particularly high-boiling point components of the non-azeotropic refrigerant stay at a high rate, and at the same time the accumulator moves to the compressor side. Gas phase refrigerant with a high proportion of boiling point components is sent, the liquid refrigerant containing a large amount of high boiling point components in the accumulator is led out to the liquid refrigerant passage, is heated by heating means in the liquid refrigerant passage and vaporized, which is By being mixed with the gas-phase refrigerant sent from the accumulator to the compressor, the component ratio of the refrigerant sucked and circulated in the compressor approaches the initial filling ratio. Therefore, a decrease in COP due to an increase in the proportion of the low boiling point component in the circulating refrigerant does not occur.

In this heat pump device, the heating means is, for example, a heat exchanger for guiding the circulating liquid refrigerant from between the condenser and the expansion valve and heating the liquid refrigerant in the liquid refrigerant passage with the circulating liquid refrigerant. Composed.

With this configuration, the high temperature liquid refrigerant is utilized between the condenser and the expansion valve, and the refrigerant is effectively heated and vaporized in the liquid refrigerant passage.

The heating means may be configured to heat the liquid refrigerant in the liquid refrigerant passage by using waste heat of an engine for driving the compressor as a heat source.

In this way, the waste heat of the engine that drives the compressor is effectively used, and the refrigerant in the liquid refrigerant passage is effectively heated and vaporized.

The control of the number of revolutions of the compressor in accordance with the load during both cooling and heating operations means that the refrigerant discharge amount of the compressor is increased as the load increases. The refrigerant discharge amount of the compressor is controlled if the discharge amount can be increased or decreased even if the number is constant.

[0017]

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

FIG. 1 is a circuit diagram showing an embodiment of an air conditioner using the heat pump device according to the present invention. As shown in this figure, in the air conditioner 1, a water-cooled gas engine 2 (hereinafter abbreviated as engine 2), a compressor 20 driven by the same, and a refrigerant circuit 30 for circulating a refrigerant.
And a cooling water circuit 80 for cooling the engine 2. As the refrigerant, a non-azeotropic refrigerant in which a plurality of types of refrigerants having different boiling points are mixed is used. For example, R32 and R125 which are relatively low-boiling refrigerants and R134a which is a relatively high-boiling refrigerant are mixed. Refrigerant is used.

An intake pipe 3 is connected to the engine 2,
An air cleaner 4 and a mixer 5 are connected to the intake pipe 3. A fuel supply pipe 6 connected to a fuel gas supply source (not shown) is connected to the mixer 5, and a flow control valve 7, a governor 8, and an electromagnetic valve 9 are interposed in the fuel supply pipe 6. . In the mixer 5, the supply amount of fuel gas and air to the engine is adjusted by the operation of the throttle by the pulse motor 5a. An oil tank 11 is connected to an oil pan of the engine 2 via an oil supply pipe 10.
Is provided with a solenoid valve 12 for adjusting the oil supply amount.

An exhaust pipe 13 is led out of the engine 2, and an exhaust gas heat exchanger 14, an exhaust silencer 15 and a mist separator 16 are interposed in the exhaust pipe 13. Reference numeral 17 denotes a heater for adjusting the oil temperature in the oil pan of the engine 2, and reference numeral 18 denotes an exhaust gas heat exchanger 14.
And a drain treatment device for neutralizing drain water from the exhaust silencer 15 and the mist separator 16.

In the illustrated example, the compressor 20 is a multi-type compressor having two unit compressors 20a and 20b, and each unit compressor 20a and 20b is an electromagnetic clutch 2.
1 is connected to the output shaft 22 of the engine. 2
Reference numeral 3 denotes a heater for adjusting the oil temperature in the compressor 20.

The refrigerant circuit 30 passes the refrigerant discharged from the compressor 20 through a condenser, an expansion valve and an evaporator to the compressor 2
A closed circuit for circulation to return to 0 is configured.

In this embodiment, a plurality of indoor heat exchangers 6 are used.
8a to 68n and the expansion valves 7 respectively provided therein
0a to 70n, two outdoor heat exchangers 75a and 75b, etc. are incorporated in the refrigerant circuit 30, and a four-way valve 41 as a means for switching the refrigerant circulation path is provided. Then, during heating, the refrigerant flows from the compressor 20 to the indoor heat exchanger 6
8a to 68n, expansion valves 70a to 70n, outdoor heat exchanger 7
By returning to the compressor 20 through 5a and 75b in this order, the indoor heat exchangers 68a to 68n serve as condensers, and the outdoor heat exchangers 75a and 75b serve as evaporators. To outdoor heat exchangers 75a, 75
b, expansion valves 70a to 70n, indoor heat exchangers 68a to 68
By being returned to the compressor 20 through n in this order,
The indoor heat exchangers are evaporators 68a to 68n and the outdoor heat exchanger 7
5a and 75b are configured as condensers.

Therefore, in the refrigerant circuit 30, during heating, from the discharge portion of the compressor 20 to the expansion valves 70a to 70n via the indoor heat exchangers 68a to 68n, after passing through the high pressure circuit and the expansion valves 70a to 70n. Outdoor heat exchangers 75a, 75
A low pressure circuit extends from b to the suction portion of the compressor 20, while a high pressure circuit extends from the discharge portion of the compressor 20 to the expansion valves 70a to 70n via the outdoor heat exchangers 75a and 75b during cooling. A low-pressure circuit extends from the expansion valves 70a to 70n to the suction portions of the compressor 20 via the indoor heat exchangers 68a to 68d.

Further, in the refrigerant circuit 30, an accumulator is arranged in the path through which the refrigerant returns from the evaporator to the compressor 20, and in this embodiment, the four-way valve 41 to the compressor 2 are arranged.
A main accumulator 45 and a sub accumulator 46 are arranged in the path leading to the suction unit of 0.
Further, the liquid refrigerant passage 6 that connects the lower portions of the accumulators 45 and 46 and the line 32c downstream of the accumulators.
2 is formed, and in the middle of the liquid refrigerant passage 62, a heating means for heating and vaporizing the liquid phase refrigerant in the passage is provided. In the present embodiment, the heating means guides the high-temperature high-pressure gas-phase refrigerant on the way from the compressor 20 to the four-way valve 41 and heats the liquid refrigerant in the liquid-refrigerant passage 62 by the gas-phase refrigerant. It is composed of a container 64.

It should be noted that instead of the gas-phase refrigerant, a condenser (the outdoor heat exchangers 75a and 75b during cooling) and the expansion valves 70a-7 are used.
The circulating liquid refrigerant between 0n and 0n may be introduced so that the circulating liquid refrigerant heats the liquid refrigerant in the liquid refrigerant passage 62. In this case, since the liquid phase refrigerant is used for heating, the heat transfer efficiency is improved, while the heat is dissipated by the condenser, the temperature on the heating side is lowered, and the heating efficiency is lower than that of the present embodiment as a whole. Further, it is necessary to change the circulating liquid refrigerant position that is introduced during heating and during cooling.

Explaining the structure of the refrigerant circuit 30 in detail, a discharge side line 31 and a suction side line 32 are provided between the compressor 20 and the four-way valve 41, and the discharge side line 31 is , Is discharged from the discharge portion of the compressor 20 and is connected to the first port 41 a of the four-way valve 41 via the oil separator 42. The oil separator 42
The oil return line 43 derived from the
Downstream side line 32c in the suction side line 32 via
It is connected to the.

On the other hand, the suction side line 32 is connected to the four-way valve 4 described above.
The line 32a derived from the first third port 41c to the main accumulator 45, the line 32b derived from the main accumulator 45 to the sub accumulator 46, and the downstream branch portion derived from the sub accumulator 46 to the check valve. And a line 32c reaching the suction portion of the compressor 20 via 47. The portion of the discharge side line 31 near the downstream side is the suction side line 3
The line 32a in 2 is connected via a line 33 having a strainer 48 and an on-off valve 49, and the on-off valve 49 is opened when the pressure is abnormally high.

The main accumulator 45 is provided with a heat exchanger 51 and the accumulator 4
A composition ratio detector 101 for detecting the composition ratio of the liquid-phase refrigerant stored in 5 is provided. Further, the predetermined high level position and the predetermined low level position of the main accumulator 45 are
The liquid level in the main accumulator 45 is connected to the line 32b by a passage having the strainer 53 and the capillary tube 54 and a passage having the strainer 55 and the capillary tube 56, and temperature sensors 102 and 103 are provided for these passages. The liquid phase refrigerant is led out to the passage according to the rise of the level, and the temperature change accompanying it is detected by the temperature sensors 102 and 103, so that the temperature sensors 102 and 103 detect the liquid level in the main accumulator 45. It has a function to do.

A capillary tube 57 is provided in the line 32b between the main accumulator 45 and the sub accumulator 46.

A U-shaped tube 58 is provided inside the sub accumulator 46. This U-shaped tube 58
Has an opening at one end above and an orifice 58 at the bottom.
It communicates with the bottom of the sub accumulator 46 through a, and the other end is connected to the downstream line 32c. In the sub accumulator 46, normally, only oil is collected at the bottom, and the oil is sucked into the U-shaped pipe 58 from the orifice 58a and returned to the compressor 20. Reference numeral 65 is a heater, which is used to heat the sub accumulator 46 as needed.

Further, a position slightly lower than the opening position of the U-shaped tube 58 is connected to the line 32c by a passage having a strainer 60 and a capillary tube 61, and a temperature having a liquid level detecting function for this passage. A sensor 104 is provided. The liquid level is detected in order to prevent the liquid refrigerant from flowing from the sub accumulator 46 to the compressor 20, and the liquid phase refrigerant originally stays in the sub accumulator 46 where the liquid phase refrigerant is empty, and When the level rises, this is detected and the operation of reducing the retention of the liquid-phase refrigerant (for example, operating the heater 65)
Done for.

A liquid refrigerant passage 62 is formed between the lower portions of the accumulators 45 and 46 and the downstream line 32c. The liquid refrigerant passage 62 has passages 62a and 62b led out from the lower portions of the accumulators 45 and 46. The passages 62a and 62b join together, and the downstream ends of the joined passages are connected to the line 32c. ing.
The main accumulator 4 is provided in each of the passages 62a and 62b.
5 and control valves 63a and 63b for adjusting the amount of liquid refrigerant flowing out from the sub accumulator 46. Then, in the liquid refrigerant passage 62 downstream of the confluence portion, the heat exchanger 64
Is provided.

The compressor 20 has a compressor temperature sensor 1
05 is provided, and the compressor 2 is provided in the discharge side line 31.
A high pressure side pressure sensor 106 for detecting the pressure of the refrigerant discharged from 0 is provided, while a low pressure side for detecting the pressure of the refrigerant sucked into the compressor 20 is provided in the downstream side line 32c of the suction side line 32. A pressure sensor 107 and a suction refrigerant temperature sensor 108 for detecting the temperature of this refrigerant are provided. The discharge-side line 31 is connected to the first port 41a of the four-way valve 41 via the heat separator 64 as described above after passing through the oil separator 42.

The second port 41b of the four-way valve 41
From which the line 34 is led out, and this line 34 reaches each of the indoor heat exchangers 68a to 68n via the on-off valve 65 and the joint 66. The line 34 is provided with a composition ratio detector 109 that detects the composition ratio of the circulating refrigerant. The on-off valve 65 is normally open except when it is closed for maintenance.

The indoor heat exchangers 68a to 68n are arranged in parallel with each other as shown in the figure, and the input / output portions on one side (lower side in the figure) are connected to the line 34, and The input / output portions on the other side (upper side in the figure) are connected to the line 35 via expansion valves 70a to 70n, respectively. Note that 110a to 110n are expansion valve upstream temperature sensors that detect the refrigerant temperature of the expansion valve upstream portion during heating, and 111a to 111n are indoor temperature sensors.

The line 35 includes a joint 71 and an opening / closing valve 7.
2, the dryer 73, the filter 74, etc., and is connected to the outdoor heat exchanger 75a. A line 36 is led out from the outdoor heat exchanger 75a, and this line 36 is connected to the four-way valve 4 described above.
1 is connected to the fourth port 41d. A line 37 branched from the line 35 is an outdoor heat exchanger 75b.
And the line 38 led out from the outdoor heat exchanger 75b is connected to the line 36. The lines 37 and 38 are provided with open / close valves 76 and 77. The liquid gas heat exchanger 44 and the outdoor heat exchanger 75a,
The line 35 to 75b is connected to the upstream line 32a in the suction side line 32 via a bypass line 39 having a control valve 78 and a strainer 79. The control valve 78 is closed during normal operation.

The cooling water circuit 80 includes a pump 82.
A cooling water line 81a is led out from the discharge side of the cooling water line 81a, and the cooling water line 81a is connected to the cooling water introduction port of the water jacket 83 of the engine 2 via the exhaust gas heat exchanger 14 and the cooling of the water jacket 83 is performed. A cooling water line 81b is led out from the water outlet and is connected to the linear three-way valve 84.

Cooling water lines 81c and 81e are led out from the linear three-way valve 84, respectively. The cooling water line 81c is connected to the radiator 85, and the cooling water line 81d led out from the radiator 85 is connected to the suction side of the pump 82. On the other hand, the cooling water line 81e reaches the heat exchanger 51 provided in the main accumulator 45, and is connected to the cooling water line 81d via the heat exchanger 51.

The linear three-way valve 84 is adapted to adjust the flow rate of the cooling water to the cooling water lines 81c and 81e. Specifically, as shown in FIG. 3, in accordance with the operating position of the three-way valve 84, 100% of the cooling water guided to the three-way valve 84 flows from the cooling water line 81c to the cooling water line 81e. The ratio of the amount of cooling water in both the cooling water lines 81c and 81e can be linearly changed. Then, in the cooling water circuit 80, the cooling water that has received heat from the exhaust gas heat exchanger 14 and the like is guided to the linear three-way valve 84, and the cooling water line 81e is further provided in an amount corresponding to the operating position of the linear three-way valve 84. By being guided to the heat exchanger 51 via the heat exchanger 51, heat is supplied to the refrigerant in the main accumulator 45 by the heat exchanger 51, and the amount of heat supplied is adjusted by the linear three-way valve 84.

81g is a cooling water supply line connected to the cooling water line 81d, and 86 is a cooling water supply line 81.
is a water tank connected to g.

Next, the control system of the air conditioner 1 will be described with reference to the block diagram of FIG. It should be noted that this figure mainly shows the configuration of the control system relating to the refrigerant circuit 30.

As shown in the figure, the control system of the air conditioner is
The indoor heat exchangers 68a to 68n and the expansion valves 70a to 7
The indoor units control devices 91a to 91n for individually controlling the indoor units 90a to 90n provided with 0n, the compressor 20, the outdoor heat exchangers 75a and 75b, the four-way valve 41, the accumulators 45 and 46, and the like are provided. And an outdoor unit control device 92 for controlling the outdoor unit being installed, and electrically connected so that each of the indoor unit control devices 91a to 91n and the outdoor unit control device 92 can perform control in association with each other. Has been done.

In the indoor units 90a to 90n, fans 93a to 93n for blowing air and expansion valves 70a to 70n, respectively.
n, expansion valve upstream-side refrigerant temperature sensors 110a to 110n
And an operation unit 9 equipped with an on / off switch and a temperature setting key
4a to 94n and indoor temperature sensors 110a to 110n that detect the temperature of each room are provided. Then, for example, when the desired temperature is input to the indoor unit 90a via the operation unit 94a, the indoor unit controller 91a obtains the indoor temperature with the indoor temperature sensor 110a, and the difference between this temperature and the desired temperature is calculated. The output of the fan 93a is controlled so as to reduce the temperature difference.

On the other hand, the outdoor unit controller 92 includes an engine 2, a four-way valve 41, a linear three-way valve 84, an opening / closing valve 49,
65, 72, 76, 77, control valves 63a, 63b, outdoor unit side fan 95, and other controlled elements are connected, and a suction refrigerant temperature sensor 108, a compressor temperature sensor 105, and an accumulator liquid level detection function are provided. Control input elements such as the temperature sensors 102 and 103, the high-pressure side pressure sensor 106, the low-pressure side pressure sensor 107, the outside air temperature sensor 112, and the composition ratio detectors 101 and 109 are connected, and further various data and programs for control are provided. Is connected to a storage device 96 for storing

The outdoor unit controller 92 controls each indoor unit 90.
As described above, the four-way valve 41 is switch-controlled to switch the circulation direction of the refrigerant in the refrigerant circuit 30 in response to the cooling / heating switching of a to 90n. Further, the outdoor unit control device 92 checks a load that changes depending on, for example, the number of operating indoor units and other operation states during cooling and heating, and controls the driving of the engine 2 according to the load, thereby controlling the compressor 20. The number of revolutions is adjusted, and control is performed so that the number of revolutions of the compressor 20 decreases as the load decreases.

In addition, each of the control devices 91a to 91n, 9
Reference numeral 2 controls the expansion valves 70a to 70n and the like so as to execute subcool control during heating and cooling as described later in detail. In addition to such control, the accumulator 4 is controlled by controlling the control valves 63a and 63b.
By adjusting the amount of liquid flowing out of the liquid refrigerant passage 62 from the liquid flow path 5, 46 and controlling the three-way valve 84, the amount of heat exchange of the heat exchanger 51 provided in the main accumulator 37 is adjusted. .

The operation of the air conditioner of this embodiment as described above will be described below.

When the air conditioner is in the cooling operation, the four-way valve 41 connects the first port 41a and the fourth port 42d with each other and the second port 41b and the third port 41c.
Is communicated with In this state, as indicated by the broken line arrow in FIG. 1, the refrigerant discharged from the compressor 20 is the heat exchanger 64, the four-way valve 41, and the outdoor heat exchangers 75a, 75.
b, expansion valves 70a to 70n, indoor heat exchangers 68a to 68
n, the four-way valve 41, the main accumulator 45, and the sub accumulator 46 are circulated to the compressor 20 in this order. The outdoor heat exchangers 75a and 75b act as condensers to radiate heat, while the indoor heat exchanger 6
8a to 68n act as an evaporator to absorb heat and cool the room.

On the other hand, when the air conditioner is operated for heating, the four-way valve 41 is connected to the first port 41a and the second port 4a.
1b and the third port 41c and the fourth port 41d are in communication with each other. In this state, the refrigerant discharged from the compressor 20 is the heat exchanger 64, the four-way valve 41, and the indoor heat exchanger 68, as indicated by the solid arrow in FIG.
a-68n, expansion valves 70a-70n, outdoor heat exchanger 75
a, 75b, four-way valve 41, main accumulator 45,
It is circulated to the compressor 20 through the sub accumulator 46 in this order. The indoor heat exchangers 68a to 68n function as condensers to radiate heat, thereby heating the interior of the room, and the outdoor heat exchangers 75a and 75b function as evaporators to absorb heat.

During such cooling and heating operations, the refrigerant exists in each part of the refrigerant circulation path as follows.

That is, the gas-phase refrigerant and the condenser are provided in the conduit between the compressor 20 and the condenser (the outdoor heat exchangers 75a and 75b during cooling or the indoor heat exchangers 68a to 68n during heating). Both the vapor-phase and liquid-phase refrigerants are present in the internal conduit of the. Liquid-phase refrigerant is provided in the conduit between the condenser and the expansion valves 70a to 70n, and the expansion valves 70a to 70n and the evaporator (indoor heat exchangers 68a to 68n during cooling or the outdoor heat exchanger 75a during heating). , 75b), a gas-liquid two-phase refrigerant is present in the conduit. Both vapor-phase and liquid-phase refrigerants are present in the internal conduit of the evaporator. Further, in each of the accumulators 45 and 46, a liquid-phase refrigerant exists in the lower part and a gas-phase refrigerant exists in the upper part. The total amount of the refrigerant in each of these parts is the filled refrigerant amount.

However, the liquid-phase refrigerant in the sub-accumulator 46 is controlled to be zero or very small during normal operation so that the liquid-phase refrigerant does not overflow from the main accumulator 45.

When there is a change in cooling / heating or a change in load (change in room temperature, outside temperature, number of rooms, etc.), the capacity of the condenser changes, and the gas-phase refrigerant existing in the internal pipeline is changed. The proportion of the liquid-phase refrigerant changes, and likewise, the proportion of the vapor-phase refrigerant and the liquid-phase refrigerant present in the internal conduit changes due to the change of the capacity of the evaporator.

More specifically, in the condenser,
For example, when the ambient temperature rises or the fan speed decreases, the condensation action decreases and the proportion of the gas phase increases. Further, when the compressor rotation speed increases while the ambient temperature and the fan rotation speed remain constant, the refrigerant circulation amount increases, and the proportion of the gas phase in the condenser increases accordingly. When the expansion valve opening is increased while the ambient temperature, fan rotation speed, and compressor rotation speed remain constant, the line resistance decreases and the circulation amount slightly increases. The percentage increases slightly.

On the other hand, in the evaporator, for example, when the ambient temperature rises or the fan rotation speed increases, the evaporation action is enhanced and the proportion of the gas phase increases. Also,
When the compressor rotation speed decreases while the ambient temperature and the fan rotation speed remain constant, the refrigerant circulation amount decreases, and the proportion of the gas phase in the evaporator increases accordingly. Further, when the expansion valve opening becomes small while the ambient temperature, the fan rotation speed, and the compressor rotation speed remain constant, the line resistance increases and the circulation amount slightly decreases.
As a result, the proportion of the gas phase in the evaporator slightly increases.

When the gas-liquid ratio changes in the condenser and the evaporator in this way, the amounts of the refrigerant existing in the respective pipelines of the refrigerant circuit 30 and in the condenser and the evaporator change, and the amount of the filled refrigerant does not change. The change is mainly absorbed by a change in the ratio of the gas-liquid refrigerant in the accumulator 45.

That is, when the capacity of the condenser is lowered, for example, when the external temperature becomes high during cooling, when the rotation speed of the outdoor unit fan decreases, or when the indoor temperature becomes high during heating or the indoor unit fan. When the number of rotations of No. 1 decreases, the proportion of the gas phase in the condenser increases, and the amount of liquid-phase refrigerant in the accumulator increases correspondingly. In addition, when the capacity of the evaporator increases, for example, when the external temperature rises during heating or when the rotation speed of the outdoor unit fan increases, or when the indoor temperature rises during cooling or when the rotation speed of the indoor unit fan increases. If rises, the proportion of the gas phase in the evaporator increases, and the amount of liquid-phase refrigerant in the accumulator increases by that amount.

The change in the number of revolutions of the compressor has little effect on the increase or decrease in the amount of the liquid-phase refrigerant in each of the condenser and the evaporator, but the change in the specific volume on the high-pressure side is particularly large with the change in the pressure in the gas phase. Accordingly, the amount of liquid refrigerant in the accumulator 45 decreases and increases in inverse proportion to the compressor rotation speed as the compressor rotation speed increases and decreases.

When the expansion valve opening is increased or decreased while keeping the performance of the compressor 20 constant, for example, when the expansion valve opening is increased, the volume ratio of the liquid phase in the condenser decreases while the evaporation The volume ratio occupied by the liquid phase in the vessel increases and is offset, and the change in the pressure of the gas-phase refrigerant is small and the specific volume is small, so there is almost no change in the amount of the liquid-phase refrigerant in the accumulator 45 as a whole. . This is the same when the opening degree of the expansion valve is reduced.

When the expansion valves of some of the indoor units arranged in parallel are closed at the time of heating, the liquid phase refrigerant is introduced into the internal pipe of the indoor heat exchanger of the closed indoor units. May accumulate, and in this case, the amount of liquid-phase refrigerant in the accumulator decreases. On the other hand, when the expansion valves of some of the indoor units arranged in parallel are closed during cooling, the liquid that was present in the internal pipe of the indoor heat exchanger of the indoor unit before it was closed. By changing all the phase refrigerant to the gas phase, the amount of liquid phase refrigerant existing in all the indoor units decreases, and in this case, the amount of liquid phase refrigerant in the accumulator increases.

By the way, in the apparatus of this embodiment,
During heating operation or cooling operation, the compressor rotation speed is controlled according to the load, etc., and subcool control is performed by controlling the expansion valve opening.

Here, the subcool control is a control for cooling the refrigerant temperature near the expansion valve on the high pressure side so as to be equal to or lower than the saturated liquid temperature. Specifically, the refrigerant temperature on the upstream side of the expansion valve is detected, and the expansion valve opening degree is controlled so as to be decreased so as to reduce this temperature to a predetermined value equal to or lower than the saturated liquid temperature.

Alternatively, the saturated liquid temperature is calculated from the high pressure side pressure detected by the high pressure side pressure sensor 106 and the circulating refrigerant composition ratio detected by the composition ratio detector 109, and the expansion liquid upstream side from the saturated liquid temperature is calculated from this saturated liquid temperature. Even if the expansion valve opening degree is controlled so that the value obtained by subtracting the refrigerant temperature becomes a predetermined positive value or the value obtained by dividing the saturated liquid temperature by the refrigerant temperature becomes a predetermined value larger than 1, Good.

When this control is performed, the liquid-phase refrigerant accumulates in the main accumulator 45. Therefore, the liquid level of the liquid-phase refrigerant in the main accumulator 45 is detected, and this liquid level is set to a predetermined value (low level). When it is lower than (level), the expansion valve opening degree may be controlled to be expanded until it becomes a predetermined value or more.

According to this subcool control, the Ph diagram of the refrigeration cycle is as shown in FIG. That is, after the gas-phase refrigerant is compressed by the compressor 20 and the pressure P and the enthalpy h rise (a1 → b1), the indoor heat exchangers 68a to 68a.
The refrigerant changes from the gas phase to the liquid phase as it condenses and radiates heat at n and the enthalpy h decreases (b1 → c1). At this time, the refrigerant is supercooled so that it is significantly below the saturated liquid line, and subcool control is performed. Is performed. Next, the liquid-phase refrigerant is added to the expansion valve 70.
The pressure is expanded at a to 70n to a low pressure (c1 → d1), and the enthalpy h is further increased by evaporation in the outdoor heat exchangers 75a and 75b (d2 → a2). Note that SC is the enthalpy change due to supercooling.

By this subcool control, the COP (coefficient of performance) is increased, and the performance of the air conditioner is enhanced.

That is, the COP represents the efficiency of the refrigeration cycle, where A is the amount of increase in enthalpy due to compression in the compressor 20, and B is the amount of increase in enthalpy due to evaporation in the evaporator (see FIG. 4). ), And the following during cooling and heating.

(At cooling) COP = B / A ... (At heating) COP = (A + B) / A ... Then, when subcool control is performed, only the enthalpy change SC due to supercooling, the value of B in the above equation Is increased, COP is improved.

However, if the subcool control is simply performed in the air conditioner using the non-azeotropic refrigerant, the liquid phase refrigerant stays in the accumulators 45 and 46, and particularly the non-azeotropic refrigerant is liquefied. The high-boiling point component (for example, R134a), which tends to do so, stays at a high rate over time, so that the ratio of the low-boiling point component (for example, R32, R125) in the gas-phase refrigerant sucked into the compressor 20 is higher than the initial filling rate. There is a tendency for the COP to increase, which leads to a decrease in COP and offsets the increase in COP due to subcool control.

This will be described with reference to FIG. In this figure, the horizontal axis shows the composition ratio of the low boiling point component in the non-azeotropic refrigerant, and the vertical axis shows the temperature, showing the saturated vapor line and the saturated liquid line under a constant pressure, as shown in the same figure. In addition, when the temperature of the refrigerant introduced into the accumulator by the subcool control becomes relatively low, the composition ratio of the low boiling point component in the liquid non-azeotropic refrigerant staying in the accumulator becomes a low value X1 (high boiling point component). On the other hand, from the accumulator to the compressor 2
There is a tendency that the composition ratio of the low boiling point component of the vapor phase non-azeotropic refrigerant sent to 0 becomes a high value X2 (the ratio of the low boiling point component increases). .

However, in the apparatus of this embodiment, the heat exchanger 64 is provided in the middle of the liquid refrigerant passage 62 that connects the lower portions of the accumulators 45 and 46 and the line 32c downstream of the accumulator, and further the main accumulator 45.
Since the heat exchanger 51 is also provided inside and the liquid phase refrigerant is heated by these, the above tendency is corrected.

That is, since the high-temperature and high-pressure circulating gas-phase refrigerant is guided to the heat exchanger 64 provided in the middle of the liquid refrigerant passage 62, the circulating gas-phase refrigerant is used for both cooling and heating. Liquid refrigerant passage 6 from accumulators 45 and 46
The liquid refrigerant containing a large amount of the high-boiling point component derived in 2 is heated and the high-boiling point component is vaporized. Then, the vaporized high-boiling point component is sent to the downstream line 32c and mixed with the gas-phase refrigerant containing a large amount of the low-boiling point component from the accumulator, so that the component ratio of the refrigerant sucked into the compressor 20 is initially filled. Maintained at the same rate.

Further, the waste heat of the engine is supplied to the heat exchanger 51 provided in the main accumulator 45 by using the cooling water as a medium to heat the refrigerant in the main accumulator 45, which also vaporizes the high boiling point component. Is promoted. Therefore, the heat exchanger 64 of the liquid refrigerant passage 62 may be used to heat the liquid refrigerant in this passage, and the heat exchanger 51 of the main accumulator 45 may also be used supplementarily if necessary.

In this way, by properly maintaining the component ratio of the refrigerant sucked into the compressor 20, it is possible to avoid a decrease in COP due to a change in the composition ratio of the circulating refrigerant (increase in the low boiling point component), and the subcool The improvement of COP by control is effectively achieved.

FIG. 6 shows another embodiment of the heating means provided in the liquid refrigerant passage 62. In this embodiment, the heating means provided in the liquid refrigerant passage 62 that connects the accumulators 45 and 46 and the line 32c on the downstream side is configured by the heat exchanger 120 that uses the waste heat of the engine.

More specifically, in the cooling water circuit 80, in addition to the linear three-way valve 84 for adjusting the flow rate of the cooling water to the heat exchanger 51 of the main accumulator 45, the linear three-way valve 121 is also provided downstream (or upstream) thereof. Is provided,
From this three-way valve 121, a cooling water line 81c to the radiator side and a cooling water line 122 are led out. The cooling water line 122 reaches the heat exchanger 120 provided in the liquid refrigerant passage 62, and is connected to the cooling water line 81d via the heat exchanger 120.

Like the linear three-way valve 84, the linear three-way valve 121 is adapted to linearly adjust the ratio of the amount of cooling water in the cooling water line 122 and the amount of cooling water in the cooling water line 81c. In addition to the heat exchanger 51 into which cooling water is introduced, the main accumulator 45 also includes a heat exchanger 1 into which a circulating refrigerant is introduced between the condenser and the expansion valve.
23 are provided.

Also in this embodiment, during the cooling operation or the heating operation, the compressor rotation speed is controlled according to the load and the subcool control is performed by controlling the expansion valve opening. Further, when the sub-cool control is performed, the waste heat of the engine is supplied to the heat exchanger 120 by using the cooling water as a medium, so that the liquid refrigerant in the liquid refrigerant passage 62 is heated and vaporized. In this way, an operation similar to that of the previous embodiment can be obtained.

In particular, according to this embodiment, the waste heat of the engine can be effectively used, and the heat exchanger 120 can heat and vaporize the liquid refrigerant during both the cooling operation and the heating operation. And linear three-way valve 121
It is possible to control the heating of the liquid refrigerant by the heat exchanger 120 and maintain the component ratio of the refrigerant sucked into the compressor 20 at an appropriate value by controlling the above.

The heat exchangers 51 and 123 provided in the main accumulator 45 assist the vaporization of the liquid refrigerant, but these may be omitted.

In each of the above embodiments, the main and sub accumulators 45 and 46 are provided as accumulators, but one accumulator may be provided as shown in FIG. 7 or 8.

That is, in the embodiment shown in FIG. 7, in the refrigerant circuit 30, the discharge side line 31 and the suction side line 32 are provided between the compressor 20 and the four-way valve 41,
The discharge side line 31 is led out of the discharge part of the compressor 20 and connected to the first port 41a of the four-way valve 41 via the oil separator 42, while the suction side line 32 is connected to the third port 41c of the four-way valve 41. From the compressor 20 via the silencer 130 and the accumulator 131.
Has reached the inhalation part. The accumulator 131 is provided with a composition ratio detector 132 and a liquid level sensor 133.

A liquid refrigerant passage 134 is formed between the lower part of the accumulator 131 and the downstream side line 32c, and the control valve 135 and the high-pressure side gas-phase refrigerant are introduced into the liquid refrigerant passage 134 to guide the liquid refrigerant. A heat exchanger 136 for heating the liquid refrigerant in the passage 134 is provided.

The second port 41b of the four-way valve 41 is also provided.
The line 34 derived from is connected to the indoor heat exchangers 68a to 68n via the joint 66 and the like, and the indoor heat exchangers 68a to 68n are connected to the line 35 via the expansion valves 70a to 70n. . The line 35 reaches the heat exchanger 136 via a joint 71, a strainer 73, a drier 74, etc., and the line 35 passing through the heat exchanger 136 and the line 37 branched therefrom are connected to the outdoor heat exchangers 75a, 75b. Has been done. Lines 36 and 38 are led out from the outdoor heat exchangers 75a and 75b, and these lines 36 and 38 merge to form the double pipe heat exchanger 13
It is connected to the fourth port 41 d of the four-way valve 41 via 7. The double tube heat exchanger 137 has a cooling water circuit 8
Cooling water is introduced from 0 through the thermostat 138,
The refrigerant can be heated.

The same parts as those shown in FIG. 1 are designated by the same reference numerals and their explanations are omitted.

Further, in the embodiment shown in FIG. 8, the four-way valve 4
Intake-side line 32 derived from the third port 41c of No. 1
Through the liquid-gas heat exchanger 140, the silencer 130, and the accumulator 131, reach the suction portion of the compressor 20. A control valve 135 is provided in the liquid refrigerant passage 134 between the lower portion of the accumulator 131 and the downstream line 32c.
And a heat exchanger 141 utilizing waste heat of the engine.

Cooling water lines 81b, 8 of the cooling water circuit 80
A linear three-way valve 142 is provided between 1c, and a cooling water line 143 led out from the linear three-way valve 142 reaches the heat exchanger 141 and is connected to the cooling water line 80d via the heat exchanger 141. . Thus heat exchanger 1
The waste heat of the engine is introduced into the cooling pipe 41 by using the cooling water as a medium, and the amount of heat supplied is adjusted by the linear three-way valve 142. In addition, the liquid gas heat exchanger 1
The circulating liquid refrigerant in the line between the outdoor heat exchanger and the expansion valve is guided to 40.

The same parts as those shown in FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted.

In the embodiment shown in FIG. 7 and the embodiment shown in FIG. 8 as well, during the cooling operation or the heating operation, the compressor rotation speed is controlled according to the load and the expansion valve opening degree is controlled. Subcool control is performed. Further, when the sub-cool control is being performed, the heat exchanger 136
Alternatively, 141, the liquid refrigerant in the liquid refrigerant passage 134 is heated and vaporized. In this way, an operation similar to that of the previous embodiment can be obtained.

The structure and control of each part in the apparatus of the present invention can be modified in various ways other than the above embodiments.

For example, the subcool control may be performed only during one of cooling and heating, for example, during heating, and so-called superheat control may be performed during cooling.

Here, the superheat control is control for heating the refrigerant temperature of the compressor suction portion to the saturated vapor temperature or higher. Specifically, depending on the suction refrigerant temperature or the compressor temperature, the expansion valve opening degree is controlled so as to increase the temperature to a predetermined high temperature.

Alternatively, the saturated gas temperature is calculated from the low pressure side pressure detected by the low pressure side pressure sensor and the circulating refrigerant composition ratio detected by the composition ratio detector, and the saturated gas temperature is calculated from the suction refrigerant temperature to the compressor. The expansion valve opening may be controlled so that the subtracted value becomes a predetermined positive value or the value obtained by dividing the suction refrigerant temperature by the saturated gas temperature becomes a predetermined value larger than 1. What is the temperature of the refrigerant sucked into the compressor?
The refrigerant temperature between the evaporator in the low pressure circuit and the compression chamber of the compressor may be any temperature.

Further, if this control is performed, the amount of liquid-phase refrigerant accumulated in the accumulator decreases, so the liquid level of the liquid-phase refrigerant in the accumulator is detected, and when this liquid level is higher than a predetermined value. The expansion valve opening may be controlled so as to be reduced to a predetermined value or less.

According to this superheat control, the Ph diagram of the refrigeration cycle is as shown in FIG. That is, after the gas-phase refrigerant is compressed by the compressor 20 to increase the pressure P and the enthalpy h (a2 → b2), the outdoor heat exchanger 75a,
As the refrigerant is condensed at 75b and the enthalpy h is lowered, the refrigerant changes from a gas phase to a gas-liquid mixture or a liquid phase (b2 → c
2), the liquid-phase refrigerant is then expanded by the expansion valves 70a to 70n to a low pressure (c2 → d2), and the indoor heat exchanger 6
The enthalpy h rises due to evaporation and heat absorption at 8a to 68n (d2 → a2), but at this time, the refrigerant is excessively heated so as to greatly exceed the saturated vapor line, and superheat control is performed. SH is the change in enthalpy due to excessive heating.

Even by this superheat control, the value of B in the above equation is increased by the amount SH of enthalpy change due to excessive heating, so that COP is improved.

Moreover, since the excess refrigerant in the accumulator decreases (becomes zero during steady operation) by this control, the high boiling point component does not stay in the accumulator, and therefore the refrigerant circulated by being sucked into the compressor. The situation in which the proportion of low boiling point components in the inside increases and COP decreases is not caused.

However, if this superheat control is performed during heating, it becomes difficult to effectively achieve superheat control when the outside air temperature is low, and the heating capacity tends to decrease, so subcool control is performed during heating. It is preferable to carry out.

In the above embodiment, a plurality of indoor heat exchangers are provided and two outdoor heat exchangers are provided.
One indoor heat exchanger and one outdoor heat exchanger may be used.

Further, the present invention can be applied to a refrigerating device and the like in addition to the air conditioner.

[0102]

As described above, according to the present invention, in the heat pump device using the non-azeotropic refrigerant, the accumulator is arranged in the path through which the refrigerant returns from the evaporator to the compressor, and the compressor of the compressor is arranged according to the load. While the rotation speed is controlled, the subcool control is performed to adjust the opening degree of the expansion valve so that the temperature of the refrigerant near the high-pressure side expansion valve is lower than the saturated liquid temperature. The performance of can be improved. Moreover, a liquid refrigerant passage that connects the lower part of the accumulator and the refrigerant circuit downstream of the accumulator is formed, and in the middle of this liquid refrigerant passage, by providing a heating means for heating and vaporizing the liquid phase refrigerant in the passage. , Out of the non-azeotropic refrigerant, the excess refrigerant in the liquid phase containing a large amount of high boiling point components is drawn out from the accumulator, heated, vaporized, and mixed with the vapor phase refrigerant sent from the accumulator to the compressor. Maintaining the component ratio of the refrigerant sucked into the compressor and circulating to the same level as the initial filling ratio, avoiding the decrease of COP due to the increase of low boiling point components in the circulating refrigerant, and achieving the improvement of COP by the subcool control. Is something that can be done.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a structure of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a diagram showing a control system of the air conditioner.

FIG. 3 is a diagram showing operating characteristics of a three-way valve incorporated in a cooling water circuit of the air conditioner.

FIG. 4 is a Ph diagram of a refrigeration cycle during subcool control.

FIG. 5 is a diagram showing a relationship between a composition ratio of a non-azeotropic refrigerant and a temperature.

FIG. 6 is a circuit diagram of essential parts showing another embodiment of heating means provided in the liquid refrigerant passage.

FIG. 7 is a circuit diagram showing another embodiment of a refrigerant circuit.

FIG. 8 is a circuit diagram of a main part showing still another embodiment.

FIG. 9 Ph of refrigeration cycle during superheat control
FIG.

[Explanation of symbols]

 1 Refrigerant circuit 20 Compressor 30 Refrigerant circuit 41 Four-way valve 45,46,131 Accumulator 62,134 Liquid refrigerant passage 64,120,136,141 Heat exchanger 68a-68n Indoor heat exchanger 70a-70n Expansion valve 75a, 75b Outdoor Heat exchanger

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F25B 27/00 F25B 27/00 A 29/00 361 29/00 361A (72) Inventor Nobuyuki Kawashima Shizuoka 2500 Shingai, Iwata, Japan Yamaha Motor Co., Ltd.

Claims (3)

[Claims] 1. A refrigerant, comprising a compressor, a condenser, an expansion valve, and an evaporator, such that the refrigerant discharged from the compressor is returned to the compressor via the condenser, expansion valve, and evaporator. With the circuit is a heat pump device using a non-azeotropic refrigerant as the refrigerant, the accumulator is arranged in the path of the refrigerant returning from the evaporator to the compressor, the compressor depending on the load. While controlling the number of revolutions, the control means is provided for performing subcool control to make the temperature of the refrigerant near the expansion valve on the high pressure side lower than the saturated liquid temperature by adjusting the opening of the expansion valve, and the lower part of the accumulator. A liquid refrigerant passage communicating with a refrigerant circuit downstream of the accumulator is formed, and a heating means for heating and vaporizing the liquid phase refrigerant in the passage is provided in the middle of the liquid refrigerant passage. Pump device. 2. The heat pump device according to claim 1, wherein the heating means guides the circulating liquid refrigerant between the condenser and the expansion valve and heats the liquid refrigerant in the liquid refrigerant passage by the circulating liquid refrigerant. A heat pump device comprising a heat exchanger. 3. The heat pump device according to claim 1, wherein the compressor is driven by an engine, and
The heat pump device, wherein the heating means is configured to heat the liquid refrigerant in the liquid refrigerant passage by using waste heat of the engine as a heat source.